Scientists Find Way To Dissolve One Of The Toughest Plastics And Reuse Its Fibers

Researchers from The University of Texas at Austin and Sandia National Laboratories have developed a method to break down durable plastics that currently have no practical recycling method, using less energy and producing less waste than incineration.

The technique targets poly(dicyclopentadiene), or pDCPD, a lightweight and durable plastic used in vehicle bumpers, construction equipment and chemical storage tanks. Such products are often incinerated because the material is extremely difficult to recycle, requiring substantial energy and producing harmful byproducts while degrading reinforcement fibers.

The new process places pDCPD in a solution containing an eco-friendly solvent and a ruthenium catalyst. After being stirred for hours or days depending on the object’s size, the plastic dissolves and leaves behind reusable powder. Carbon or glass fibers added for reinforcement can also be recovered in pristine form.

“Before now, people might have avoided using these materials, despite their strength, durability and lightness, because they didn’t have a good way to recycle them,” said Zak Page, a UT associate professor of chemistry and corresponding author.

The researchers still need to determine whether the ruthenium catalyst can be recovered and reused to make the process more sustainable and affordable.

The discovery came unexpectedly when graduate student Keldy Mason exposed pDCPD to a solvent and catalyst intended to make it more durable. Instead, the material dissolved.

“This type of material has been around a long time, and the wisdom was that it was just too thermodynamically stable for this reaction to go the other way,” Page said. “So, this was quite a surprise.”

The research was primarily funded by the U.S. Department of Energy, with additional support from four foundations. The institutions and four study authors have applied for a U.S. patent covering the technology.