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Decay resistance of slurry erominated wet-process high-density hardboard Hong, Hon-Min 1978

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DECAY RESISTANCE OF SLOBBY  EROMINATED WET-PROCESS  HIGH-DENSITY HARDBOABD  by  HON-MIN jjaONG B.Sc., N a t i o n a l C h u n g - H s i n g U n i v e r s i t y , 1972  A THESIS SUBMITTED IN PAfiTIAL THE  REQUIREMENTS  FULFILLMENT OF  FOB THE DEGBEE OF  MASTER OF FOBESTBY  in THE FACULTY OF GRJ*3>UATE STUDIES. (FORESTRY) ' we a c c e p t t h i s t h e s i s a s c o n f i r m i n g to the reguired standard  THE  UNIVERSITY OF BRITISH COLUMBIA September, 1978 @  H-M.  Hong,  1978  In  presenting  an  advanced degree  the I  Library  further  for  shall  agree  scholarly  by  his  of  this  thesis  in  at  University  the  make  that  thesis  partial  freely  permission  for  for  is  financial  University  of  British  2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1WS  October 5, 1978  of  Columbia,  British  by  gain  Columbia  for  the  understood  FORESTRY  of  of  extensive  p u r p o s e s may be g r a n t e d It  fulfilment  available  permission.  Department  Date  it  representatives.  written  The  this  shall  requirements  reference copying  Head o f  that  not  the  of  I  agree  and this  be a l l o w e d  or  that  study. thesis  my D e p a r t m e n t  copying  for  or  publication  w i t h o u t my  ii  A8STBACT  Biodeterioration resistance density will  property  hardboard.  increase  the  of  developed  only.  Non-brominated  using  a  brcwn-rot used;  and  fiber  only,  polyethyleniffline for  these  the  adhesive  and  three on  the  of  compound,  some s t i m u l a t o r y  significantly brown-rot leaching  increased  fungi, the  brcminated  It  lignin  by b r o m i n a t i o n  Lenzites  growing fungi  on  were  brominated of  probable  hardboards  fungi,  as  by  of  two  more  of  cold  formation  hardboard fungi.  It  was  also  hardboard  were  and  fiber  both  Using either of  plus  counterparts  influence  of  the of  hardboard could  of  the  be  nitrogen  to  attack  bromhydrins  most  the  the  boards,  by  the  of  sensitive  of  to  brown-rot  a moisture or  by  attack  non-brominated  heat  by  brown-rot  that  wet  decay  reduced  before  found  were i n i t i a l l y a t  treatments  four  Among t h e  board.  sterilization  by  prevented  was  20%,  decay  Bromination  water  Fr,  which  of  examined,  h i g h amount  effect.  decaying  were to  small,  ex  in  materials  A l t h o u g h the  Pers.  active  with  the  white-rot  trabea  hardboard  the  board  brominated  resistance in  brominated  resin,  resistance  board  decay  types  was  decay  against  hardboards  contained  this  that  brominated  8% c o m p a r e d  oxide,  the  although  fungi.  the  is  which  high-  the  three  decay  resin,  showed  of  Six  as  polyethylenimine  wet-process  resistance  treatments.  rates  the  resistance  phenolic  well  investigate  fire-resistant  fungi.  as  control  a  their  plus  resin,  as  brominated  white-rot fiber  of  economics  for  to  brominated  initially  method,  two  done  advantage  marginal  was  were  slurry  The  which  soil-jar  tests  and content  ethylene gave  no  iii  difference boards  in  by t h e  ethylene  oxide  susceptibility modified for  from  evaluating  the  subsequent  brown-rot treatment to &STM the  decay  fungi.  rates  With  appeared by t h e s e  D1413-76, decay  decay  to  non-brominated  brominated increase  fungi.  proved to  resistance  of  of  boards, their  The s o i l - j a r be  a  the  suitable  hardboard.  method, technique  TABLE  OF C O N T E N T S  Page  TITLE  PAGE  ABSTEACT  TABLE  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  i  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  i i  OF CONTENTS  LIST  OF T A B L E S  LIST  OF F I G U R E S  iv  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v i i  ACKNOWLEDGEMENTS  viii  . . . . . . . . . . . . . . . . . . . . . , . . . . . .  . . . . . . . . . . . . . . > X  Chapter I.  II.  INTRODUCTION  1  L I T E R A T U R E SURVEY  4  1.  Definition  . . . . . . . . . . . . . . . . . . . . .  4  2.  C h e m i c a l Changes During Hardboard Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5  Fire-Retardant  . . . . . . . . . . . . . . . . . . .  8  General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Particleboards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fiberboards  8 9 10  3. A. B. C.  of  Hardboard  Treatments  4.  Chemistry  of  5.  Losses  Decay  6.  Mechanism of  7.  Decay  in  8.  Board  D u r a b i l i t y and  in  Bromination  . . . . . . . . . . . . . . . . . . . .  12  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16  Hood  Deterioration  Buildings in  Relation Decay  . . . . . . . . . . . . . to  wetting  17  . . .  20  . . . . . . . . . . . . . . . . . .  22  V  Chapter  Page  9.  Decay  . . . . . . . .  25  A. , P a r t i c l e b o a r d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. P i b e r b o a r d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25 27  10.  i n Composition Board  Protection A.  B. 11.  Against  Decay  Materials  . . . . . . . . . . . . . . . . . . . . 3 0  General (a) . J J a t e r - s o l u f c l e i n o r g a n i c s a l t s . . . . . . . . (b) . O r g a n i c - s o l v e n t s u b s t a n c e s . . . . . . . . . . . Treatment o f Composition M a t e r i a l s . . . . . . . . . Laboratory Resistance  T e s t Methods f o r Decay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30 30 31 32  .34  A.  General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 (a) . F u n g a l g r o w t h m e t h o d s . . . . . . . . . . . . . . . . , 3 4 (b) . H e i g h t - l o s s m e t h o d s . . . . . . . . . . . . . . . . . . 34 (c) . S t r e n g t h - l e s s methods . . . . . . . . . . . . . . . . 36 (d) . B e s p i r o m e t r y m e t h o d s . . . . . . . . . . . . . . . . . 37 B. T e s t s o f C o m p o s i t i o n B o a r d s . . . . . . . . . . . . . . . . . 3 7 C . , F a c t o r s To Be C o n s i d e r e d . . . . . . . . . . . . . . . . . . . 40 (a) . L e a c h i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 (b) . I n i t i a l m o i s t u r e c o n t e n t . . . . . . . . . . . . . 41 (c) . S t e r i l i z a t i o n m e t h o d s . . . . . . . . . . . . . . . . 43  III.  M A T E R I A L S AND METHODS 1.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Materials A. E. C.  2., A. B. C. D.  E.  Asplund Pulp Pulp Bromination Boards  •••(•••  . . . . . . . . . . . . . . . . . . . . . . . . . . .  Methods Composition and S i z e o f t h e Hardboard Test Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W o o d - D e s t r o y i n g F u n g i Used . . . . . . . . . . . . . . . . . Preparation of S o i l Jars . . . . . . . . . . . . . . . . . . . P r e p a r a t i o n o f T e s t Samples . . . . . . . . . . . . . . . . (a) . L e a c h i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (b) . S e t t i n g o f i n i t i a l m o i s t u r e content and method o f s t e r i l i z a t i o n . . . . . . . . . . Evaluation of Results . . . . . . . . . . . . . . . . . . . . . .  46 46 46 46 47 48  49 50 50 51 51 52 53  vi  Chapter  IV.  V.  Page  RESULTS  FIGURES  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . the  Hardboard  54  1.  Composition  of  . . . . . . . . . . . . . . . .  55  2.  Bromination  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58  3.  Leaching  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  60  4.  Moisture  Content  63  5.  Sterilization  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Method  . . . . . . . . . . . . . . . . . . . . . . . .  CONCLUSIONS  LITERATURE  TABLES  AND D I S C U S S I O N  67  CITED  . . . . . . . . .  65  69  . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . . . . , . . .  80  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  86  vii  LIST  OF T A B L E S  Table  1.  2.  3.  4.  5.  6.  Page  weight  l o s s e s of t e s t b l o c k s d u r i n g the preparation p e r i o d and under c o m p a r a t i v e control situation i n s o i l jars during incubation., Weight l o s s e s i n p e r c e n t  80  o f l e a c h i n g on t h e r e s i s t a n c e t o d e c a y o f n o n - b r o m i n a t e d and b r o m i n a t e d hardboard. Decay weight l o s s e s i n p e r c e n t  81  of the i n i t i a l moisture content of leached, n c n - b r o m i n a t e d and b r o m i n a t e d h a r d b o a r d on i t s r e s i s t a n c e to decay. Decay weight l o s s e s i n p e r c e n t . . . . . . . . . . . . . . .  82  o f method o f s t e r i l i z a t i o n of leached, n o n - b r o m i n a t e d and b r o m i n a t e d h a r d b o a r d on i t s resistance to decay. Decay w e i g h t l o s s e s i n p e r c e n t . . . . . . . . . . . . . . .  83  Statistical e v a l u a t i o n of the decay r e s u l t s for non-brominated hardboard . . . . . . . . . . . . . . . . . . . . .  84  Statistical e v a l u a t i o n of the decay r e s u l t s f o r brominated hardboard . . . . . . . . . . . . . . . . . . . . . . . . .  85  Effect  Effect  Effect  viii  LIST  OF  FIGURES  Figure  1.  Page  Production  of  thermomechanical  according  2.  Sample  to  the  for  method  Bar  4.  different factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . C o m p a r i s o n t o show t h e e f f e c t s o f b r o m i n a t i o n a n d l e a c h i n g o n d e c a y by P o r i a i n c r a s s a t a . . . . . . . .  89 90  C o m p a r i s o n t o show e f f e c t o f b o a r d c o m p o s i t i o n on d e c a y by P o r i a i n c r a s s a t a g r o w i n g on n o n - b r o m i n a t e d and n o n - l e a c h e d boards . . . . . . . .  91  C o m p a r i s o n t o show e f f e c t o f b o a r d c o m p o s i t i o n o n d e c a y by P o r i a i n c r a s s a t a g r o w i n g on b r o m i n a t e d and n o n - l e a c h e d boards . . . . . . . . . . . .  91  C o m p a r i s o n t o show e f f e c t s o f b o a r d c o m p o s i t i o n a n d l e a c h i n g o n d e c a y by P o r i a incrassata g r o w i n g on n o n - b r o m i n a t e d b o a r d s . . . . . . . . . . . . .  92  C o m p a r i s o n t o show e f f e c t s o f b o a r d c o m p o s i t i o n a n d l e a c h i n g o n d e c a y by P o r i a incrassata g r o w i n g on b r o m i n a t e d b o a r d s . . . . . . . . . . . . . . . . .  92  C o m p a r i s o n t o show e f f e c t o f b r o m i n a t i o n o n d e c a y by P o l y p o r u s v e r s i c o l o r g r o w i n g o n non-leached boards . . . . . . . . . . . . . . . . . . . . . . . . . . .  93  C o m p a r i s o n t o show e f f e c t o f b r o m i n a t i o n o n d e c a y by L e n z i t e s t r a b e a g r o w i n g o n leached boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  94  C o m p a r i s o n t o show e f f e c t o f b r o m i n a t i o n o n d e c a y by P o l j j o o r u s a d u s t u s g r o w i n g o n leached boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  94  6.  7.  8.  9.  10.  11.  decay  affected  incubation  86  3.  showing  for  . . . . . . . . . . . . . .  87  diagram  procedure  hardboard  . . . .  5.  preconditioning  Asplund  pulp  by  ix  Figure  12.  Page  C o m p a r i s o n t o show e f f e c t o f l e a c h i n g o n d e c a y by C o n i o p h o r a £ S £ e a n a g r o w i n g o n brominated boards . . . . . . . . . . . . . . . . . . . . . . . . . . . .  95  13.  C o m p a r i s o n t o show e f f e c t o f s t e r i l i z a t i o n method on decay by P o l y _ £ o r u s v e r s i c o l o r g r o w i n g o n leached and non-brominated boards . . . . . . . . . . . . 9 6  14.  C o m p a r i s o n t o show e f f e c t o f i n i t i a l moisture c o n t e n t o f b l o c k s c n decay by P o r i a montji.cg3.a g r o w i n g on l e a c h e d a n d b r o m i n a t e d b o a r d s . . . . . 97  X  ACKNOWLEDGEMENTS  The  auther  Dr.  L.  his  valuable  and  preparing  acknowledges  Paszner,  Associate  assistance the  guidance  University;  to  at  Western  Forest  assistance the  Dr.  for  experimental  SFPL,  to  technician  of  text;  Mr. G.  in  Faculty  making  and  student which  in  of  HFPL,  three  years  for  and  his  phases to  providing  Forestry,  for  Research Ms.  and Mr.  to his  P.E., Ltd.,  Mr. L ,  review of  Valg,  of  the  WFPI,  Clark,  technician  biological tests;  to  B.E.  producing the  prints  photo  Mr. E . H .  U.B.-C.,  for  Mr.  for  Burke, both  their  his  assistance  in  computer  constructing  the  format  this  text.  given  to  the  of  U n i v e r s i t y of  f i n a n c i a l support  during  the  of  Fox, this  technicians  assistance  for  repeated  providing  technical  M r . R.  also  section  Prod.  to  is  this  Scientist  J.E.  and  professional  preparation;  to  subject  Wood P r o t e c t i o n  Canadian Forest  board of  at  to  for  conscientious  Laboratory;  material  for  Forestry,  preparation;  Acknowledgement  programme.  blocks  Forestry,  for  his  of  his  of  appreciation  experimental  experimental  Bohnenkamp S  Forestry,  sample  helps  Columbia  for  for  Laboratory,  analysis; in  the  head  M . G . Warren,  assistance  to  as  past  Smith,  Faculty  Dr.  statistical  for  the  at  pulp  Professor,  manuscript; the  well  Wood T e c h n o l o g i s t ,  and f a c i l i t i e s  Assistant  for  R. S .  facilities  Senior  guidance  over  Products  Jurazs, the  as  his  Faculty  in suggesting  i n s u p e r v i s i n g the  necessary  gratitude  Professor,  thesis,  understanding  with  in  Yang,  board graduate  technigue  British academic  1  CHAPTER  Hardboards uses  in  used  exposed  and  domestic losses.  Such the  efforts  dwellings  condensation building  components  preferably,  resistance  to  the  are  wood  attack  may  recent  result  in  an  by  microorganisms  of  wood was  may  be  crisis,  higher  humidities  a  prevent  greater  materials,  chemical  possess  in  to  protected  with  (e.g.,  fuel  to  under  sealed  create  building  found  commodity  environment,  closely  freguently  a  biodeterioration  therefore,  on t h e  as  have  domestic  internally  the  more  and  b u i l d i n g s and  of  of  freguently  years  recognized  risk  result  and,  many  external  by t r e a t m e n t  the  for  when u s e d  being  within or  biodeterioration or  are  use  the  even  As a  dwellings  in  primarily  kitchens),  significant.  INTRODUCTION  commercial  to  circumstances,  bathrooms  within  of  Although not  openly  certain  guite  been  construction  dwellings. be  have  I.  risk  heat  of  Wooden  against wood  inherent capable  preservatives, natural  of  causing  biodeterioration. The  bromination  potential But  fire  incidentally,  bromine,  it  resistant  was  to  Subseguently, that  retardant  suggested  the  that  fungi  spruce  kleineana  significantly  by  of  wood  the  and  from  lignified  may  in Israel  African  attack  a  materials  w o u l d be  cause  brominated  as  i n c l u s i o n of  product  which  P i e r r e ) , 'an  protected  of  initially  molecular  unpublished studies  brominated  ( iacoumea  treatment  because  attack  developed  (63). the  more  biodeterioration., (31)  clearly  veneers hardwood,  by s e v e r a l  of  showed  Okume  were  wood-destroying  2  fungi  used  in  laboratory  However, of  bromine  as  Particularly gain  more a  little  against  dual  is  the  acceptance  advantages  application Investigation is  drastic  fiberboard  of  the  wood  prove  of  moisture  moisture other  of  better  (91)  the  had  removed  some  fungi.  f o r m a l d e h y d e (PF) it  The  resin.  seemed  not  that  been  Following  he  P F was  hardboard  ASTH  heretofore.  a  that  free  test  s o i l — b l o c k method  to  at  control  various tc  in  comparison the  inhibitory to  his  solid  results  Further  i d e n t i f i e d was  for  comparison  indicated  in  used  respect  satisfactory  used  the  for  applicable  w h i c h was  involves  components.  methods  the  blocks  of  evaluate  by  and  material.  production,  is  factor  the  of  procedure  test  usefulness  problem  with  method.  will  treatment,  standardized  methods  soil.  resistance  cladding  wood  to  recommended  obtained  factor  as  the  required  soil-block  a  improved  particleboard  other  of  and u n l e a c h e d  procedure  general,  levels  and  bromination  process  of  which  successful,  materials.,Test  method  the  be  construction  are  have  than  as  Savory  greatly  fungi.  materials  biodeterioration  of  methods  content  the  the  effectiveness  materials.  retardance  modifications  studies  plywood by  test  that  composite  of  since  new b u i l d i n g  content  leached  the  soil-block  methods  testing  test  decay  However, may  unlike  chemical  Realistic performance  have  the  wood-destroying  proven t o  building  into  clarify  building  fire  i f  interesting  manufacturing, some  as  of  could  in  to  against  marginal economics  whereby f i b e r b o a r d s  hardboards  needed  known a b o u t  biodeterioration,  increase  wider  is  preservative  increasing The  work  tests.  leaching growth  phenol-  materials.  could  be  more  In  of  3  suitable other  board  resins. as  than  Some p a n e l s  effect  water  to  effect  another  tests  Scheffer  (45) ,  moisture  content  moisture effect. oxide  the  effectiveness lignins,  Effects  of  content,  moisture were  under  material.  purpose  as  needed  Leaching of  the  test  i n c l u d e d and  in  content several  Foster  positive  and  study  was  find  to  as  the  was  for  attempt  reliable  it  tried  could  modified  to  different this  was a l s o  decay to  test  see  if  provide a  and  and  test and  low  the  ethylene  their  as  a  on  building mechanism  board  test  to  materials.  original soil-block  biodeterioration  linked  fungi.  methods,  sorting for  the  moisture  new s p e c i a l t y  procedure the  results  bromine  sample  sterilization  taken  has  sample*s  wood—destroying  initial  rather  The  investigate  against  well  in  hardboards.  preservative  and  blocks  to  out  study  material  high  used of  remove  A c c o r d i n g l y , two  C)  performance  treatment  of  wet-heat(121 to  to  Highley  representing  included in this  were  test  effect  results.  methods,  of  studies.  (42)  resin  investigated.  a  This  hardboards.  was  unknown compound,  as  phenolic  treatment  content,  this  of  phenolic  a relatively  Thereby, be  types  of  evaluated  more  of  plywood and  had  test  vacuum,  on d e c a y  leaching  were  a  decay  Two s t e r i l i z a t i o n  effect  the  testing  also  moisture  by H e d l e y a n d  of  study  was  concern  on t h e  levels  Thus  find  test  demonstrated  treatment  decay  cf  situations,  possible  to  results.  for  various  special  initial  subject  with  in this  decay  of  reported  different  used  test  the  method  bonded  therefore,  on t h e  prior The  been  agar-block  materials  binder and,  its  of  the  for  method  4  CHAPTER  1.  Definition  of  two  major  component  wood and  fibers, other  hand,  together or  largely  wall  formed  the  basis  of  boards and  compressed  type  forth  Standard  in  are  the  manufactured  wood),  hot  sp.  press  greater,  to  and to  manufacture sp.  gr.  lbs/ft ) 3  a  to  high—density  of  is  called  a  and  if  generic  board  the  of  wood,  basis  the  most  bonded  Both  of  density,  highly  the  and  term  may  31  definitions  Materials  for  and  a  (3),  panel  been  properties.  is  pressure  lbs'/ft3)  have  between  hardboard  s p . g r ,  lignin  other  resins.  the  heat  of  0.80(density  the  of  lignocellulosic  under  materials  of  urea-formaldehyde(UF)  Testing  0.50{density  medium-density  hardboard  for  size  separate  on  According to  interfelted  improve c e r t a i n 0.50  being  (66),  consolidated  which other  between is  gr.  from  as  from  complex  shavings  such  hardboard  hardboard  fibers(usually  or  bond and  made  inherent  s u b d i v i d e d on  fiberboard  primarily  are  classified  (b)  of  polyisocyanate  American S o c i e t y  D1554-67,  the  be  and  type  former  chips  and  further  of  can  Particleboards,  adhesives  additives; of  with  larger  synthetic  thickness,  set  The  compounds,  from  boards  fiberboards,  bonded t o g e t h e r  with  SURVEY  (a)  phenol-formaldehyde(PF),  types  a  on  building  wood p a r t i c l e s .  cell  are  wood-based  categories:  particleboards, the  LITERATURE  Hardboard  Manufactured into  II.  31  added  and it  than  a  or during  A hardboard  while  greater  in  is  of  50 called 0.80.  5  2.  Chemical Changes  Host is  virgin  generated  processes. for  Asplund  been  It  softened  means  in  the  130  and  C will  to  the  aid  by  produced  with  pulp it  yield  is  The  in  same  for  of  in  for  (108).  time  pressurized that  Very  the  fine  energy  lignin  that  sheet  of  had  the  is  shown  rapidly  since  changes were  of  wood  given  Saturated as  refiner  whole  fiber  of  steam  applies  shear  is  can  be low  solubles  and  on  above  it  Also,  examinations  during  by  middle lamella  formation  to  the  refiner  pulping  exploits  produce  lignin-rich  pulp  the fibers  productin.  analysis  of  the  liguor  can  be  understood  affected  by  furnish  hot-water  pulps  early  hardboard  consumption.  anatomical  it  the  progressed  processes  Spalt  minimize  board  chemical  wood a r e  A flow  chemical  thermomechanical  nature  has  in  the  refiner.  The  steam.  From  manufacture  increase  and  mechanical  high.  a  generate  l i g n i n - r i c h middle lamella  pressures  suitable  Through  changes  the  low  thermoplastic  hardboard  the  saturated  is  pulping  on t h e  wood c h i p s .  found that  highly  (82),  (88).  process  pulp manufacturing  at  steam  steam  pressurized  Wilson  softened  cooking  of  pulping  discussions  wood c h i p s  to  fiberizing chips  the  the  used  for  soften  penetrates  is  forces  Thermomechanical  mechanical  Paszner  which  today  pulping  mechanical  1.  Detailed  thermomechanical  developed  with  of  manufacture  was  in  advent  fiberboard  study,  thermo-mechanical  the  in  Manufacturing  this  Asplund Fig.  of  process,  used  uses  Hardboard  woodpulp used  by some  hardboard  1930»s.  During  solubles  produced  which  chemical  preparation  developed  during  during  processes. the  6 increasing of  acetyl  rise  to  steam groups  The  the  the  can  to  be  h e m i c e l l u l o s e s.  caused  This  other  by  cleavage  process  cell  wall  gives  components,  divided  of  into  carbohydrate  holocellulose origin  and an  and  the  aromatic  latter  of  origin.  extracts,  chromatography  after  with  acetic  five  distinct  hydrogenation  anhydride, peaks,  commonly f o u n d  L-arabinose  and  D—galactose, proportions  of  sugars  fraction  to  The  in  wood. and  in  pulping  wash  The  the  of  the  five  relative  liquors  liberates does  of  least  pentoses:  wood r e v e a l s  and  with at  D—mannose,  hydrolyzate in  acetylation  that  only  not  with  similar  the  the  affect  the  cellulose  fraction  can  indeed  chromatography the  vanillin,  presence  vanillic  of of  be  traced  ether  extracts  guaiacol-  acid,  to  syringic  of  and acid,  and  acid.  evidence  saturated  are  liguor  degree.  liquors indicated  hydroxybenzoic  of  acetates  The o c c u r r e n c e  measurable  syringyl-aldehyde,  alditol  hexoses:  process  Gas-liquid  chromatograms  These  the  the  non-carbohydrate  hydrolyzates  with borohydride and  polysaccharides  source.  the  representing  c o m p o s i t i o n as  any  of  produce  D—glucose.  therraomechanical hemicellulose  can  D-xylose  and  hemicellulose  the  believed  hydrolysis of  be  former  Gas-liquid  lignin  is  carbohydrates.,  liquor  fraction:  sugars  from the  acid-catalyzed  especially  lignin  pressures  steam  lamella  to  fail  plates.  Parallel  indicates  above when  130  that  C causes  subjected  with the  treating  to  the  lignin-rich  shearing  thermoplastic  wood c h i p s  action  separation  with  middle of of  refiner fibers  7  hydrolytic and  degradation  water—soluble  lignin  fragments  Conversion operation.  are of  Cold-press  expels  most  hot  of  pressing  designated  100  operation water.  densify  in  and  pressing  and  also  occur,  aliphatic  board  water  Hardboard  and  are  mat  reduces  begins  by  with the  deposited removing  interfiber processes  consolidate  the  is  at  on a  the  void  to  wire  and  suspending space  require  mat  felting  and  further  the  gravity. change  cold  some  as  in  interfelted  chemical C)  properties hot  an  specific  Little (below  to  lignin  aromatic  pulp furnish to  the  and  generated.  suspended  into  water.  hemicelluloses  oligosaccharides,  Fibers  concentrated  of  effected  pressing.  changes  higher  in  the  Major changes chemical  densities  are  temperatures in  board  composition  developed  used  occur  by h e a t  during  and  pressure. Lignocellulosic under  heat  mechanism schools  and of  of  substances viewing  the of  lignin  report heat  during  impressive  development  was  and  described  a  form as  Spalt  a  water—insoluble thermoplastic  (108)  wet-strength  concentrated concluded  and  at  is  defibration  on the that  attended  gassify  in  by  surfaces  is  of  However,  pyrolytic  The  several wall or  the  studies  confirmed  that  thermoplastic—fusion  the  conversion  fibers.  and  The  same  consolidation  reactions  low—molecular—weight  hydrolysis.  cell  Corporation  hardboards  board  of  by  bonding substance,  adhesive.  Hasonite  densified  wet-strength.  to  treatment  breakdown  develop  interfelted  including polycondensation  of  also  when  theory,  by  source  pressure,  wet—strength  lignin  conducted  fibers,  which  products  by  further  generated  8  3.  Fire-Retardant  A.  General With  develop been  the  better  fire  Juneja  ignition explain  the  that  retardants meet  the  for  fire  safety  wood a n d  restrictions  and t h e  multidisciplinary  the  over  reviewed extensively  principal  A second heat,  (56)  concern  and c o m b u s t i o n ,  The  of  increased  i n t e n s i f i e d to  codes,  is  Treatments  advantage  of  wood  the  of  in f i r e  advantage  especially  is  the  that  the  volatile  treated  of  retardancy  combustion  are  of  during  the  wood  decreased.  wood c o n t r i b u t e s  products,  to  research.  treatment  surface—flammability characteristics  have  building  procesess  fire—retardant  to  products  imposed by  synergism  nature  efforts  less  initial  part  fires. The  water  fire-retardant  solutions  Brush,  dip,  or  of  the  retentions.  treatment  of  (47)  made a  treatments  Fire-retardant wood-treating are  limited  on  are  chemicals  The f o r m u l a t i o n s f o r  salts.  These  known  e x c l u s i v e l y to  acid  are  believed to  be  formulations are  in  zinc  the  of  the  standards  effect of  a  half  century  di—ammonium  chloride,  borax,  based  fire-  commercial  for  other  of  of  wood.,  mono— a n d  some  the  fire—retardant  in various  the  pressure.,  usually give  properties  used by  been  wood u n d e r  do n o t  review  performance  ammonium s u l f a t e ,  treatments  the  described  phosphate, (34).  into  detailed  i n d u s t r y have  almost  wood i n v o l v e s i m p r e g n a t i n g  General practices  wood p r o d u c t s  Holmes  retardant  chemicals  of  immersion treatments  necessary  AWPA.  treatment  current  principally  on  usually dissolved in  and  and  boric  commercial the  same  water  at  12  9  to  15  percent  impregnation  of  Besides be u s e d the  in  concentration  salts,  combination with  fire—retardancy  members  products  treated  with  surface  the  or  blooming, exterior  literature  used:  urea,  shows  and are  melamine,  and  formaldehyde  (53,  shown  for  a  treatments  55,  For  that  acid,  urea—based  additives  58).  to  can  increase  (35).  inorganic  use.  are  salts  are  subject  unsuitable for  either  leach-resistant  some  or  a l l  of  type  the  dicyandiamide, phosphoric Decay  resistance  is  also  (54).  Particleboards In-process  particleboard Paper  flame-retardant  where  a  dry  an  drying  particles,  aqueous  or  mixed  flame-retardant effective  borate  operation.  Syska  effect  of  can  the  green  Abitibi  also  be  flakes  prior  added t o  the  is  by to  the  n o r m a l l y the  most  (59).  board weight  adverse  solution to  to  f l a k e b o a r d made  s o l u t i o n form  reported  The  flame-retardant  employed.  in  15  performance.  is  adapted  but adding  and  of  well  binder r e s i n ,  particleboard percent  is  the  chemicals  (111)  a  Dry chemicals  with  procedure  treatment  formation process  Company m a n u f a c t u r e s  applying the  pressure  oil-borne preservatives  following  B.  i n the  fire—retardant  treated  decorative  treatments,  used  of  l e a c h i n g and  interior  be  wood.,  water—soluble  However, to  to  found  on f i r e - r e t a r d a n t  that  a chemical  was r e g u i r e d  most  critical  the  treatment  treatments  treatment for  level  adequate  problem pointed out chemicals  on  the  for of  10  to  fire  was  resin  the binders.  10  Such  effects  resins set  were  before  lead being  the  Baloney  (68)  C.  Fiberboards  the  applications  seriously large  buildings. cabinets,  used  These motor  flammability Myers the  is  fibers  is  (78)  for  retardants  were  past solid used:  polyphosphates,  material can  produce  selected  The  experience  also  wood  products.  water-soluble  moderate  increasing This  since  can  a  and  office  u s e d o n TV  where  reduced  attention. research be  boards process  determine  treated  involved  salts,  determining  were  some  and  selected  fire  of  liquid  fire ammonium  phosphates. flame  with  chemicals  types  if  satisfactory  systems  Three  in  to  with  providing  organic  reduction  are  finishes.  be  in  their  i n houses  fire-retardant  in  limited  products,  m o b i l e homes  and curing—type a  and  applications  of  officials  hardboard  conducted  to  been  because  Twenty-one f i r e - r e t a r d a n t  of  that  have  combustible  decorative  performance.  between  retardancy  indicated  for  industrial  dry-formed hardboard could  binders. basis  with  code  increased  and f i r e  the  and  receiving  strength  on  market  retardants  compatibility  materials  and  fire  resin  building  the  products  vehicles,  selected  chemicals  the  particleboards.  hardboard products  and Holmes for  to  structural  as  fire-retardant  recently  protection  the  He c o n c l u d e d t h a t  closed.  on m a t e r i a l s  affect  volume  as  Fire  limitations  was  strength.  by t h e  treatments  fiber-base  flammability.  board  discussed  fire-retardant  some  lower  catalyzed  press  of  Hood  to  Results  s p r e a d (to  60%)  can  11  be  obtained  with to  the  10  seme r e d u c t i o n  20  percent  little with a  at  gave  additional  a treatment  water-soluble  of  problems.  Potential and  were  The  to  hardboard.  use  retention can  be  wet  mat.  incorporate  of  to  the  However,  chemicals,  expelled  uneconomical  loss  fire-retardant  subsequent  water  Chemical individual  (78).  to  the  and  fibers  of  of  or  pulp,  developed  to  comparable  the in  lignin many  In  these  acidic  hardboard  difficult  exploratory into  of  of  Other the  low  dewatered  with  water, thus  attempts  chemicals  partially  difficult  to  wet—formed  because  pressing,  a logical  of  linked  is  fire-retardant  w o u l d seem  solution.  with  acid,  including  making  problems  drainage  the  involve  water  the  and  (57),  treatment  good  the  with  wet-process  a  with  particularly  more  salts  volume  hot  with  be  much  1960s,  to  large  problem  to  level  compatibility  during  is  salts  retention  wood  the  spread  Common f l a m e - r e t a r d a n t  chemicals  linking  avoid  impractical.  pollution  use  unsuccessful  slurry  t r e a t stent  evaluated.  early  d u r i n g the  process of  the  were  pulp  due  be  however>  retention  board  to  water—soluble  efforts  chemicals  added  wet-pressed  In  of  tetrahydrate-boric for  problems  must  flame  strength,  system  chosen  hardboard,  These  in  bending  resin  corrosion  flame-retardant.  made  in  level  rupture.,Increasing  reductions  carefully  during  Wet—process  of  retardent  disodium octaborate  salt. be  fire  modulus  reduction  must  render  in  further  solutions  production  percent  this  portion  respects  of to  chemicals way  to  hardboard. by  Lewin  process the  (63)  bromine  fibers  chlorination  the  overcome  the  Bromination in is  (112), of  to  Israel  seems  chemically a  reaction  p u l p s as  applied  12  during pulps  the had  bleaching a lower  process.  The  flame-spread  hardboard  index  than  untreated  pulps.  The i n f l a m m a b i l i t y t e s t s  products,  run  different  by  non-inflammability present  in  the  experience its  the  work  published  Products  by  one  hardboards.  than  3  made  brominated  from  on b r o m i n a t e d  produced  Larsen  bromination  Jurazs  dealing  The  Chemistry  high  percent  fiber  ratings  of  of  bromine  and  Yan  (59)  process  and  pointed  of  of  had  was  some out  seme  of  brcminating  agents  is  to  oven-dry  applied about  to  the  5.0.  bubbling  a  chlorine  gas  had  been  is  the  most  recently  experienced  with  brominated  initiated  some t i m e  as  aqueous  that were  effected  bromide(NaBr)  problems  process,  treating such  the  with  (57)  at  Canadian  Forest  ago.,  Bromination  suspension,  Treatment  and P a s z h e r  projects  bromination  consisted  of  (64).  Limited guite  The  on  more  that  from  drawbacks. The  4.  provided  product  with  methods,  made  from added  as  it  high the at  was  Asplund 2.0  to  provide  10  percent(by  the  pulp suspension Bromine  is  g u a n t i t y (15$ through  the  C with  pulp.  without  liberated based  The  on  from  to  The  consistency.  enough  weight)  sodium of  bromine,  sodium bromide a buffer its  OD w e i g h t  suspension  Israel,  pulp  process.  percent  40  of  50  in  lignin—content  at  weight  developed  at  salt of  is  solution  solution  the  initiate  a  pulp)  rapid  based  of  pulp  by  pH  13  bromination content to  pH  under t h e  c o n d i t i o n s . T h e average ;  following neutralization  5.5  pH  hydrobromic  drops  and  neutralization The  t o about  1,H  the c o u r s e o f  due  w i t h Ca(OH>2.  has  been i n v e s t i g a t e d  bromine i s almost  two  are converted  becomes a t t a c h e d t o t h e  guantitatively  into  bonds, formed t h r o u g h a hydrogen  atom on  by  (122,  consumed, s i n c e o f  hydrobromic  electrophilic  the aromatic  of  Zabicky  a c i d and  woodpulp. Most of t h e b r o m i n e  an  these  p r e s e n t as f r e e bromine i n  becomes a s s o c i a t e d w i t h t h e wood s h o u l d be  The  wood u n d e r  in detail  e v e r y t h r e e b r o m i n e atoms o r i g i n a l l y solution,  of  h y d r o c h l o r i c a c i d s , hence t h e n e c e s s i t y of  i s s i m i l a r i n many r e s p e c t s t o c h l o r i n a t i o n  woodpulps and The  bromination  to the f o r m a t i o n  c h e m i c a l r e a c t i o n o f bromine w i t h  conditions  bromine  w i t h c a l c i u m h y d r o x i d e (Ca (0H)2 )  i s 5 to 8 percent. During  the s l u r r y  123).  prevailing  lignin  bromine g e n e r a t i o n by c h l o r i n e  a t t a c h e d by  one that chemical  aromatic  substitution  building  units.  gas  i s represented  of  by:  H0 2  Br  + ci  The  resulting  two  ways:  A.  ~£o"c"  2  B r C 1  *  B r C l r e a c t s with  £  c l  lignin  ( r e p r e s e n t e d by L i g : H )  1 3  in  Bromination  BrCl  +  Lig:H  •  •  Iig:Br  *•  HCl  [2]  14  B.  Oxidation  BrCl  The  +  Lig:H  +  broaide  formed  in  regenerated There on  the  these  in  three  aromatic  the  possible  rings  in  lignin  by Z a b i c k y  bromine  per  lignin  bromine  atcm  attack  per  reactions  formation aromatic  is  of  in  in  the  demethylaticn  or  The  are  reactions  on  the  position  of  the  slurry  bromine  of  £3]  be  the  lignin  as  side-chain extremely  and  but  0.54  previous  mole  of  lignin.  sites  Other  bromine  exclusively  participates described in  in  above  oxidation  bromine  reaction  can  the  one  hypobromite  rapid  on  of  approximately  almost  available  and  bromine  to  Thus t h e  engages  oxidation  accessibility  the  0.48 to  atom  substitution  ascertain,  wood  is  lignin, other  of  of  that  unimportant.  The  one-third  depending  ring  which one  substitution.  participates  HCl  can  bromine  corresponds  initial  bromhydrins  Approximately  f 3J  •  of  showed  methoxyl  the  reaction  d i f f i c u l t to  (122)  aromatic  from  HBr  positions  exact  were c o n s i d e r e d  consumption two  units,  sites,.The  experiments  of  oxidation  •  [ 1 ].  building  reactive  Lig:OH  2  reaction  are  lignin  H 0  which  in reactions.  leads  to  formation.  carried  out  in  60  seconds. Chlorine  *  *  also  reacts  Lig:H  Lig:H  with  lignin  Lig:Cl  •  H 0 2  +  in  the  following  HCl  Lig:0H  ways:  1*1  •  2HC1  to  the  atoms  ester  be  due  C5]  15  About reactions used  50% [1]  the  consumed  and [21  and  in chlorination  consumed report  in  oxidation  by I n s t i t u t e  Israel  affect  reacts  bromination;  about  [4])  reaction  [3]  and  and  Forest  Products  of  pulp  Fibers  and  according  (reaction  for  bromination  hydrochloric pH 1 . 4  chlorine  about [5],  42  8  to  percent  percent  according  is  is  to  a  Besearch  in  (5).  The  to  acid  2.0.  hydrochloric  It  is  Ca(0H)  conditions  the  bromine  with  and  effects  CaCl  out  that  the  the  lignin  therefore,  two  are  the  fraction,  not  i .  no c e l l u l o s e  yield  slurry  the  low  drops pH,  hydroxide;  16J  prevailing expected  mechanisms e.,  to  the  2H.20 .  the  reaction  stock  of  •  2  under  polysaccharides of  pH o f  with calcium  2  pointed  wood  the  the  detrimental  neutralized  by e i t h e r  be o p e r a t i v e oxidation,  be  oxidation  consequently  avoid  acid  should  and  and  To  2HC1  with  of  to  reaction react  shown  substitution  degradation  would  to and  be  expected. The realized readily  fire-retardant through forms  effectively  the  action  thought  to  be  leading  to  burning  bromine-containing  flame-inhibitory  relatively  inhibit  of  the  stable  free  progress  of  involved in of  wood  pyrolytic (16).  action  of  wood  bromine.  is Bromine  radicals  which  can  branching  chain  reactions  and  combustion  processes  16  5.  Losses  i n Decay  Deterioration brought fungi,  about  by a c t i o n  bacteria,  Fungi  o f wood a n d w o o d - b a s e d  are  of f o r e i g n  insects,  t h e most  deterioration  and t h e attack  be  under  very  wood  rapid  weight  Hood-based well  as  materials,  including  from  shortages  wood  industries.  gain  i .  e.,  prefabricated  o f raw m a t e r i a l The p r o t e c t i o n  protect very  large.  Based  (105)  estimated  decay  of  for  feet  more  than  amount  Association for per year  i n U.S.A.  Total  fungi  in  can  dramatic  as  building  result  of  pressure  of technology  fungi,  which  attack  c a n be  or  in  i s expected,  unwillingness to  biodeterioration  statistics  million  of Canada,  annual loss  service.  about  as  studies.  from  dwelling to  as a  our i n a b i l i t y  $90  using the s t a t i s t i c s  of timber  plants  of  on c o n s t r u c t i o n  the U . S . A would  Preservers  where  i n service  wood i n d o m e s t i c  reported,  a  a  parts  and f u r t h e r  because  wood m a t e r i a l s  f o r wood  particleboards,  importance  aganist  attention cost  and r e s u l t  and advancement  reguires  total  responsible  wood-destroying  plywood,  increasing  under circumstances  The  organisms  by t r u e  indispensable more  as  losses.  materials,  hardboards,  such  borers.  optimum c o n d i t i o n s ,  and s t r e n g t h  c a n be  b i o l o g i c a l agencies,  and marine  important  material  $500  c a n be Smith  due t o  A comparable  million.  the  figure  Stranks  (110)  c o m p i l e d b y t h e A m e r i c a n Hood  1971,  that  was p r e s e r v e d preservative  about  26,896  i n some  usage  is  million  390 said  cubic  treating to increase  3%  year. Although  bacteria  and moulds  will  often  affect  the  end-use  17  of  wood p r o d u c t s  group (beetles) some  tropical  investigate  6.  enabling fungi  areas  their  as  (a) . use  cellulose  varied one  be  as  a  a  important  was  in this  of  their  some  source  organisms.  made  in  to  study.  unique  of  This  means  own o r g a n i c  characteristics  required nutrients.  from t h e i r  reguirements.  Almost a l l  carbon  which i s  may b e  or  more amino  source.  fungi the  that  they  environment  constituents  Two m a j o r  contain may b e  I l l  must  in  order  and  nutrient  inorganic  or  of  inorganic  suppliers or  amides.  to  sources  capacity  maltose,  starch,  sources  of  nitrogen,  In  some  n i t r i t e (NO2 )  obtain  nitrogen  are  or  quite  A l l fungi  for  carbon are  These  ammonium (NH^) . the  can  example,  instances,  nitrogen.  via  and  wood.  i n nature.  containing  to  carbon  compounds..Numerous f u n g i  salts  n i t r a t e (NO3) ,  the  suppliers of  main component  by t h e s e  to  Other  have  include sucrose,  organic  acids,  able  fungi  Fungal nitrogen  organic  supplied  utilizing  fungi  hardboards  substances  energy  b y many  and  peptones,  may  wood a s  Nitrogen source.  also  no a t t e m p t  wood p o s s e s s  Carbon source.  (b) .  are  Coleoptera  follows:  utilizable  of  focd  like  Deterioration  use  most  their  glucose  use  cn  heterotrophic  synthesize  are  Wood  to  organic  satisfy  effect  insects  group (termites)  particularly,  which decay  them  are  obtain to  and I s o p t e r a  Mechanism of  Fungi  and w o o d - d e s t r o y i n g  direct  my  capable salts A few  utilization  18  of  molecular  nitrogen  Hood-destroying that  enable  them  to  fungi  are capable  utilize  enzymes  large  carbon-containing(cellulose)  filaments wood  in  is  nitrogen  to  suggest  by which  deficient  They  into  released  cleave smaller,  from  readily  this  the  hyphal  move t h r o u g h  enzymatic  the  walls.  action  occurs  hyphae. wood-destroying fungi  substrate,  grow  i . e . , t h e wood o f  ratio  may v a r y  1250/1  still  unclear  i s  molecules  enzymes  materials.  t h e breakdown o f c e l l  that  carbon/nitrogen (24),  wood  depolymerize or  t h e wood.  of the growing  process  tc  Enzymes a r e  and c a t a l y z e  evidence  advance The  units.  growing i n s i d e  by d i f f u s i o n  There  the capacity  assimilated  of s y n t h e s i z i n g  polymeric organic  These  readily  have  (107).  which the  from approximately although  on a  350/1  hypotheses  have  to been  proposed. , Because  wood-destroying  enzymes t o  digest  substances  that  fungus enzymes  enzymatic  t h e decay  by p h e n o l s h a s been  Based specific  the substrates,  inhibit  and i n h i b i t  fungi  it  is  excrete  cellulolytic  easy  postulate  activity  development. reported  on t h e a b i l i t y o f  wood c o m p o n e n t s  must  to  could  Inactivation  extensively  the microorganisms  they  are  divided  starve  into  (46, to  that  the of  67,  69),  metabolize  different  categories. Bacteria  frequently  occur  products  (102).Normally  there  h a r d l y any complaint  is  composition The  they  i n both cause  living  trees  no s i g n i f i c a n t  reported  about  their  a n d i n wood problems and damage  material.  mould  and s a p s t a i n  fungi  metabolize  mainly  simple  on any  19  sugars  available  within  Generally  speaking,  or  and,  lignin  cells,  they  particularly  do n o t  therefore,  degrade  cause  i n the  the  sapwood.  structural  no m e c h a n i c a l  cellulose  injury to  the  wood. The  "classical"  flasidiomycetes  have  Basidicmycetes, it  and  and  Fungi  it  is  of  following In white as  left  be and  the  and  to  of  a  infect  to  relationship 49,  cause  93,  color.  In  fibrils  the  while  fungi  walls  of  the cavities  (23),  organisms  move t h r o u g h  and  which  cause  between,  with  are  generally  wood c a r b o h y d r a t e s Brown-rot  as  those  fungi  causing  causing  assumed and  fungi  carbohydrates,,The  general,  well  white  to  lignin,  are  wood t e n d s brown rots  to  rots  tend  are  angiosperms. on f u n g a l a c t i v i t y  wood h a v e 119)  walls,  and s p i n d l e - s h a p e d  fungi,  color.  while  discussions  101,  These  secondary  white r o t s  u t i l i z a t i o n of  with  secondary  attack  walls.  gymnosperms,  Detailed  cell  soft—rot  through  Ascomycetes  the  cellulose  wood l o s e s  associated  the  mainly  m e t a b o l i z i n g both  brown  Most  The o r g a n i s m s  the  the  fungi.  fungi,  unaffected.  generally  belong to  grow g u i c k l y  lower  elongated  the  the  which  resulting  typically  19,  to  of  wood,  the  through  leaving  angle  fungi  restricted acguire  move  which  long time.  soft—rot  of  relatively  wood c e l l  capable  to  in  a  the  (30, 9 0 ) .  brown r o t s  within,  the  wood,  contrast  The  belong  constituents  characteristically elements  than  fungi  for  established  imperfecti  lignin  studied  faster  fungi  polysaccharide the  been  once  destroy  Soft-rot  wood—destryoing  been  before.  offered  in  and  its  several  works  (14,  20  7.  Decay  in  Buildings  Hood-based cladding, used  in  materials  construction  animals,  waste  both  moisture  making  them  The  growth  the  (2)  adeguate  (3)  supply  (4)  favorable  constructions  is  included  and  used  to  in  buildings  different  fungal  food of  buildings  furniture  and n u t r i e n t  parts.  where  forms level  Some  water the  wall are  contact  of in  as  with  may  raise  materials,  attack. depends  on:  supply,  moisture, and  temperature. wood o r  wood-based  from decay,  first  dry  wood a n d t o  use  in  structure.  the  of  wet  for  concern  Therefore,  and c i r c u m s t a n c e s  sufficiently  materials  the  ensure  possibilities becomes  of  Setting  mostly  farm  and  to  wood-inhabiting fungi  oxygen,  protect  to  a  amount  of  of  content  of  presence  measures  are  materials,  susceptible  (1)  To  Relation  underfloor covering,  the  the  in  in is  buildings for  keep i t an  practical dry  awareness  u n d e r w h i c h wood i n  decay  to  take  hold,  arise  from  five  or  after  it  as  the  to  buildings  should  be  increased. Hater  to  support  decay  can  (92): A.  Original  B.  Ground  moisture  moisture,  C.  Rainwater,  D.  Condensate,  E.  Piped  water.  and  in  unseasoned  wood,  main  sources  21  A. cause  Installation  trouble  fungi,  or  of  seepage  and  usually  less  joints decay  parts  of  fungi  like  buildings.  conducting  develop  even  C. is can  be  flow.  Also  between  D. contact it  will  cold hold.  temperature  It  and  floors  by  to  is  near  back  of  is  Burt]  )  wood  which  circumstances  for  well  in  isolated  between  of  with  the  fungi  to  their  may  raise  movement  and  members.  It  and  that the  gravity  permeable  wooden  important  Cooling  joints  or  local  humidity of  at  night  results  cooling of  moist  warm a i r  the  in  siding.  from The  movement  warmer of  governed  by  entry  restricted,  the  water  air,  vapor  pressure  differences.  unless  joint  pressure  walls  decay  very  the  surface.  and  to  fungi(water-conducting  wind  joints  results  The  are  moisture  by c a p i l l a r y  masonary  lead  by t e m p e r a t u r e exists,  spaces  joints  in buildings is  created  ceiling,  on t h e  with a  create  and s h e a t h i n g .  Condensation  structure are  wall  walls.  siding  condensation  vapor  inter facial  water  or  rain  materials  ground  & Curt.)  wood l a r g e l y  s p l a s h i n g on  of  the  [ (Berk. can  decay  moisture.  enters  embedded i n  bring  also  by  warping  promote  panel  can  effects.  b u i l d i n g s are  occasionally  accumulations air  the  into  rain  will  strands  ground  the  carried  joints beams  from  in  are  can  to  lumber  attack  splitting,  Wood—based  moisture  dried  support  shrinkage,  damp s o i l There  though  Rainwater  trapped  such  to  through  of  incrassata  through  foundations  places,  to  incompletely  moisture  because  with  Poria  or  infection.  prone  Contact  wet  providing  by e x p o s i n g  loosening  B.  by  of  of  the  through  a  vapor  into  water  a  gradients  Where  damaging  more  on  which  dewpoint walls,  condensation  will  22  occur  within  permeable  particleboard, noted  that  the  hardboard,  the  use  not  prevent  point  where  Wetting the  of  near  b.  in  floors,  c.  in  areas  perimeter walls,  where  the  floor  of and  wood,  concrete.  without  but  change  may  It  condensation  merely  temperature occur  spaces  should  exist a  within  vapor  the  be a  barrier  location  of  occurs.  at in  least cold  ceilings  of  cold  amounts  of  steam  allowed to  plywood,  insulation  crawl  sizable  unintentionally in  dewpoint  by c o n d e n s a t i o n  a.  d.  thermal  as  and  promoting  condensation the  such  plaster,  when c o n d i t i o n s  structure, will  structures  in  four  areas:  weather;  storage are  rooms;  released  or  escape;  below a i r - c o n d i t i o n e d  rooms  over  a  damp  crawl  space. E. wet  to  Certain decay  sprinkling  components  because  and  accumulation  support  Metabolic  water,  down  the  will  half  as  wood, much a s  sufficient  8.  Beard  Very  to  the  and  produced  work  by  promote  destroyed decay  D u r a b i l i t y and  are  may g e t neglected.  may a l s o lead  sufficiently  to  cause  Frequent  heavy  sufficient  lawn  wetting  in  moisture  decay.  also  support  little  building  washing  wood f l o o r s ,  to  a  plumbing leaks  and e x c e s s i v e  wood s i d i n g  of  in  fungus decay.  wood;  itself This  water  therefore,  poorly  as  i t  ventilated  it  breaks  weighs may  be  spaces.  Decay  has  been  done  in  the  past  on  decay  about  23  resistance  properties  particularly  scarce  application  of  Reasons  for  the  history  of  products, for of  and  interior this  (b)  of  with  the  industry's  this  new v e r s a t i l e  makes  decay  surface  treatments,  to  suit  a  to  be  The  occasions of  of  study,  The some  property  of  due  (a)  of are  further  very  short  wood  best  suited Ignorance  development Therefore  hardboard should the  and  fast.  solid  confidence.  37,  the  keep  confidence  pace  toward  boards  38,  the  its  boards.  test  41,  of  additives,  Standard results  density, be  altered  methods  need  different  evaluated.  has  52,  of  durable  been  60,  exterior  61).  This  into  durability  exterior  relationship  damage  the  on  led to  or several a  broad  exterior treatment,  but  studies.  durability  with  boards  discussed  and p r e s e r v a t i v e  The r e s u l t i n g  can  test  in  also  involved in  bonding agents,  investigations  into  materials  variables  wood,  production  resistance to  The  end-uses.  the  including  to  of  comparatively  investigation  cases  very  main c o n c e r n .  composition  and amount  that  for  33,  restricted  of  difficult.  kind  be  decay  that  products  ensure  wood—based  non-durable  <32,  durability, mostly  can  to  to  is  development  growing  the  of  the  twofold:  impede  lack  species  so  necessity  protection  field  of  number o f  established  laboratories  and  Information  product.  e . g . ,  large  might  not  resistance  investigation  manufacturing,  these  is  expansion  wide range  the  been  compared  decay  uncertainties, on  though  has  that  property  work  The  fact  where  research  boards.  information are  products  the  uses  product  of  new  composition  hardboards,  new  lack  important  because  on  this  these  of  is  decay  important  in  resistance  during exterior  service  24  may  create  found  better  important  similar  or  tests  reflect  usage  of  the  is  the  factors  in  useful  and  factors  d u r a b i l i t y may  investigation  the  they  of  be  decay  encountered  found  to  contributing  to  high  intermediate  between  with  to  the  in  for be  board  in  type,  the  do.  such out,  of  the  just is  and/or  found  particleboards other  assessing the  most  resistance exterior changes  practical fungal  and  results  are  the  as  necessary  be  used  as  outdoors.  by s t r e n g t h  loss  and h u m i d i t y  to  be  the  main  (38).  dimensional changes  exterior  important values  plywood  in  to  the  Although  tests  temperature  were  s w e l l i n g and  useful criteria  in  tests  carried  visually  changes  agent  conditions  provide i n f o r m a t i o n about  estimated  to  the  Weatherproofing i s  Cyclical  Resistance  that  laboratory  also  durability of  respect  those  deliberately  bonding  was  in  f u n g i c i d e when t h e  usually  besides  content  the  exterior  prime c o n s i d e r a t i o n  moisture.  measurements.  most  are  than  not  that  with  Damage i s  in  closely  board  in  of  treating  related  more  not  inoculation  effects  fungal attack;  determining the  tests  the  important  for  property.  Exterior  is  in  closely  resistance  attack  conditions  durability. single  (32). and  thickness  the  Resin  variable  Particleboard  high and  is  density  linear  is  hardboard  dimensions  (41). Ruffin of  wood s p e c i e s  listed  several  hardboard. or  (87),  heat  in  a  report  and d e g r e e factors  Factors  treatment  such on  of  concerned  hydrolysis during  which might as  affect  wood s p e c i e s ,  fibers,  mainly with  type  the  durability  of  effect  manufacture,  severity  and amount  the  of  of  hydrolysis  binder,  water  25  repellency refining are  and  and  sheet  formation,  Information  durability  Decay  (decay  &.  of  are  of  severity in  variable  hardboard  the  of  fiber  exposure  hardboard  effects are  of  on  largely  lacking.  Materials  made  on t h e  decay  particularly  difficult  board  and  uniformity  to  types  the  of  particleboards.  evaluate  and  resistance  due  to  the  But  large  corresponding  variables.  Particleboards the  particleboard particle  amount  In  of  an  increased  amount  board  adhesive to  fungi  on  are  decay  the  a l l  (101,  trabea  investigating  determined  structure  and  that  wood  density  involved in  as  species, well  as  susceptibility  type of  120).  into  soil-block  resistant of  research  d u r a b i l i t y has  and L e n z i t e s  naturally  decade,  investigation  particleboard Murr.  past  geometry,  particleboard  that  been  and  variations  individual  boards,  often  different  During  and  have  composite  results  number  on  the  resistance)  studies  wood-based the  for  degree  density  i n C o m p o s i t i o n Board  Some  the  additives,  mainly r e s p o n s i b l e  quality.  9,  other  the  test  Pers.  resistance wood ( e . g . ,  effect results  ex  Fr.,  might western  urea-formaldehyde  of  variables  with Clark  be  Poria (20)  attained  red  binder.  cedar)  of montico^a  indicated by  using  or  increasing  Increasing  the  26  amount  of  PF r e s i n s  appreciably  increase  However, durability resistant  the  occur,  81,  so  particleboard  closely in  that  attacked  be  caused  18  by  of  failure,  and  less  guite  losses  measurements  in conjunction of  decay.  subjective has  In  Factors  the affecting are  both  particles  by d e c a y  on P F -  necessary  thus  reduction and  fungi.  and UF~bonded  boards  Stolley  (109)  found  that  although  susceptible  than  timber  they  were  blocks  also  mechanical  Strength  where  promote  wood  greatly  urea-bonded  particleboard  destruction  resistant  in  (81).  of leaching  is  was c o n s i d e r e d  made t h a t  the  against  where  particleboard  will  bond  more  protected  situation  percent  s w e l l i n g of  were  pH a n d a b u n d a n c e  service  of  not  {13).  well  high  moisture  by B a s i d i o m y c e t e s ,  attack.  a  used  exceed  uptake  fully  softwood  In  its  physical degradation  not  It  to  resins  UF r e s i n s  considered  due  not  may  definitely  extent  is  PF  and resin—wood  in situations  are  use  than  resin  fungicide protection  particleboards  fungal  of  did  boards.  s u s c e p t i b i l i t y of  weight-loss  high  the  a d d i n g wax  should  glue  Using  of  or  was  related:  conseguent  percent)  The recommendation  and  strength  6  shown t h a t  (28).  decay  content  biological  fungi  phenols  116),  moisture  of  the  increased, (6,  generally  PF-bonded board  activities  to  investigations  fungal attack  noncondensed may  3  resistance  other  have to  The  (from  testing  to  decay.  strength has  this  after  exposure  bjsen h i g h l y  with weight-loss practice  Test  probably a  to  recommended  determinations  is  showed  to  show  for the  rather  procedure. been  chips  found  are  that  decayed  boards more  containing  than  those  mixed hardwood and  made  of  softwood  27  chips  alone  (121)  .  As c o m p o s i t i o n fiberboards, rapidly dried  have  affected  out  microfungi to  effect In  high  including  thus  suitable  rather  than  conditions  often for  providing  fungal  tests  watersoaking  to  determine  and  static  b e n d i n g p r o p e r t i e s ( M O B and  on  board  than  B,  ,  samples  losses  in  on t h e  Schmidt et  al,  incubated  with  samples  are  l i a b l e to  wood—rotting Oeyama  wetted  and  conditions  c o n d i t i o n s i n which  Basidiomycetes  the  internal  effect  a  found  fungi for  of  b o n d (IB)  MOE) o f  (94)  submerged  (1),  boards  were  are  likely  fungal  strength  variety  and  of  graded—density  that  strength  considerably  extended  attack  and hardboards  by  a very  Basidiomycetes using  hardboard  common  periods  losses greater  in  and o t h e r  with P o r i a  lost  50  weight  percent.  It  non-tempered Although  was  also  hardboard  well  wide range mould  composite  incubation percent  to  as  of  species  as  water,  particleboards  fungi, (71).  from Akai  and  wood—destroying Basidiomycetes  days  10  be  are  Fiberboards Insulating  on  will  p r o d u c e d phenol— and urea—bonded,  particleboards  they  moisture  growth,  and  (50),  attack  commercially  ratios,  and  wood-destroying  colonization  laboratory  particleboards  surface-to-volume  by w e a t h e r  easily,  intermittenly  boards,  boards,  vaporaria  Fr.  found  that  sensu  Bres,,  while particleboard demonstrated suffered  knowledge i n  this  that  similar regard  showed a tempered  weight is  not  in  after  tests 100  hardboard  loss  of  only  and  losses.. complete  there  is  2 8  basic  agreement  that  board  substantial  during  the  lignin  and h y d r o l y s i s  hemicellulose (65).  production Much moulds  in  moisture  to  the  removes  Asplund has  they  could  than  loss,  that  attack  A possible was  permitting  in  easier  loss  of  moulds  that  the  to  the  French  suggested  would  exposed  be  available the  lumen.  individual at  without This  the  broken  need  for  explanation  may  on  of  hardboard  the  (72,  fungi  for  this  decayed  fibers,  the  removal  board  a  is  ends,  layer thus  of to  the  thus  On b a s i s  of  (76)  boards  the  in  mould  process,  cell  and  were wall  nutrients  through  true  action  Merrill  making  penetration hold  of  it  or  material.  since  means  tests  rate  altered  manufacturing  S2  By  their  slower  was  lower  composition in  of It  susceptibility  that,  not  a (74).  fiberboards,  the  role 76).  wood a t  cellulose  Merrill  of  for  similar  lignin  of  composed  were  for  examination (72)  used  fiberboards  except  microscopic and  of  soluble  centered  during the  access  and  and c h e m i c a l  explanation  way  fibers  place  alteration  Masonite type  salts  been  trabea  some  take  H y d r o l y s i s and  Basidicmycete  the  in  e.g.,  probably attack  could  of  advanced  repositioned  fact decay  weight  most  from  changes  process.  in  and  content  mineral  also,  brown-rotting  attack,  cellulose.  attack  that  found the  the  process,  pronounced with  material  by  strength  of  more  interest  suggested  was  is  Pulp washing  carbohydrate  of  manufacturing  chemical  the  the  wall  case  from  of  particleboards. With dependent are  expansion  of  markets  on c o n s t r u c t i o n  expected  to  be  for  panel  and e x t e r i o r  resistant  to  products  partly  applications,  biodeterioration,  such  either  boards by  29  addition  of  preservatives  natural the  resistance  possible  decay  ways  resistance  I ?. yj§  to of  L.) ,  and d e b a r k e r  hardwood  tree-tops,  than The  controls  former  percent  aspen  were  cedar  resistant  than  or  to  or  a l l  manufacture of  intact  the  of  of  famous  for  its  Dcnn) ,  high  reason  for  composition,  is  the  such  a  that  more  for  decay  compared  in  surface  or  and  P.  to  fine  steam  is  is  and,  mill  mixed of  a  white  to  termites  L.)  sapwood. 50 were  monticola  than  more  resistant  control.  Both  extractive  to  termite  for cf  able  the  decay  western  to  caused  resistance red  inhibit makes  a  cedar  the this  wood  property.  solid  wood o r  structure  in  may h a v e  therefore,  decay  to  cedar  boards  encountered  greater  exposed  the  less  responsible  of  cf  experiment.  resistance  state  white  made o f  contributed  example,  internal  one  but  Heartwood e x t r a c t i v e s  fiberboards,  is  this  wood-destroying fungi  Another  fiber  in  boards  controls,  have  extractives  heartwood.  growth  used  p i nus  A l l such  heartwood  to  resistant  pine(  than  or  boards  medium-density fiberboards  the  ( fJ^jaJS p l i c a t a  more  Lt%;rabea  is  hardwood p l a n i n g  that  southern  cedar  temperatures  of  seme  by  appear  samples  high  or  were  p i n e sapwood  white  and hardness  The  reported  material..  Comparing  from n o r t h e r n  hardwood r e s i d u e .  caused  boards.  northern  mixture  raw  wood s o u r c e  durable  more r e s i s t a n t  southern  of  by t h e  of  hardwood sawdust,  (10)  cedar  also  northern  resistance  of  of  decay  the  the  content  loss  Behr  by s e l e c t i o n  made  mixed  scraps,  heartwood-sapwocd the  more  fiberboards  residues  cedar  imparted  obtain  gccidentalis  h  or  (8)  susceptibility in  the  particleboards  of  of  T h e wood  division  the  boards.  within  a t t a c k /under  similar  fiberboards  swollen conditions  30  than  in  the  case  of  fiberboards  have  increased  because  these  cellulose.  10.  A.  T h e s a m e may  Against  It  has  susceptibility  microorganisms  Protection  be  have  true  easier  in  been to  suggested  mould  access  relation  to  that  attack  to  the  decay  fungi  (75).  Decay  General Wood  need  to  they  are  products  be in  i f  service  make  good  not  dangerous  be  impregnated a  the  resistance  into  combination penetration  detrimental applying  to  of of  natural  the  against  The  or  Wood  using  into to  a  involve  dipping,  either are  but  surface  which  vacuum,  pressure, to  maximize  keeping  Other  must  are  designed  minimum.  sap  under  agents,  wood w h i l e  and t h e  organisms  preservatives  tiood p r e s e r v a t i v e s  processes  strength  preservatives  spraying  Most  preservative on  possible.  against  conditions  deteriorating  wood c e l l s both.  resistance  environmental  attack  humans.  the  effect  wood  brushing,  without  protected  impart  or  particleboards.  any  methods  treatment replacement  cf  by method  (86). Hood p r e s e r v a t i v e s (a).  ifater-soluble  can  be  arranged  inorganic  salts  and  Hater-soluble  inorganic  salts  These  chemicals  which are  into (b) ,  two  broad  groups  organic—solvent  substances.  (a).  involve  soluble  in  water,  toxic  of  31  to  fungi,  wood,  and  preferably  show  thereby  preventing  their  when  in  contact  tin,  fluorine  and  preservatives. the  ether  the  only  salts  in  Standard  of  which in  for  Hood  bulk  the  three  of  being  preservatives development  are  of  combinations  of  special  purposes odour,  to  leaching  rain  soil  used  in  wet  Canada  (18).  arsenic  arsenic,  rendering is  (7).  Approved  covered  examples  arsenate), additive),  s t i l l  water-soluble  are  Good  wood  wood  of  or  the  by  of  such  ACA(ammoniacal the  preservatives  first  two  currently  of  used  substances  best of  of  in  resistant  suitable  for  solvent-type  with  easy  known e x a m p l e s  reasonably  (70,  and copper  preservatives  most  properties  products.  as  in  from  zinc,  performance  water-borne  special  substances  desired  copper,  against  Preservation  organic  organic  little  leaching  histories  stable  pentachlorophenol  Preparation  advantage  fixation  chromium compounds f o r  successful  of  for  (105).  Creosote,  Canada.  less  CAA ( c o p p e r  (b).Organic-solvent  probably  long  CCA(chromated copper  arsenate),  Canada  have  preservatives  are  form the  Compounds o f  wood e x p o s e d  CSA-080  formulations  or  ability  subsequent  addition of  more  solution  formulations  water.  boron  The  preservatives  copper  with  some  to  different  carriers  in addition  p a i n t i n g of to  the  the  in  the  These  applications.  and  lack  The  includes  various  and a d d i t i o n s  Deep p e n e t r a t i o n , and  has  wood p r e s e r v a t i v e s creosote  are  chemicals  leaching.  exterior  of  gluing  these  o i l carrier  fractions  44).  naphthenate  of  for  color,  treated  effectiveness  other  of  wood  were  these  32  Extensive tested  and  processes  coverage  used can  as  be  well  found  of  a l l  the  as  the  description  in  the  Some n o n - c o n v e n t i o n a l reviewed  by  Bowell  (1)  irradiation,  (2)  thiamine  (3)  heat  (4)  plastic  (5)  literature  cf  (19,  wood p r e s e r v a t i o n  these  that  have  been  the  preservation  39,  49).  methods  have  been  include:  destruction,  treatment, composites,  repellents,  (6)  bound  (7)  metabolic  (8)  chemical  toxins, difference,  chemicals  as  Treatment The  part  which are  considered  difficult.  of  in  the  Composition of  proper  treating  with of  the  such  methods mentioned  of  toxic  preservation  affect board  and  and  that  methods  may  purpose  In  most  are  their  is  very  used  in  very often  the  cases,  p h y s i c a l and  mechanical  materials.  preservative  treatment  by D e p p e a n d G e r s o n d e  in  (28),  be  methods.  of  fiberboard  processes  materials.  manufactured  particleboards  for  technological  properties  that  Materials  used  board  is  wood c o m p o n e n t s  preferable  particleboard  detrimentally  among f i v e  bcund t o  preservatives  preservatives of  conclusions  permanently  Preservatives  incompatible manufacture  of  environmentally  choice  application  and  modification.  fin i m p o r t a n t  B.  (86);  preservatives  only  two  33  methods (1)  are  irixing  being cf  used on  the  preservative  s i m u l t a n e o u s (but blender, (2)  chemicals  separate)  the  of  the  preservative through  effects  the  highly  for  pressure  expensive  board  treated  Several by  as  a n d common  both  fluids  powder b e f o r e ,  of  many r e s e a r c h e r s .  pentachlorophenol Copper-PCP,  are  fungal  attack  tested  were  is  and i t s  43,  48,  surface  or  in  the  during,  or  widely salts,  of  while  calls  little cost  is if  added the  manufacture. been  accepted including  for  protecting  71,  79,  used  Na-PCP  building  118).  and  evaluated  that  Other  BHC(Benzenehexachloride), "Xylamon",  naphthenate, CCA.  the  was  preservative  have  80,  of  the  production also  facilities  stages  yield  penetration  after  preservative It  may n o t  compressed  panels  the  effective  (8,  the  e x c l u d i n g the  during  kinds  board  i f  treating  production cost is  resin  spraying of  finished  T r e a t i n g the  the  the  preservative  insufficient.  to  with  gluing.  A treatment expected  scale:  and  application of after  a large  and boards  against  chemicals copper  3<i  1-1. L a b o r a t o r y  A.  Test  explanation protect  of  of  wood f r o m  developed f o r  over  the  last  80  comparative  relative altered  (a) .  evaluation  of  under  methods  on a g a r widely  the  the  a  Height-loss  serve  the  conditions,  this  type  of  test  substrate  rate  of  does  has  instead  been  of  cf of  62).  growth have  cf  been  potential not  i n wood p r o d u c t s .  screening  study  (11,  samples  of  purpose  evaluation  others  preservative  have  preservatives  laboratory  the  able  evaluate A  modified  proposed  agar  the  recently  (29).  methods  Determination wood h a s  wood  and  are  methods  preservatives,  preservative  cellulosic  chemicals  also  which measure  which p r o v i d e s r a p i d  uses  can  preliminary screening  However, of  potential  an  existing  media c o n t a i n i n g  for  these  quality control,  Fungal  growth  of  These t e s t s  methods  method  (b) .  years.  extent  demand  Numerous l a b o r a t o r y  evaluation  formulations,  effectiveness  and  fungi.  performances  preservatives.  in  Resistance  preservatives  what  Fungal growth  fungi used  effective  how a n d t o  been  of  Decay  General Development  to  Methods f o r  become  of the  type  weight  loss  standard  evaluation.  This  of  determining  preservative  test  is  due t o  method  d e c o m p o s i t i o n by  for  especially  thresholds  as  the  fungi  preservative well  suited  wood f o r  this  for test  35  can  be  treated  national D1413,  standards  BS  In  838,  a  sterile  blocks so  of  that  able  the  flask  fungus  is  medium i s  or  the  do n o t  in oven-dry weight  obtained  g.,  Most  ASTM  weight  of  before  are  measured  is  exposure  a supplement  by s e v e r a l  to  exposed  available Cockcr.oft  researchers  a  the  the to  by  the  to  shorten  is  the  fungus  the  and  culture.  weight-less  has  using the  rod  fungus  to  (22)  and  support  attack  is  eguipment,  on t h e but  examination  in  mat,  malt-agar  months  are  malt—agar  fungus  set  4  methods  method.,  with mycelium..Then  on t h e  untreated, the  sterile  to  of  e.  agar-block  3  cost  chemicals.  method,  covered  placed  Degree  after  Modified  the  well  touch  blocks.  use  grown on  treated  visual  lessen  tests  wood,  oven-dry  results  test  blocks  of  etc.  rod i s  percentages. or  weight-loss  support  reach  Recorded  the  standard  the  concentrations  glass  difference the  prefer  most  until  the  to  different  DIN 5 2 1 7 6 ,  Europe  Basically, Kolle  with  the  test  reviewed  agar-block  method. In  North  Standard widely soil  America the  MiO-77  (4)  used.  It  is  used  as  the  is  strips  on s t e r i l i z e d  The in  block  (1) .  weeks*  to  the  soil.  of  agar-block  for  fungus  D1413-76  (2)  test,  growing the  g r o w i n g on  outlined in  are  the  fungus  culture.  soil  as  the  most  except  that  untreated  blocks  using  the  fungus.  Test  to  is  AHPA  Wood  wood  feeder  weighed b e f o r e  medium i n s t e a d  of  and  agar  are:  higher  water  can  better  be  a  exposure  advantages test  Standard  substrate  are  12  ASTM  much l i k e  blocks  after  exposed  or  s o i l - b l o c k method as  holding  capacity  contrclled  over  i n lengthy  agar  in  tests,  that and  the M . C .  36  (ii).  the  ability  substrate, The  its  strength  weight.  strength  for  preservatives. almost  an  of  hardness,  crushing,  to  biodeterioration  thin  strip  veneer (15)  is  also  method, the  a  of  veneer,  made t o use  bend  major  variability difficult  to  in  has  find  for  (84),  In  that  used  test  of  fungi  isolated  of  employed and  review and  the  describes toughness  (114)  as  a  wood p r e s e r v a t i v e . method f o r the  clamps  Sharp  determining  technigue  supports  fracture  than  use  evaluating  by T o o l e  essence, which  were  bending  strength  when t h e  strength  for  in his  various  rapidly  possible to  consists  horizontally a move a p a r t  the  occurs.  Bravery  and  Grant  on t h i n  strips.  The  latest  Safo—Sampah and Graham  drawback the  method  criteria  (40)  been  rapid  until  breaking radius  The  and  wood.  so  a tensile  capacity  fungi.  effectiveness  devices  Hartley  tensicmeter  d e v e l o p e d by  decay  called  of  testing  evolved a  for  strength  p e n t a c h l o r o p h e n c l as  the  clamps  of  values  much m o r e  theoretically  of  tensile  Eggins  two  is  used.  and  of  the  growth  higher  the-agar-block,  determination of  strength  evaluate (95)  it  number o f been  method  affect  d e c a y i n g wood d r o p s  rapid  have  Crushing  from  methods  strengths  tests.  otherwise  than  Many k i n d s  egual  substances  method n o r m a l l y g i v e s  Therefore,  loss  toxic  will  thresholds  Strength-loss The  absorb  which  soil-block  preservative  (c).  to  from  (89)  to  wood i n  determine  service,  was  test. of  strength  strength-loss properties  compatibility in  of  methods wood.  specimen  size  is It  the is  used  inherent  also in  weight-  37  loss  and  strength-loss  methods  if  both  were  adopted  in  single  test.  (d).  Respircmetry a rather  is  new m e t h o d  respircmetry.  dioxide  methods  This  evolution or  activity  (9,  up-to-date  detection  103,  review  on  as  it  However, the  laboratory  nature. fungi  program  be  this  Smith  method.  The  the  as  the  Tests  Composition Boards  their  relatively Europe. the  preservation  of  tests  service  in  laboratory  though  standard  widely  used.  there  evaluation methods  of  carbon  of  is  the  accepted  an  any  for  gas  laboratory conditions that  use. in  occur  in  wood-destroying  part  of  any  evaluation They  should  (21).  of  composition America  achievements  decay for  decay  best  in  a l l  no r e c o g n i z e d  the  the  situations  North  unexplored c o n s i d e r i n g the  Consequently,  detection  preservatives.  biodegradation  in  be  initial  activity  B.  and  fungi  provided  reproduce  with  service  of  by  flexibility  tests  by f i e l d  field  to  of  followed  The e n t i r e  (104)  variety  laboratory  and  caused  automated  appears  i m p o s s i b l e to  fungicidal  on the  117).  regarded  decay  consumption during  be  of  based  greatest  imitating  only  on the  115,  is  technigue  is  Therefore,  can  method  provides  it  measuring the  oxygen  98,  gas-chromatographic  in  testing  remains made  standard  resistance solid  boards  of  in  method  for  fiberboard,  wood  are  38  According the  use  of  the  Further,  the  Opinions  were  severe,  need also  (48)  hardboard compared  the  soil-block  in  his  less  was  fiberboards  the  tests  more  soil-block  most  test  (91)  The r e p o r t  of  test  applicable  method  to  to  Behr test  compared  in  and the  the  found  agar-block that  soil—block series  control  in  of  the  test  volatile  glue  method  testing  plywood and  phenolic have  to  estimate  (73,  a p p l i e d such  diminution  of  and  French that  because the  resistance  of  been  the  other  used  strength  made  extent  methods  nailhead be  soil-block  partly but  board  are  because also  the  much  of  perhaps  by t h e  made t h a t than  methods  soil  the  agar-block  materials  bonded  with  resin.  also  strength  can  decay  components  suitable  resistance  Na-PCP  applied  and  pieces  more  that  of  and c o n c l u d e d  inhibitory effects  method c o u l d be  concluded  too  exposure  fiberboards  the  soil-block  77)  may b e  Merrill  (10)  therefore  Studies  by  methods  were  of  stressed.  in evaluation  Recommendations  type  were  moderate  particles.  some  general.  s o i l - b l o c k method  and p r a c t i c a b i l i t y ,  adsorption  for  in  recommended  fiberboards.  moisture of  FAO h a s  value.  suitability  plywood t e s t  because  that  greater the  (50),  resistance  reflecting  soil-block  pronounced  better  for  particleboard.  test  medium—density Savory  of  the  ASTM  test  offered  used  accuracy  standard  and S a v o r y  mould  tests  and  (72)  its  for  may b e  Huber  of  Jackson  soil-block  and t h a t  conditions  on  to  by m e a s u r i n g of  in  decay.  their  the  Merrill  properties  of  and  for  and  as  a  and  lateral  measurements  boards  in  French  fiberboard studies  pull-through resistance satisfactorily  decrease  result  of of  nail  39  decay. Deppe and advances i n  Gersonde  production  (28) and  described  the  technological  t e s t i n g cf preserved  p r o d u c t s i n Germany. C o o p e r a t i v e t e s t s r e v e a l e d flask  method{agar-block  generally  used f o r e v a l u a t i n g  appropriate test  be  at  satisfactory  t o decay  small  reported  concept of standard  Gersonde  t e s t i n g and  preservatives  Kolle  for fiber  f l a s k and  plywood and by  bcth  (28)  evaluating  enough. However, t h e the  also  the  agreed t h a t  fungus c e l l a r  very  l e s s s u i t a b l e as  absorption  as  described  to  i t can  moderate  improvement  suitable  is  not  methods  wood progressed  effects  previously.  by  unlike  be  tested  against  due  or to  s o i l - b l o c k method, i n  Kolle flask) provide  far  fiberboards  a l e s s e r degree  Apparently, the  with a g a r - b l o c k ( o r  or  a  A f t e r a l l , wood e x t r a c t i v e s  their  no  low  b u i l d i n g b o a r d s may  components a f f e c t f i b e r b o a r d s  be  a  t e s t s of  preservative  Basidiomycetes.  Berlin,  preserved  methods showed t h a t ,  resin  comparison  cellar  (27).  comparative fungal  amounts.  of  decay t e s t s and  b u i l d i n g b o a r d s had  methods a s t o t h e i r  low  fungus  tests create  e f f e c t i v e n e s s of  particleboard, fiber  wood-destroying  Kolle  i s less  t e s t sample s i z e i s a n  t o have some p r e d i c t i v e v a l u e  Deppe and for  where t h e  block  resistance  t e s t which s i m u l a t e s  panel  52176, w h i c h i s  while the  f u n g i . Fungus c e l l a r  accelerated  decay environment  t o DIN  the  Bundesanstalt fur Materialprufung,  s u i t a b l e f o r t e s t i n g the  particleboards  the  the  that  wood p r e s e r v a t i v e s ,  for testing particleboards,  developed  proved t o  on  method) a c c o r d i n g  wood-based  method, would seem  even h i g h e r  capacity  of  to  40  C.  Factors  (a).  T o Be  Considered  leaching Smith  solid  (101)  wood  doubted  products  were  particleboard,  where  because  adhesives  of  the  Dsing  24-hour  pretreatment found  that,  on  the  that  untreated used  soaking  in  the  in  blocks  that  received  no  treatment.  particleboard  at  room  as  biocides,  fractions  of  phenolics,  failed  to  pieces  except  overgrow  leaching. method, the  It  in  of  point  growth from  and  also  all  cases  in  the  d i d not  the  at  ambient  caused  that  Barnes  than  increased  of  tests,  attack  previously  when u s i n g attack  a  weight  for  those  of  materials  resin  biodeterioration.  agar-block  been  as  soaking  low—molecular-weight  that,  fungi  (116)  more  extraction  appreciably  vigour  and  pretreatment  concluded  had  to  temperature  significantly  the  blocks  toxic  boards,  hence  for  manufacture.  soaking  in  appeared  the  was  the  the  fungi  test  subjected  to  soil—block  increased  after  treatment.  and Gersonde  particleboard  situations did  that,  be  Toole  They  and  might  tests  to  blocks,  probably  when t h e  leaching Deppe  test  reported  its  temperature  act  (91)  with  accepted  applicable  board  water  phenolic  occurred  Savory  in  particleboard  with  normally  necessarily  loss  which  the  set  in  the  out  and  the  Kolle  resin,  test  argued samples  German  agreed  its  (27)  against on  building  that  the  the  were t h e  alkali  content  basis  for  liberation or  severe of  regulations.  reasons  flasks  the  the  leaching  service However,  inhibited of  presence  they  fungal  formaldehyde of  unbound  phenols. , However,  Hedley  (43)  said  that  little  difference  in  extent  41  of  decay  his  was o b t a i n e d  using leached  Initial The  wood  samples  in  be  place.  the In  with  decay  wood g e n e r a l l y  that  that  its  lack  is  content of  similar  be  taken  most  and  (19).  threshold percent higher percent  is  for  than  the  test  i n a d d i t i o n to  being  fully  water  in  of  also  gases can  take  place  point  when or  its  which  their  must  fungus  structure.  free  action  remain  the  Thus, content  M.C. is  respiration  can  in  (19).  moisture  when t h e  is  except Por  so  high  by  26,5  practical  Scots  moisture 22  additional wetting  C for is  in  is  the  of  can  of 22  to  decay while  Both  reached  respective to  it  Risborough  hardboard.  needed  timbers  growth  region  p i n e sapwood  content  to  purposes, the  the  Princes  the  moisture  relation  percent  and t e m p e r e d  humidity at  in  optimum  i n wood f o r  from the  for  equilibrium  exact  somewhere  that  content  environments.  any  moisture  fungi  standard  relative  apparently,  of  indicated  moisture  in  products  inhibit€d  information  (17)  fungi  spaces  establish  minimum  wood-destroying  Laboratory  such  the  of  is  the  air  of  liguid  growth  (83),  species  density  percent  of  the  probably prevents  fungi  any  that  of  and  impossible to  for  film  saturation  oxygen  wood—destroying It  walls  diffusion  fiber  of  cell  a d d i t i o n some  so  below  a  enzymes  cavities of  condition for  when t h e  coated  of  content  favorable  to  are  diffusion take  moisture  most  seems  imbibed  24  non-leached  own p r e l i m i n a r y i n v e s t i g a t i o n ,  (b).  is  and  promote  18.0  values under  were 100  materials, decay  under  42  Deppe content  of  and S e r s o n d e  (28)  greater  18  susceptible materials  to  to  than  decay.  fungal  investigation  is  also  reported  percent,  However, the  attack  needed  could  to  that  a  moisture  wood-based m a t e r i a l s response  be  clarify  at  of  different the  different and  nature  became  more  of  the  susceptibility. Hedley soil—block  and F o s t e r method i s  weight  losses  fungus  is  block"  technigue  lower  in  used  one  not  test  as  buried  claimed  the  most  blocks,  the in  (42)  decay  which  flush  that  suitable  two  the  soil  standard  o b t a i n i n g optimum  when a  They  b l o c k s were  i&STM  for  particularly  organism.  with  the  white—rot  proposed the stacked,  surface.  "double  with  With  all  the white-rot  £ ungdj, lower:- blocks'^of.' either"'spee?ies, , Rinu s,, r ad iateaD. DonCand, ff  :  Populus  robusta  rapidly,  conductors developed  fungi, than only  DeGroot interactions  the  strips  greatest  cloest  attained  and l o s t  brown—rot  feeder  ,  to  the  more  are  white^rot  (26)  and  5  loss  was  feeder  decay  the  strip,  able  to  transport  several  tiers  of  test  blocks.  appeared  v i r t u a l l y dependent  wood.  more  upper b l o c k s .  With  water  relationship  light pine  was  that  the  In  upon t h e  each  moisture two  the  those  content  brown-rot soil  two  on  fungus,  i . e . ,  from the  contrast,  moisture  with  blocks, the  moisture  and  sapwood b l o c k s  that,  lowest  and so  were  the  decay  effective  same  fungus,  two  species  of  this  He f o u n d  blocks.  were  also  d i d the  southern  fungi. in  for  blocks.  decayed  fungi  It  fungi,  stacked  four  than  p r o b a b l y more  Populus  tested  using  M.C. suitable  weight,  which  with  a  of  Lenzites  through  white-rot  i n t r i n s i c water  content  43  Peterson initial first  and  moisture  Cowling  (83)  c o n t e n t s on  t e s t e d the i n f l u e n c e of  decay  and  f o u r weeks o f i n c u b a t i o n , t e s t  moisture  of 6 - 4 5  percent  c o n t e n t t o w e l l above the whether o r n o t t h e t e s t following that the  fiber  wafers  of Polyporus  even t h o u g h i t c a u s e d moisture  no  present. T e s t s i n the  L.  had  no e f f e c t  i n the  denser  out  water t o t e s t  t o add  on t h e f u n g u s c u l t u r e s . should  not  be  the unwetted  Sterilization Test  incubated  loss  was  boards as (12)  by  a  carried them  fungicidal this  treatment, twelve  methods sterilized  with a s i n g l e  t o make s u r e  fungus c u l t u r e  methods f o r s t e r i l i z i n g  interfere  ( i i ) treatment  condition  that  decay.  b l o c k s need t o be c o m p l e t e l y  or propylene  wafers  blocks.  commonly used  oxide  test  i n c r e a s e d as much a s  will  and  Behr  t h a t any  a p p r e c i a b l y removed  contamination  C),  caused  pieces before placing  I t i s thought  n e v e r t h e l e s s decay weight over  indicated  Fr.  on r a t e o f  decay weight l o s s e s ,  experiments  ex  amount o f water i n t o t h e  p o s s i b l e c a u s e f o r low  (c).  moisture  decay i n them.,He c o n c l u d e d  content  the  initial  increased i n  versicolor  Assuming t h e l a c k o f m o i s t u r e  times  with  f o u r t h t o e i g h t h weeks o f i n c u b a t i o n a l s o mycelium  compound  that, during  saturation point regardless  f u n g u s was  movement o f an a d d i t i o n a l  initial  actually  reported  various  with  with  the t e s t  results.  wood a r e :  gaseous c h e m i c a l s  o x i d e . However, h e a t i n g  drives off extractives  before  being  no The  two  (i) wet-heat(121  like  ethylene  wood under humid  already present  as w e l l  as  44  preservatives the  wood f o r  cases like  the  that  may h a v e  purpose  applied  of  toxicity  steaming  hydrolysis in  been  might  deliberately  introduced  test  (100).In  studies  cause  wood c o m p o n e n t s ,  chemical  under  into some  modification,  suitable  acidic  conditions. Propylene gaseous Smith  of  moisture  10  (96).  and  to  In  were  Alkylene  (85).  contact  is the  substrate is  hydrophilic  the  substrate have  a  to  changed,  with  can  also  to  the  of  to  used rot  theory  wood.  chemical  nature  which a l l o w s good  reaction  due t o  with  hydroxyl groups  The  use  the  wood c e l l  the  ethylene wall.  a  The  oxide  of  gas  some  toxic  or  lignin)  selective also  advantages  If  points.  wood a r e of  They can  were were  the  directly and  the  the  substrate cannot  the  the  alkylene volatile  removal react  low  polyethylene oxide  polyethylene oxide  below  compound.  using  at  two  stability  change  and ease  these  wood  reaction  of  effect  modification of  must  configuration.  a  than  with  more  wood c o m p o n e n t s  gives  However,  Basidiomycetes  enzymes  m o d i f i c a t i o n of  low b e l l i n g  summarized  content  and d i m e n s i o n a l  penetration  cold  using  moisture  i n chemical  that  highly  as  being  wood  react  form a  Chemical m o d i f i c a t i o n can nature  use  propylene oxide  been  this  used  Smith s t u d i e d the  sterilize.  specific  for  of  (97)  (wood c e l l u l o s e  oxides  the  to  resistance on  widely  general  wood b l o c k s  have  are  s t e r i l i z a t i o n of  creosote,  oxides  must  place.  the  resistant  based  chemically  take  report  difficult  e.g,,  improve  It  their  Propylene oxide  preservative,  to  on  that  be l e s s  Ascomycetes.  wood  a later  content found  percent  found  oxides  s t e r i l i z i n g agents,  by  gases,  and e t h y l e n e  after  guickly  temperatures. polymer  polymers  have  in  45  the  disadvantage  the  molecular  that, not  at  of  weight  levels  of  is  23  decay  gaseous  test  to  chemicals  the  to  sufficient  quantity  fungi  this  percent  soluble,  report  weight  fungi.  of  especially  if  summarizes  (85)  gains,  the  wood  They  found  with no  percentage-weight-loss ethylene result  in  oxide the  of  that  (100)  treatment  significant for  sterilization  retention  of  of  does  blocks  may s t i l l  remain  subsequent  but  growth  i t  is  any  is  of  two  decay  w o o d was  toxic  known of  under  the concluded  efficient  residues  three  compared  oxide  and  if  certain  of  and  between  methods  in  decaying  effect  with ethylene difference  not  growth  the  subsequent  of  after  readily  s t i l l  could retard  the  with  the  investigated  wood o n  values  that  wood b l o c k s  Ethylene oxide  ventilation,  Sharman  method  the  wood.  residues  test  ventilation  residues  retard the  sterilization  wet—heat  vacuum.  to  onto  leaves  S m i t h and  impregnation of  free  f r o m wood b y  process  kinds  remove  inoculated  removed  not  30  T h e same  necessitates  treatment,  that  low.  water  decay. In  the  being largely  by t h e  and  did  wood.  46  CHAPTER  1.  III.  MATERIALS  Materials  A*  Asplund The  was  Pulp  commercial  normally  before mill  collected  resin  at  Asplund  and  wax  at  Franco  spruce  J,  western  ( Tsu<ja s p p . ) . consistency, actually  B.  Pulp  was  of  each  [  the  was  hardboard  was to  mill,  hardboard  menziesii  Abies balsamea  plicata  obtained  broitination  [  CANFOR  of a m i x t u r e _ o f western  Pseudotsuga  Balsam  study,  regulators,  i n the  consisted  ( Thuja  thus  experiment  oven-dry  The  calculated  to  the  pulp.  The  of  the  bromine  was  amount  vessel 10%  starting  occurred  slurry  amount  Donn)  and  undrained be  i .  in  on  the  of  carried e. ,  (Mirfa.) (L.)  hemlock and out,  had  a  that  2%.  pulp corresponding  used.  The  the  slurry  C by p u r g i n g  provide  of  the  40  resistant to  an  material  appropriate  corrosion  through  pulp  in  fir  this  consistency  additions,  spp.),  cedar  which  used  adjusted  bucket.  The  at  is  red  throughout  Bromination  For grams  { Picea  used the  B . C . ..It  i n c l u d i n g Douglas  Mill,  of  emulsion  New W e s t m i n s t e r ,  ],  pulp,  one  softwood,  a  AND METHODS  of  and  was  the  of  based  solution  12 t o  15%  of  in  a to  added,  oven-dry  was  (bubbling)  steam  transferred  was  on t h e  700  temperature  live  sodium bromide  addition amount  with  pulp slurry  bromine, pH o f  pulp s l u r r y  to  5.6,  weight  Liberation  chlorine  (calculated  gas on  the  47  b a s i s o f oven-dry  pulp  additions the s l u r r y stirrer.  Stirring  completion calcium  was s t i r r e d  continued  a l l phases o f  v i g o r o u s l y with  chemical  a "lightening"  up t o 60 s e c o n d s f o l l o w i n g  <Ca (0H)2 ) was added t o n e u t r a l i z e t h e a c i d i c  and t o r a i s e t h e s l u r r y  stabilization decreasing  During  o f t h e g a s a d d i t i o n , whereupon a measured g u a n t i t y o f  hydroxide  by-products  weight).  was o b t a i n e d  pH ( w i t h  time)  pH from  by r e a d j u s t m e n t with  1.4 t o 5.5. F i n a l  pH  of t h e s l i g h t l y  f u r t h e r a d d i t i o n o f Ca (0H)2 .  G. B o a r d s The forming  neutralized slurry box w h i c h c o n t a i n e d  consistency cationic  was p o u r e d  wax e m u l s i o n  was added a t t h i s  enough water t o r e a d j u s t t h e s l u r r y  (Mobilcer  stage  called  by a d d i n g  small  much water from r e s u l t i n g  excess with  was c o n t i n u e d  w e t - l a p was f i r s t  for a  pressed  total  F i n a l l y , the  by s u c t i o n t o remove a s  cold-pressed  a t 170 p s i t o remove t h e  w a t e r . A l l wet-^laps made o f b r o m i n a t e d f i b e r  g/1) t o p r e v e n t  resin, i t  pH a d j u s t m e n t t o 4.5 was  followed  of borax  (77.3 g/1)  were  sprayed  and b o r i c a c i d  surface c h a r r i n g during hot-pressing.  wet-laps o f the c o n t r o l board  700  or other  mat a s p o s s s i b l e . /  240 c c o f h o t s o l u t i o n  (89.4  f o r phenolic  s t i r r i n g at  amounts o f s u l p h u r i c a c i d .  was g r a v i t y d r a i n e d ,  The  46) was added w i t h  and s t i r r i n g  o f two m i n u t e s . Where n e c e s s a r y  slurry  a 16 i n . s g u a r e  t o 1%. To i m i t a t e t h e c o m m e r c i a l f o r m u l a t i o n , 7.0 g  40 C. I f t h e f o r m u l a t i o n  effected  into  thus  ay 175 C p l a t e t e m p e r a r t u r e  procured i n three  The  were t h e n h o t stages:  70 s e c a t  p s i , 110 s e c a t 40 p s i ( b r e a t h i n g ) , and 7 min a t 350 p s i .  48  The  brominated  slightly final  b o a r d s were p r e s s e d  reduced  specific  h o l d ) , and r e d u c e d  occurrence  a t t h e same s c h e d u l e  pressures temperature  (60 0 p s i i n i t i a l  and 27 5 p s i  (135 C) t o e l i m i n a t e t h e  of c h a r r i n g .  b o a r d s were h u m i d i f i e d a t 50 ± 3% r e l a t i v e  All  with  23 ± 2 C u n t i l  equilibrium  moisture  content  humidity  o f t h e board  and  was  reached.  2. Methods S i n c e t h e r e i s no r e c o g n i z e d s t a n d a r d laboratory  e v a l u a t i o n o f the decay r e s i s t a n c e o f f i b e r b o a r d s , i t  was d e c i d e d  t o f o l l o w a d v i c e g i v e n by some p r e v i o u s w o r k e r s (50,  72) and t o use a m o d i f i e d  soil-block  all  sterile  manipulations  horizontal-flow, soil-jar  method f o r t h e  needinq  sterile-air  l i d s , recommended  f r e e d o m from  contamination  technique  ( 2 ) . F o r example,  c o n d i t i o n s were done i n a  b e n c h . A l s o , t h e new  by S m i t h  (106),  mite-proof  were u s e d  to  ensure  d u r i n g t h e i n c u b a t i o n p e r i o d o f 10  weeks. For  a l l test  adhering weights  t o t h e b l o c k s was c a r e f u l l y  throughout  t h i s study  away b e f o r e  dry-weight  and t h e s e ,  the t e s t  l o s s and f i n a l  final  (105 ± 2 C o v e r n i g h t ) together  measured f o l l o w i n g i n c u b a t i o n , were u s e d  percentage all  scraped  were measured. O v e n - d r y w e i g h t s  were used weights  b l o c k s , f o l l o w i n g i n c u b a t i o n t h e mycelium  moisture  with  t h e wet  to calculate  content  values f o r  blocks.  Because of r e c o g n i z e d  u n c e r t a i n t i e s i n the t e s t  technique.  49  the  following i.  specific  Cold-water before  i i .  leaching  were  evaluated;  {AWPA M 1 1 - 7 7 )  of  the  hardboard  blocks  decay;  C o n d i t i o n i n g of moisture fungi;  i i i .  variables  the  contents  hardboard  before  blocks  exposure  to  to  two  different  wood-destroying  and  Ethylene  oxide  and  wet-heat  as  alternative  sterilization  methods.  A.  C o m p o s i t i o n and  1.  Fiber  only  mill-run  (  f  2.  Pice a  Tsuga  Fiber  spp.),  fiber  a  the  for  pulp  Hardboard  a l l  six  of  Balsam  ( Thuja  Abies  plicata  hardboard  Products  softwoods:  (Mirb.)  p  Blocks  of  Forest  western  menziesii  15%  Test  types  {Canadian  mixture  redcedar  Franco  ],  balsaaea Donn)  ltd.)  75%  Douglas  10%  spruce  (L.)  and  was  Hill,  1,  hemlock  spp,).  plus  Chemicals with  of  of  Pseudotsuga  western (  —  Asplund  consisting fir  Size  alum  1% p h e n o l i c Ltd.)]  and  (0.15%)  and  resin  0.30%  fBB-140  cationic  adjusted  to  Foraside wax,  pH 4 , 7  (Reichhold  precipitated with  sulphuric  acid; 3.  4.  Fiber  plus  Co.) ]  and  polyethylenimine 0.30% fiber  the  of  based  fPEI  600  (Dow  Chemical  wax;  Brcminated method  resin  only  Jurazs  on o v e n - d r y  — and  fiber  fibers Paszner weight;  were b r o m i n a t e d (57)  using  10%  following bromine,  50  5.  Brominated  fiber  precipitated 5.5 6.  using  with  alum  sulphuric  Brominated  1$ p h e n o l i c  plus  fiber  (0.J51&)  resin  and  and a d j u s t e d  0.30% to  wax  pH 5 . 0  -  acid;  plus  If p o l y e t h y l e n i m i n e  resin  and  0.30SS  wax.  To  avoid  the  hardboard  on  hardboard  were  sanded,  20  mm s q u a r e  mm.  Blocks  loose  fibers.  treatment  B.  the  effects rate  Poria  were  jjuteana  trabea  four  of  the  faces  of  thickness  of  about  to  remove  finely blocks  sanded was  Polypgrus  versicolor  fungi  ex  Fr.)  Karst.  Fr.  & Curt.)  Burt  Murr.  adustus  first  ex  {Berk.  Polyporus  Willd.  four  L.  ex ex  fungi  used  the  for  3 any  each  Fr. Fr.  are  brown-rot  and  =  WFPL n o .  9H  =  WFPL n o ,  47D  =  WFPL n o .  118D  =  WFPL n o .  120C  =  WFPL n o .  75C  =  WFPL n o .  the  last  105E  two  white-  (51).  Preparation  of  16-oz  jars  moisture  both  final  and  finish  Osed:  (Schura.  Pers.  incrasata  The  cut of  surface  attack,  providing a  A replication  Jtoria j o n t i c o l a  C.  fungal  Hood-Destroying Fungi  Lenzites  natural  combination.  Conic£hora  rot  of  of  round  content  to  Soil  Jars  were f i l l e d  more  than  half  with of  packed their  soil  of  capacity.  45-505? The  soil  51  medium w a s organic feeder and at  fresh  matter strip  the 121  C.  and  of  total  garden was  ccmpost sifted  ponderosa  assay  After  was  pine  the  f u n g i which  were  plates,  and  mite-proof  the  laminar then and  i n i t i a l  flow  incubated a  relative  blocks lids  in  were  a  air  humidity  planted  were u s e d  to  on  with of  the  ensure  ±  a  was  pressed  on t h e  soil  autoclave  feeder  freedom  for  were i n o c u l a t e d about  work  six  was  two  soil  the  o n -the  out  set  on  a  were  at  before  Mite-proof  agar  used  jars  contamination  hour  with  carried  weeks  one  those  suitably  strips, from  days  for  inoculated  5% f o r  of  sieve,  temperature  75  content  mm g a u g e  exchanged  This The  20-40%  5  an  for  lids  bench.  room  in  jars  cultured  autoclaving.  sterile  a  sapwood  soil  desired  during  with  through  sterilized  cooling  sterile  soil  25  the  C test  soil-jar during  the  incubation.  D.,  Preparation Different  decay  were  effects  Test  of  Samples  procedures  meticulously different  manipulations  (a)  of  of  in  preparing  followed  factors  procedures  to  the  allow  involved in are  shown  in  the  hardboard  test  samples  distinction this Fig.  test.  prior  among  The  to  the  detailed  2,  .Leaching Cold-water  done  similarly  Following initial sample  to  the  leaching,  dry of  leaching  method  the  weights,  non-leached  of  suggested  blocks  Then  all  blocks,  were  oven  blocks, were  in  blocks  ASPA M 1 1 - 7 7 dried to  including a  vacuum  for  14  days  was  (4).  obtain  their  replicate  impregnated  with  water  52  using left  a d e s i c c a t o r and i n the  water o v e r n i g h t and  sterile-air reached the  an  a o n e - h o u r vacuum p e r i o d . The  ventilation average  until  value  the  c f 20%.  desired moisture-content The  30 min.,  b l o c k s were t h e n c o o l e d on  into  soil  jars  (b).  Setting  then  allowed  moisture  to a i r dry  content  were  under  of the  E x t r a b l o c k s were used  blocks  to  check  level.  steam  sterilized  at  15  a laminar-flow, s t e r i l e - a i r  (ASTH  blocks  psi  (121  b e n c h and  C)  for  planted  B1413-76).  of i n i t i a l  moisture  content  and  method  of  sterilization Following  l e a c h i n g and  pre-wetting  t o 20% M.C.,  p r e v i o u s l y d e s c r i b e d , b l o c k s were s t e r i l i z e d their to  moisture  8%.  content  This allowed  moisture  contents  ncn-brcminated Two  me  t o examine t h e e f f e c t 8%)  brominated  sterilization  on  t h e decay  methods were u s e d  a substantial  were u s e d  t o check changes i n moisture  produce c o r r e c t i o n resulting  from  soaking  b l o c k s were a l s o agent  factors and  initial  rates of  leached,  , e i t h e r wet  of f a c t o r s .  content  during  jars  blocks air-drying  as a c h e c k  steam s t e r i l i z a t i o n .  Some c h e c k  f r e e o f any  as a v e r a g e s  to  weights  biological  l o s s e s were i n v o l v e d .  c o r r e c t i o n f a c t o r s were c a l c u l a t e d  (121  blocks  f o r c h a n g e s i n sample  additional  heat  These e x t r a  They a l s o s e r v e d  planted i n s o i l  t o c h e c k i f any  in sterile air  o f two  number o f r e f e r e n c e  f o r each combination  ascertain exact control.  had  (100).  allocated  to  some  boards.  C) , o r e t h y l e n e o x i d e u n d e r vacuum T h e r e was  then  a d j u s t e d under v e n t i l a t i o n  (20% and  and  and  as  The  of weight  changes  53  and  involved  E.  Evaluation of Weight  the  planting,  corrected jar.  dry  loss  o r i g i n a l dry  before  of  four  for  above  mass.  Results in  dry  mass,  mass after  minus the  changes  The w e i g h t  the  replicates.  loss  in  due t o  final  weight  loss  activity  being corrected  percentage  corrected  fungal  of  d r y mass due t o  for  was c a l c u l a t e d mass  of  the  taken  weight  w h i c h was  leaching  was  as  a  corrected  changes  also  inside  as  being  the  soil  percentile original  54  CHAPTER  To e s t a b l i s h conditions control soil given  for  in  enumerates  are  the  sterilization  between  different  is  also  general  of  of  of  loss  with P,  that  differs level  i ?  and  the  in  leaching of  blank and  decaying  the  weight that  of  extent  and  test  in  fungi  the  in  results  different  board  makeup.,Conseguently, the  different  3,  and  4.  Table  3  the  4 the  of  to  the  are  test  Table  2  effect  effect  the  of  of  zero  but  from  attack 5651  for  P.  of  the  also,  of  by  the  under  adustus  .  not  only  apparently,  in  e.,  relative  to  differences  responses  carried  non-brominated  the  in  i .  were  It  brominated  patterns,  analyses  and  to  non-brominated  conditions  brominated  analysis  differences  boards  response  decay  the  the  major  ranging  near  loss  of  was  reveals  treatment-response treatment  2,  In  losses  l ncr as s at a  from  for  employed  data  weight  the  decay  Table  response  under  each  to  tool  respective  for  and  given.,,  their  separately  level  calculated  in Tables  are  analytical  and  clear  absence  leaching.  content,  methods  fungi,  monticola  ground initial  are  due  tabulated  weight  £s.  material  losses  A scanning the  the  factors  effect  basic  variance.  at  during in  AND D I S C U S S I O N  1.  moisture  The  i.e.,  weight  combinations  losses  blocks  correction  Percent  initial  test  Table  RESULTS  weight  conditions,  jars,  17.  in  out  material  for  fungus. The  planting  effects (I),  of  board  initial  composition  moisture  content  (C); of  leaching•prior the  test  blocks  to (M),  55  and  sterilization  Figure  3,  were  variance, and  also  Results  brominated  fungal  1,  growth  the and  four  fungi  of  the  any  the  resin  board  was  particleboard observed  a  resin  5).  but  in  largest  the  The decay from  of the  with  A  This  promoting  presentations  4 through  of  of  the  14,  between  leaching board  (Table  a  5),  more  decay. a  whether  fungi  or  or  (Table  phenolic  was the  cr  where  largest  for  (109), a  The in  boards  using resin,  weight  phenolic-glued  the  since  urea  the  without  not  2).  exception,  Stolley  situation,  Pers.  than  phenolic resin  clear  with  containing  observed  was  hardboard  significantly  by t h e  with  vajooraria  loss  caused  urea-glued  board  resulted  loss.  effect  in  for  polyethylenimine-treated  to  anomalous  non-brominated nitrogen  Visual  with  was  decay  either  weight  and  boards  resistance  P  non-brominated  decayed  non-brominated  CcnioBhora cerebella  board,  6  5 and  observable  a  similar  Tables  Figs.  P ,-versicolor  glued  in  analysis  content  was  before  greatest  diagram  i n an  non-brominated  leached  the  showed  the  2,  this  in  a bar  Hardboard  (Tables  fungus  case  the  non-brominated  white-rot  Y  presented  in  interactions  respectively.  moisture  polyethylenimine either  in  interaction  composition  presented  for  given  groups, are  (S),  tested  are  Composition of  Despite  D  method  the  of  p o l y e t h y l e n i m i n e on  boards  by  adhesive  four  of  (32%)  .  the  the  fungi  A similar  rate could  of result  conclusion  56  would  explain  the  apparant  urea-foroaldehyde wood-destroying The  the from  levels  these  in  Consequently,  for  of  accelerated  the  levels  was  of  nitrogen have  levels  no  in  very the  5  and  three  7  weeks  incubation.  be  consistent  with  where  show  the  by  P  chemical  effect  on  the  entity  the  potential  growth  bonded and  the  fiber-only  non-leached of  all ,  a  presented  herein  would  reduce  fungi  in contrast  process  unlikely  on  boards.  to  that  observed  phenol-formaldehyde r e s i n fungi  and  an  toxic  composition  board  materials  and have  been  any to This for  of  were  proposed  for  free  as  an  would  hardboard  phenols  affect  any  situation  with  particleboard attack  resin  by s e v e r a l  explanation  of  promoted  phenol-formaldehyde suggested  after  steam  impeded t h e  urea-formaldehyde  effcts  used  resulting  levels the  leached  fungus,  and  of  and  brown-rot  water  to  wet  (NL)  rates  non-brominated  by  These  116),  low.  decay  leaching  attack.  (50,  nitrogen  the  the  boards  the  effect  between  of  i n the  wood-destroying  the  providing  effects  remaining  where  low  extremely  significant  several  leaching  method, be  for  by  normally  high  of  The o b s e r v a t i o n s  hot-pressing  (120),  part  incrassata  A  during  is  as  difference  formation  hardboard  the  boards,  compositions  10  subsequent  are  would  phenolic-resin  decayed  production,  added a  wood of  observed  particleboard  production  boards  consistent  hardboards, of  pulp  of  in  because  effects  decay.  Figs.  groups  and  ftsplund  ncn-brcainated  boards. (L)  nitrogen  would  nitrogen  There  120).  experimental  any  decay  (109,  the  adhesive  overall  on t h e  sapwood)  resulting  an  fungi  residual  (excluding  of  resin  accelerating  resin  in  workers  for  the  57  r e s i s t a n c e t o decay with  phenolic Since  wax was i n c l u d e d among t h e p r e s e n t with  the phenolic  that the r e s u l t i n g  reduce i t s r a t e o f decay wax a d d i t i v e . T h i s there or  i n b o a r d w e t t a b i l i t y would  t o board m a t e r i a l s without  the  since  boards  with  decay t e s t ,  untreated  to attack  o u t by L e v i  metabolic  source  wood. A l s o ,  layers,  hardboard  by d e s t r o y i n g has a h i g h  general  c a n be r e g a r d e d  s u r f a c e area/volume r a t i o ,  ( 6 2 ) , which a l l o w s  higher  t o enzymatic a c t i v i t y  having  hardboards  on f u n g a l g r o w t h .  are manufactured  pressures  a r e used,  than i s the case  to penetrate  The c o n d i t i o n s  are g u i t e severe.  undoubtedly a f f e c t i n g  might r e n d e r  material  f o r f u n g i such  allowing  easier access  explain obtained  as w h i t e - r o t s ,  while  t o the carbohydrate  t h e wide d i s c r e p a n c y by u s i n g  the l i g n i n  brown-rot  makes  w a l l . The and h a s a  under  High  which  temperatures  the natural repositioned,  u n s u i t a b l e as food a t t h e same  material. This  between t h e w e i g h t and w h i t e - r o t  with  any p r o t e c t i v e  i s important  bonding agent i n f i b e r b o a r d s . L i g n i n i s probably not a l t e r e d . This  as  a c c e s s i b i l i t y of  t h e p r e s e n c e o f b r o k e n wood f i b e r s  of n u t r i e n t s i n hardboard  bearing  as  f u n g i , e s p e c i a l l y t h e brown-  the materials of a l l layers of the c e l l  availability  if  be  however, was n o t o b s e r v e d ,  a v a i l a b l e t o f u n g i , without  and  i t could  wax.  f u n g i . Hardboard  solid  reduction  relative  effect,  adhesive,  hardboard  under t h e c o n d i t i o n s a d a p t e d i n c o n t r o l l i n g  pointed the  bonded  Apparently,  vulnerable rot  plywood  was no c o n s i s t e n t d i f f e r e n c e i n d e c a y between  without  this  pressed  glues (91).  treatments along expected  e x h i b i t e d by f r e s h l y  loss  tiae may  values  f u n g i as the decaying  58  agents  2.  (Tables  2  to  4,  Bromination  of  the  3).  Bromination  hardboard  greatly  brown-rot  fungi  the  Fig.  more  than  increased (Fig.  non-leached  Asplund  3),  boards  its  with  being  3%.  Leaching  on  the  non-brominated  increased  the  average  effect  18%  weight  leaching boards.  earlier at  Asplund  wood pulp  occurred The attack  either two  can  brominated  This  in  was  formation  to  expected, of  the  Figs.  or  puteana is  and t h e i r  the of  on  little  to  about how  monticola, than  .  an  brominated  In  that the  those  observed  latter  used  negligible  herein  leached  Figs.  9  and  brominated  versicolor  just  to  for  decay  the losses  leaching.,  employed  in  50%  demonstrates  less  to  after  for  had  and  similar  experiment,  four  losses  boards  growth  levels  be  bromhydrins  mycelial  8  (31)  either  since  and  the  of  significantly  Frydman  boards,  P.  decay  wood b y  fungi  seen  but  6  by  weight  brominated  hardboard,  present  white-rot  exposure  of  manufacture  more t h a n  before  material,  b y C__  spruce  decay  from  boards  decay  before  boards  decay  to  the  also  to  and  bromination  brcminated  2).,This  after  solid  resistance  decay  bromination of  for  the  the  Resistance by  to  reduced  the  decay  prior  average  Comparison of  affected  imparted  case,  loss.  of  pulp  and  P.  and  unable  or  non-leached  11  where  both  counterparts adustus  bromination of lignin  were  also  .  wood  to (Table  non-  are  shoun  respectively. results  lignin  in  oxidation  the  59  with  the  assumed the  production that  decay  these  by  utilization cellulose  hydrobromic  reactions  white-rot of  by  both  the  hydrochloric supposedly  of  than  lignin  latter  acids,  would  and  The  by the  hydroxide  following bromination.  generated  and  and  presumably  blocks toxic  used  14  in  these  material.  boards,  although fungi,  The  attacked  following  days  increase  similar  which  presumably of  lignin.  bromhydrins  of  lignin  systems thirds  of the  the rate  of  such  effect  the  bromine  Of c o u r s e , hemicelluloses,  (57)  a  suggests  which  was  also  atom  are  and,  boards  reaction is  is  attacked known,  known t o  be  in  brominated 3%  of  to  18%  these  acids,  white-rot by  the  the  the  cellulase by  by t h e s e  fungi.  although  the  twoThe  toxic  (31).  the  extremely  during the  this  reducing  recognized  results  of  of  that  with  leachable small  about  therefore,  not  well  also  created  possible  are  acids  most  the  only  calcium  repressed  interfering  fungi of  for  the  lignin,  the  removal  with  and  be  loss  from  observed  considerably  are  should  weight  the  of  the  of  was  and  of  of  remove  fungi,  w o u l d seem  bromination  conditions  bromine  hydrolysis labile  to  of the  liberation  step  . Therefore,  and  It  decay  for  hydrolysis  are  brown-rot  mechanism of  4)  response  brcmhydrins  decay  brown-rot  (Fig.  any  of  former  oxidation  leaching  should  in  because  addition  it  seriously  hydrobromic  hot-pressing  cold-water  more  by t h e  However,  experiments  by t h e  leaching no  after of  free  during the  (neutralized)  Therefore,  fungi,  cellulose  fungi.  remaining  (57).  interfere  brown-rot  produced  removed  acid  also  prior  leaching to  decay  during testing  hot-pressing  of  the  hardboard  would r e s u l t  in  losses  of  sugars  60  otherwise  available  of  source  a  food  brominated The decay that  also  boards  to  stronger  process seme  as  a  food  could fungi  source  help  white-rot  synergistic  of  than  effect  lignin  which s i m u l t a n e o u s l y  react  lignin.  The n e a r - z e r o  loss  brcminated cellulase the  boards system  seems is  also  because  of  substrate  by  cellulose  and l i g n i n  •|i  trabea-,  a  decay  losses  weight  be  depicts  on t h e  made the  Thus,  the  that  the  effect  of  of  decay  the  suggest  and on  activity  in a d d i t i o n to  the  enzyme  cellulose  of  interaction  understandably  simultaneous  of  been  modification of  the  removal  lignin of  difficult. fungus,  was  found  g r o w i n g on b r o m i n a t e d almost  with other  may a l s o  separate  white-rot  to  be  board,  n e g l i g i b l e compared  non-brominated counterpart.  also  three  brown-rot  b r o m i n a t i o n on t h e  with  Similar  of  its  those  comparisons  fungi.  growth  where  Fig. L.  10  trabea  .  leaching  Leaching boards 1%.  were  in  extensive  brown-rot to  with  which has  becomes  sensitive  produced  the  bromination,  surprisingly  3.  retarded  removal  resistance  fungi  between  indicate  l i g n i n - d e g r a d i n g enzyme  inactivated  can  to  the  This  brcmhydrins with  brown-rot  systems  fungi.  decay.  exists  weight  the  explain  causing  interference  by  to  for  for  resulted  However,  in  14  days  of  in dry-weight similar  the  three  losses  leaching  of  types  before the  of  non-brominated  decay  brominated  of  less  boards,  than the  61  fiber  only,  fiber  polyethylenimine 8,7  and  8,81  expected, Paszner  phenolic  resin  (Table  boards,  1),  following the  incubation  loss  on  period  created  seme  resulted  in  work  even  though  condensation additional  values  obtained and  leaching  on  degree  readily  the  observable  These  be  soluble  expected salts,  pressing, be  of  plus losses  weight  (31)  and  products  expected  to  larger  formed  in  the  be  the  of  7.0,  losses  were  Jurazs  soil  jars  Table  and  The  are  reasonably  various  stages  residual  acids  and  retained small  and  pressing  in  have  the the  of  weight testing  board  f u n g i employed  board  is  the  with  the  facts  manufacture, products  soluble  the  boards  involved.  environment  consistent  as  high-temperature  boards  following  these  materials  of  untreated  boards,  soluble  compounds  additional  the  the  6.  amounts  generated  amount  by  reaction  within  was  of  effects  of  other  during  and might  stages  and  5,  agent  1 tabulates  various  2,  occurred  incubation  biodegradation  remove  organic  also  biological  planting.  Tables  the to  no  within  in  While r e l a t i v e l y  considerably be  after  in  during  decomposition  could  Such  board  leaching.  observations  water,  would  fiber  dry-weight  Frydman  d u r i n g the  before  would  of  brominated  process,  that  gave  and  respectively.  h i g h l y humid c o n d i t i o n s  loss  resin  (57) .  Height  The  plus  made  of  hot-  brominated  fibers. Leaching subseguent resulted result  in  was  of  rate  the of  non-brominated  attack  significantly obtained  by P f  versicolor  increased  by D a C o s t a  boards  and  weight Osborne  only ,  affected  where  the  leaching  loss.  A similar  (25),  using  Douglas-  62  fir  blocks,  losses  where  by a b o u t  the  increase  the  present  Asplund seemed which  25%  was  leaching  the  other the  increased  JP.  6%.  was  fungi  ,  relative whereas  Although  the  14  days  of  materials  toxic  were  sensitive.  brominated  less  boards  has  weight ..trabea; -  woodpulp used during  cold-water  to  been  decay  with  c o n s i d e r a b l y washed  subseguent  some  the  versicolor  about  experiments  remove  the  for  only  process, to  leaching  in  the leaching  ^versicolor  ,  but  The s i g n i f i c a n c e  discussed  under  to of  the  "Brcmination". Interestingly, of  Frydman  losses  (31)  on t h e  regardless present three though  whether  of  the  a  good  shows  exposed a  very  Therefore, water  possible wetting  means  indoors  attack of  the  leaching especially  in to  decay  would  waters  example  brominated  be  or were  water  resistance high  to  leached  during  out  boards  are  sealed they  or  In  4%, the  recorded  for  leaching  of  the  if  non-  following  the  fungi, boards  Fig.  12  effect. protected  should  maximum e f f e c t i v e n e s s fungi  3 to  not.  service. leaching  by w o o d - d e s t r o y i n g  weight-  brown-rot  the  service,  those  remained n e g l i g i b l e .  of  exterior retain  fungi  relatively  resistance leaching  unless  while  is  20%  following  decay  exceeded  removed  over  white-rot  that,  significant  b y some  preferably  to  the  of  contradict of  rarely  were  fungi  data  magnitude  wood s a m p l e s  boards  the  the  weight-losses  indicate  of  present  leachables  with  brominated  the  that  brown-rot  losses  part  become  the  decay four  Results leached  who f o u n d brominated  study  out  however,  be  from  used  against limited  board., also  after  contributes  14-day  soaking  to in  the  swelling of  water.„Swelling  hardboard, can  result  in  63  opening  of  cellulose and, of  any or  thus,  surface  (57)  to  only  area/volume  all  for  the  at  least  P.  versicolor  at  the  C.  Scots below  authors  enzymatic The  poor  attack response  by  resin  disintegration  of  fibers  and  leaching.  5,  for 6).  decay  were  increase  in  the  and  four  when  moisture  pine 20%  and/or initial  suggested  hardboard  from  lay  was  fungi  and a  the  below  equilibrium its  and  decay  at  20%  theories (presumably attack  burial even  on  blocks  those  little  findings that,  fungus  those  with  vermiculite  and  the  hardboard  showed  20%  visible  of  results  who u s e d  M.C. in their  the  were  significant,  clearly  mycelium  ,  initial  when t h e y  compared  with  spruce)  well  the  up a n d o v e r g r o w  (36)  conditions,  if  rate  was  trabea  t  ^on-brominated  brown-rot  the  content  conflicts Savory  8% t h a n  decay  by L  either  rates  The e f f e c t  period,  result  boards  decaying  quickly fluffed  atmospheric  for  boards  level,  initial  by G r a n t  saturated  the  (Tables  14). T h i s  content  5%  strips  puteana  These  3).  the  low  from  tc  the  improvement  brominated  higher  incubation  feeder  made  making  losses.  serious  gave  boards,  This  proposed  the  when  Tab.  (Fig.  increase  fungi,  (Fig.  a  wall,  accessible  strength  of  of  having  board  decay  contents  the  cell  weight  under  moisture  during  more  ratio  brown-rot  brominated  3,  the  Content  Except almost  in  in higher  fibers can  voids  complex  resulting  flcisture  4.  or  lignin  brominated  addition  minute  test.  under  moisture  threshold.  by  ea  Observations rot  fungi,  would  including  suggest  laboratory hardboard 100%  that  decay  relative  made  test  results (12)  for cn  particleboard. and  solid  different  due  to  decay  The fungal  effect  active  this  the  to  12  M . C . and in  the  may h o l d  or  i t  whole was  rapidly  wetted  responses  normal  under  rapidly  when  equilibrium  two  true  the  M.C.  at  only  one  content  growth  stages  fungus  period  if  surface  the  guite  of  of  resin  the  to  level  three seemed  on  stages for  glossy  the  of  a  bigger  facilitate  or  the  development  answer  to  was u s e d .  As  conditions protective  design  such  area/volume  by v a r y i n g w e a t h e r  especially  be  The e x p e r i m e n t a l  conclusive  high  non-wetted  i n i t i a l M.C,  the  find  a  in  stimulate  period.  using  and b r o o i n a t e d ,  early  incubation  has  affected  easily,  to  fungi  the  incubation  losses,  itself.  at  the  pre-wetting  amount  wood  differences  only  a  over  could  size,  the  moisture  observations  particleboard,  white-rot  may a f f e c t  unable  weight  of  non-brominated to  where  decay  of  from  times  particle  low i n i t i a l  hardboard  be  the  both  out  be  much a s  by  as  earlier,  least  differ  fungal population i n early  test  brown(36),  its  decay  by as  unrelated of  also  modification  suppositions  will  than  four  and S a v o r y  more  particleboard,  may a c t u a l l y  attack;  throughout  M.C. less  variations  and  activity  further  for  ,  rates  incubation,,It more  at  occurs  subseguent  wood  hardboard,  inconsistent  involving  by G r a n t  hardboard,  hardboard  the  and c h e m i c a l  of  a  However,  hardboard  types  used  of  spruce  trabea  t  The  one  conditions,  has  increased  fungus L ,  binders  the  experiment  humidity.  by B e h r  procedure  present  attack  initially  These  the  from the  pointed  ratio, and  it will  surface  65  wears time  away  or  is  removed  required  to  reach  creating  initially  5,  the for  the  equilibrium  disparity the  of  blocks.  case may b e  at  the  moisture  If  so,  here.  Therefore,  within  early  stages  conditions  the  answer  first  the  few  and,  days,  thus,  superimposed  might  lie  in  the  hypothesis.  S t e r i l i z a t i o n Method  With P.  was  eguilibrium conditions  offsetting  former  as  non-brominated  yersicclor  oxide  or  wet  incubation  gave heat  (Table  significantly ethylene Figure  13).  pondercsa effects  used  pine  to  that  With  brown-rot  using  P  heat was  heat.  with  studies, (100), oxide  in  a  the  losses those  about  4,  seem  differed in blocks  using P  blocks  wet  heat  versicolor  A  to  wet-heat  as  sterilizing of  before giving  (Table  difference  strain  ethylene  sterilized  no  5*  decay between  M]  the  agents,  versicolor  P  using  was  tests. ethylene more  with  sterilization  susceptible  3).  more  that  oxide  similar  Figure  one-third  would  whether  find  present  6,  except  losses,  with  using  hardboard,  (Tables  weight  different  compared  fungi  versicolor  could or  all  s t e r i l i z i n g the  significantly  fungi  It  t  weight  study  material  loss wet  Only  brominated  four  weight  H).  wood  used  the  wet  for  compared  that  made  using  used  ethylene  in  decay  was  Previous  of  although  similar  greater  oxide  hardboard,  the  strong  decay  by  the  sterilized  The i n c r e a s e  than  the  boards  to  values  in  decay  obtained  alkylating  effect  66  of  ethylene  generated decay  oxide  by  weight  is  interfering  with the  b r o m i n a t i o n of  the  losses  white-rot  for  the  Asplund  pulp. .Considering  fungi,  differences  being formally s i g n i f i c a n t  for  mean  loss  are  weight  therefore,  rather  conclusions.  values low  to  for  both  form  the  fungitoxicity  fungi basis  for  in spite  the  of  these  versicolor  the  a l l any  less  than  strong  2% a n d ,  67  CHAPTER  Hardboards deterioration that  some o f  board the  decay  testing  the  as  sometimes  f u n g i and  as  bacteria.  well  as  methods.  there  were  no  soil-jar  method,  technigue  It  specific of  of  to  recognized  differences  adapted fungi  in  in  controlling  may a l s o  f u n g i recommended  be  for  hardboard.  modified from  for  resistant  now b e e n  reflect  conditions choice  highly has  results  The  biodegradation  suitable  considered  contradictory  testing  the  The a  by  composition  important  be  are  V . .. C O N C L U S I O N S  evaluating  ASTH the  D1413-76,  decay  proved  resistance  to  of  hardboard. Bromination results decay is  in  by  a  sensitive was  about  to  negligible board.  the  white-rot  the  is  the  enzymes  of  the  at  least  common  of  lignin  source  of  as  food,  through  been  was  weight  decayed  not  at  a l l .  bromination  board i .  very  non-  tested  the  of  decay  boards  treated  substrate,  has  its  fungi  brominated  the  period  on  e.,  altered,  against lignin,  rendering  inactive. ,  Leaching  can  cause  drastic  decrease  in  to  resistance  L«_ t r a b e a  produced  of  resistance  this  where  white-rot  formed  the  14-day  fungus  that  high r e s i s t a n c e fungi  times  board,  and  production  although  The  with  slightly  16  following a  brominated  two  hardboard  fungi,  board.  compared  decaying main  for  times  the  on  boards  may e x p l a i n  which  four  The  bromhydrins  has  pulp  brown-rot  growing  non-brominated  pulp  which  leaching  brominated  The  Asplund  common  to  cold-water  loss  board  four  reduced  of  resistance  created  of  68  by  bromination.  sealed  I t seems t h a t , u n l e s s t h e t r e a t e d b o a r d i s  o r p r o t e c t e d from  water by seme means i n s e r v i c e , i t  s h o u l d be used p r e f e r a b l y i n d o o r s t o r e t a i n effectiveness against T h e r e was l i t t l e  decay. difference of practical  decay r e s i s t a n c e c f h a r d b o a r d with  made e i t h e r  phenolic or polyethylenimine  evidence  suggests  boards s l i g h t l y  maximum  importance  without  adhesive  adhesive or  p l u s wax. However,  that addition of polyethylenimine  more s u s c e p t i b l e t o d e c a y  i n the  made t h e  by s e v e r a l o f t h e  fungi, H a r d b o a r d s a m p l e s c o u l d be s t e r i l i z e d oxide  o r wet-heat, a l t h o u g h  bromhydrins of l i g n i n rapid low  decay o c c u r r e d  culture  jars.  some i n t e r a c t i o n  and e t h y l e n e  oxide  when t h e h a r d b o a r d  (8%) i n s t e a d o f h i g h  with e i t h e r  ethylene  between t h e  was s u g g e s t e d .  The most  samples i n i t i a l l y had  (20%) M.C. upon b e i n g p l a c e d  i n the  69  LITERATURE  S.  CITED  1.  Akai,  and Ueyama, A. 1960. S t u d i e s on t h e m i c r o b i a l s t a i n and decay o f b u i l d i n g boards and t h e i r p r e v e n t i o n . I . F o r c e d - d e c a y t e s t s on b u i l d i n g b o a r d s u s i n g some w o o d - d e s t r o y i n g f u n g i . J. Japan Wood R e s c h . S o c . 6 (3): 128-132.  2.  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Pollut D e t e r i o r a t i o n and i t s Treatments, Nicholas, II. Preservatives and Syracuse Univ. Press, 395. E . B. using 183.  OSDA  ion control. I n : Wood Prevention by Preservative D. D, (Ed.) 1 s t E d . , V o l . Preservative Systems. S y r a c u s e , N. Y. pp. 345-  1971. E v a l u a t i o n o f wood preservatives crushing strength. Phytopathology 61:  182-  ___••,' 1 9 7 3 . Oxygen u t i l i z a t i o n and weight loss associated with d e c a y by wood—decaying f u n g i . Wood S c i . 6(1): 55-60,  f  116.  , B a r n e s , H . M. 1974. Biodeterioration of particleboard. Forest Prod. J. 24 ( 1 0 ) : 55-57.  117,,  1975. O x y g e n u t i l i z a t i o n by d e c a y f u n g i t h e e v a l u a t i o n o f wood p r e s e r v a t i v e s . , F o r e s t Prod. J . 25(7): 46-48.  118.  Urbanik,  for  E. 1969. Investigations on t h e p r e s e r v a t i o n o f p a r t i c l e b o a r d and f i b e r b o a r d a g a i n s t f u n g i and insects. Duncker and Humblot, B e r l i n . M a t . und Org. Suppl. 2: 95-102.  79  119.  Wilcox,  120.  H i l l e i t n e r , H. 1 9 6 5 . , T h e b e h a v i o r o f wood particleboards u n d e r a t t a c k by B a s i d i o m y c e t e s . Part I. Decomposition of p a r t i c l e b o a r d s by B a s i d i o m y c e t e s . Holz Boh- Werkstoff 23: 264-271.  121.  •  122.  Zabicky,  123.  W. W. 1973. D e g r a d a t i o n i n r e l a t i o n t o wood structure. I n : Wood D e t e r i o r a t i o n a n d i t s P r e v e n t i o n by P r e s e r v a t i v e T r e a t m e n t s . Nicholas, D. D . ( E d . ) 1st E d . V o l . I . D e g r a d a t i o n and Protection o f Wood. Syracuse Univ. Press, Syracuse, New Y o r k . pp. 107-148.  .,„_____ . 1966. Uber den durch M o d e r f a e u l e p i l z e . 77-88.  ftbbau v o n H o l z s p a n p l a t t e n M a t . und O r g . S u p p l . 1:  J. 1967. The c h e m i s t r y o f b r o m i n a t i o n o f wood. III. Main paths o f bromine c o n s u m p t i o n . , , Israel J, Chem. 5: 146.  Weight losses of test blocks during the preparation period and under comparative control situation i n s o i l jars during incubation.  Table 1.  HARDBOARD COMPOSITION •.-.-.•V , ' -f ;  PROCEDURE : 1  Before Planting  After Planting  :  7  FIBER ONLY  FIBER & PHENOLIC RESIN & WAX  FIBER & PEI RESIN & WAX  Non-Brominated  Brominated  Non-Brominated  Brominated  Non-Brominated  Brominated  NL-S-MH  1  0.3  3.2  0.5  3.7  0  4.0  L-S-MH  2  0.7 / ;  7.0  0.9  8.7  0.1  8.8  L-S-ML  3  0.9  7.6  1.2  9.6  0.5  9.3  L-EO-ML  4  0.6 .  6.8  0.7  7.4  0.2  6.6  NL-S-MH  .1  0  3.6  0  4.8  0  6.8  L-S-MH  2  0  1.7  0  2.3  0  4.3  L-S-ML  3  0  0.7  0  2.2  0  3.9  L-EO-ML  4  0  0.3  0  1.5  0  1.6  1  For procedures 1, 2, 3, 4 refer to Figure 2.  Table 2.  Effect of leaching on the resistance to decay of non-brominated and brominated hardboard. Decay weight losses i n percent.  HARDBOARD COMPOSITION HARDBOARD TREATMENT  FUNGUS  Noh-Brominated Non-Leached (NL) Leached (L) NL L NL  Coniophora puteana  Lenzites trabea  Poria incrassata  L NL  Poria mentiaola  L NL L NL  Polyporus adustus  Polyporus versicolor  FIBER & PHENOLIC RESIN &.WAX  FIBER ONLY Brominated  Non-Brominated  Brominated  FIBER & PEI RESIN & WAX Non-Brorainated Brominated  38.2  10.0  39.6  6.6  37.6  7.9  40.0  25.7  34.6  13.6  39.4  19.3  58.5  2.2  59.3  1.0  63.5  1.2  54.6  2.4  56.9  1.0  63.6  0.1  50.8  0  53.2  0.1  60.9  7.4  54.8  32.4  52.3  58.9  25.6  50.1  0  55.8  1.0  58.8  0.8  49.3  26.5  53.7  26.2  57.8  17.3  0.8  0  0.4  0.9  0.3  0.3  0.7  1.2  10.2  1.8  9.6  0  4.2  0.6  1.2  0.3  15.8  0  10.6  0.4  8.6  0.2  27.9  7.3  1.1 OO  E f f e c t o f t h e i n i t i a l m o i s t u r e c o n t e n t o f l e a c h e d , non-brominated and brominated h a r d b o a r d on i t s r e s i s t a n c e t o d e c a y . Decay w e i g h t l o s s e s i n p e r c e n t .  T a b l e 3.  HARDBOARD COMPOSITION HARDBOARD TREATMENT  FUNGUS FIBER & PHENOLIC RESIN & WAX  FIBER ONLY  FIBER & P E I RESIN & WAX  Non-Brominated  Brominated  Non-Brominated  Brominated  40.0  25.7  34.6  13.6  39.4  19.3  41.9  28.0  38.3  29.2  45.6  27.4  54.6  2.4  56.9  1.0  63.6  0.1  57.6  6.1  62.7  0.3  63.8  0.4  54.8  32.4  52.3  27.9  58.9  25.6  54.6  38.6  55.4  32.0  62.2  27.9  49.3  26.5  53.7  26.2  57.8  17.3  8  56.8  39.9  59.3  42.4  59.5  33.9  20  0.3  0.3  0.7  1.2  10.2  1.8  0.1  0.9  0.1  0.1  6.6  1.4  15.8  0  10.6  0.4  8.6  0.2  14.0  1.2  6.7  1.4  14.8  1.3  I n i t i a l 20 Moisture Content  Coniophora puteana  8 20  Lenzites trabea  8 20 Poria incrassata 8 20 Poria monticola  8  Polyporus actus tus  20 Polyporus versicolor 8  Non-Brominated  Brominated  OO  E f f e c t o f method o f s t e r i l i z a t i o n o f l e a c h e d , non-brominated and brominated h a r d b o a r d on i t s r e s i s t a n c e t o decay. Decay w e i g h t l o s s e s i n p e r c e n t .  T a b l e 4.  HARDBOARD COMPOSITION TMATMEOT TREATMENT  F  U  N  G  U  FIBER FIBER ONLY ONLY  S  Non-Brominated Sterilization Method* EO  Brominated  F  I  B  E  R  &  P  H  E  N  0  L  I  FIBER & P&E IWAX RESIN  C  RESIN & WAX  Non-Brominated  Brominated  Non-Brominated  Brominated  38.3  38.5  39.7  43.6  42.9  35.9  41.9  28.0  38.3  29.2  45.6  27.4  57.7  9.7  59.0  5.3  64.3  3.4  57.6  6.1  62.7  0.3  63.8  0.4  53.3  46.2  55.2  44.8  60.6  37.6  54.6  38.6  55.4  32.0  62.2  27.9  57.4  49.3  57.0  50.5  60.2  35.5  56.8  39.9  59.3  42.4  59.5  33.9  0.0  0.8  0.0  0.8  0.4  0.5  0.1  0.9  0.1  0.1  6.6  1.4  17.3  0  13.9  0.4  20.3  0  14.0  1.2  6.7  1.4  14.8  1.3  Coniophora puteana S EO Lenzites tvabea S EO Porta inorassata •S EO Porta montiaola S EO Polyporus adustus S EO Polyporus versicolor *  EO - e t h y l e n e o x i d e under vacuum;  S - wet heat (121°C)  Table 5.  S t a t i s t i c a l evaluation of the decay results for non-brominated  Coniophora puteana  Source DF Composition (C) 2 S t e r i l i z a t i o n (S) 1 Moisture Content (M) 1 Leaching (L) 1 C xS 2 C xM 2 C xL 2 36 Residual  MS 43.60 16.17 91.65  1.45 14.10 9.33 30.83 14.79  Sign  2.95 1.09 6.20* 0.10 0.95 0.63 2.09  DF Composition (C) S t e r i l i z a t i o n (S) Moisture content (M) Leaching (L) C xS C xM C xL Residual  2 1 1 1 2 2 2 36  MS  F  Lenzites trabea MS  F  Poria incrassata Sign  183.66 47.50*** 6.10 1.58 53.10 13.70*** 25.22 6.52*. 11.35 2.93 16.25 4.20* 8.18 2.12 3.87  Poria montioola  Source  NOTES:  F  hardboard.  MS  127.59 39.70*** 0.63 0.20 146.52 45.60*** 10.27 3.20 6.17 1.92 17.33 5.40* 0.91 0.28 3.21  MS .  F  Sign  259.83 231.30*** 6.62 5.89* 26.67 23.70* 0.60 0.59 + 0.90 1.01 7.68 6.83** 19.80 17.60*** 1.12  Polyporus adustus Sign  F  Polyporus versicolor Sign  25.96 19.00*** 39.02 3.84 13.50 1.33 + 5.32 0.52 + 19.73 1.94 6.86 0.68 6.26 0.62 10.15  MS  F  Sign  113.85 24.80*** 172.81 • 37.60*** + 0.02 0.09 266.00 57.90*** + 7.36 1.60 56.00 12.20*** 0.83 0.20 4.60  * Significant at 5% level ** Significant at 1% level *** Significant at 0.1% level + means weight losses greater with ethylene oxide, higher moisture content and leaching than with wet heat, lower moisture content or non-leaching respectively; - means opposite to +.  Table 6.  S t a t i s t i c a l evaluation of the decay results for brominated hardboard.  Source DF Composition (C) 2 S t e r i l i z a t i o n (S) 1 Moisture Content (M) 1 1 Leaching (L) C xS 2 2 C xM 2 C xL Residual 36  MS  F  Sign  37.27 1.06 742.59 21.20*** + 453.27 12.90*** 771.20 22.00*** + 18.64 0.53 89.59 2.55 38.51 1.10 35.09  MS  DF 2 Composition (C) S t e r i l i z a t i o n (S) 1 Moisture content (M) 1 Leaching (L) 1 C xS 2 C xM 2 C xL 2 Residual 36  MS 309.50 244.48 1418.34 3148.75 35.04 5.83 64.58 21.83  F  F  Poria inorassata Sign  66.65 38.40*** 88.94 51.20*** + 7.59 4.37* 0.48 0.28 2.16 1.25 10.42 6.00** 1.17 0.67 1.74  Poria montioola  Source  NOTES:  Lenzites trabea  Coniophora puteana  MS  14.20*** 11.20** + 65.00*** 144.20*** + 1.61 0.27 2.96  MS  F  2.12 12.40** 0.07 0.41 0.57 3.33 1.22 7.10* 1.13 6.57** 1.30 7.60** 0.09 0.53 0.17  Sign  89.60 8.32*** 604.01 56.10*** + 109.23 10.15** 4089.87 379.87*** + 13.79 1.28 7.92 0.73 105.93 9.84*** 10.77  Polyporus versicolor  Polyporus adustus Sign  F  Sign + +  MS 1.41 14.26 7.48 0.00 0.32 0.01 0.08 0.17  F  Sign  8.18** 87.70*** 43.40*** 0.02 1.83 0.06 0.49  * Significant at 5% level ** Significant at 1% level *** Significant at 0.1% level + means weight losses greater with ethylene oxide, higher moisture content and leaching, than with wet heat, lower moisture content or non-leaching respectively; - means opposite to +.  Sofedutf from chip icretn Sowtfusf ond borh  CHI OTTJrjJTJ fTTD LTJIJ LLLD LLUJ tTTn  Bffl B l M BH  ^T~~,  Bolttr plant  Pulp  KreenfA  F^Z7>  J  I  i 1  f c r » « n t d pulp j .  igc3__J__l RottMMtor-  Oisinttgrofor for over»iz« chip*  f Pulp  jthicktner  Wood chipper |  t  JIv 5|y §ld Pylp chvtlt  DischOfQing rock  Trun—mg towt  Figure 1.  Sler>9<  Production of thermomechanical pulp.for hardboard according to the Asplund method (Defibrator B u l l e t i n ) ( 8 8 ) .  "87  3  4  ovendrying  ovendrying  ovendrying  No-leaching  leaching 2 weeks  leaching 2 weeks  leaching 2 weeks  ovendrying  ovendrying  ovendrying  ovendrying  vacuum, 1 hr; soak,overnight  vacuum, 1 hr; soak,overnight  vacuum, 1 hr; soak,overnight  vacuum, 1 hr; soak, o v e r n i g h t  ventilate to  ventilate to  ventilate to  ventilate to  20% M . C .  20% M . C .  20% M . C .  20% M . C .  autoclave 121°C 30 m i n .  autoclave 121°C 30 m i n .  autoclave  ethylene oxide  planting  planting  1  2  121°C 30 m i n .  ventilate to 8% M . C .  planting  Note:  F i g u r e 2.  25°C  ventilate to 8% M . C .  planting  D o u b l e frame i n d i c a t e s p o i n t s o f n o t a b l e d i f f e r e n c e s among treatments.  Sample p r e c o n d i t i o n i n g p r o c e d u r e f o r i n c u b a t i o n .  88  CAPTIONS  Fig,  3  Bar d i a g r a m o f a v e r a g e w e i g h t l o s s v a l u e s showing t h e e f f e c t s o f l e a c h i n g , i n i t i a l m o i s t u r e c o n t e n t , and method o f s t e r i l i z a t i o n on t h e d e c a y o f n o n - b r o m i n a t e d and b r o m i n a t e d h a r d b o a r d by b r o w n - r o t and w h i t e - r e t fungi. (NB = n o n - b r o m i n a t e d , B = NL = n o n - l e a c h e d ,  L =  brominated,  leached,  S = wet-heat s t e r i l i z a t i o n , sterilization, MH = i n i t i a l m o i s t u r e moisture content  Figs.  4 through  EO = e t h y l e n e  c o n t e n t 20%, HL = 8% ).  oxide  initial  14 :  Decay by v a r i o u s f u n g i  o f hardboard  b l o c k s made o f :  f i b e r o n l y , n o n - b r o m i n a t e d (1) and i t s b r o m i n a t e d c o u n t e r p a r t (4) ; f i b e r p l u s 1% p h e n o l i c r e s i n and 0.30% wax, n c n brcminated (2) and i t s b r o m i n a t e d c o u n t e r p a r t ( 5 ) ; f i b e r p l u s 1% p o l y e t h y l e n i m i n e r e s i n a n d 0.3031 wax, n o n - b r o m i n a t e d (3) and i t s b r o m i n a t e d c o u n t e r p a r t ( 6 ) ; non-leached sterilization initial using  (NI) and l e a c h e d by w e t - h e a t  moisture  content  the s o i l - j a r  (L) ;  (S) and e t h y l e n e o x i d e ( E O ) ; 20% (H) and 8%  technique  (L) ,  and m i t e - p r o o f  lids.  89 •  BROWN -ROT FUNGI,  NB  NL—S—MH L-S-MH  B  N L-S-MH L-S-MH EFFECT OF LEACHING  WHITE -ROT FUNGI  BROWN -ROT FUNGI  WHITE -ROT FUNGI  BROWN — ROT FUNGI  WHITE -ROT FUNGI  NL-S-MH ] L-S-MH  NB  B  1  NL-S-MH L-S-MH  L-S-MH L-S-ML  NB  L-S-MH|  B  NB  1  ?  L-S-ML  EFFECT OF MOISTURE CONTENT  L-S-MH L-S-ML L-S-MH L-S-ML  NB  L-EO-ML L-S-ML  B  L-EO-ML L-S-ML  NB  1  ?  EFFECT OF STERILIZATION METHOD L-EO-ML L-S-ML L-EO-ML L-S-ML  B  10  20  30 W E I G H T  F i g u r e 3.  Bar  40 L O S S  d i a g r a m shewing decay a f f e c t e d  50  60  (%)  by d i f f e r e n t  factors.  70  F i g . 4.  Comparison t o show t h e e f f e c t s o f b r o m i n a t i o n and l e a c h i n g on decay by Poria incrassata .  F i g . 5.  Comparison t o show e f f e c t o f b o a r d c o m p o s i t i o n on decay by Poria incrassata g r o w i n g on non-brominated and n o n - l e a c h e d b o a r d s .  F i g . 6.  Comparison to show effect of board composition on decay by Poria incrassata growing on brominated and non-leached boards.  F i g . 7.  Comparison t o show e f f e c t of board c o m p o s i t i o n and l e a c h i n g on decay by Poria incrassata growing on non-brominated b o a r d s .  F i g . 8.  Comparison t o show e f f e c t of board c o m p o s i t i o n and l e a c h i n g on decay by Poria incrassata growing on b r o m i n a t e d b o a r d s .  F i g . 9.  Comparison to show e f f e c t of b r o m i n a t i o n on decay by Polyporus v e r s i c o l o r growing on non-leached boards.  F i g . 10.  Comparison t o show e f f e c t o f b r o m i n a t i o n on decay by Lenzites trabea g r o w i n g on leached boards.  F i g . 11.  Comparison t o show e f f e c t o f b r o m i n a t i o n on decay by Polyporus adustus growing on leached boards.  95  F i g . 12.  Comparison t o show e f f e c t of l e a c h i n g on decay by Coniophora puteara g r o w i n g on brominated boards.  9 6  Comparison t o show e f f e c t o f i n i t i a l m o i s t u r e c o n t e n t o f b l o c k s on decay by Poria montioola growing on l e a c h e d and b r o m i n a t e d b o a r d s .  

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