Thermoset polymers have become integral to our daily lives due to their exceptional durability, making them feasible for a myriad of applications; however, this ubiquity also raises serious environmental concerns. Covalent adaptable networks (CANs) with dynamic covalent linkages that impart efficient reprocessability and recyclability to thermosets have garnered increasing attention. While various dynamic exchange reactions have been explored in CANs, many rely on the stimuli of active nucleophilic groups and/or catalysts, introducing performance instability and escalating the initial investment. Herein, we propose a new direct and catalyst-free C═C/C═N metathesis reaction between α-cyanocinnamate and aldimine as a novel dynamic covalent motif for constructing recyclable thermosets. This chemistry offers mild reaction conditions (room temperature and catalyst-free), ensuring high yields and simple isolation procedures. By incorporating dynamic C═C/C═N linkages into covalently cross-linked polymer networks, we obtained dynamic thermosets that exhibit both malleability and reconfigurability. The resulting tunable dynamic properties, coupled with the high thermal stability and recyclability of the C═C/C═N linkage-based networks, enrich the toolbox of dynamic covalent chemistry.

中文翻译：

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通过 C=C/C=N 动态共价复分解化学推进可回收热固性材料


热固性聚合物因其卓越的耐用性而成为我们日常生活中不可或缺的一部分，使其可用于多种应用；然而，这种普遍存在也引起了严重的环境问题。具有动态共价键的共价适应性网络（CAN）赋予热固性材料高效的可再加工性和可回收性，已引起越来越多的关注。虽然 CAN 中已经探索了各种动态交换反应，但许多反应依赖于活性亲核基团和/或催化剂的刺激，从而引入性能不稳定并增加初始投资。在此，我们提出了α-氰基肉桂酸酯和醛亚胺之间的一种新的直接且无催化剂的C=C/C=N复分解反应，作为构建可回收热固性材料的新型动态共价基序。这种化学反应提供温和的反应条件（室温和无催化剂），确保高产率和简单的分离程序。通过将动态 C=C/C=N 键合到共价交联聚合物网络中，我们获得了具有延展性和可重构性的动态热固性材料。由此产生的可调动态特性，加上基于 C=C/C=N 键合的网络的高热稳定性和可回收性，丰富了动态共价化学的工具箱。