An efficient method for recycling polycarbonate (PC) waste has been developed by researchers from Taiwan. A team led by Shenghong Dai from the National Chung Hsing University has converted PC waste into a commercially useful polymer, polyurethane, via a unique and economical one-pot process.

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Dai and co-workers report promising thermal and mechanical properties for the polyurethanes made by their method, and even claim that their polyurethane samples 'appear to possess appropriate properties that might make them strong candidates to replace PVC in the market'.

The waste material is digested using alkylene glycols and then transformed into alcohols of bis-phenol A by a zinc oxide catalyst in high yield. Upon treatment with the inexpensive compound urea, these alcohols were converted to polyurethane.

PCs have become important commercial materials with many applications, most notably in the manufacture of compact discs. Unfortunately, the high market consumption of PCs has lead to the production of high amounts of waste material, with more than 6000 billion discs of PC waste estimated to have been generated in 2005 alone, encouraging researchers to investigate the problem of recycling such waste.

Mark Keane, a leading researcher in environmental catalysis at Heriot-Watt University, Edinburgh, Scotland, agreed that the authors' work is a 'viable one-pot means of recycling PC waste' and a 'laudable and progressive approach to treating what is accepted to be a burgeoning waste treatment issue'.

Ian Gray