摘要
本文以氨丙基封端聚(氰丙基,甲基)硅氧烷(CH_2)_3CN:CH_3=1:5),MDI和EDA为原料,采用DMAC单一溶剂合成了一系列高软段分子量(Mn=3000～9000)和高硬段含量(7～30%wt)的多嵌段共聚物。产物为透明热塑性弹性体,具有良好的成膜性能和宽阔的使用温区,其杨氏模量比相应的聚二甲基硅氧烷-聚脲显著提高。通过FT-IR,WAXD,DSC,DMA等证明其硬段为近程有序结构,氰丙基与聚脲硬段有氢键作用,这一作用力使两相相溶性提高,“界面厚度”增加。氰丙基的引入和硬段含量的增加对材料相结构和力学性能有显著影响。
A series of polyurea biock copolymers based on either aminopropyl-terminatcd polycyanopropylmcthylsiloxanc (ATPCS) or polydimethylsiloxane (ATPS) soft segments were synthesized. The hard segment consisted of 4,4-methylenediphenyiene diisocyanate (MDI) chain-extended with ethylenediamine. The length of soft segments changed from 3000 to 9000 and the hard segment contents varied from 7 to 28%. The cyanopropyl side group concentration was in constant during the synthesis of the ATPCS oligomer in single solvent DMAC. The morphology and properties of these polymers were studied by DSC FTIR DMA WAXD and tensile testing. These materials exhibited microphase separation of the hard and soft segments however attaching polar cyanopropyl side groups alone the apolar siloxane chain promoted phase mixing and decreased the regularity of the hard segments in comparison with polydimethylsiloxane-based polyureas. The increased phase mixing is postulated to lead to improve interfacial adhension. Hence the high hard segment content in the samples based on ATPCS could be obtained which was hardly to achieve in the samples based on ATPS series. The results showed that the urea segments are short range ordered and hydrogen bonded with cyano group in soft segments. The hard segments content and cyanopropyl groups are important factors in governing the morphological and tensile properties of these polymers.
出处
《功能高分子学报》
CAS
CSCD
1991年第1期19-28,共10页
Journal of Functional Polymers
基金
国家自然科学基金
