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Colloidal stability of Pinus radiata wood extractives Part 1: Effect of extractives composition and process variables


Stack, KR and Yaqoob, N and Ngwenya, E and Richardson, DE and Lewis, TW, Colloidal stability of Pinus radiata wood extractives Part 1: Effect of extractives composition and process variables, Appita Journal, 72, (1) pp. 15-29. ISSN 1038-6807 (2019) [Refereed Article]


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Copyright 2019 Appita


This paper presents the results of a study undertaken to investigate the interaction between the various key factors that have been identified to affect wood extractive colloid stability and pitch deposition of wood extractives released in thermomechanical pulp of Pinus radiata. These key factors are temperature, soluble calcium, pH, dissolved carbohydrates and wood extractive concentration and composition. Very little work has been undertaken to study the effect of composition and seasonal changes in Pinus radiata wood extractives on their colloidal stability and pitch deposition. Two different compositions of the wood extractives, representing the maximum and minimum in ester to acid ratio (EAR) that occur during the summer and winter periods, were investigated. The EAR of the extracts was found to significantly affect the wood extract colloidal properties. Low EAR (EAR = 0.31) extracts, typical of the summer period, were found to be more unstable and more susceptible to deposition and destabilisation by soluble calcium than higher EAR (EAR = 0.66) extracts, typical of the winter period. Complex interactions between the various process variables were found. In particular, the dissolved organic matter (DOM) level was found to cause both stabilisation and destabilisation depending on the concentration and the pH. This was more apparent in the higher EAR extract.

Item Details

Item Type:Refereed Article
Keywords:Pinus radiata, wood extractives, colloidal stability, ester to acid ratio, dissolved organic matter
Research Division:Chemical Sciences
Research Group:Physical chemistry
Research Field:Colloid and surface chemistry
Objective Division:Manufacturing
Objective Group:Wood, wood products and paper
Objective Field:Wood, wood products and paper not elsewhere classified
UTAS Author:Stack, KR (Dr Karen Stack)
UTAS Author:Yaqoob, N (Dr Naila Yaqoob)
UTAS Author:Ngwenya, E (Dr Elkana Ngwenya)
UTAS Author:Lewis, TW (Associate Professor Trevor Lewis)
ID Code:132566
Year Published:2019
Funding Support:Australian Research Council (LP120200241)
Web of Science® Times Cited:2
Deposited By:Chemistry
Deposited On:2019-05-13
Last Modified:2019-06-07
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