Impact and flexural properties of PP/CaSiO₃ composites

The effects of filler surface treatment and content on the impact fracture toughness and flexural properties of polypropylene (PP) composites filled with wollastonite (CaSiO₃) were investigated. The results showed that the introduction of the filler could toughen and reinforce the PP; the influences of the filler surface treatment on the toughness and strength were significant; the values of the Izod V‐notched impact strength and the Charpy V‐notched impact strength of the composites increased with increasing the filler weight fractions; the values of flexural modulus increased with increasing the filler weight fractions; the flexural strength increased when the filler weight fraction was lower than 10% and then varied slightly. This toughening effect should be attributed to the stress concentration because of strip shape of the filler and to block the development of the notched cracks in the matrix, improving the notched sensitivity to the impact fracture of the PP composites. This study should be helpful to understand the mechanisms of CaSiO₃ reinforcing and toughening PP resin. POLYM. COMPOS., 39:398–404, 2018. © 2016 Society of Plastics Engineers