The chemical recycling of plastics to monomers provides efficient assistance for sustainable development of plastics. For polyglycolide (PGA), it has gained widespread attention to be a highly promising plastic material due to its excellent performance. However, research on the ring-closing depolymerization of PGA has yet to break through. The depolymerization is mainly limited by the challenges brought by high crystallinity and melting point of PGA, and instability of glycolide (GL). In this work, a synergistic transesterification strategy is proposed to achieve efficient depolymerization of PGA to monomer GL. Utilizing the versatile catalyst zinc bis[bis(trimethylsilyl)amide] (Zn(HMDS)2) to promote simultaneous intramolecular and intermolecular transesterification, the random chain scission and back-biting depolymerization is achieved in succession. Therefore, the depolymerization product GL can be obtained in high yield and purity. This strategy will provide new research ideas for the chemical recycling of plastics.

中文翻译：

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通过协同酯交换策略将聚乙二醇成乙二醇的闭环解聚为乙二内酯


塑料的化学回收为单体为塑料的可持续发展提供了有效的帮助。对于聚乙二醇 （PGA），由于其优异的性能，它已成为一种非常有前途的塑料材料，因此受到广泛关注。然而，关于 PGA 闭环解聚的研究尚未取得突破。解聚主要受到 PGA 的高结晶度和熔点以及乙交酯 （GL） 的不稳定性带来的挑战的限制。在这项工作中，提出了一种协同酯交换策略，以实现 PGA 高效解聚为单体 GL。利用多功能催化剂双[双（三甲基甲硅烷基）酰胺锌] （Zn（HMDS）2） 促进分子内和分子间酯交换同时进行，连续实现无规断链和反咬式解聚。因此，可以获得高产率和高纯度的解聚产物 GL。该策略将为塑料的化学回收提供新的研究思路。