不同分子量高脱乙酰度壳聚糖的制备及表征

Preparation and characterization of chitosans of high degree of deacetylation with different molecular weights

目的制备不同分子量高脱乙酰度壳聚糖。方法在强碱备件下通过不同方式的水解从原料壳聚糖制备一系列高脱乙酰度壳聚糖，用HAc／H2O2体系对制备的高脱乙酰度壳聚糖进行不同时间的降解得到中低分子量高脱乙酰壳聚糖，并用乌氏黏度计测定其黏均分子量。结果在实验条件下成功制备了一系列中低分子量高脱乙酰壳聚糖，并用红外和核磁光谱进行分析表征。结论采用10mol·L^-1 NaOH水溶液110℃间歇水解的方法可以制备90％～100％脱乙酰度的壳聚糖，用0．35mol·L^-1 HAc／0．45mol·L^-1 H2O2体系可以制备黏均分子量10，000～100，000Da的壳聚糖样品。

Objective To prepare chitosans of high degree of deacetylation with different molecular weights. Methods A series of chitosan samples of high degree of deacetylation were prepared by different approaches of hydrolysis from commercial chitosan in the presence of strong base. The obtained deacetylchitosans were then degraded into samples with medium or low molecular weight in the system of acetic acid and hydrogen peroxide. Their corresponding molecular weights were further determinied with Ubbelohde viscometer. Results Chitosans of high degree of deacetylation with different molecular weights were successfully prepared under the experiment conditions. Their characteristics were indicated and analysed by IR and 1H-NMR. Conclusion Chitosans of 90% - 100% degree of deacetylation can be prepared by the intermittent approach of hydrolysis using 10mol·L^-1 NaOH solution at 110℃. Chitosan samples with the viscosity-average molecular weigh between 10,000 ～100, 000 Da can be prepared in the system of 0.35 mol·L^-1 acetic acid and 0.45 mol·L^-1 hydrogen hyperoxide.