Alkaline degradation of cellulose: Mechanisms and kinetics
2003 (English)In: Journal of polymers and the environment, ISSN 1566-2543, Vol. 11, no 2, 39-47 p.Article in journal (Refereed) Published
Cellulose powder and softwood sawdust were subjected to alkaline degradation under conditions representative of a cementitious environment for periods of 7 and 3 years, respectively. During the first 3 years, sampling was frequent, and data on the degradation of cellulose and production of isosaccharinic acid was used for establishing long-term prediction models. Samples after an additional period of 4 years were compared to the predicted values. The total rate of degradation was measured as the increase in total organic carbon (TOC) in corresponding solutions. A previously published theoretical model of degradation kinetics gave a good approximation of the present experimental data. Peeling-off, stopping, and alkaline hydrolysis reaction rate constants were obtained as model parameters, and the results suggested that the transformation of the glucose end group is the rate-limiting step in the cellulose peeling-off reaction and also determines the pH dependence of that reaction. After 3 years, isosaccharinic (ISA) acid represented 70-85% of all degradation products as quantified by capillary zone electrophoresis. The long-term prediction model indicated that all of the cellulose would be degraded after only 150-550 years. The control sampling after 7 years points toward a lower degradation of cellulose and production of ISA than predicted by the model, reflecting either a degradation of ISA that was faster than the production or a termination of the ISA production.
Place, publisher, year, edition, pages
2003. Vol. 11, no 2, 39-47 p.
alkaline degradation of cellulose, isosaccharinic acid, prediction models
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-48630OAI: oai:DiVA.org:liu-48630DiVA: diva2:269526