液化MDI/PHMA体系形状记忆聚氨酯结构与性能的研究

STUDIES ON MORPHOLOGY AND PROPERTIES OF PHMA LIQUIFIED MDI/BDO SHAPE MEMORY POLYURETHANES(PU)

用聚已二酸已二酯（PHMA）为软段，液化MDI和BDO为硬段，采用两步溶液法合成了具有形状记忆功能的多嵌段聚氨酯，利用DSC，WAXD等测试手段分析了该体系的形态结构，同时讨沧了该体系的形状记忆行为、拉伸力学性能及动态力学性能．结果发现，该体系SMPU的硬段以无定形存在，软段具有很好的结品性能；具有很好的形状记忆性能，形状固定率可达100％，形状回复率在97％以上，回复温度在35。45℃；同时它兼有较高的拉伸强度（约为28～50MPa）和断裂伸长率（约为900％．1400％）；动态力学性能卓越，其室温模量可达279．8MPa，软段熔融前后模量比可达140．

Segmented polyurethanes, Poly （ hexamethylene adipate）/liquified 4,4＇- methylenedi （phenylisocyanate） （L-MDI）/butanediol （PHMA/L-MDI/BDO） were prepared by a two-step process, and their structure and shape memory effect were investigated by DSC, WAXD testing, the tensile mechanical, dynamical mechanical properties were discussed also in this paper. It was found that the hard segment regions of these PUs were amorphous, and the soft segment ones were crystalline. The samples exhibited obvious shape memory behavior with shape recovery temperature around 35 -45℃. The strain fixity was close to 100% ,and the maximum shape recovery rate was more than 97 % . The sample showed high tensile strength, 28 - 50 MPa, and large elongation at break, 900 % - 1400 %, at room temperature. Dynamic mechanical tests indicated that the modulus at room temperature was about 140 times as high as that in the rubbery platean region, it shown an excellent dynamical property.