Vitrimers are a class of polymeric materials with outstanding properties. Intramolecular substitution reactions lead to a dynamic exchange within the polymer network which enables thermoreversible stress relaxation in yet permanently crosslinked materials. In this paper, the acid‐mediated autocatalysis is explored as a rearrangement pathway for vinylogous urethane vitrimers. The autocatalysis enables transimination reactions, resulting in a dynamic exchange among the enamine‐one species, without an excess of free amines. Therefore, the enamine‐ones are protonated by a Brønsted acid and turn into electrophilic iminium‐ones, thus enabling fast backward and substitution reactions with water and free amines. This work provides an in‐depth investigation of the mechanism by kinetic studies of selected compounds. In addition, novel elastomeric and thermosetting poly(vinylogous urethane) networks with and without free amine groups and additional para‐toluene sulfonic acid as a Brønsted catalyst are prepared by bulk polymerization of hexane‐1,6‐diylbis(3‐oxobutanoate) and tris(2‐aminoethyl)amine. The underlying exchange mechanisms are determined by stress‐relaxation experiments with stress relaxation times of 0.3–54 000 s at 110 °C.

中文翻译：

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乙烯基氨基甲酸乙酯微晶酸中的酸介导的自催化。

微晶粉是一类具有出色性能的聚合材料。分子内取代反应导致聚合物网络内发生动态交换，从而使永久交联的材料中的热可逆应力松弛。在本文中，酸介导的自催化被探索为乙烯基类氨基甲酸酯三聚体的重排途径。自动催化能够进行转氨反应，从而使烯胺一类物质之间发生动态交换，而不会产生过量的游离胺。因此，烯胺酮被布朗斯台德酸质子化并变成亲电亚胺酮，从而能够快速逆向反应并与水和游离胺进行取代反应。这项工作通过对选定化合物的动力学研究提供了对该机理的深入研究。此外，对苯磺酸作为布朗斯台德催化剂的制备方法是将己烷-1,6-二丁基双（3-氧代丁酸酯）与三（2-氨基乙基）胺本体聚合制得。潜在的交换机制由应力松弛实验确定，应力松弛时间在110°C时为0.3–54 000 s。