壳聚糖理化性能：粘均分子量、脱乙酰度及结晶性能测定

Physicochemical Properties of Chitosan: Determination of Viscosity Average Molecular Weight, Degree of Deacetylation and Crystallinity

使用粘度法测定了阿拉丁牌低粘、中粘、高粘和沪试牌四种壳聚糖的分子量,分别约为126万,115万,69万和56万。分别使用酸碱滴定法和双突跃电位滴定法测定了脱乙酰度,结果表明后者更精密,四类壳聚糖的脱乙酰度值均在78%~86%之间。X射线衍射测得阿拉丁牌壳聚糖具有相对较低的结晶度,脱乙酰度降低导致结晶度下降。

The molecular weights of four kinds of chitosan,Aladdin low,medium,high viscosity and Hushi brand,were determined by viscometric method,which were about 1.26,1.15,6.9 and 5.6×10^6 respectively.The degree of deacetylation was determined by acid-base titration and potentiometric titration respectively.The results showed that the latter was more precise.The degree of deacetylation of four kinds of chitosan ranged from 78 to 86%.The crystallinity of Aladdin chitosan was lower than Hushi brand by X-ray diffraction.The decrease of deacetylation degree resulted in the decrease of crystallinity.