PULLMAN, Wash. — A method to convert a commonly thrown-away plastic to a resin used in 3D-printing could allow for making better use of plastic waste.
A team of Washington State University researchers developed a simple and efficient way to convert polylactic acid (PLA), a bio-based plastic used in products such as filament, plastic silverware and food packaging to a high-quality 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,” said Yu-Chung Chang, a postdoctoral researcher in the WSU School of Mechanical and Materials Engineering and a co-corresponding author on the work. “We made stronger materials just straight out of trash. We believe this could be a great opportunity.”
About 300,000 tons of PLA are produced annually, and its use is increasing dramatically.
Although it’s bio-based, PLA, which is categorized as a #7 plastic, doesn’t break down easily. It can float in fresh or salt water for a year without degrading. It is also rarely recycled because like many plastics, when it’s melted down and re-formed, it doesn’t perform as well as the original version and becomes less valuable.
“It’s biodegradable and compostable, but once you look into it, it turns out that it can take up to 100 years for it to decompose in a landfill,” Chang said. “In reality, it still creates a lot of pollution. We want to make sure that when we do start producing PLA on the million-tons scale, we will know how to deal with it.”
In their study, published in the journal, Green Chemistry, the researchers, led by Professor Jinwen Zhang in the School of Mechanical and Materials Engineering, developed a fast and catalyst-free method to recycle the PLA, breaking the long chain of molecules down into simple monomers – the building blocks for many plastics. The entire chemical process can be done at mild temperatures in about two days. The chemical they used to break down the PLA, aminoethanol, is also inexpensive.
“If you want to rebuild a Lego castle into a car, you have to break it down brick by brick,” Chang 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.”
Once the PLA was broken down to its basic building blocks, the researchers rebuilt the plastic and created a type of photo-curable liquid resin that is commonly used as printing “ink” for 3D printers. When it was used in a 3D printer and cured into plastic pieces, the product showed equal or better mechanical and thermal properties than commercially available resins.
While the researchers focused on PLA for the study, they hope to apply the work to polyethylene terephthalate (PET), which is more common than PLA, has a similar chemical structure and presents a bigger waste problem.
They have filed a provisional patent and are working to further optimize the process. The researchers are also looking into other applications for the upcycling method.
It was a highly complicated procedure but the surgical team was able to practice and prepare using a 3D-printed model of the puppy’s legs.
It was a highly complicated procedure but the surgical team was able to practice and prepare using a 3D-printed model of the puppy’s legs.
Pilot and WSU alum Mark Showalter charted a course for crimson and gray glory and landed lots of attention for waving the flag at 10,500 feet.
The story chronicles one of the Washington Territory’s first celebrity homesteaders and draws from his life to illuminate some of today’s pressing questions. Meet the authors at 9:30 a.m. Monday on the Pullman campus.
Washington Superintendent of Public Instruction Chris Reykdal will headline this year’s summit, held Saturday, Oct. 15, at WSU Tri‑Cities.
A collection of equine photographs by local photographer Shaundra Baumwart will be on display as part of the fall 2022 “Art in the Library” exhibit in the Animal Health Library.
Getting people out of their comfort zone to experience an ‘aha’ moment is one of the key goals of University Recreation’s Challenge Program.
Subscribe to WSU Insider to receive free daily updates by email. University employees are automatically subscribed—no sign up is necessary.
Washington State University and University of Idaho are teaming up to support the new terminal construction at Pullman-Moscow Regional Airport.