PREPARATION OF HOLLOW FIBER TYPE PERVAPORATION MEMBRANES FOR ORGANIC-LIQUID SEPARATION MADE BY PLASMA-GRAFT FILLING POLYMERIZATION

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Hollow fiber type pervaporation membranes were successfully prepared by plasma-graft filling polymerization. The membrane is composed of two different polymers ; a porous substrate which can suppress membrane swelling, and a grafted polymer whic forms in the pores of the substrate and exhibits selectivity due to its solubility. Specifically, a porous high-density polyethylene membrane and poly (methylacrylate) were emlployed as the porous substrate and grafted polymer, respectively. Through this technique, the grafted polymer was formed in the pores of the substrate, and the thickness of the grafted layr was around 20mum. Pervaporation separation of benzene/cyclohexane or chloroform/carbontetrachloride were performed with the membranes. The mechanical strength of hollow-fiber substrate was weaker than flat sheet membranes, and the pervaporation selectivity was lower than the membranes. Crosslinking and copolymerization technique were employed to reduce the membrane swelling. Both method allowed us to obtain higher selectivity although permeability was sacrificed. Using these method, we obtained a hollow-fiber membranes having the same level of separation performances that the flat sheet membrane showed.