Thermal Behavior, Mechanical Properties and Microstructure of Polypropylene Composites Filled by Calcium Carbonate Whiskers

Abstract

CaCO3 whiskers were treated by stearic acid and the surface property of the treated whisker were evaluated by activation index. When the mass fraction of stearic acid was 4.0%, activation exponential increased to 80.0% almost from zero. The composites were prepared by blending with polypropylene and the treated whiskers. The performance of the composites, such as thermal behavior, mechanical properties and microstructure, were analyzed with differential scanning calorimetry, scanning electron microscopy and tensile testing. The results showed that CaCO3 whisker played heterogeneous nucleation to induce crystalline behavior of PP phase in the blends and the crystallization rate of PP phase also increased because of CaCO3 whiskers intervening. Moreover thermo-decomposing temperature and tensile strengths of the blends all increased with increasing whisker content, except a little less than that of pure PP as filling 3.22% CaCO3 whiskers, but the elongation at break increased with increasing whisker content.