Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea.
Department of Organic and Nano System Engineering, Konkuk University, Seoul 143-701, Republic of Korea.
Carbohydr Polym. 2016 Feb 10;137:321-327. doi: 10.1016/j.carbpol.2015.10.006. Epub 2015 Oct 20.
This research focused on the preparation of highly ordered cellulose II crystalline by cellulose hydrolysis in ionic liquid, and the influence of molecular mobility on recrystallization of cellulose. The molar mass of cellulose was controlled by hydrolysis using 1-butyl-3-methylimidazolium chloride (BmimCl). The molecular mobility of cellulose dissolved in BmimCl was characterized by rheological properties. After characterization of cellulose solution and regeneration, change of molar mass and conversion to crystalline were monitored using gel-permeation chromatography and powder X-ray diffraction, respectively. The molar mass of the cellulose in BmimCl was remarkably decreased with an increase in duration time, resulting in better mobility and a lower conformational constraint below critical molar mass. The decrease in molar mass surprisingly increased the crystallinity up to ∼ 85%, suggesting a recrystallization rate dependence of the mobility. The correlation between the mobility and recrystallization rate represented quit different behavior above and below a critical molar mass, which strongly demonstrated to the effect of mobility on the conversion of amorphous state to crystalline structure.
本研究专注于在离子液体中通过纤维素水解制备高度有序的纤维素 II 晶体，以及分子迁移率对纤维素再结晶的影响。纤维素的摩尔质量通过 1-丁基-3-甲基咪唑氯（BmimCl）的水解来控制。通过流变性质来表征纤维素在 BmimCl 中的分子迁移率。在对纤维素溶液进行表征并再生后，使用凝胶渗透色谱法和粉末 X 射线衍射法分别监测摩尔质量的变化和转化为结晶。纤维素在 BmimCl 中的摩尔质量随着时间的延长而显著降低，导致流动性更好，低于临界摩尔质量时构象约束更低。摩尔质量的降低出人意料地提高了结晶度，达到约 85%，这表明迁移率与再结晶速率之间存在依赖性。迁移率和再结晶速率之间的相关性在临界摩尔质量以上和以下表现出截然不同的行为，这有力地证明了迁移率对无定形状态向晶体结构转化的影响。
