Thermosetting polymers possess high dimensional stability, chemical resistance and thermal stability, and they are indispensable for many applications. However, conventional thermosetting polymers cannot be reprocessed and reshaped due to their permanent cross-linked structure. Therefore, recycling of thermosetting polymers is a serious challenge. Degrading thermosetting polymers into soluble oligomers and reuse of the oligomers in new resin systems may provide a favorable way to solve this problem. In this work, we developed an efficient method for chemical degradation of anhydride-cured epoxy using environmentally benign phosphotungstic acid (HPW) aqueous solution as the catalyst system at a mild reaction temperature of 190 °C. During reaction, the ester bond in the cross-linked structure was selectively cleaved, and the thermosetting polymer was fully converted to oligomers that contain multifunctional reactive groups. When the decomposed matrix polymer (DMP) was used as a reactive ingredient and added up to 40 wt% in the preparation of a new anhydride-cured epoxy curing system, the resulting cross-linked polymers still retained the mechanical properties of the neat polymer.

中文翻译：

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使用良性方法选择性裂解酸酐固化的环氧树脂的酯键，并在新的环氧树脂制备中重复使用分解的聚合物

热固性聚合物具有高的尺寸稳定性，耐化学性和热稳定性，并且它们对于许多应用都是必不可少的。但是，常规的热固性聚合物由于其永久性的交联结构而不能进行再加工和重塑。因此，热固性聚合物的回收是一个严峻的挑战。将热固性聚合物降解为可溶性低聚物并在新的树脂体系中重新使用低聚物可能为解决该问题提供了一种有利的途径。在这项工作中，我们开发了一种有效的方法，以环境无害的磷钨酸（HPW）水溶液为催化剂体系，在190°C的温和反应温度下化学降解酸酐固化的环氧树脂。在反应过程中，交联结构中的酯键被选择性裂解，然后将热固性聚合物完全转化为含有多功能反应性基团的低聚物。当将分解的基体聚合物（DMP）用作反应性成分并在新的酸酐固化的环氧固化体系的制备中添加至多40 wt％时，所得的交联聚合物仍保留了纯聚合物的机械性能。