硬段结构对分子链含亲水基团的聚氨酯形状记忆性能的影响

Effect of Hard Segment Structure on Polyurethane Shape Memory Effect with Hydrophilic Group in the Chain

采用自乳化法,用聚酯二元醇、二苯基甲烷二异氰酸酯(MDI)或异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、乙二胺(EDA)、三羟甲基丙烷(TMP)等单体合成了分子链含亲水基团的聚氨酯。用FTIR对聚氨酯进行了结构表征,并测试了胶膜力学性能和形状记忆性能。主要探讨了硬段结构与质量分数,回复温度和多次拉伸-回复对聚氨酯形状回复率的影响。结果表明,聚氨酯分子链内引入苯环或化学交联结构,可以改善材料的力学性能和形状记忆性能;聚氨酯的硬段质量分数有一最佳值,达到此值形状回复率最大;不同硬段结构的聚氨酯达到最大形变回复率的临界硬段质量分数不同,硬段的结构越稳定,其在形状记忆聚氨酯中的质量分数越低。多次拉伸-回复可以提高形状记忆性能。

The polyurethane with hydrophilic group in the chain was synthesized from polyesterglycol, di- phenylmethane diisocyanate （MDI）, isophorne diisocyanate （IPDI）, dimethylol propionic acid （DMPA）, ethylenediamine （EDA） and trimethylolpropane （TMP） and other monomers by self-emulsified method. The structure of polyurethane was characterized by Fourier transform infrared spectrometer （FTIR）. The me- chanical properties and the shape memory properties were measured. The effects of the structure, the content of hard segment, the recovery temperature and the draw-recovery times on shape recovery ratio of polyurethane were discussed. The results showed that： the aromatic ring and chemical cross-linked structure were intro- duced into the polyurethane chain; the mechanical property and the shape memory property of the polyure- thane were improved. The shape recovery ratio of the polyurethane was the highest, when the hard segment content reached its optimum value. The different hard segments which could reach the maximum shape recov- ery ratio had different critical hard segment content. The more stable the hard segment structure was, the less the hard segment content in the shape memory polyurethane became. Several times of draw-recovery could enhance the shape memory effect.