Korhonen Oona, Budtova Tatiana
Aalto University, School of Chemical Engineering, Department of Bioproducts and Biosystems, P.O. Box 16300, 00076 AaltoFinland.
Aalto University, School of Chemical Engineering, Department of Bioproducts and Biosystems, P.O. Box 16300, 00076 AaltoFinland; MINES ParisTech, PSL Research University, CEMEF - Center for materials forming, UMR CNRS 7635, CS 10207, 06904 Sophia Antipolis, France.
Carbohydr Polym. 2019 Nov 15;224:115152. doi: 10.1016/j.carbpol.2019.115152. Epub 2019 Aug 1.
It is well known that when cellulose is dissolved in aqueous NaOH-based solvent, solutions are gelling with increasing time and temperature. The goal of this work was to understand if the presence of non-dissolved cellulose fibers influences gelation behavior of the whole system. One of the motivations is to control gelation when making all-cellulose composites with short fibers dispersed in cellulose-NaOH-water solutions. Gelation kinetics of cellulose(dissolving pulp)-NaOH-water solutions with added softwood kraft fibers were investigated using dynamic rheology. Fiber concentration, dissolving pulp degree of polymerization and solution temperature were varied. In all cases the addition of kraft fibers accelerates gelation and increases modulus at gel point while the presence of "inert" carbon fibers does not influence solution gelation kinetics. It was suggested that acceleration of gelation and reinforcement of cellulose gels is due to the interactions between dissolved and non-dissolved cellulose.
众所周知，当纤维素溶解在基于氢氧化钠的水性溶剂中时，溶液会随着时间和温度的增加而凝胶化。这项工作的目标是了解未溶解的纤维素纤维的存在是否会影响整个系统的凝胶化行为。动机之一是在制备短纤维分散在纤维素-氢氧化钠-水溶液中的全纤维素复合材料时控制凝胶化。使用动态流变学研究了添加软木牛皮纸纤维的纤维素（溶解浆）-氢氧化钠-水溶液的凝胶化动力学。改变了纤维浓度、溶解浆的聚合度和溶液温度。在所有情况下，牛皮纸纤维的添加都会加速凝胶化并增加凝胶点处的模量，而“惰性”碳纤维的存在不会影响溶液的凝胶化动力学。有人认为，凝胶化的加速和纤维素凝胶的增强是由于溶解的和未溶解的纤维素之间的相互作用。
