Polypropylene reinforced with hollow glass microspheres: effect of thermal aging and reprocessing

Abstract The hollow glass microspheres (HGM), exhibit low density, reduced dielectric constant, and good thermal conductivity. This study assessed the mechanical performance of polypropylene (PP) reinforced with HGM under artificial thermal aging conditions. The compositions underwent two rounds of reprocessing in a single-screw extruder, and samples were prepared for both tensile and impact testing. Tensile specimens were subjected to thermal aging at 100 ºC for seven and 21 days. Mechanical tests were carried out on samples before and after aging, while exposed samples underwent visual inspection, optical microscopy, and Fourier transform infrared spectroscopy analysis. Visual inspection and microscopy revealed improved PP-HGM interaction due to the additives, with no deformation or damage from reprocessing. Infrared spectroscopy showed minor degradation in the PP structure post-exposure. In summary, the presence and content of HGM, reprocessing, and aging time significantly affect the mechanical properties (elastic modulus, breaking stress, elongation at break, and impact resistance).