Improvement of impact resistant property of polypropylene filled with calcium carbonate - Effect of blending method on impact resistance

The impact resistant property of polypropylene (PP) could be improved by th e addition of finely powdered calcium carbonate (CC), and the factors for t he improvement were investigated including kind of PP and CC, and the blend ing process with a heat twin roller. PP with high melt viscosity showed exc ellent effects, and CC of 0.1 similar to0.3 mum in diameter treated with fa tty acid salts showed excellent effects. The blending process with a heat t win roller was also a significant factor. An addition of large amounts of C C to PP induced high melt viscosity due to breaking of second coaggulation of CC. These results suggest that the sufficient dispersion of powdery CC i n the PP matrix was significant for the improvement of the impact resistant properties. However, SEM observation failed to relate the sufficient dispe rsion of powdery CC in the PP matrix with remarkable improvement of the imp act resistant property.