基于聚四氢呋喃的形状记忆聚氨酯的合成及形状记忆性能

Synthesis and Characterization of Polytetrahydrofuran-Based Shape Memory Polyurethane

采用两步法合成了以聚四氢呋喃(PTMG)为软段,4,4′-二苯基甲烷二异氰酸酯(MDI)、扩链剂2,2-二羟甲基丙酸(DMPA)和封端剂4-(2-(吡啶-4-基)乙烯基)苯酚为硬段的形状记忆聚氨酯(PTMGUs)。通过傅里叶变换红外光谱和核磁共振氢谱等表征了其结构,将聚氨酯制成薄膜后,分别通过热重分析、差示扫描量热及循环拉力动态力学分析等测试研究了硬段含量对其热性能和形状记忆性能的影响,摄像记录其形状回复过程。结果表明,不同硬段含量的PTMGUs都具有较好的形状记忆性能,4次重复形状记忆循环中PTMGUs的平均固定率与回复率都高于90%,其中PTMGU3(硬段质量分数为35%)的形状记忆性能最佳,平均固定率达到96.9%,平均回复率达到99.5%。

Taking polytetrahydrofuran(PTMG)as soft segment,4,4′-diphenylmethane diisocyanate(MDI),chain extender 2,2-dimethylolpropionic acid(DMPA)and blocking agent 4-(2-(pyridin-4-yl)vinyl)phenol as hard segment,shape memory polyurethanes(PTMGUs)were synthesized by two-step method.The structures of PTMGUs were characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy.After the polyurethanes were made into films,the effects of different hard segment contents on the thermal performance and shape memory properties were investigated by thermogravimetric analysis,differential scanning calorimetry and cyclic tensile dynamic thermomechanical test.Shape recovery processes were recorded via videos,and the results show that PTMGUs with different hard segment contents exhibit good shape memory performance.Both average fixed rates and recovery rates of PTMGUs are up to 90%.Among them,PTMGU32(mass fraction of 35%)has the best shape memory performance,the average fixed rate is up to 96.9%,and the average recovery rate is up to 99.5%.