The role of fibre size in highly alkaline peroxide treatment of thermomechanical pulp
department or school: Applied Science, Faculty of
department or school: Chemical and Biological Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Noki, Gloria
issued: 2025-05-02T13:33:29Z
issued: 2025
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Peroxide brightening of thermomechanical pulp (TMP) in high alkali conditions, has been proven to develop the brightness and tensile properties of the treated pulp. Previous studies have generated a robust understanding of the effects the process has on the optical and strength properties of pulps. The rise in demand for pulps with low bulk and high tensile (better suited to board and packaging grades) has motivated this study on the contributions TMP fines (< 76 μm) make to the development of pulp properties using highly alkaline peroxide treatment (HAPT). When TMP fibres and fines are separately treated with high alkali peroxide, the peroxide reacts more rapidly with the fines, during the initial stages of the treatment. Likewise, weak acid groups are generated more rapidly in fines compared to fibres. Weak acid groups increase the surface charge, promoting fibre swelling and increasing the bonded area between adjacent fibres, which results in sheet densification. Thus, a correlation has emerged between the development of tensile strength and the generation of weak acid groups during HAPT. Due to their smaller size and larger specific surface area, fines are more accessible to the peroxide. Furthermore, fines consume peroxide more rapidly due to their higher lignin content; hence, weak acid groups form more readily on the surfaces of fines. Consequently, it is hypothesized that preferential formation of acid groups on the external surface of fines and fibres makes a significant contribution to tensile strength development. In this investigation, the effect of HAPT on pulp properties is evaluated by varying pulp compositions (fibres and fines % w/w) and treatment time. A better understanding of the correlation between acid group generation and tensile strength development during HAPT will lead to the cost-effective production of customizable pulp grades.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/90958
note: THE ROLE OF FIBRE SIZE IN HIGHLY ALKALINE PEROXIDE TREATMENT OF THERMOMECHANICAL PULP by Gloria Noki BASc., The University of British Columbia, 2017 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Chemical and Biological Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April 2025 © Gloria Noki, 2025ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: The Role of Fibre Size in Highly Alkaline Peroxide Treatment of Thermomechanical Pu lp submitted by Gloria Noki in partial fulfilment of the requirements for the degree of Master of Applied Science in Chemical and Biological Engineering Examining Committee: Heather Trajano, Associate Professor, Chemical and Biological Engineering, UBC Supervisor Scott Renneckar, Professor, Forestry, UBC Supervisory Committee Member Peter Englezos, Professor, Chemical and Biological Engineering, UBC Supervisory Committee Member iii Abstract Peroxide brightening of thermomechanical pulp (TMP) in high alkali conditions, has been proven to develop the brightness and tensile properties of the treated pulp. Previous studies have generated a robust understanding of the effects the process has on the optical and strength properties of pulps. The rise in demand for pulps with low bulk and high tensile (better suited to board and packaging grades) has motivated this study on the contributions TMP fines (< 76 μm) make to the development of pulp properties using highly alkaline peroxide treatment (HAPT). When TMP fibres and fines are separately treated with high alkali peroxide, the peroxide reacts more rapidly with the fines, during the initial stages of the treatment. Likewise, weak acid groups are generated more rapidly in fines compared to fibres. Weak acid groups increase the surface charge, promoting fibre swelling…
has type: Thesis/Dissertation
date issued: 2025-11
is shown at: 10.14288/1.0448713
language: eng
degree discipline: Chemical and Biological Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Trajano, Heather L.
type: Text
identifier URI: http://hdl.handle.net/2429/90958