壳聚糖浓溶液流变性质研究──分子量的依赖性

RHEOLOGICAL PROPERTIES OF CONCENTRATED SOLUTION OF CHITOSAN:MOLECULAR WEIGHT DEPENDENCE

壳聚糖浓溶液流变性质研究──分子量的依赖性王伟，徐德时（中国科学院长春应用化学研究所高分子物理开放实验室长春１３００２２）关键词壳聚糖，浓溶液，粘度，零剪切粘度，分子量作者曾研究了一些外部条件对壳聚糖浓溶液流变学性质的影响，如浓度、温度、溶剂性质、外...

series of chitosan samlpes with 91% deacetylation but different molecular weight were obtained by varying the time of chitosan solution in acetic acid aqueous solution at 70℃.The viscosities and flow behavior of the concentrated solutions of chitosan were investigated in 10% (vol%) formic acid aqueous solution after the solutions were prepared for two days by using RPX-705 Rheopexy Analyzer.For each chitosan sample,at the concentration of 3.5 g/100ml,the log (ηr/η0)versus lgγη0,M curves superimpose each other within the same rheogramme. Then the relationship between logs.and ig M was studied under different shear rates. For'the highest M sample,the experimental data deviate from the straight lines greatly.This was because the chitosan chain degradated in acid solution during dissolving. The molecular weights were measured in acid solution after two days of dissolving, they were right on their own straight lines. However, no obvious degradatioll was observed after two days in the same solution for the other lower M chitosan samples. In addition, the plot of ηr against M was not a straight line, probably due to particular interaction of chitosan.