Injection Molded Short Glass and Carbon Fibers Reinforced Polycarbonate Hybrid Composites: Effects of Fiber Loading

Hybrid composites of polycarbonate (PC) reinforced with short glass fibers (GF) and short carbon fibers (CF) were prepared by twin-screw extrusion and injection molding techniques. Composites were produced in different ratios of GF and CF by maintaining the total fiber loading at 40 wt%. The mechanical properties such as tensile, flexural strength, and impact of these composites were investigated. It was noted that an increase in GF content led to a higher strength of the hybrid composites as compared to CF. Morphological analysis by using scanning electron microscope reveals that CF had poor fiber-matrix interactions with PC, which brought about the decrement of stress-transfer efficiency. A poor fiber-matrix interaction is believed to be the main cause of the lower strength enhancement by CF than expected. Heat deflection temperatures of composites increased with the increment of GF content. From dynamic mechanical thermal analysis, high-storage modulus is observed at the temperature below T-g. Meanwhile, it was observed that surface and volume electrical resistivity decreased by increasing the CF content owing to its conductivity.