New tool could make plastics recycling more profitable

As a result of the incompatibility of the giant molecules of different types of plastics, efficient recycling processes need to easily identify the compounds that comprise end-of-life durables such as cars, computers and audio equipment, Michael Fisher, Director of Technology at the American Plastics Council explained to edie. Black plastic – which is widely used, for example in car bumpers and stereos, makes such analysis difficult by being loaded with carbon, which absorbs so much light from the lasers being used to analyse them extent that the material heats up, giving off light, or even igniting. The signal from the luminescence or burning of the plastic, in turn, obscures its spectroscopic signature, making it difficult to accurately read the plastic’s composition.

“A large fraction of this waste stream is composed of black plastics,” says Mark Lieberman, Chief Executive Officer of American Commodities Inc. “Automotive black plastics – from bumpers to instrument panels to fender liners – have several strikes against them when it comes to recycling. Mid-infrared spectrometers haven’t been successful at analysing them because of their unusual shapes and surface textures.”

The new technology, developed by Indiana company, SpectraCode Inc, enables instant identification of black plastics through a modified probe that uses a sampling technique known by its developers as ‘distributed focusing’. When employed in conjunction with the company’s current system of plastics analysis which uses the vibrational signatures of light scattered by the plastic, samples can be tested at full laser power with no burning.

“This technology will be of great interest to the plastics community,” said Edward Grant, chief executive officer of SpectraCode and Purdue University professor of chemistry. “Being unable to instantly identify and separate post-consumer black plastics by resin type has presented a significant barrier to their wide-scale recycling.”

Recycling processes need to be cost effective in order to take hold in the market place, points out Fisher. “There is no question that the plastics industry sees growth in the need for recycled materials in the future. New technology that supports environmentally sound and economically sustainable recycling is a critical need. As manufacturers cut back costs and continue to look for ways to save money, the use of recycled plastics is high on the list for potential cost savings.”