Production and assessment of polycarbonate composites reinforced with vapour-grown carbon fibres

Vapour-grown carbon fibres were produced from methane in a flow reactor. The fibres were compounded with poly-carbonate in a co-rotating twin-screw extruder and the composites were subsequently injection moulded. The rheological characteristics of the polycarbonate composites reinforced with these vapour-grown carbon fibres were determined by using capillary and rotational rheometry. The tensile properties of the injection-moulded specimens were marginally better than those of the un-reinforced polycarbonate, but the impact resistance was severely diminished by the addition of the carbon fibres. This was attributed to the presence of polycyclic aromatic hydrocarbons on the surface of the fibres, that may impair the impact resistance of polycarbonate by chemical stress cracking.