【摘要】 本文以差热分析(DSC)、动态力学分析(DMA)研究了聚氨酯-酰亚胺(PUI)、聚氨(?)(PU)、聚(氨酯-脲)(PU-U)材料的微相分离特征。DSC分析表明:软段聚醚分子量为1000时PUI软段相的T_g=46.2～-48.6℃,随PI硬段含量的增加而略有下降,相应PU的T_g为-33.8℃PU-U为-17.2℃,这一规律表明,硬、软段之间的氢键作用部分抵消了它们之间固有的不相容性,使相混合程度增加。 提高聚醚段的分子量使软段相的T_g下降,但这仅仅是T_g对链柔性依赖性的自然结果,与相分离程度无直接关系。 动态力学试验的E"～T分析支持了DSC结果。PUI样品的E’～T曲线均显示了明显的“橡胶平台区”,平台区的宽度及模量值随硬段含量的增加而增加,硬段(PI)含量为38％的PUI样品在190℃时仍有2.19×10~8dyn/cm~2的弹性模量值,说明PUI材料兼具良好的低温性能和卓越的热-机械性能。更多还原

【Abstract】 The microphase separation featuies of poly-(urethane-imide)-, polyurethane ( PU ) , and poly-(urethane-urea)-(PU-U) were investigated by using DSC and DMA (Dynamic Mechanical Analysis) .DSC analysis indicate that Tg for soft-phase of PUI, lying in a range of -46 ,2℃ to -48, 6℃, is independent of the hard-segment (PI) contents. It has been confirmed that the increase of the extent of H-bond interaction will result in a more phase-mixing texture which is characterized by a rising trend of Tg for soft phase. A longer softsegment will lead to lowering of Tg of soft-phase. This fact, however, may not be correlated with phase-separation extent.E’-T curves have supported the results of DSC. E’ -T curves for PUI samples clearly demonstrate a "rubbery plateau" , the width and height of which increase with the increase of hard-segment content. As compared with usual elastomers,PUI proved to have both low-temperature flexibility and excellent thermo-mechanical properties.更多还原