Your car’s bumper is probably made of a plastic called ABS, shorthand for its acrylonitrile, butadiene and styrene components. Light, strong and tough, ABS is also used to make ventilation pipes, protective headgear, kitchen appliances, Lego bricks and many other consumer products. Useful as it is, one of its drawbacks is that it is made using chemicals derived from petroleum.
Now, researchers at Oak Ridge National Laboratory (ORNL) have made a better plastic by replacing styrene with lignin, a brittle, rigid polymer that forms the woody cell walls of plants, along with cellulose.
In doing so, they have invented a new production process that combines powdered lignin and a synthetic rubber matrix. The result is a meltable, moldable material that’s at least 10 times tougher than ABS and 50 percent renewable.
The resulting plastic -- called ABL for acrylonitrile, butadiene, lignin -- is recyclable, as it can be melted down three times and still perform well.
“The new ORNL thermoplastic has better performance than commodity plastics like ABS,” said Amit Naskar in ORNL’s Materials Science and Technology Division. He and co-inventor Chau Tran filed a patent application for the process to make the new material. “We can call it a green product because 50 percent of its content is renewable,” which would reduce the need for chemicals derived from petroleum.
Instead of petroleum, the technology could make use of the byproducts of biorefineries and paper mills, which are rich in lignin.
“Lignin is a very brittle natural polymer, so it needs to be toughened,” explained Naskar. Combining it with the rubber matrix created a material with the properties of neither lignin nor rubber, but something in between -- a combination of lignin’s stiffness and nitrile rubber’s elasticity.
Part of the research was performed at ORNL’s Center for Nanophase Materials Sciences, a Department of Energy Office of Science User Facility.