Microporous membrane formation via thermally-induced phase separation. IV. Effect of isotactic polypropylene crystallization kinetics on membrane structure

Abstract Non-nucleated and nucleated isotactic polypropylene microporous membranes have been prepared via thermally-induced solid—liquid phase separation of polymer-diluent mixtures. Three linear alkanes and mineral oil were used as the diluents and adipic acid was used as the nucleating agent. The membranes were formed under isothermal and non-isothermal crystallizing conditions. Membrane structures as determined by scanning electron microscope depended on polymer concentration, cooling rate, and the addition of nucleating agent.