Effect of Nucleating Agents on morphology and performances of iPP Hollow Fiber Microporous Membranes via Thermally Induced Phase Separation

摘要

Isotactic polypropylene (iPP) hollow fiber microporous membranes were prepared via thermally induced phase separation (TIPS) process. The casting solution was composed of iPP, diluents and nucleating agent. Diluents were the mixtures of Di-n-butyl phthalate (DBP) and Dioctyl phthalate (DOP). The nucleating agents were 1,3:2,4-bis (3,4-dimethyl) benzylidene sorbitol (M3988) and adipic acid, respectively. DOP mass fraction in the diluent and iPP mass fraction in casting solution were fixed at 0.65 and 0.45, respectively. The content of M3988 and adipic acid ranged from 0 to 0.5 wt % and from 0 to 0.2 wt % (based on the mass of iPP), respectively. The effect of nucleating agents on the morphology and performance of hollow fibers were investigated. It is suggested that nucleating agent can adjust the competition between thermally induced liquid-liquid phase separation and polymer crystallization of the casting solution. The pore connectivity of the membrane can be improved at appropriate additon of the nucleating agent; moreover, other performances of the resulting membrane are improved also.