Conducting carbon/polypropylene (PP) and carbon/poly(butylene terephthalate) (PBT) composites containing crystalline natural graphite and carbon black (CB) were prepared by compression and injection molding. The effect of the processing technology on the electrical, mechanical, and morphological properties was investigated. Determination of the constant torque at the end of the mixing process and differential scanning calorimetric (DSC) measurements showed that graphite had better connectivity with the more polar matrix (PBT) than with the less polar one (PP). Scanning electron microscopy (SEM) studies showed that compression molding results in a homogeneous structure, while injection molding results in a skin-core structure with different orientations. Layered electrical conductivity studies showed that the electrical conductivity of the compression molded samples did not change along the thickness of the sample, while that of the injection molded samples changed throughout the material, which is due to the different structures developed with each type of processing.
Corresponding author: Ferenc Ronkay, Faculty of Mechanical Engineering, Department of Polymer Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Műegyetem rkp. 3, Hungary, e-mail:
Journal of Polymer Engineering publishes reviews, original basic and applied research contributions as well as recent technological developments in polymer engineering. Polymer engineering is a strongly interdisciplinary field and papers published by the journal may span areas such as polymer physics, polymer processing and engineering of polymer-based materials and their applications.