Nonreactive Processing of Recycled Polycarbonate/Acrylonitrile–Butadiene–Styrene

Abstract

Abstract

Front covers of Motorola cellular phones, ground by a knife mill, contain 15.2 wt% metals, 1.9 wt% foams, 1.4 wt% rubbers, and 81.4 wt% thermoplastics with polycarbonate/acrylonitrile–butadiene–styrene blends. Separation of the thermoplastic scraps was performed using sink-float processes in water and salt solutions and electrostatic processes such as free-fall methods and roll separations. Impact modification of all housing containing six thermoplastic parts was carried out by the addition of a polyolefin elastomer. Unprinted and printed glass fiber-reinforced epoxy circuit boards were finely pulverized using a knife mill and a hammer mill. Ground printed circuit boards, separated by a roll separator, were compounded with desired thermoplastic mixtures. Izod impact strengths at various temperatures, tensile tests, scanning electron microscopy on fracture surfaces, and dynamic mechanical spectroscopy were performed to characterize the alloys and mixtures compounded by a batch mixer and twin screw extruder. Impact strength of the pure housing materials was almost twice higher than that of all housing materials compounded by the batch mixer. The polymer alloys compounded by the twin screw extruder showed lower impact strengths but higher tensile properties than those by the batch mixer because of the break-up of the interfacial instability.