End-of-life upcycling of polyurethanes using a room temperature, mechanism-based degradation
End-of-life upcycling of polyurethanes using a room temperature, mechanism-based degradation
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DOI：
10.1038/s41557-023-01151-y
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发表时间：
2023-03-02
期刊：
影响因子：
21.8
通讯作者：
Zimmerman, Steven C.
中科院分区：
文献类型：
--
作者：
Morado, Ephraim G.;Paterson, Mara L.;Zimmerman, Steven C.
开发可回收聚合物材料的一个主要挑战是其使用寿命期间和之后所需性能之间的固有冲突。特别是，材料在使用时必须坚固耐用，但当材料接近其使用寿命时，最好在温和的条件下发生完全和快速的降解。我们报告了一种称为环化触发链断裂（CATCH 断裂）的聚合物降解机制，它实现了这种二元性。 CATCH 裂解采用简单的基于甘油的无环缩醛单元作为门控链破碎的动力学和热力学陷阱。因此，有机酸诱导瞬时链断裂，形成氧碳鎓离子，并随后发生分子内环化，从而在室温下使聚合物主链完全解聚。通过最少的化学改性，聚氨酯弹性体产生的降解产物可以重新用于强力粘合剂和光致变色涂料，展示了升级回收的潜力。用于低能量输入分解和后续升级循环的 CATCH 裂解策略可以推广到更广泛的合成聚合物及其报废废物流。
A major challenge in developing recyclable polymeric materials is the inherent conflict between the properties required during and after their life span. In particular, materials must be strong and durable when in use, but undergo complete and rapid degradation, ideally under mild conditions, as they approach the end of their life span. We report a mechanism for degrading polymers called cyclization-triggered chain cleavage (CATCH cleavage) that achieves this duality. CATCH cleavage features a simple glycerol-based acyclic acetal unit as a kinetic and thermodynamic trap for gated chain shattering. Thus, an organic acid induces transient chain breaks with oxocarbenium ion formation and subsequent intramolecular cyclization to fully depolymerize the polymer backbone at room temperature. With minimal chemical modification, the resulting degradation products from a polyurethane elastomer can be repurposed into strong adhesives and photochromic coatings, demonstrating the potential for upcycling. The CATCH cleavage strategy for low-energy input breakdown and subsequent upcycling may be generalizable to a broader range of synthetic polymers and their end-of-life waste streams.