Isotactic polypropylene(iPP) hollow fiber microporous membranes were prepared via thermally induced phase separation(TIPS)method.The mixture of di-n-butyl phthalate(DBP)and dioctyl phthalate(DOP)was used as diluent.The effects of α(DBP mass fraction in mixed diluent)and β(iPP mass fraction in polymer solution)on pore size distribution of the membrane were investigated by N2-liquid displacement measurement.The connectivity of the membrane was evaluated with membrane tortuosity.It is noted that resulting membrane is apt to possess a narrow pore size distribution.For same β,the mean pore size and connectivity of resulting membrane decrease with increasing α.For α=0.20,with increasing β,mean pore size of resulting membrane increases with subsequent decreasing,while resulting membrane connectivity increases slightly.For α=0.35 or α=0.50,the mean pore size and connectivity of resulting membrane decrease with increasing β.It is indicated that the change of connectivity is attributed to the difference of the membrane topology.It is shown that membrane pore size and connectivity can be controlled effectively by choosing proper α and β.
