低分子量范围内壳聚糖分子量的调控及其线性关系研究

Study on the control and linear relationship of chitosan in the range of low molecular weight

通过固定H_2O2用量为壳聚糖（CS）摩尔单元量的2倍,60℃下氧化降解制备了分子量小于15000的低分子量CS。在低分子量范围内,根据Mark-Houwink方程测定了降解后CS的黏均分子量,并研究了通过控制降解反应时间来调控CS的分子量,结果表明降解反应3h后,CS的黏均分子量变化不大,可降低至5000;在0.5~2.0h之间,CS的黏均分子量与反应时间有着较好的线性关系,线性拟合方程为y=4422.8x＋15854,R2=0.9973。该线性方程的建立为低分子量范围内CS分子量的调控制备提供了理论指导。

Chitosan with molecular weight below 15000 was prepared by oxidative degradation at 60℃ and the fixed H2 02 dosage in which the molar ratio of Hz Oz to chitosan unit was 211. In the range of low molecular weight,the viscosity- average molecular weight of degraded chitosan was determined by Mark-Houwink equation and the relationship between the controllable molecular weight of chitosan and degradation time was also investigated. The results showed that the viscosity- average molecular weight of chitosan was decreased to approximately 5000 after 3h. The viscosity-average molecular weight of the chitosan was linear with the reaction time in 0.5 ~ 2h and the linear equation was y = 4422.8xq-15854 ,R2= 0. 9973. This established linear equation would give the direction on preparing the chitosan with controllable low molecular weight.