羧甲基壳聚糖和季铵盐壳聚糖的制备工艺

【目的】对羧甲基壳聚糖和季铵盐壳聚糖的制备工艺进行优化,改善壳聚糖在水中的溶解性。【方法】分别以氯乙酸(ClCH₂COOH)和3-氯-2-羟丙基三甲基氯化铵(CTA)为改性剂,对壳聚糖进行羧甲基化和季铵化改性,并以改性壳聚糖对蒙脱土的插层效果为基准进行有关CM-CTS合成条件研究。【结果】通过X-射线衍射(XRD)、透射电镜(TEM)、红外吸收光谱(FT-IR)和核磁共振氢谱(¹H-NMR)的分析,得出了壳聚糖的优化改性条件。制备羧甲基壳聚糖的优化条件为:反应时间6.0 h,反应温度60 ℃,m(氯乙酸)/m(壳聚糖)为3,m(NaOH)/m(壳聚糖)为4.5; 制备季铵盐壳聚糖的优化条件为:反应时间10 h,反应温度75 ℃,m(CTA)/m(壳聚糖)为4.5,m(NaOH)/m(壳聚糖)为0.8。【结论】对壳聚糖进行羧甲基化和季铵化改性,向壳聚糖中引入新的官能团,不仅可以改善壳聚糖的水溶性,同时壳聚糖/蒙脱土纳米复合材料的制备也极大地扩展了壳聚糖的应用范围。

Preparation technology of carboxymethyl chitosan and quaternary chitosan

[Objective] Carboxymethylation or quaternization of chitosan (CTS) improved its solubility in water.[Method]We investigated the effect of modifying chitosan by carboxymethylation or quaternization using chloroacetic acid (ClCH2COOH) or 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) as grafting agents.CTS intercalation by montmorillonite was used to evaluate the effect of the above modification.[Result]Optimal modification conditions determined by X-ray diffraction,transmission electron microscopy,Fourier transform infrared spectroscopy and 1H-nuclear magnetic resonance analyses were as follows:reaction time =6.0 h,reaction temperature =60 ℃,m(ClCH2COOH) ∶m(CTS) =3.0∶1.0,m(NaOH) ∶m(CTS) =4.5∶1.0.The following optimum conditions for CTA-CTS synthesis were determined:reaction time =10 h,reaction temperature =75 ℃,m (CTA) ∶ m (CTS) =4.5 ∶ 1.0,m (NaOH) ∶ m (CTS) =0.8∶1.0.[Conclusion] Introduction of new functional groups by carboxymethylation or quaternization of chitosan can not only improve its solubility in water,but also afford chitosan/montmorillonite nanocomposites,greatly expanding the application scope of chitosan.