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CBE plastic recycling class video still image
April 4, 2022

New CBE class gets students excited about the future of plastics recycling

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Like many people, Dell Zimmerman, a PhD student in chemical and biological engineering at the University of Wisconsin-Madison, assumed plastic recycling was an efficient, mature technology.

Then he signed up for CBE 562: Technology for Plastic Recycling.

The course, offered both for undergraduates and graduate students, is designed to engage students with the current issues and emerging solutions in recycling. And Zimmerman was surprised to learn the dirty truth: Most plastic items are simply not recyclable, despite the triple arrow symbol printed on their bottoms, and less than 10 percent of all plastic produced since the 1950s has actually been reused. “I was very surprised to see that plastic recycling fundamentally hasn’t changed in the last 40 years,” he says. “I knew we had a lot of the infrastructure in place for traditional recycling, but it really blew me away how we really don’t recycle that much and how inefficient the process is in general.”

That type of reaction is exactly what George Huber, the Richard L. Antoine Professor in chemical and biological engineering, was looking for when he designed the course, which is an offshoot of the Chemical Upcycling of Waste Plastics, a multi-university research center funded by the Department of Energy and led by Huber.

The goal of the course is to give students an understanding of the challenges and opportunities in the recycling industry and the ability to look at the industry from a chemical engineer’s perspective. Not only do they study current recycling techniques and their limitations, but they also look at a wide array of potential chemical solutions for recovering and reusing plastic polymers in a more sustainable manner.

Students benefited from Huber’s research experience in chemical recycling of plastic. He’s currently working on and overseeing several projects, including new methods of pyrolysis to recover virgin polymers for recycling and catalytic recovery of polymers from multilayered plastics, a process called STRAP he’s pioneering at UW-Madison.

His students also learned from guest lecturers including Tim Osswald, the Kuo K. and Cindy F. Wang Professor in mechanical engineering and co-director of the UW-Madison Polymer Engineering Center; Craig Benson, civil and environmental engineering professor emeritus and an expert on upcycling waste material; Kevin Nelson, a UW-Madison CBE alumnus and senior fellow at Neenah, Wisconsin-based Amcor, the world’s largest manufacturer of plastic packaging; Cory Fitzgerald, an environmental health and safety specialist at custom plastic packaging manufacturer Placon who discussed mechanical recycling; and Jorge Rubalcaba, a senior research and development manager at Dow Chemical working in performance plastics.

For the students, the culmination of the course was creating a two-minute video that distilled complex topics including enzymatic PET recycling, treating PVC so it doesn’t produce hydrochloric acid during recycling, and producing syngas from waste plastic through gasification. Classmates voted on the best videos, selecting the submissions by Zimmerman, who presented a low-budget parody of how catalytic pyrolysis can be used to improve plastic recycling, and undergraduate Jazsmin Washington, who created a stop-motion animation about policy differences among Europe, the United States and individual states and how they encourage and discourage recycling.

Zimmerman, who did some research on polymers as an undergraduate, is currently studying fluid flow and rheology in sickle cell anemia, a blood disease. But he says in the future he could see himself studying polymers again, and the class has primed him and his classmates to pay attention to what’s happening in the chemical recycling of plastics. “Being able to understand and keep tabs on recycling is something I’m very invested in at this point,” he says. “The class really made most of the students invested in watching how the landscape will be changing in the next few years. There’s some really cool things on the horizon.”

Huber says that he considers the first class a success and plans to expand it in 2022 to other universities involved in the CUWP, including partner institutions in the United States, Mexico and Canada.

To view the other videos from the class, go to this YouTube page.

Rotated CBE 562 Jazsmin Washington

Dell Zimmerman Catalytic Pyrolysis