Effects of Filler Content and Size on Drop-Weight Dart Impact Fracture Behavior of Glass Bead-Filled Polypropylene Composites

Three sizes of A-glass beads, 6000 (4 [im), 3000 (35 prm), and 1922 (219 μm), were chosen in this work to identify the effects of filler content and size on the drop-weight dart impact fracture behavior of filled polypropylene (PP) composites at room temperature. At higher filler concentration, the values of the maximum impact load and the crack initiation energy for the PP filled with smaller glass beads were higher than those of the unfilled PP and the systems filled with larger glass beads. However, the crack propagation energy of the former was lower than that of the latter. The influence of the filler content and size on the impact fracture energy of these composites was insignificant. Comparatively, the drop-weight dart impact resistance of the systems filled with smaller glass beads was somewhat improved. Furthermore, the impact fracture morphology of the specimens was observed and analyzed. The results indicated that the smaller particles were more beneficial to initiate and increase microcracks in the PP matrix interlayer around them and thus to improve the impact resistance of the composites at high filler concentrations.