作者:Cheng-Che Tsai、Chia-Cheng Chang、Ching-Shiang Yu、Shenghong A. Dai、Tzong-Ming Wu、Wen-Chiung Su、Chang-Nan Chen、Franklin M. C. Chen、Ru-Jong Jeng
DOI:10.1039/b910614f
日期:——
In this study, thermally reversible polyurethanes (PUs) with shape memory effect were developed by using hydrogen bonding to enhance physical interactions. Two different types of PUs were synthesized: (1) a linear PU whose hard segment consists of methylene di-para-phenyl isocyanate (MDI) and di(ethylene glycol) (DEG); its soft segment is made of Tone 0260 polyol, a polyester polyol; (2) a side-chain dendritic PU which replaces DEG with different generations of dendritic chain extenders. By incorporation of the dendritic structure with peripheral long alkyl chains (strong van der Waals forces), the miscibility between hard and soft segments can be significantly improved. Consequently, the hydrogen bonding reinforced hard segments (malonamide linkages) of side chain dendritic PUs result in greatly enhanced mechanical properties and shape memory effect. During cyclic shape memory tests, one of the series can effortlessly achieve complete recovery in less than 10 second without any deficiency.
本研究利用氢键增强物理相互作用,开发出了具有形状记忆效应的热可逆聚氨酯(PUs)。研究人员合成了两种不同类型的聚氨酯:(1)线性聚氨酯,其硬段由二对苯二甲异氰酸酯(MDI)和二乙二醇(DEG)组成,软段由聚酯多元醇 Tone 0260 多元醇制成;(2)侧链树枝状聚氨酯,用不同代树枝状链延伸剂取代二乙二醇。通过在树枝状结构中加入外围长烷基链(范德华力很强),可显著提高软硬片段之间的相溶性。因此,侧链树枝状聚氨酯的氢键强化硬段(丙二酰胺连接)可大大提高机械性能和形状记忆效果。在循环形状记忆测试中,其中一个系列可以毫不费力地在不到 10 秒的时间内实现完全恢复,而不会出现任何缺陷。