Anhydride cured epoxy vitrimers usually exhibit desired mechanical strength but poor toughness and slow transesterification rate. Therefore, the repairing property of the material was restricted. In this paper, polyurethane modified epoxy vitrimer (PU-Epv) was prepared. PU was introduced into the vitrimer system of tetrahydrophthalic anhydride cured epoxy to improve the toughness of the material. Meanwhile, because of the presence of amino ester, the transesterification reaction was promoted and the activation energy of the transesterification was only 33.59 kJ/mol. In the thermal welding experiment, the material could be welded at least five times, and scratches on the surface of the samples could be efficiently repaired within 30 min. The toughness of the material was improved without damaging the strength. Meanwhile, the hard thermosetting epoxy was endowed with excellent repairing properties to increase the service life of the material.

中文翻译：

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聚氨酯改性环氧微晶玻璃及其应力松弛行为

酸酐固化的环氧微晶玻璃通常表现出所需的机械强度，但韧性较差，酯交换速度较慢。因此，限制了材料的修复性能。本文制备了聚氨酯改性环氧玻璃体（PU-Epv）。将PU引入到四氢邻苯二甲酸酐固化的环氧树脂的玻璃体体系中，以提高材料的韧性。同时，由于存在氨基酯，促进了酯交换反应，并且酯交换的活化能仅为33.59kJ / mol。在热焊接实验中，材料可以焊接至少五次，并且可以在30分钟内有效修复样品表面的划痕。在不损害强度的情况下提高了材料的韧性。同时，