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Magnetic field-induced orientation of a chiral side chain liquid crystalline polyacrylate(P-11) was studied by using IR dichroism. For the investigated P-11, it has been shown thatthe magnetic alignment takes place over the entire temperature range between its meltingpoint and clearing point and the orientation level is strongly temperature-dependent, thedevelopment with time of the magnetic orieatation follows an exponeotial-type relation,and the smectic phase state influences the thermal relaxation process in the absence of themagnetic field. 相似文献
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Blends of polyamide (Nylon 66) with two different kinds of liquid crystalline polyesters were studied in all the composition range. Homogeneous samples were obtained by coprccipitation from 2 wt%. solution of blends. The thermal properties, crystallinity and morphology of these blends were studied by using DSC, polarizing microscopy, and scanning electron microscopy. The phase transition and morphology of the blends are markedly-influenced by the composition of liquid crystalline polyesters. The mechanical behaviour of PHB/HNA-Nylon 66 blend was improved. although polyamidc (Nylon 66)with the liquid crystalline polyesters were incompatible, but a rather strong interaction between the polymers did exist. 相似文献
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Five kinds of side chain liquid crystalline polymers with a chiral component in the pendant group were synthesized and characterized by GPC, polarizing microscopy, DSC, X-ray diffraction ano Dielectric Relaxation Spectroscopy. The liquid crystalline behaviour of the polymers is affected by the length of flexible spacer, which links the mesogenic side chain to the polymer backbone and mesogenic moiety. The characteristic of smectic phase is observed for all the polymers. 相似文献
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插层聚合聚丙烯-蒙脱土纳米复合材料的微观结构形态 总被引:25,自引:0,他引:25
使用偏光显微镜,扫描电镜,透射电镜和广角X射线衍射法研究了插层聚合法制备的聚丙烯-蒙脱土(PP-MMT)纳米复合材料的微观结构和形态发展。结果表明,随着插层聚合反应的进行,较大的初级MMT粒子逐渐剥离成较小的次级粒子。次级粒子由2-20片的单个MMT片层组成,其层间充满了PP分子链。提出了插层聚合过程中PP-MMT复合材料的形态发展模型。另外,MMT的加入对PP的球晶形态也有重要影响,PP完整的球晶随MMT的加入逐渐变小和趋于扭曲甚至破坏。 相似文献
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插层聚合制备聚丙烯/蒙脱土纳米复合材料及其结构性能表征 总被引:32,自引:0,他引:32
将插层聚合的概念引入烯烃聚合,制备了聚丙烯/蒙脱土(PP/MMT)纳米复合材料。X射线衍射和TEM分析结果表明,蒙脱土在聚丙烯基体中达到了纳米级的分散,动态力学性能研究结果表明,在高于Tg的温度区域内PP/MMT纳米复合材料的储能模量(E′)成倍增加,加入8%的蒙脱土(MMT),PP/MMT的E′提高近3倍。PP/MMT的玻璃化转变温度Tg有一定程度的提高,随蒙脱土含量的增加,PP/MMT的热分解温度和热变形温度(HDT)都有大幅度提高。 相似文献