Metallocene-catalyzed polymerization of ethylene in the presence of graphite. II. Structure and electrical properties of the composites

Structure and electrical properties of conducting polyethylene/graphite com posites have been studied in relation to the preparation method, i.e. (i) t he polymerization-filling technique (PFT), in which the polyolefinic chains are growing from the graphite surface, (ii) the slurry polymerization of e thylene in the presence of untreated graphite, and (iii) the mechanical ble nding of preformed polyethylene and graphite. The extent of the filler disp ersion depends on the method used for the composite preparation. Moreover, the graphite particles can be oriented by the molding of the samples used f or the measurement of the electrical properties. This orientation is as pro nounced as the melt viscosity of polyethylene is low, this characteristic f eature changing with the preparation method. These structural details have consequences on the electrophysical properties and the percolation threshol d. Finally, the thermal dependence of the electrical resistivity has been s tudied. (C) 2001 Elsevier Science Ltd. All rights reserved.