Preparation and characterization of porous microfiltration membranes by using tailor-made propylene/1-octadecene copolymers

Tailor-made isotactic polypropylene (iPP) and propylene/1-octadecene (CiPP-OD) copolymers synthesized via a metallocene catalyst were used for membrane preparation by the thermally induced phase separation (TIPS) process. Although the resulting morphology of the membranes and porosity were found similar, the water permeability for propylene/1-octadecene copolymer membrane (1.0 mol-% of 1-octadecene) was twofold higher compared to iPP membranes. Further increase of 1-octadecene in the polypropylene did not improve the performance of membrane (decrease of permeability). This behaviour was attributed to the compressibility of the pores due to the ductile behaviour of the copolymer. Thus, the presence of a small amount of 1-octadecene (1.0 mol-%) in the polypropylene chain can lead to obtain membranes with improved water permeability for the microfiltration process.