Influence of Filler on the Structure, Thermal Stability, and Mechanical Properties of Compositions Based on a Modified Polypropylene

The effect of a filler on the structure, thermal stability, strength, elongation, and impact strength before and after freezing in compositions based on polypropylene modified with a polyolefin elastomer is considered. It is found that the presence of filler reduces the effective activation energy of the thermooxidative destruction of composites and the technological characteristics of thermal stability, which indicated a decrease in the structuredness of the system. The study showed a tendency to increase the melting and crystallization temperatures of polypropylene with a filler content of up to 20 wt%, as well as to a certain narrowing of the temperature range of melting and crystallization with increasing calcite concentration. This was probably associated with the formation of polymer crystallites more uniform in size. It is found that, at a filler content up to 5 wt%, modified calcite particles can serve as additional nucleators. This was reflected in the increasing strength and impact strength by 5 and 6%, respectively, compared with those of the unfilled one.