微晶纤维素制备过程中纤维素结构与形态特征的变化

Changes of Structure and Morphological Characteristics of Cellulose during Preparation of Microcrystalline Cellulose

关键词:  水解纤维素  选择性  结晶度  形态  结晶区  无定形区

Key Words:hydrocellulose  selectivity  crystallinity  morphology  crystalline region  amorphous region

摘要:纤维素的超分子结构是由分子链排列整齐、有规则的结晶区和分子链排列松散、无规则的无定形区交错结合组成的。通过研究HCl在不同反应时间阶段(20～120 min)降解纤维素的特性,在HCl浓度2.5 mol/L,反应温度80℃,固液比1∶15,搅拌器转速120 r/min的条件下,纤维素选择性酸水解的最佳反应时间为60 min,此条件下水解纤维素的得率达96.04%,纤维素的聚合度、结晶度由661、58.92%变为99、76.01%。此外,长纤维和细小纤维平均长度分别为288、59 μm,细小纤维含量达90.31%。

Abstract:The supramolecular structure of cellulose is consisted of the crystalline region and amorphous region, the molecular chains of the former are well-regulated, while that of the latter are ruleless. Based on the study of the properties of cellulose degraded by HCl in different reaction time stages (20～120 min), under the constant condition of HCl concentration 2.5 mol/L, reaction temperature 80℃, solid-to-liquid ratio 1∶15, rotating speed 120 r/min, the optimal reaction time was 60 min for selective hydrolysis of cellulose. The results showed that the yield of hydrocellulose could reach to 96.04%, its polymerization degree and crystallinity charged from 661 and 58.92% before hydrolysis to 99 and 76.01%, respectively, under the optimal reaction time of 60 min. Furthermore, the average length of fibers and fines were 288 μm, 59 μm, respectively, and the fines content reached to 90.13%.