聚硅氧烷聚脲的结构与性能研究

STUDIES ON THE STRUCTURE AND PROPERTIES OF POLYSILOXANE POLYUREA BLOCKCOPOLYMERS

利用４，４′－．二异氰酸酯二苯醚与胺丙基封端的聚二甲基硅氧烷反应，合成了一类新型聚硅氧烷聚脲嵌段共聚物。结合热分析、动态力学分析以及小角Ｘ光散射的结果对其结构进行了表征。另外还采用紫外吸收、荧光光谱分析、热失重分析和应力－应变分析等手段研究了这一体系的耐热性、抗光老化性及其力学性能。结果表明，将ＭＤＩ中的亚甲基换成醚键后，有利于防止聚脲分子在光作用下形成醌式结构，提高了聚脲的抗光老化性能。醚键的引入也使硬段堆积紧密，但这一材料的拉伸强度要低于相应的用ＭＤＩ合成的聚脲。

A series of polyuers bolckcopolymers based either aminopropylteminated polydimethylsiloxane or cyano side group containing polysiloxane were synthesized. The hard segments consisted of 4,4-methylenediphenylene diisocyanate (MDI ) or 4, 4'-oxygendiphenylene diisocyanate (ODI ),chainextended with 1, 2-ethylendiamine, The hard segment content varied from 11% to 16%(mass). The morphology and properties of these polymers were studied by DSC, FT-IR, DMA, UV, SAXS tensile testing and fluorescence analysis.These materials exhibited microphase separation of the hard and soft segments; however,attaching polar cyano side groups along the nonpolar polysiloxane chains or changing the methylene group in MDI with oxygen atom promoted phase mixing in comparision with polydimethyisiloxane and MDI based copolymers. In addition, ODI based samples showed better oxidation resistant property and more regular distribution of hard segments than MDI based polyureas.