This paper describes the experimental findings of the study of a series of PU/epoxy composites, which formed interpenetrating networks and have shape-memory properties. The morphological variation for different chemical compositions and the influences of morphology on mechanical performance and shape-memory behavior are discussed. Length and mass fraction of polyethylene glycol (PEG) units are chosen as the key parameters in this study. The molecular weight of PEG was varied from 400 (as such PEG units are unable to crystallize) to 1500, 4000, and 6000, which are crystallizable. It was shown that the crystallization of PEG units is the key parameter, which determines the mechanical performance and shape-memory behavior of PU/epoxy composites in this study. DMTA results show the linear dependence of glass transition temperature and tensile strength, elongation, and other mechanical parameters on the amount of PEG in PU/epoxy composites independently of the amount of PEG unit lengths. The maximal value of shape fixation rate was achieved for 30–40 mass percentage of PEG 4000 (4.5 × 10⁻² s⁻¹ at T_g + 20°C) or PEG 6000(4.1 × 10⁻² s⁻¹ at T_g + 20°C) in PU/epoxy composites.

中文翻译：

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多元醇组分分子量对环氧-聚氨酯复合材料形状记忆效应的影响

本文描述了一系列 PU/环氧树脂复合材料研究的实验结果，这些复合材料形成互穿网络并具有形状记忆特性。讨论了不同化学成分的形态变化以及形态对机械性能和形状记忆行为的影响。选择聚乙二醇 (PEG) 单元的长度和质量分数作为本研究的关键参数。PEG 的分子量从 400（因为 PEG 单元不能结晶）到 1500、4000 和 6000（可结晶）不等。结果表明，PEG单元的结晶是决定本研究中PU/环氧树脂复合材料力学性能和形状记忆行为的关键参数。DMTA 结果显示玻璃化转变温度和拉伸强度的线性相关性，伸长率和其他机械参数对 PU/环氧树脂复合材料中 PEG 量的影响与 PEG 单位长度的量无关。PEG 4000 (4.5 × 10^-2  s ^-1 at T _g  + 20°C) 或 PEG 6000(4.1 × 10 ^-2  s ^-1 at T _g  + 20°C) 在 PU/环氧树脂复合材料中。