硬弹性材料拉伸成孔机理及PVDF多孔膜的制备

Micro-pore forming Mechanisms and Preparation of PVDF Hardelastic Materials and Porous Membrane by Melt-extrusion

对硬弹性材料结构特征和拉伸成孔机理进行了总结,重点介绍了聚偏氟乙烯(PVDF)硬弹性材料及多孔膜的研究发展现状。结果表明,硬弹性材料是一类经特殊加工的具有排状片晶结构的合成聚合物材料,截然不同于普通弹性材料,具有高弹、高模等特性,并且低温弹性优异,特别是在拉伸时可以形成微孔,该特性已被用于多孔膜的制备。同时指出,目前熔纺拉伸PVDF膜孔隙率和渗透性能有待进一步提高;应进一步深入研究PVDF结晶等超分子结构形态的形成机理,优化挤出及后处理过程,或打破传统的熔融挤出-拉伸成孔工艺,提高膜孔隙率和渗透性能。

The structure characteristics and micro-pore forming mechanisms of hard elastic materials were introduced and the development of PVDF hard elastic material and its porous membrane were reviewed emphatically in this paper. The results showed that hard elastic materials are a kind of synthetic polymer with row- nucleated lamellar crystalline from special processing, which is distinct from traditional elastic materials. They own high elasticity and modulus even at low temperature. It should be noted that micro-pores could be presented in hard elastic materials when stretching. This characteristic could be used to preparing porous membrane. However, for PVDF, the porosity and permeability of membrane by melt-extrusion and stretching （MES） should be improved. The crystallization morphology and process of PVDF need investigating deeply. Melt-extrusion and post-treatment process should be optimized. A novel technique may be employed to improving properties of PVDF membrane by MES.