壳聚糖的降解动力学研究

Study on the Degradation Kinetics of Chitosan

用亚硝酸钠降解壳聚糖,研究了降解温度、降解时间对壳聚糖降解过程的影响。结果表明,在20 min内,壳聚糖分子量迅速减小,30 min后,壳聚糖分子量减小的趋势变缓;随着温度的升高,壳聚糖分子量减小的速度加快,但对脱乙酰度影响不大。壳聚糖的降解符合无规降解过程,其降解表观速率常数随温度升高而增大,降解活化能为63.3 kJ.mol-1。用亚硝酸钠降解壳聚糖是一种制备低分子量壳聚糖的快速且分子量可控的方法。

The effects of degradation temperature and degradation time on the degradation process of chitosan were investigated by sodium nitrite. The results showed that molecular weight of chitosan decreased rapidly in 20 minutes, and reduction trend slowed down after 30 minutes; molecular weight reduction of chitosan was speeded up with temperature. Deacetylation degree, however, was not greatly affected. The degradation of chitosan was in agreement with the irregular degradation process, and constant of apparent degradation rate increased with the rising of temperature, activated energy of degradation was 63.3 kJ · mol^-1. Degradation of chitosan by sodium nitrite is a fast and molecular weight-controllable method for preparation of low molecular weight chitosan.