热拉伸温度对聚偏氟乙烯微孔膜结构与性能的影响

Effect of Hot-Stretching Temperature on Structure and Properties of Poly(vinylidene fluoride)Microporous Membranes

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%。

Poly(vinylidene fluoride)(PVDF)microporous membranes were fabricated via melt extrusion-stretching method(MES)using high and low molecular weight PVDF mixture as raw material.The effect of hot-stretching temperature during hot-stretch step on the surface morphology and crystallization behavior of PVDF microporous membranes were investigated by SEM,FT-IR,XRD,differential scanning calorimetry(DSC)and so on.The results indicate that hot-stretching temperature has profound influences on the pore morphology,porosity,crystallinity and content ofβphase.When the stretching temperature is 80℃,the crystallinity of microporous membranes is 58.86%,and the relative content ofβphase increases to 42.50%,the microporous membranes exhibit the best mechanical properties.When the stretching temperature rises to 120℃,the amount and uniformity of pores are greatly improved.The porosity of microporous membrane can reach as high as 31.51%.