PH sensitive microporous polypropylene membrane prepared through ozone induced surface grafting

Abstract

AbstractPeroxide was introduced onto the microporous polypropylene (PP) membrane through ozone treatment. The acrylic acid monomer was further grafted onto the membrane by peroxide initiation. The effects of different ozone treatment and grafting conditions on the structure, tensile properties, graft yield of the membrane, and the water permeability of the grafted membrane were studied in this paper. The experimental results show that with the increase of ozone treatment time and the raising of ozone treatment temperature, more carbonyl groups (CO) and peroxide were introduced onto the microporous PP membrane. However, excessive ozone treatment made the mechanical properties of the membrane deteriorate, which means the ozone treatment time should be restricted within an appropriate range. With the increase of grafting time, concentration of acrylic acid and the raising of grafting temperature, the graft yield of microporous PP membrane increased. The graft yield could be controlled by altering these reaction conditions. After grafting, the amount of the pores in the microporous PP membrane decreased and the pore size became smaller. The water flux through the grafted membranes decreased dramatically when pH value varied from 3 to 6 because the conformation of the PAA varied significantly with the change of pH value of the contacting solution. Copyright © 2008 John Wiley & Sons, Ltd.