L-半胱氨酸-聚乙烯醇/羟乙基纤维素三重形状记忆水凝胶的制备及表征

Preparation and Characterization of Cys-PVA/HEC Triple Shape Memory Hydrogel

基于超分子作用与动态共价键,制备一种具有形状记忆功能的水凝胶。聚乙烯醇(PVA)作为水凝胶主体,通过酯化反应将L-半胱氨酸(Cys)接枝在PVA上形成共聚物L-半胱氨酸-聚乙烯醇(Cys-PVA)。随后加入羟乙基纤维素(HEC)引入双网络结构提高水凝胶的机械性能,与Cys-PVA制备出L-半胱氨酸-聚乙烯醇/羟乙基纤维素(Cys-PVA/HEC)复合水凝胶。红外光谱与核磁共振表征结果表明,PVA与Cys反应摩尔比n(PVA)∶n(Cys)=1∶1,酯化反应18 h时,PVA的羟基上几乎全接枝上Cys。扫描电镜(SEM)与比表面积和孔径分布测试观察到Cys-PVA/HEC水凝胶有明显的网状多孔结构。形状记忆测试表明,Cys-PVA/HEC水凝胶具有多响应的三重形状记忆。机械性能测试表明,加入HEC改善了Cys-PVA/HEC水凝胶机械性能,但也影响了其形状记忆性能,当HEC添加量为0.4 g时水凝胶性能较好。

Based on supramolecular action and dynamic covalent bonds,a hydrogel with shape memory function was prepared.Poly(vinyl alcohol)(PVA)was used as the main body of the hydrogel,and L-cysteine(Cys)was grafted onto PVA through an esterification reaction to form a copolymer of L-cysteine-polyvinyl alcohol(Cys-PVA).Subsequently,hydroxyethyl cellulose(HEC)was added to introduce a double network structure to improve the mechanical properties of the hydrogel,and to prepare L-cysteine-polyvinyl alcohol/hydroxyethyl cellulose(Cys-PVA/HEC)by combining with Cys-PVA.The results of infrared spectroscopy and nuclear magnetic resonance showed that the reaction molar ratio of PVA to Cys was n(PVA)∶n(Cys)=1∶1.When the esterification reaction was 18 h,almost all the hydroxyl groups of PVA were grafted with Cys.Scanning electron microscopy(SEM)and BET surface area observed that Cys-PVA/HEC hydrogel has obvious network porous structure.The shape memory test shows that Cys-PVA/HEC hydrogel has multi-response triple shape memory.The mechanical performance test showed that the addition of HEC improved the mechanical performance of Cys-PVA/HEC hydrogel,but also affected its shape memory performance.The hydrogel performance was better when the amount of HEC added was 0.4 g.