Non-planar-ring epoxies together with non-planar-ring hardeners could achieve thermosets combining ultra-high shape recovery speed and excellent thermal properties. High shape recovery speed reflected high efficiency, and could decrease the energy consumption and the harmful effect of external stimuli on the materials, while it often conflicts with the thermal properties of shape memory polymers. In this paper, for the first time, epoxy resins with the super-short shape recovery time within 3 s were developed from non-planar-ring epoxies and hardeners, and their glass transition temperature (T_g) were ~127 °C much higher than their benzene ring analogues. The effects of non-planar-ring structures of the epoxies and hardeners on the curing behavior, thermal properties as well as the shape memory properties of the thermosets were systematically investigated; the structure-property relationships were disclosed with the help of computational simulation of structure parameters and ESP maps. The faster shape recovery speed of the non-planar-ring epoxy thermosets is from their higher molecular mobility contributed by the conformational transition of non-planar-rings as well as their higher recovery force compared with benzene ring analogs. Their higher T_gs are from the steric hindrance by the larger molecular volume of the non-planar-rings than benzene ring. This work will provide an effective method to produce shape memory polymers with excellent shape memory effects and high performance.

中文翻译：

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结合超强形状记忆效应和高性能的非平面环型环氧树脂热固性材料的制备

非平面环型环氧树脂与非平面环型固化剂可以实现具有超高形状恢复速度和出色热性能的热固性材料。较高的形状恢复速度反映了高效率，并且可以减少能量消耗和外部刺激对材料的有害影响，而它通常与形状记忆聚合物的热性能相冲突。本文首次从非平面环型环氧树脂和固化剂及其玻璃化转变温度（T _g）比苯环类似物高约127°C。系统地研究了环氧树脂和固化剂的非平面环结构对热固性树脂的固化性能，热性能以及形状记忆性能的影响；通过结构参数和ESP图的计算仿真，揭示了结构-特性关系。与苯环类似物相比，非平面环环氧树脂热固性材料更快的形状恢复速度是由于非平面环的构象转变以及较高的恢复力所致。他们更高的T _gs来自于空间位阻，因为非平面环的分子体积比苯环大。这项工作将提供一种生产具有优异形状记忆效果和高性能的形状记忆聚合物的有效方法。