高温自修复双马来酰亚胺树脂体系的构筑及修复机理研究

The project describes a bismaleimde (BMI) resin system which is capable to repair internal micro-cracks or partial injuries automatically at higher temperature based on a self-repairing microcapsule containing healing agent and catalyst. Polymeric microcapsule is prepared via a solvent volatilization technique, and amine-modified thermoplastic poly(phthalazinon ether sulfone ketone) (PPESK) and passivated BMI are employed as microcapsule shell material and healing agent，respectively. Sequentially, the microcapsules are heat-treated, and a small quantity of healing agent penetrates into the inner wall of microcapsule and crosslinking reaction with shell material is carried out simultaneously, resulting in an improved tightness of microcapsule. Afterwards, the microcapsules are marinated in a solution containing catalyst for a period of time to render catalyst infiltrate into membrane material of microcapsule. And then outer wall of the microcapsules are crosslinked by a cross-linking agent to encapsulate the catalyst. The incorporation of self-repairing microcapsules into commercial modified BMI resin not only improves the fracture toughness of cured resin and makes self-diagnose，self-response, and self-repairing function be achieved, resulting in a greatly improved performance of BMI resin. Therefore, this research project, which provides a novel means for more high-performance, functional and complex development of heat-resistant resins, takes on great significance in academic research and potential engineering application.

本项目以双马来酰亚胺树脂（BMI）在高温条件下对微损伤可实现自修复为研究目标，制备一种同时包覆修复剂和催化剂的自修复微胶囊。首先以含二氮杂萘联苯结构聚芳醚砜酮（PPESK）氨基化改性树脂为囊材，钝化的BMI树脂为修复剂，采用溶剂挥发法制备微胶囊；其次对微胶囊进行加热处理使少量的修复剂渗入囊材并发生交联反应，提高微胶囊的密封性；然后在一定浓度催化剂溶液中浸泡微胶囊，挥去溶剂使催化剂残留在囊壁膜材的微孔中；最后再用交联剂与微胶囊壳层中的氨基反应，使囊壁的外表层也发生交联进而将催化剂密封在微胶囊的壳层中。将制备的自修复微胶囊添加到传统BMI改性树脂体系中，不仅改善了固化物的韧性还可以实现对损伤自动响应和自修复的功能，大大提升了BMI树脂的使用性能。本项目的开展为耐高温树脂的高性能化、功能化、复合化提供了一种新的思路，具有重要的理论研究意义和潜在的工程应用价值。

通过自修复技术消除内部的缺陷和疲劳裂纹从而提升先进聚合物基复合材料的使用寿命是目前国际上研究的一个热点问题。双马来酰亚胺树脂（双马树脂）是航空航天领域耐高温结构复合材料最为重要的基体树脂，因此研究在高温服役过程中能够诊断且同步修复自身微缺陷的双马树脂具有重要意义。目前自修复高分子复合材料的研究均处于探索阶段且主要基于微胶囊技术开发室温下具有自修复功能的材料。双马树脂基复合材料在固化成型和使用过程均在高温下进行，微胶囊中修复剂活性的保持是个关键的技术难题。双马树脂在高温下主要是进行热引发自由基固化机制，加入阻聚剂能够钝化其反应活性而当加入阴离子催化剂则能显著降低固化温度。基于此，本项目设计合成了含1,3,4-噁二唑不对称结构的双马来酰亚胺，表征了化学结构和性能；利用其改性商业化双马树脂，并加入阻聚剂制备出熔点和固化特性与服役温度相符的的修复剂。另外针对常规双马树脂韧性差的问题设计合成了一系列链延长双马来酰亚胺作为自修复双马树脂的本体树脂；研究了该类树脂在多种阴离子催化剂作用下的催化机理和效率，筛选出合适的催化剂。采用溶剂挥发工艺制备微胶囊，优化了合成工艺，并对微胶囊结构进行表征。将微胶囊加入双马树脂并制备了复合材料，根据复合材料的拉伸强度、层间剪切强度以及冲击后压缩强度等指标提出了新的评价了自修复效率的方法。结果显示微胶囊的含量、粒径均对自修复效率有影响。