可回收高性能热固性聚六氢三嗪树脂的分子设计、固化机理及结构-性能关系研究

The hard degradation of traditional high-performance thermosetting resin has caused the gradually outstanding problems of waste of non-renewable petrochemical resources and environmental pollutant. However, the effective solution to these problems is the development of recyclable thermosetting resins with high-performance. This project starts from the molecular design, several aromatic diamines and polyarylether oligomers capped with amido or with amido pedant would be synthesized firstly, which contain both phenyl ether and heat-resistant heteroaromatic groups. Then polyhexahydrotriazine (PHT) based on acid sensitive hexahydrotriazine (HT) networks will be prepared through the condensation of formaldehyde and aromatic amine groups from the above-mentioned ammonia-based raw materials, and the subsequent curing process. It is hopeful to obtain PHT owning both high performance and recyclable property for the "hardness with softness" chemical structure of PHT and the mild acidolysis of HT. What's more, the curing mechanism of PHT will be revealed by intensively studying on the progress of condensation of formaldehyde and aromatic amine groups, and the relationship between structure and properties will be adequately explained through testing the thermal, electrical, surface properties, chemical stability and recyclability of PHTs with different structures. And then, those research results could be further used to guide the designing of molecular structure and optimize the curing and recovery processes of PHT. This project will provide a new idea for the development of recyclable and high-performance thermosets, which will provide scientific basis for the degradation and recycling of high-performance thermosetting polymer materials in high-tech field.

传统高性能热固性树脂难以降解回收，由此引起的不可再生石化资源和环境危害等问题日益突出，而开发可回收高性能热固性材料是从根源上解决上述问题的有效途径。本项目拟通过分子设计，合成包含柔性苯醚和耐热性芳杂环的芳香二胺，以及氨基位于末端或侧链的聚芳醚类齐聚物，利用它们结构中的氨基与多聚甲醛的缩醛胺反应，固化成型制得以酸敏感型六氢三嗪（HT）环为交联结构的热固性聚六氢三嗪（PHT）树脂。PHT树脂“刚柔并济”的结构和HT环的温和酸解特性有望同时赋予其高性能和回收性。通过深入研究缩醛胺反应的进程，探明PHT树脂的固化机理；通过研究不同结构PHT材料的力学、热学、表面性能、化学稳定性和回收性等性能，揭示PHT材料结构与性能的关系，进而指导PHT的结构设计、固化成型和回收工艺的优化。本项目将为可回收高性能热固性树脂的研发提供新思路，对高新技术领域用高性能热固性高分子材料的降解和回收循环使用提供科学依据。

热固性树脂因稳定的三维交联结构而难以降解回收，因此其大量的废弃物给自然生态环境造成了严重的危害。如何使热固性树脂兼具良好综合性能和回收性是解决热固性树脂回收难题面临的主要问题，解决该问题的关键是在热固性树脂中引入不弱化树脂性能的可降解结构。本项目重点研究了基于酸敏感性六氢三嗪（HT）环构建高性能可降解热固性树脂的两种路径，一是采用“刚柔并济”结构特征的芳香醚胺与多聚甲醛制备具有HT环交联结构的聚六氢三嗪（PHT）树脂，二是直接将含HT环结构的衍生物引入到环氧树脂、聚氨酯等热固性树脂中，探明了含HT环结构热固性树脂的固化机理和降解机理，揭示了上述热固性树脂结构对性能的影响规律，阐明了兼具良好综合性能和降解回收性的高性能热固性树脂的分子结构设计原理，取得了预期的结果。本项目首先研究了不同芳香醚胺结构对PHT树脂性能的影响规律，发现高刚性芳香醚胺结构单元赋予了热固性树脂良好的力学强度、疏水性、耐有机试剂性能的同时，也抑制了HT环结构的形成，未转化为HT环的非环化结构相比HT环更容易被酸解还原得到原料芳香醚胺，但也降低了PHT树脂的耐热性，研究也发现4,4'-双(4-氨苯氧基)联苯制备的PHT树脂兼具良好的综合性能和降解回收性，可作为传统难降解高性能热固性树脂的潜在替代品。基于上述研究发现，为了避免HT未环化结构的存在劣化热固性树脂耐热性的问题，开发了含完善HT环结构的胺类、多元醇和丙烯酸酯类衍生物，并将其用于环氧树脂和聚氨酯等可降解热固性树脂的制备，研究了HT衍生结构及其含量对热固性树脂性能和降解性的影响规律，揭示了热固性树脂的降解机理。该项目为从根源上解决热固性树脂降解回收难题提供了新思路和新方法，对发展具有潜在应用价值的可降解高性能热固性树脂具有重要意义。项目执行以来，共发表论文5篇，其中SCI收录4篇，申请发明专利2项。