热固性树脂基复合材料的变革性制造方法研究进展

Advances in the novel fabrication methods for thermoset composites

热固性树脂所特有的共价键交联网络结构,使其及其复合材料的降解回收再利用、连接、损伤修复、3D打印等成为世界难题,也对学术界和工业界提出了重大挑战.人们为此付出了巨大的努力,但并未取得预期效果.最近出现的自适应热固性树脂,为解决这些难题提供了新的机会.本课题组针对典型的自适应热固性树脂,构建了跨尺度热压辅助连接界面力学模型及有限元实现方法,研究了小分子介入的酯键交换反应原理,实现了自适应热固性树脂的无压力连接,连接界面的断裂能可达4000 J/m2,实现了自适应热固性树脂的循环3D打印,自适应热固性树脂基复合材料的损伤修复、基体和纤维的近乎100%的回收再利用,实现了工业用环氧树脂基复合材料中碳纤维和玻璃纤维的回收.这些方法有希望成为热固性树脂基复合材料的变革性制造技术.本文拟综述这方面的最新研究进展,并指出存在的问题和挑战,提出理论研究、材料设计、工业应用等未来发展方向.

The permanently covalent cross-links in thermosetting polymers is a worldwide concern that impedes degradation and recycling as well as joining, repairing and 3 D-printing of thermoset composites, which remains an enormous challenge in both academic and industrial fields. Great efforts have been devoted to this field, which, however, are not effective and are still open problems. With this regard, the recently-developed covalent adaptable networks(CANs) open up a new window for reprocessing thermoset composites. In view of the typical CANs, we established a multi-scale mechanical model and the correspondingly computational method for surface welding in covalent adaptable networks with assistance of thermal compression. Moreover, we investigated a novel transesterification reaction mechanism assisted with a small hydroxyl-based molecule, and it has been successfully used in the field of pressure-free joining of CANs attaining a maximum interfacial fracture energy of up to 4000 J/m2. Simultaneously, a sustainable 3 D-printing of CANs was achieved. Also, the surface damage repair of CANs-based thermosetting composites as well as near 100% reclamation and re-fabrication for CANs resins and fabrics have been attained. Particularly, this has been extended to the successful recycling of advanced carbon-and glass-fabrics from industrial grade epoxy composites. These tries possess a tremendous potential to be the revolutionary fabrication method for thermoset composites. Accordingly, this article systematically reviews the advances in CANs mentioned above and highlights their current issues and challenges. Finally, we suggest an outlook on the future of theoretical model,material design and industrial application of CANs that are in highly demanded.