Thermal,Tensile and Dynamic Mechanical Properties of Short Carbon Fibre Reinforced Polypropylene Composites

Abstract

Short carbon fibre (SCF) reinforced composites have made great progress in the last few decades due to their useful properties, and have been used in many areas. In this paper, carbon fibres were cut into short ones with the length from 40 μm to 100 μm and mixed with polypropylene (PP) fibres at the high speed of 10⁵ rpm by High-Speed Dispersator in reference to the way of papermaking. Three concentrations of SCF, 5, 15 and 25 w%, were used. Composites with good uniform dispersion of SCF in PP matrix were prepared via melting compounding in a twin-screw extruder followed by injection moulding. The effect of SCF content on the thermal and dynamic mechanical properties was studies by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). The SCF dispersed uniformly and aligned along a direction in PP matrix according to the SEM photographs and the incorporation of SCF enhanced the nucleation process, which was confirmed by DSC results. The heat of fusion and crystallinity of the composites also decreased with increasing CFs concentration. In addition, the stiffness of SCF/PP composites increased as the content of SCF increased. Finally, DMA results showed that an increment of SCF could improve the damping properties.