壳聚糖
磷酸
化学
水解
分子质量
核化学
反应速率
溶解度
摩尔质量分布
粘度
高分子化学
有机化学
聚合物
催化作用
材料科学
酶
复合材料
作者
Zhishen Jia,Dongfeng Shen
标识
DOI:10.1016/s0144-8617(02)00026-7
摘要
Low-molecular-weight chitosan were prepared using 85% phosphoric acid at different reaction temperatures and reaction time. At room temperature, the viscosity average-molecular weights (Mv) of chitosan decreased to 7.1×104 from 21.4×104 after 35 days treatment. The degradation rate decreased with increasing hydrolysis time. The yields of chitosan also continuously decreased from 68.4 to 40.2% after 35 days. At 40, 60 and 80 °C, the molecular weight decreased to 3.70×104, 3.50×104 and 2.00×104 on 8 h hydrolysis, respectively. The yields of chitosan remain at a high level compared with that at room temperature and were 86.5, 71.4 and 61.3% at 40, 60 and 80 °C treatment, respectively. The different reaction time gave chitosan with different molecular weights. At 60 °C, the molecular weight of products decreased to 7.40×104 from 21.4×104 within 4 h, then decreased slowly to 1.90×104 in 15 h. It was also found that the water-solubility of chitosan increased as the molecular weight decreased. Results show the changes in yields and molecular weight of chitooligomers were strongly dependent on the reaction temperature and reaction time.
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