香蕉纤维素在离子液体中的均相改性

Homogeneous Modification of Banana Cellulose in Ionic Liquids

以香蕉纤维素为原料,1-烯丙基-3-甲基咪唑氯盐([Amim]Cl)离子液体为反应介质,乙酸酐为酯化剂,在不加任何催化剂条件下,实现了香蕉纤维素的均相改性。研究了反应时间、反应温度以及乙酸酐与纤维素葡萄糖单元的摩尔比对产物取代度的影响。结果表明,其最优条件为:反应温度为80℃,反应时间为4h,乙酸酐与纤维素葡萄糖单元的摩尔比为5∶1。采用傅里叶变换红外光谱仪(FTIR)、核磁共振氢谱(1HNMR)、热重分析仪(TGA)和扫描电镜(SEM)对其进行表征。结果表明产物的FTIR和1HNMR谱图中有明显的乙酰基特征峰;TGA和SEM表明产物纤维素醋酸酯的热稳定性较原纤维素有所提高,并失去了原纤维状。

The banana cellulose was homogeneous modified in ionic liquids l-allyl-3-methylimidazolium chloride （[Amim]C1） without any catalyst, using acetic anhydride as esterifying agent. The effect of reaction time, reaction temperature and molar ratio of acetic anhydride/cellulose anhydroglucose unit on the degree of substitution, was studied. The results showed that the optimum conditions were： the reaction temperature was 80℃ , the reaction time was 4h, the molar ratio of acetic anhydride/AGU was 5 ： 1. The products were characterized by ^1 HNMR, FTIR, TGA and SEM. The obvious peaks for the acetylation were showed in FTIR and ^1 HNMR. TGA and SEM showed that the thermal stability of cellulose acetate was better than the original cellulose, and the original fibers micro structure of cellulose acetate lost.