Making porous polypropylene films by aid of hollow glass beads and hot stretching: strain softening effect

Porous polypropylene films filled with mineral filler are commonly used in separation processes such as battery separators. Uniaxial stretching of precursor polypropylene films containing glass spheres consequences in porous polypropylene films. The pore size and shapes are affected by controlling the filler content and drawing ratio. The yielding behavior of porous polypropylene films prepared by hot stretching was analyzed by tensile testing.