壳聚糖对竹溶解浆溶液流变性能的影响

Effect of chitosan on rheological properties of bamboo dissolving pulp solution

采用浓度为84.2%的N-甲基吗啉-N-氧化物(NMMO)水溶液为溶剂,设计竹溶解浆(BP)-壳聚糖(CS)不同质量分数,依次加入CS粉末和BP,BP充分溶解后制备BP与CS不同质量比的共混溶液。研究了CS对NMMO溶解BP溶液的稳态和动态流变性能。研究表明:在NMMO溶解体系中,BP-CS共混溶液为剪切稀化的假塑性流体,在持续摇振过程中,随着溶液温度(θ)升高,溶液的储能模量(G′)和损耗模量(G″)、复数黏度(η*)均下降,加入适量的CS(CS∶BP=1∶10)可有效阻碍BP大分子不同链间即时物理交联位点的形成,从而改善NMMO溶解BP溶液的流变性能,但是,随着CS添加量的增大,CS与BP大分子链间的相互作用增加又导致了溶液的流变性能降低。

The effect of chitosan(CS)on the steady state and dynamic rheological properties of bamboo dissolving pulp(BP)solutions prepared in 84.2%N-methylmorpholine-N-oxide(NMMO)as the solvent were studied.Blended solutions of different mass percentages of CS and BP were prepared by adding CS followed by BP.The BP-CS solutions were all shear dilute pseudoplastic fluids in the NMMO solution system.During continuous shaking,the storage modulus,loss modulus,and complex viscosity decreased as the temperature increased.Adding an appropriate amount of CS(CS∶BP=1∶10)effectively prevented the real-time formation of physical cross-linking sites between different chains of BP macromolecules,which improved the rheological properties of BP solutions.As the amount of added CS increased,the interaction between chitosan CS and BP macromolecules chains increased,resulting in decreased rheological properties of the BP-CS solutions.