环氧衍生物开环法制备壳聚糖季铵盐的工艺研究

Study on the Preparation of Quaternary Ammonium Salt of Chitosan By Open-loop Method of Epoxy Derivatives

摘要:

采用异丙醇为溶剂，以壳聚糖(CTS)、2,3-环氧丙基三甲基氯化铵(GTA)为原料，用环氧衍生物开环法制备了壳聚糖季铵盐(HACC)，通过单因素实验，考察了反应物摩尔比，反应时间，反应温度等因素对产物取代度的影响，结果表明，制备壳聚糖季铵盐的最优工艺为：nCTS: nGTA=1: 4，壳聚糖相对分子质量3.2×105，碱化时间14h，预处理壳聚糖含水率20%，反应pH值7，反应温度75℃，反应时间8h。通过红外光谱、扫描电镜、热重分析对壳聚糖、壳聚糖季铵盐的结构、外观形貌、热稳定性进行了表征与分析，结果表明壳聚糖季铵化改性以N取代为主，改性后外貌和粒度有了明显变化，并且热稳定性降低。

Abstract:

Reported in this paper is a practical method to synthesize quaternary ammonium salt of chitosan (HACC) in high substitution rate by reacting chitosan with 2,3-epoxypropyltrimethyl ammonium chloride. Reaction conditions were screened and the main factors were analyzed independently. Optimized condition factors were determined as follow: mole ratio of the reactants nc:ng = 1:4; molecular weight of Chitosan MWc = 320000g/mol; alkaline pretreatment time ta = 14h; moisture content of the pretreated chitosan Wi = 20%; reaction pH = 7; reaction temperature T = 75℃; reaction time tr =8h. The substituted product was analyzed by IR, SEM and TG/DTG. The analysis results indicate that the substitution occurred mainly on the amino groups of chitosan. Compared to unsubstituted chitosan, the substituted product has a smaller particle size and slightly lower thermostability.