对具有良好液晶聚合物微纤结构的聚丙烯/热致液晶聚合物/玻璃纤维(PP/TLCP/GF)混杂复合材料,使用静态拉伸和动态力学分析(DMA)的方法研究了材料的力学性能。拉伸实验结果表明,混杂复合材料的拉伸强度和模量随着PP和TLCP挤出后的牵伸... 对具有良好液晶聚合物微纤结构的聚丙烯/热致液晶聚合物/玻璃纤维(PP/TLCP/GF)混杂复合材料,使用静态拉伸和动态力学分析(DMA)的方法研究了材料的力学性能。拉伸实验结果表明,混杂复合材料的拉伸强度和模量随着PP和TLCP挤出后的牵伸速率增大而上升,并且含有增容剂PP g MAH的体系,力学性能更优异。DMA测试结果表明,混杂复合材料的动态模量E′随着体系中玻纤的含量增加而增大;当体系中加入增容剂后,复合材料的刚性得到进一步提高。但无论是否使用了增容剂PP g MAH,当体系中玻纤含量高于20%后,模量随玻纤含量增大的趋势变缓。当体系中增强相的含量增加,以及加入增容剂使增强相与基体的界面粘结得到改善后,PP基体的损耗因子(tanδ)峰值都有一定的减小。展开更多
A mesogen-jacketed liquid crystal polymer,poly{2,5 -bis［(4′-hexyloxyphenyl)oxycarbonyl］styrene}(PHPCS),with number-average d molecular weight of 1.28×１０5 and polydispersity of 1.48 was prepared vi a 2,2,6,6 ...A mesogen-jacketed liquid crystal polymer,poly{2,5 -bis［(4′-hexyloxyphenyl)oxycarbonyl］styrene}(PHPCS),with number-average d molecular weight of 1.28×１０5 and polydispersity of 1.48 was prepared vi a 2,2,6,6 -tetramethyl-piperidinyloxy mediated free radical polymerization.The thermotr opic behavior was studied by a combination of differential scanning calorimetry, thermogravimetry,polarized optical microscope and wide-angle X-ray diffracti on.PHPCS was not crystalline over the entire temperature region studied.On hea ting,PHPCS first became an isotropic melt at glass transition temperature (T g) and then a mesophase at temperatures much higher than T g.On subseq uent cooling,the formed ordered phase disappeared above T g.Contrary to t heoretical predictions and previous experimental observations,the transition fr om isotropic melt to liquid crystalline phase was an endothermic process and th e order-disorder transition took place with concurrence of heat release.展开更多
Novel thermotropic liquid crystalline poly(aryl ether ketone) was synthesized via the random copolycondensation of 4,4′ difluorobenzophenone, 4,4′ biphenol and tert butylhydroquinone. The results of differential sca...Novel thermotropic liquid crystalline poly(aryl ether ketone) was synthesized via the random copolycondensation of 4,4′ difluorobenzophenone, 4,4′ biphenol and tert butylhydroquinone. The results of differential scanning calorimetry, polarizing light microscope and X ray diffraction confirmed the liquid crystalline property of the polymer. The polymer may be of great use in blending with normal poly(aryl ether ketone)s.展开更多
Microcellular polystyrene/LCP in situ composites with cell diameter less than 4 μm are prepared by using pressure quenching after supercritical CO 2 saturating at 25?MPa, 80℃ for 6 h. Characterization of the microce...Microcellular polystyrene/LCP in situ composites with cell diameter less than 4 μm are prepared by using pressure quenching after supercritical CO 2 saturating at 25?MPa, 80℃ for 6 h. Characterization of the microcellular structure of these blends is conducted to reveal the influence of LCP addition, LCP ratio and compatibilizer on the microcellular blends. The typical structure of these microcellular PS/LCP blends is that the microvoids only exist in the polystyrene phase. This structure results from the poor adsorption of supercritical CO 2 by LCP under the experimental conditions. The cell diameter of the microcellular blends is smaller than that of microcellular PS. An increase of cell size is also found from skin to core in microcellular blends. The microcellular blends with ZnSPS has larger cell size than those without ZnSPS, which is the consequence of the improvement of interfacial adhesion. It is because CO 2 could easily diffuse out through the gap between poor adhesion interface of blends without ZnSPS.展开更多
文摘 对具有良好液晶聚合物微纤结构的聚丙烯/热致液晶聚合物/玻璃纤维(PP/TLCP/GF)混杂复合材料,使用静态拉伸和动态力学分析(DMA)的方法研究了材料的力学性能。拉伸实验结果表明,混杂复合材料的拉伸强度和模量随着PP和TLCP挤出后的牵伸速率增大而上升,并且含有增容剂PP g MAH的体系,力学性能更优异。DMA测试结果表明,混杂复合材料的动态模量E′随着体系中玻纤的含量增加而增大;当体系中加入增容剂后,复合材料的刚性得到进一步提高。但无论是否使用了增容剂PP g MAH,当体系中玻纤含量高于20%后,模量随玻纤含量增大的趋势变缓。当体系中增强相的含量增加,以及加入增容剂使增强相与基体的界面粘结得到改善后,PP基体的损耗因子(tanδ)峰值都有一定的减小。
文摘A mesogen-jacketed liquid crystal polymer,poly{2,5 -bis［(4′-hexyloxyphenyl)oxycarbonyl］styrene}(PHPCS),with number-average d molecular weight of 1.28×１０5 and polydispersity of 1.48 was prepared vi a 2,2,6,6 -tetramethyl-piperidinyloxy mediated free radical polymerization.The thermotr opic behavior was studied by a combination of differential scanning calorimetry, thermogravimetry,polarized optical microscope and wide-angle X-ray diffracti on.PHPCS was not crystalline over the entire temperature region studied.On hea ting,PHPCS first became an isotropic melt at glass transition temperature (T g) and then a mesophase at temperatures much higher than T g.On subseq uent cooling,the formed ordered phase disappeared above T g.Contrary to t heoretical predictions and previous experimental observations,the transition fr om isotropic melt to liquid crystalline phase was an endothermic process and th e order-disorder transition took place with concurrence of heat release.
文摘Novel thermotropic liquid crystalline poly(aryl ether ketone) was synthesized via the random copolycondensation of 4,4′ difluorobenzophenone, 4,4′ biphenol and tert butylhydroquinone. The results of differential scanning calorimetry, polarizing light microscope and X ray diffraction confirmed the liquid crystalline property of the polymer. The polymer may be of great use in blending with normal poly(aryl ether ketone)s.
文摘Microcellular polystyrene/LCP in situ composites with cell diameter less than 4 μm are prepared by using pressure quenching after supercritical CO 2 saturating at 25?MPa, 80℃ for 6 h. Characterization of the microcellular structure of these blends is conducted to reveal the influence of LCP addition, LCP ratio and compatibilizer on the microcellular blends. The typical structure of these microcellular PS/LCP blends is that the microvoids only exist in the polystyrene phase. This structure results from the poor adsorption of supercritical CO 2 by LCP under the experimental conditions. The cell diameter of the microcellular blends is smaller than that of microcellular PS. An increase of cell size is also found from skin to core in microcellular blends. The microcellular blends with ZnSPS has larger cell size than those without ZnSPS, which is the consequence of the improvement of interfacial adhesion. It is because CO 2 could easily diffuse out through the gap between poor adhesion interface of blends without ZnSPS.
