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Washington State researchers convert plastic waste into 3D printing material

A mechanical assembly uses motors and belts to move in three planes: side to side, in and out and up and down, which is why they're called 3D printers.

PORTLAND, Ore. (KOIN) — Researchers from Washington State University have developed a new way to convert rarely recycled plastic waste into a sturdy 3D printing material, the school announced.

Postdoctoral Researcher Yu-Chung Chang of Washington State University’s School of Mechanical and Materials Engineering said in a university press release that the process transforms polylactic acid — commonly used to make plastic silverware and food packaging — into a sturdy resin.

“We found a way to immediately turn this into something that’s stronger and better, and we hope that will provide people the incentive to upcycle this stuff instead of just toss it away,” Yu-Chung said. “We made stronger materials just straight out of trash. We believe this could be a great opportunity.”

Approximately 300,000 tons of the commonly discarded plastic are produced each year. Although the material is biodegradable and compostable, it can take up to 100 years to decompose, WSU researchers say.

“In reality, it still creates a lot of pollution,” Yu-Chung said. “We want to make sure that when we do start producing [polylactic acid] on the million-tons scale, we will know how to deal with it.”

The process is also simple and efficient, the study says. The transformation is achieved by using aminoethanol to break the plastic’s long chain of molecules down into “monomers” — the simple building blocks for many plastics. This process can be completed in about two days.

“If you want to rebuild a Lego castle into a car, you have to break it down brick by brick,” Yu-Chung said. “That’s what we did. The aminoethanol precision cut the PLA back to a monomer, and once it’s back to a monomer, the sky’s the limit because you can re-polymerize it into something stronger.”

After breaking the plastic down to a simpler form, the researchers rebuilt it and created a liquid resin commonly used as “ink” for 3D printers. Once printed and cured, the product reportedly showed equal or better mechanical and thermal properties than other commercially sold resins. 

Researchers hope to one day apply this process to polyethylene terephthalate, or PET, a popular plastic that is commonly used in water and soda bottles. The two types of plastic reportedly have a similar chemical structure. If possible, the technique could help reduce the significant amount of plastic waste created by PET every year.

The study, led by Professor Jinwen Zhang, was published in the journal Green Chemistry.