含动态共价键光敏3D打印树脂的设计制备及其自修复和再加工性的研究

Due to their superior mechanical stability at high temperature, excellent chemical resistances as well as good compatibility with high-resolution three-dimensional (3D) printing technologies, thermosetting photopolymers have claimed almost half of 3D printing materials market. However, the chemically cross-linked nature brings considerable difficulty in reprocessing and recycling such materials. In the previous study, the applicant developed a reprocessable thermosetting photopolymers which are suitable for UV based 3D printing technique, and initially explored the feasibility of reprocessing such resin. In view of this, the project intends to introduce dynamic covalent bonds into the photosensitive printing system, and develops a dynamic covalent bond based photosensitive resin, which is suitable for photocuring based 3D printing, and also is self-healable and reprocessable. The implementation of this project is expected to develop dynamic covalent bond-based photopolymers with controllable mechanical properties, which can further improve the self-healing ability by introducing dynamic physical bonds. Moreover, the recyclable 3D printing of the thermosetting photopolymers could be realized, providing a practical solution to address environmental challenges associated with the rapid increase in consumption of 3D printing materials.

热固性光敏树脂因其优异的高温力学稳定性、耐化学性以及与高精度3D打印系统良好的兼容性，几乎占据了3D打印材料市场的半壁江山。然而其共价交联的特性使得该树脂难以回收和再加工，这种不可再处理性导致大量的材料浪费从而产生严峻的环境污染问题。因此开发可再加工的热固性光敏树脂迫在眉睫。申请人前期初步探索了设计制备可再处理热固性光敏树脂3D打印材料的可行性。鉴于此，本项目拟将动态共价键引入到光敏打印体系中，开发出含动态共价键的光敏树脂，使其适用于光固化3D打印的同时，也具备自修复功能和再加工性。本项目的实施，预期开发出机械性能可调控的含动态共价键光敏树脂材料，并通过引入其他非共价键等方法进一步提高所制备材料的自修复能力和再加工性，实现光敏树脂的可循环3D打印，缓解由于3D打印材料消耗量持续增加带来的环境挑战。

热固性光敏树脂因其优秀的高温力学稳定性、耐化学性以及与高精度3D打印系统良好的兼容性被广泛的应用于3D打印领域。但是传统的热固性光敏树脂在打印过程中形成了共价交联网络，使得所打印的结构不具备再塑形、再修复和再回收的能力，导致了大量材料的浪费，加剧了环境污染。因此，迫切需要开发既具有经济优势又能减轻环境负担的可回收的3D打印热固性光敏树脂。本项目针对热固性光敏3D打印材料的再加工（再塑形、再修复和再回收）问题，通过分子结构设计制备含动态共价键的单体/预聚物，开发出一系列机械性能可调控的含动态共价键的光敏树脂，考察了紫外光照射条件下单体/预聚物固化成型工艺参数，并采用光固化3D打印技术，实现了三维结构的快速一体成型，通过引入非共价键，如氢键等，进一步增强了打印结构的强度和韧性，深入优化分析结构、功能和力学性能的自修复情况，并最终通过3D打印和键交换反应使废弃的含动态共价键树脂被制造成为高精度的复杂产品，实现该种材料的升级回收。借助溶剂化策略实现了含动态共价键光敏树脂的可循环3D打印。通过改变树脂溶液中单体和交联剂的比例等手段调整打印结构的交联密度，解决了有效调控光敏树脂3D打印材料机械功能的问题。利用含动态共价键基团的小分子对制备的含动态共价键光敏树脂进行解离、溶解、回收，并进一步对其进行功能化，实现了将打印出来的物件再转变成光敏树脂材料的难点问题。同时，基于光固化3D打印功能材料、多材料等方式实现智能结构与器件方面的研究工作，初步探索了基于含动态共价键光敏树脂在智能驱动、航空航天、柔性电子器件等领域的应用。基于上述成果，主持者在国际知名期刊Nature Communications, Science Advances, Advanced Materials, Advanced Functional Materials, Additive Manufacturing, Chemical Engineering Journal等国际和国内顶级期刊上发表期刊论文13篇，其中影响因子大于10的7篇。并申请中国发明专利2项, 其中授权1项。在人才培养方面，培养在站博士后1名，博士生3名，硕士生7名。