多重氢键对动态脲键基可重塑热固性树脂强度韧性和自修复性能调节机理的研究

Most of thermosets with stable covalently cross-linked structure generally lack the ability to be reprocessed or recycled after curing, and hard to repair after damaging. Recently, researchers have been developed malleable thermosets (also called as glass like polymer, moldable thermosets or Vitrimers) by using the reversible covalent bonds as cross-linking units. With respect to the polymers networked by reversible covalent bonds for structural applications, simultaneous integration of high modulus, strength and toughness is necessary. However, most of the malleable thermosets materials published so far have either higher hardness and strength but low extensionality or higher elongation-at-break but low strength. Recently, we reported that the self-healable malleable thermosets by using the hindered urea bonds (HUBs) with high hardness but relatively low toughness. For simultaneously adjusting of the modulus, toughness, and self-healing properties of the malleable thermosets, in this project, we will develop a series of malleable thermosets bearing different multiple hydrogen bonds and dynamic hindered urea bonds. Their mechanical properties and recyclability of malleable thermosets will be studied. And the self-healing and shape-memory properties of the malleable thermosets will be tested also. Furthermore, the relationship between the multiple hydrogen bonds and dynamic property of HUBs with thermoset’s malleability, recyclability, mechanical properties and self-healing ability will be established. And the relationship of chemical structures and properties of malleable thermosets will be revealed. The achievement of this project would develop novel methods for the synthesis of recyclable self-healable malleable thermosets with high hardness and high toughness, offer new green smart dynamic polymer network materials for widely potential applications.

针对基于稳定共价键交联热固性树脂难以回收利用，动态共价键交联可重塑热固性树脂强度、韧性和自修复性能难以同时调节的难题，本项目采用将多重氢键基元作为可牺牲交联点引入到动态共价键交联网络的方法，制备出兼具刚性、韧性和自修复能力的高性能可重塑热固性树脂。首先，利用含有不同多重氢键基元、大位阻仲胺单体和异氰酸酯前体，制备出可重塑热固性树脂。进而研究该类材料的机械性能，加工性和回收利用性，探索该类材料的自修复以及形状记忆性能。系统阐述不同类型多重氢键和大位阻动态脲键组合对该类树脂材料加工、回收利用、刚性、韧性和自修复性能的影响规律。最终，揭示该类可重塑热固性树脂材料的结构-功能相关性，实现对该类可重塑热固性树脂材料的优化和丰富，为开发下一代环保多功能可重塑热固性树脂材料提供研究基础。

本项目针对传统热固性树脂难以回收利用、动态共价键交联材料的强度、韧性和自修复性能难以兼顾的问题，探索多重氢键基元对于动态共价键交联网络力学性能和加工特性的协同调控机制，设计、构建了系列兼具刚性、韧性和自修复能力的高性能聚合物材料。首先，课题组整理分析了动态共价键聚合物材料的研究进展和发展趋势，发表综述论文；继而，设计和构建了多种具有多重氢键增强作用的新型高性能聚合物材料，包括：基于重氮烷基脲多重氢键基元的强韧、耐穿刺荧光聚氨酯弹性体；基于咪唑烷基脲多重氢键基元的高性能可降解聚氨酯材料；基于N,N-双（2-羟乙基）草酰胺扩链剂的多重氢键作用的高性能聚氨酯弹性体；多重氢键无规超支化聚酰胺-胺热熔胶；动态聚硫代氨基甲酸酯透明、防水高性能粘合剂；本征近红外光控形状记忆聚（脲-肟氨酯）热固性树脂。同时，通过二聚环戊二烯的开环易位共聚合，在交联聚烯烃的侧链引入稳定自由基单元，制备获得具有高储能、高放电效率和高击穿强度的高性能介电薄膜材料。期间共计发表学术论文13篇，申请发明专利6项，培养硕士毕业生6人，博士毕业生4人，参加学术会议并作报告4次。