Searching for a substitute

The race is on to make to make something just as good polycarbonate plastics made with bisphenol A – now banned in baby products in Canada.

13 March 2010

The Globe and Mail

Hard, clear and resistant to heat and impact, polycarbonate plastics made with bisphenol A “are excellent,” says Joe Schwarcz, director of McGill University’s Office for Science and Society, “and that’s exactly the problem for suppliers now that BPA has become a dirty word.”

So the race is on to make to make something just as good.

“If it was easy, somebody would have done it already,” says Geoff Coates, a chemist at Cornell University and co-founder of Novomer, a company now testing technology he devised that produces something biodegradable, non-toxic and largely made of carbon dioxide.

According to Prof. Coates, cost is an issue, just as it is for products that employ polylactic acid, which is made from corn and biodegradable but melts at much lower temperatures.

Donald J. Darensbourg at Texas A&M University is, like Prof. Coates, chasing a successor that uses carbon dioxide, but so far can’t offer a replacement for BPA. He points out that there are other hard, clear plastics on the market. One produced in Tennessee by Eastman Chemical Co. contains no BPA, but, again, it is more expensive and melts more readily. “These are totally fine for baby bottles and water bottles – I have one on my desk right now,” Prof. Darensbourg says.

Meanwhile, Kyu Yong Choi of the University of Maryland is taking a different approach. He published a theoretical model last year for producing polycarbonates that minimize their BPA residue, he says, “fairly simply by controlling the reaction conditions.” He has since done the lab work to prove that the process is chemically possible, and now is looking for about $500,000 (U.S.) to carry out a feasibility study.

The future is more promising for the other big source of BPA exposure, the plastic lining on tin cans.

Prof. Coates’s company is working with a Dutch firm on a carbon-dioxide-derived resin that Novomer chief executive officer Jim Mahoney says will be “very cost-competitive” – and should be on the market next year.

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