Abstract: In this paper, PTFE/ZrO2 composite microporous membrane was prepared via mechanical tensile method, using PTFE resin emulsion as a matrix phase and micronanozirconium dioxide (ZrO2) powder as a reinforcer. The crystallinity of the microporous membrane was determined using XRD. The effects of the ZrO2 content, draw ratio, heattreatment temperature and time on the crystallinity of the microporous membrane were studied through a singlefactor method. It showed that the crystallinity was positively proportional to the draw ratio, calcination time, and temperature, but inverse proportional to the ZrO2 content. The optimal comprehensive performance was obtained with following parameters: ZrO2 content 7 %, draw ratio 1~2.5 times, heat treatment temperature 310 ℃, and heat treatment time 10 min.

Key words: polytetrofluoroethylene(PTFE), zirconium dioxide, microporous membrane, crystallinity