Comparative analysis of shungite and graphite effects on some properties of polylactide composites

The influence of shungite and graphite on some properties of composites with polylactide as matrix and containing up to 50 wt% of these fillers was investigated. It was found that the composites loaded with graphite, as compared to those with shungite, exhibit superior mechanical and thermomechanical properties (higher tensile strength, impact strength, and storage modulus) as well as lower melt flow rate, water vapour permeability, volume resistivity and surface resistivity. The phenomenon of percolation related to the passage of electric current was observed in the composites containing above 30 wt% of graphite, which caused abrupt reduction in volume and surface resistivity. This was not the case for the composites with shungite, the advantage of which is a lower price, especially when the filler loading is high. (C) 2011 Elsevier Ltd. All rights reserved.