Structure, thermal and mechanical properties of polypropylene composites with nano- and micro-diamonds

摘要

The influence of diamond powders on properties of isotactic polypropylene (PP) was investigated. PP composites containing 0.2-5 wt % of the powders with particles of average size between 100 nm and 1 mu m were prepared, and their structure and properties were examined. Dispersion of each filler depended on its grain size and content. The presence of fillers raised the crystallization temperature of PP matrix by up to few Celsius degrees. The modulus of elasticity of composites increased with increasing filler content, by up to 40 % in comparison to neat PP. The tensile impact strength of the composites with 1 mu m powders and also the other composites at the filler content as low as 0.2 wt % improved by up to 30 %. The composites did not exhibit any decrease in the yield strength and retained good drawability. The elongation at break exceeded 1000 % in most cases. Examination of the uniaxially drawn specimens revealed that the filler grains separated from the PP matrix during drawing.