The development of photopolymers that can be depolymerized and subsequently re-cured using the same light stimulus presents a significant technical challenge. A bio-sourced terpenoid structure, l-carvone, inspired the creation of a re-curable photopolymer in which the orthogonal reactivity of an irreversible thioether and a dynamic thiol-Michael bond enables both photopolymerization and thermally driven depolymerization of mechanically robust polymer networks. The di-alkene containing l-carvone was partially reacted with a multi-arm thiol to generate a non-crosslinked telechelic photopolymer. Upon further UV exposure, the photopolymer crosslinked into a mechanically robust network featuring reversible Michael bonds at junction points that could be activated to revert, or depolymerize, the network into a viscous telechelic photopolymer. The regenerated photopolymer displayed intrinsic re-curability over two recycles while maintaining the desirable thermomechanical properties of a conventional network: insolubility, resistance to stress relaxation, and structural integrity up to 170 °C. Our findings present an on-demand, re-curable photopolymer platform based on a sustainable feedstock.

中文翻译：

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含有动态硫醇-迈克尔键的本征可重复固化光敏聚合物

开发可以解聚并随后使用相同的光刺激重新固化的光聚合物是一项重大的技术挑战。生物来源的萜类结构l-香芹酮激发了一种可重复固化的光聚合物的创造，其中不可逆的硫醚和动态硫醇-迈克尔键的正交反应性能够实现机械稳健聚合物网络的光聚合和热驱动解聚。含l的二烯烃-香芹酮与多臂硫醇部分反应生成非交联遥爪光聚合物。在进一步的紫外线照射下，光聚合物交联成机械坚固的网络，在连接点处具有可逆的迈克尔键，可以被激活以将网络恢复或解聚成粘性的遥爪光聚合物。再生的光聚合物在两次循环后表现出内在的可再固化性，同时保持了传统网络的理想热机械性能：不溶性、抗应力松弛和高达 170°C 的结构完整性。我们的研究结果提出了一种基于可持续原料的按需、可重复固化的光敏聚合物平台。