Effect of Diluent on the Morphology and Performance of IPP Hollow Fiber Microporous Membrane via Thermally Induced Phase Separation1

Isotactic polypropylene (iPP) hollow fiber microporous membranes were prepared using thermally induced phase separation (TIPS) method. Di-n-butyl phthalate (DBP), dioctyl phthalate (DOP), and the mixed solvent were used as diluents. The effect of a (DOP mass fraction in diluent) on the morphology and performance of the hollow fiber was investigated. With increasing a, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical paniculate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.