Extrusion Process of Polypropylene Composites Reinforced Milled Carbon Fibre for Conductive Polymer Composite Application

Abstract

A polypropylene (PP) reinforced milled carbon fibre (MCF) was developed to produce high conductive polymer composites. Theoretically, by altering the filler orientation, the electrical conductivity and mechanical properties can be controlled. However, the orientation techniques which influence the MCF fibre are difficult to performed. Therefore, this study focused on controlling the filler orientation through the extrusion process. Hence, the extrusion temperature of 230°C and rotational speed of 50 rpm at 70 wt.% of MCF and 30 wt.% of PP were used. The electrical conductivity in perpendicular to the extrusion direction was higher at 2.0 S/cm as compared to 0.66 S/cm in the parallel direction. Besides, the extruded composite of rod and sheet were studied in which rod dies offers higher electrical conductivity of 3.0 S/cm and better mechanical properties of 1225 MPa than the sheet dies. Alteration in filler orientation aid in enhancing the electrical conductivity as minimum fillers breakage occurred due to the low shear rate of 2.2 s-1 which indirectly induces the filler to the desired orientation. Therefore, the extrusion process able to improve the electrical conductivity and mechanical properties of composite materials, as the filler oriented perpendicular to extrusion direction.