ORIGINAL PAPER Flammability Properties of Virgin and Recycled Polycarbonate (PC) and Acrylonitrile–Butadiene–Styrene (ABS) Recovered from End-of-Life Electronics M. Masud K. Khan Æ Carlos J. Hilado Æ Sushant Agarwal Æ Rakesh K. Gupta Ó Springer Science+Business Media, LLC 2007 Abstract Acrylonitrile–Butadiene–Styrene (ABS), Poly- carbonate (PC) and their alloys are widely used in auto- motive industry, computer and equipment housings. With increasing disposal of end-of-life electronic equipment, there is also an increased demand for recycling of these materials so that they do not pose environmental challenge as solid waste. One of the recycling approaches is mechanical recycling of these thermoplastics where recy- cled plastic is melt blended with virgin materials to obtain a high quality product. Besides obtaining desirable mechanical properties, such blends should also conform to fire safety standards. In this work, a series of blends were prepared using PC and ABS recovered from discarded computers and virgin materials using a twin-screw ex- truder. Their flammability properties were evaluated using burner flammability tests and Ohio State University (OSU) release rate tests. It was found that the extinguishing time, burning extent and weight loss appears to progressively decrease with the addition of both virgin or recycled PC to virgin or recycled ABS. It was also seen that the addition of the 70% of PC, virgin or recycled, to ABS virgin or recycled, appears to significantly decrease heat release and smoke evolution. The results of this study indicate that recycled polycarbonate can be used as an additive for virgin or recycled ABS, as a means of giving flame resis- tance to ABS in high-value applications. This result is significant when related to the result obtained by a separate study indicating that up to 25% of recycled material can be used without degradation of mechanical properties in the presence of 15% short glass fiber reinforcement. Keywords Polycarbonate Á ABS Á Flammability Á Recycling Á Blends Introduction Thermoplastics such as Acrylonitrile–Butadiene–Styrene (ABS), Polycarbonate (PC) and their alloys are widely used for enclosures and casings for electric and electronic equipment such as computer CPUs, monitors, keyboards, printers, mobile phones, and personal digital assistants (PDAs). With increased production and end of life dis- posal, there has been a rapid growth in waste product. For example average life span of a personal computer has re- duced from 4.5 years in 1992 to 2 years in year 2005 [1]. It is estimated that about 250 million computers will become obsolete in next 5 years in US and mobile phones will be discarded at a rate of more than 130 million units per year [1]. This has imposed an economic, environmental, and social pressure on the need to recycle these materials so that they do not end up in municipal landfills. Two most common approaches to plastics recycling include inciner- ation to produce energy and mechanical recycling where plastic waste is reused in manufacturing. While mechanical recycling process of single thermoplastic polymeric mate- rials, namely HDPE and LDPE, has developed to a rea- sonable level, recycling of ABS/PC thermoplastics has not progressed and remained somewhat unattractive. This is M. M. K. Khan (&) Faculty of Sciences, Engineering and Health, Central Queensland University, Rockhampton , QLD 4702, Australia e-mail: m.khan@cqu.edu.au C. J. Hilado Product Safety Corporation, Sissonville , WV, USA S. Agarwal Á R. K. Gupta Department of Chemical Engineering, West Virginia University, Morgantown WV 26506, USA 123 J Polym Environ DOI 10.1007/s10924-007-0059-2