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Synthesis, structure, and properties of phosphorus-containing flame retardants

University of British Columbia

Phosphorus-containing flame retardants were synthesized and a variety of strategies for rendering them non-leachable were investigated. Chapter 1 gives a history of flame retardants, with a focus on the issues associated with their usage. An introduction to the mechanisms of flame retardancy and the effect of flame retardants on the thermal degradation of polymeric materials is also given. An overview of the different methods of incorporating phosphorus-containing flame retardants into polymeric materials is included. Chapter 2 described the synthesis of a poly(methylene phosphine) and its oxide by the addition polymerization of MesP=CPh₂. These polymers are moderately effective non-leachable flame retardants when tested by thermogravimetric analysis, Technical Association of Pulp and Paper Industry (TAPPI) Standard Method T461 cm-00, and Limiting Oxygen Index (LOI). The C-H activated microstructure of two poly(methylene phosphine)s, synthesized by the anionic polymerization of ArP=CPh₂ (Ar = 2,4,6-trimethylphenyl, Mes; 2,6-dimethylphenyl, Xyl), is investigated in Chapter 3 using model chemistry and NMR spectroscopic analysis. A mechanism for the anionic polymerization of phosphaalkenes in which a C-H activation occurs is proposed based on kinetic studies, isotopic labelling, and theoretical calculations. The synthesis of the molecular cyclophosphazene-based flame retardant hexakis(2-aminoethyl)aminophosphazene is reported in Chapter 4. This phosphazene is an effective yet leachable flame retardant for paper when tested by thermogravimetric analysis, TAPPI Standard Method T461 cm-00, and LOI. An attempt to covalently link hexakis(2-aminoethyl)aminophosphazene to carboxylates in pulp via carbodiimide coupling is described in Chapter 5. While unsuccessful, carbodiimide coupling can be employed in the synthesis of several simpler phosphazene-amide derivatives. In Chapter 6, a non-leachable flame retardant treatment for paper using hexakis(2- aminoethyl)aminophosphazene and sodium carboxymethyl cellulose is described. The efficacy of the treatment is evaluated by TAPPI Standard Method T461 cm-00, LOI, and SEM-EDS. The solid precipitate formed in the reaction between hexakis(2-aminoethyl)aminophosphazene and carboxylmethyl cellulose is studied using solid-state CP/MAS ¹³C NMR and IR spectroscopy, and the interactions between hexakis(2-aminoethyl)aminophosphazene and carboxylmethyl cellulose is modelled using an ammonium-containing phosphazene and carboxylate salt.

Text

2019-02-28

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/60397

Chemistry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/