Tailoring of thermal and mechanical properties of hollow glass bead‐filled polypropylene porous Films via stretching ratio and filler content

The momentous role of hollow glass bead (HGB) fillers to manipulate the thermal and mechanical properties of polymers has become an issue of significant interest. As regards, the scope of this work is oriented to manifest the interplay effects of HGB contents (average size of 60 μm) and uniaxial stretching ratios (100 and 200%) on HGB‐filled bimodal polypropylene (PP) films. SEM micrographs showed that at higher stretching ratio at about 120°C the pore formation was improved which was due to performance of smaller HGB particles. Also increasing the amount of HGBs could notably decrease the permeability of microporous composite films as a result of compaction effect. Moreover, an additional peak in the differential scanning calorimetry of composite films was the nucleating performance of smaller HGB particles. The yielding behavior of the precursor and porous PP samples prepared by hot stretching was analyzed by tensile testing. The results revealed that with the increase in the number of pores, strain softening was faded and eventually completely removed. Therefore, a ductile‐brittle transition occurred in the behavior of the polymer. POLYM. COMPOS., 40:2938–2945, 2019. © 2018 Society of Plastics Engineers