Preparation of PVDF/PS blend micro-porous membrane

The micro-porous membrane was prepared from PVDF/PS blend polymer by L-S phase inversion method.The effects of polymer concentration,PVDF/PS ratio,solvents,additive,temperature and composition of coagulation bath,solvent volatilization time and heat treatment temperature on the membrane performance were studied.The results under the experimental conditions show that:(1) DMF/DMAc blend solvent was beneficial to improve the pore size and porosity of the membranes;(2) the pore size and the porosity of the membranes increased as LiCl concentration increased;(3) temperature of coagulation bath was less effective for membrane performance than composition of coagulation bath;(4) the pore size and the porosity of the membranes decreased with extending solvent volatilization time.When proper composition of casting solution were selected,the micro-porous membrane with pore diameter 0.2～1.0 μm and porosity 90% can be obtained,and porosity of PVDF/PS blends membrane was more than that of PVDF membrane,so it is a good method to improve pore size and porosity of PVDF membrane with blend method.