Researchers raise prospects of endlessly recyclable plastics

Scientists at IBM and Stanford University announced this week that they have discovered a way to make plastic that can be continuously recycled, potentially slashing the amount of waste sent to landfill sites.

Current limitations in recycling and material technology mean that common plastics used in water bottles and food containers weaken so much when recycled that they cannot be used again for the same purpose.

While a small amount of the recycled plastic might make it into another bottle, more often than not it will be turned into another product such as synthetic carpet or clothing that cannot easily be recycled for a second time. As a result many plastics tend to be recycled only once before ending up in landfill sites.

However, according to a paper published in Macromolecules, a journal of the American Chemical Society, scientists have developed a new type of polymer that addresses the problem by using organic catalysts instead of the metal oxide or metal hydroxide catalysts typically used in plastic.

Chandrasekhar Narayan, who leads IBM's science and technology team at its Almaden Research Centre in San José, California, told Green Inc blog in The New York Times that it is the metal-based catalysts that are behind the degradation of recycled plastics.

"When you try to take a product and recycle it, the metal in the polymer continues to degrade the polymer so it gets increasingly less strong," he explained. "If you use organic reactants, you can make certain types of new polymers that are quite different and have other properties plastics don't have. "

The researchers said that the organic catalysts could be used to create a new class of biodegradable plastics to replace those that are difficult to recycle, such as polyethylene terephthalate. They added that the new technology means recycled plastic bottles could be converted to higher value plastics like body panels for cars.

Narayan said that biodegradable versions of the plastic could also be used as drug delivery devices for cancer patients.

"The pharma industry has a lot of good drugs on the shelf that they can't use because they are very toxic," he said. "You could encapsulate drugs in a bioplastic polymer and deliver them directly to the cancer site. The polymer degrades locally at the site and releases the cargo."

The organic catalysts used in the new plastics would have the additional advantage of being relatively cheap to produce.

The announcement has potentially significant implications for the huge quantities of plastics thrown away every year, and the researchers are now planning a larger pilot project at the King Abdul Aziz City for Science and Technology, home to Saudi Arabia's national laboratories.

The team said that the technology could be commercially available within five years if the pilot goes well.