Scientists Develop Highly Recyclable Plastic

PhotoI.B.M. Researchers have developed a new way to make plastics that can be continuously recycled — a challenge for many plastics currently used in consumer products.

Researchers at I.B.M. and Stanford University said Tuesday that they have discovered a new way to make plastics that can be continuously recycled or developed for novel uses in health care and microelectronics.

In a paper published in Macromolecules, a journal of the American Chemical Society, the California researchers describe how they substituted organic catalysts for the metal oxide or metal hydroxide catalysts most often used to make the polymers that form plastics.

Chandrasekhar Narayan, who leads I.B.M.’s science and technology team at its Almaden Research Center in San Jose, Calif., said the presence of metal catalysts in plastics means that they often can only be recycled once before ending up in a landfill.

“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,” said Mr. Narayan. “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.”

That could give new life to the 13 billion plastic bottles that are thrown away each year in the United States.

“Plastic bottles can be converted to higher value plastics like body panels for cars,” said Mr. Narayan.

Organic catalysts could create a new class of biodegradable plastics to replace those that are difficult to recycle, such as polyethylene terephthalate, or PET, used in a variety of consumer products, including plastic beverage bottles.

These new green plastics could also potentially be used by the pharmaceutical industry as drug delivery devices to treat cancer, according to Mr. Narayan. “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.”

I.B.M. and Stanford scientists have proven that organic catalysts work in the laboratory, according to Mr. Narayan, and the company has teamed with the King Abdulaziz City for Science and Technology in Saudi Arabia to develop recyclable PET plastics.

He said the organic catalysts are “dirt cheap” to make and that I.B.M. is in discussions with pharmaceutical companies and other potential partners about developing a pilot project that could be producing plastics within two years.

“It’s really a new class of polymers,” said Mr. Narayan. “I think it’s going to revolutionize synthetic chemistry.”