树状分子接枝壳聚糖的合成与热致液晶性

甲壳素/壳聚糖是拥有多个反应性官能团的天然多糖,而树状分子则是一类可以在分子水平上控制和设计大小、形状、结构和功能基团的化合物,将其作为侧链通过接枝反应引入到壳聚糖主链上有望获得新型的天然高分子液晶材料.我们利用经典的收敛法合成了DOBOB酸(3,4,5-三对-(十二烷氧基)苄氧基]苯甲酸)树枝状分子,并且以对甲苯磺酰氯为催化剂,在吡啶/无水氯化锂的溶剂体系中将其接枝到壳聚糖分子链上,产物的化学结构经红外1、H-NMR1、3C-NMR以及元素分析表征验证.通过DSC和热台偏光显微镜研究表明,这种树枝状分子接枝壳聚糖化合物同时具有热致和溶致液晶性,是一种全新的壳聚糖衍生物液晶.

Synthesis and Liquid Crystal Behavior of Dodob Acid Grafted Chitosan

Chitin/chitosan are natural polysaccharide which have multiple functional groups,whereas dendrimers are a new category of dendritic molecules which have highly structure order.The molecule size,shape,structure and functional groups of the latter can be controlled and designed on the molecular scale.By the way of grafting reaction,dendrimers can be attached to chitosan mainchain as the side chain bearing unique qualities and functions.The resulting compound may became a new type of natural polymer liquid-crystal material.1-Bromododecane,p-hydroxybenzaldehyde and methyl-3,4,5-trihydroxybenzoate were used as raw materials to synthesize a dendrimer(DOBOB acid) by the way of constringency,then grafted onto a chitosan(CS) mainchain in reaction system of pyridine/LiCl,using p-TsCl as the catalyst.Their chemical structures were charasterized by FTIR,1H-NMR,13C-NMR and element analysis.The final product DOBOB-g-CS was observed to possess both the behaviors of thermotropic liquid crystal and lyotropic liquid crystal under POM.We achieved a new species liquid crystal of chitosan derivative ultimately.