Enhancement of electrical and thermal conductivity of polypropylene by graphene nanoplatelets

One of disadvantages of polymer composites is poor electrical and thermal conductivity. As a first step in this direction, graphene-modified polypropylene polymer is being developed to improve its electrical and thermal conductivity. Two techniques were investigated: surface coating and extrusion. In the case of coating technique, the percolation threshold was found to be 0.5 wt % of graphene and electrical conductivity of polypropylene increased around 13 log cycles. Coating technique breaks the agglomerations due to magnetic stirring followed by sonication and gives homogeneous graphene-coated polypropylene pellets. When polymer melts under compression molding, the graphene platelets network formed on the surface of polypropylene pellets as well as through-the-thickness of the molded disk, which provide continuous network of graphene. However, in extrusion technique, graphene segregated and did not disperse properly in polypropylene. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45833.