基于杜仲胶的自修复弹性体的结构设计与合成

Structure Design and Synthesis of Self-Healing Elastomer Based on Eucommia Ulmoides Gum

杜仲胶(EUG)作为我国特有的生物高分子资源而备受关注。文中首先对杜仲胶进行了环氧化,进而利用环氧基团的开环反应使EUG含有多重氢键,制备了具有自修复行为的接枝杜仲胶(GEEUG)。采用红外光谱、核磁共振氢谱、差示扫描量热分析、偏光显微镜、万能拉伸机和动态黏弹谱仪等分析了接枝产物的改性程度对聚集态结构的影响,以及改性程度和修复条件对修复效率的影响。结果表明,在反应温度50℃,pH=5的条件下,改性程度约为20%(摩尔分数),且几乎没有副反应发生。在环氧化杜仲胶(EEUG)中未观察到自修复行为,而GEEUG在50℃无任何外力作用下12 min即可基本修复裂缝。GEEUG 21.8在室温和50℃下修复2 h,修复效率分别达到72.6%和83.9%,显示出温和温度条件下的快速、高效自修复能力。弹性恢复和氢键网络的存在是本体系自修复的主要机制。

As China’s unique biopolymer resources,Eucommia ulmoides gum(EUG)has received much attention.In this work,grafted Eucommia ulmoides gum(GEEUG)with self-healing ability was prepared by epoxidation modification of EUG first,further introducing multiple hydrogen bonds into the EUG by ring opening reaction of the epoxy group.IR,~1H-NMR,DSC,POM,universal tensile testing machine and dynamic viscoelastic spectrometer were used to evaluate the effect of degree of modification on the aggregation structure and healing conditions on the self-healing efficiency of GEEUG with different degrees of modification.The results show that under the reaction conditions of 50℃and pH=5,the degree of modification is about 20%and almost no side reactions occur.No self-repairing behaviour was observed in epoxidized Eucommia ulmoides gum(EEUG),while the cracks on GEEUG 21.8 surfaces can be repaired in 12 min basically in the absence of any external force.After the two sections of GEEUG 21.8 contact at room temperature and 50℃respectively for 2 h,the self-healing efficiency is up to 72.6%and 83.9%separately,suggesting a rapid and efficient self-healing ability under mild temperature conditions.The elastic recovery and the existence of multiple hydrogen bonding network are the main self-healing mechanism of the system.