Effects of processing on the mechanical properties of carbon short‐fiber reinforced polycarbonate

Abstract The effects of varying the injection‐molding parameters of temperature, pressure, and injection rate on the mechanical properties of commercially obtained neat and carbon‐rein‐forced polycarbonate were investigated. The test specimens contained molded‐in and drilled holes so that the effect of a weld‐line could be investigated. The breaking‐strength and modulus‐of‐toughness values are reported. The results of the Young's moduli determinations showed that the stiffness of the neat materials was invariant and that the carbon‐reinforced material was orthotropic. Gel Permeation Chromatography (GPC) results showed that the neat resin was stable at the temperature investigated. The filled resin, however, underwent a decrease in molecular weight distribution at 650°F. At elevated temperatures, the breaking strength and modulus of thoughness of the carbon‐reinforced material showed a decrease where the properties were dependent upon the resin. Fiber orientation produced during molding significantly affected the toughness. The results agreed well with theory.