Characterization of talc/calcium carbonate filled polypropylene hybrid composites weathered in a natural environment

Two kinds of composites, namely single-filler polypropylene (PP) composites (containing either talc or calcium carbonate) and hybrid-filler PP composites (consist of a mixture of talc and calcium carbonate) were injection moulded into dumbbells. These specimens were subjected to natural weathering i.e. tropical climate in Penang, Malaysia for 6 months. After 6 months of exposure, the mechanical properties of single-filler PP composites deteriorated due to severe physical and chemical degradation. However, the hybrid-filler PP composites were found to show better retention in mechanical properties albeit having undergone some degree of surface-degradation as well. It is believed that the ‘hybridization’ effect has successfully increased the resistance of the hybrid composite to severe environmental degradation to the extent that it protects the internal structure of the composite from environmental damage, even though the surface of the composite gets severely degraded. Surface treatment of fillers was also found to be able to aid in the retention of the composites’ mechanical properties.