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热拉伸温度对熔体拉伸法制备聚丙烯微孔隔膜微观结构的影响
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作者 谢嘉宜 徐睿杰 雷彩红 《塑料工业》 CAS CSCD 北大核心 2019年第12期31-34,69,共5页
通过小角X射线散射(SAXS)、扫描电子显微镜(SEM)和调制差示扫描量热法(TMDSC)表征了熔体拉伸法制备聚丙烯微孔隔膜在105~145℃的热拉伸过程。发现随拉伸温度升高,拉伸带来的片晶破坏减少,105℃下热拉伸仍然存在片晶被破坏分离;130和145... 通过小角X射线散射(SAXS)、扫描电子显微镜(SEM)和调制差示扫描量热法(TMDSC)表征了熔体拉伸法制备聚丙烯微孔隔膜在105~145℃的热拉伸过程。发现随拉伸温度升高,拉伸带来的片晶破坏减少,105℃下热拉伸仍然存在片晶被破坏分离;130和145℃下热拉伸只发生片晶堆分离。微孔隔膜的孔洞尺寸主要由拉伸倍率和热拉伸温度控制;连接分离片晶的架桥直径和长度增幅随拉伸温度的升高而增大。在热拉伸过程,架桥主要由片晶转化形成,与无定型分子链的二次结晶无关。 展开更多
关键词 聚丙烯 热拉伸温度 微孔隔膜 微观结构
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热拉伸温度对聚偏氟乙烯微孔膜结构与性能的影响
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作者 高志浩 张健敏 +3 位作者 门树林 温荣严 骆林 戴作强 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2021年第10期119-125,131,共8页
采用熔体挤出拉伸法以高、低分子量混合聚偏氟乙烯(PVDF)为原料制备微孔膜,研究了不同热拉伸温度对PVDF微孔膜表面形貌及结晶行为的影响,通过扫描电子显微镜、红外光谱仪、X射线衍射仪和差示扫描量热仪等测试手段分别对微孔膜的形态、... 采用熔体挤出拉伸法以高、低分子量混合聚偏氟乙烯(PVDF)为原料制备微孔膜,研究了不同热拉伸温度对PVDF微孔膜表面形貌及结晶行为的影响,通过扫描电子显微镜、红外光谱仪、X射线衍射仪和差示扫描量热仪等测试手段分别对微孔膜的形态、结构、晶型进行表征。结果表明,热拉伸温度对PVDF微孔膜的成孔形貌、孔隙率、结晶度及β相含量均有影响。热拉伸温度为80℃时,微孔膜结晶度为58.86%,β相的相对含量最高达到42.50%,此时微孔膜的力学性能最佳;而当热拉伸温度为120℃时,PVDF微孔膜的成孔分布更加均匀,其孔隙率可达到最大值31.51%。 展开更多
关键词 聚偏氟乙烯微孔膜 热拉伸温度 β相含量 孔隙率
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MHD three-dimensional flow of Jeffrey fluid with Newtonian heating 被引量:6
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作者 S.A.Shehzad T.Hayat +1 位作者 M.S.Alhuthali S.Asghar 《Journal of Central South University》 SCIE EI CAS 2014年第4期1428-1433,共6页
The magnetohydrodynamic(MHD) three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the... The magnetohydrodynamic(MHD) three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the velocity and temperature fields. Convergence of series solutions is ensured graphically and numerically. The variations of key parameters on the physical quantities are shown and discussed in detail. Constructed series solutions are compared with the existing solutions in the limiting case and an excellent agreement is noticed. Nusselt numbers are computed with and without magnetic fields. It is observed that the Nusselt number decreases in the presence of magnetic field. 展开更多
关键词 three-dimensional flow Jeffrey fluid Newtonian heating
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Experimental Research of Automotive Needlepunched Carpets at Thermoforming Temperatures
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作者 张云青 郭志英 +1 位作者 董湘怀 李德群 《Journal of Donghua University(English Edition)》 EI CAS 2007年第6期728-733,739,共7页
Tensile properties with different thermoforming conditions and deformation mechanism at thermoforming temperatures of automotive needlepunched carpets made up of three layers of different materials were reported.Inves... Tensile properties with different thermoforming conditions and deformation mechanism at thermoforming temperatures of automotive needlepunched carpets made up of three layers of different materials were reported.Investigations on the tensile properties were performed as a function of thermoforming temperature,extensile speed and fiber orientation based on an orthogonal experiment design.The experimental results show that the automotive carpets are rate-dependent anisotropic one and very sensitive to the forming temperature.The tensile properties are strongly depended on the forming temperature when compared with the extensile speed and the fiber orientation.Experiments only varying with the temperature were performed because of the dominative effect of the temperature.Different deformation performances were observed with different temperatures.Deformation mechanisms at the thermoforming temperatures were presented to explain the nonlinear trend of the ultimate elongation with the temperatures based on the combination of the experimental observations and the corresponding polymer theories. 展开更多
关键词 automotive carpet tensile property experimental research deformation meachanism
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