N,O-羧甲基壳聚糖的制备及其理化特性研究

Study on Synthesis and Properties of N,O-carboxymethyl Chitosan

以壳聚糖为原料,在碱性条件下利用氯乙酸在壳聚糖的不同位点分别引入羧甲基制备N,O-羧甲基壳聚糖(N,O-CMC)。通过正交实验,确定影响取代度的主要因素依次为:反应温度、氢氧化钠/氯乙酸摩尔比和反应时间;最佳反应条件为:反应温度为70℃、氢氧化化钠/氯乙酸摩尔比为2.4、反应时间为4h、异丙醇用量为50mL。并研究了其理化特性,研究表明:N,O-CMC在中性和碱性水溶液中溶解性明显优于壳聚糖;N,O-CMC的等电点随取代度的增大而向酸性方向偏移;高取代度的N,O-羧甲基壳聚糖保湿性和吸湿性都优于透明质酸,在湿度较高(RH81%)的条件下,取代度为1.36的N,O-CMC的吸湿性是透明质酸的1.8倍。

To improve the properties of chitosan, this research used chitosan and chloroacetic acid to synthesize a new type chitosan derivative-N,O-carboxymethyl chitosan. The experiment results （orthogonal test） showed that the optimum condition for making N,O-carboxymethyl chitosan was： reaction temperature 70℃ , the mole ratio of sodium hydroxide and chloroacetic acid was 2.4, reaction time was 4h, amount of isopropyl alcohol was 50ml. Analyzed the chemical and physical properties of N,O-earboxymethyl chitosan, the result showed that the isoelectric point of N, O-CMC migrated toward the acid with the increasing degree of substitution; N, O-carboxymethyl ehitosan with high degree of substitution had a better moisture content and superior moisture absorption than hyaluronic acid. In the condition of high humidity（RH81% ） ,the hygroseopicity of N, O-CMC with 1.36 degree of substitution was 1.8 times of hyaluronic acid.