University of Minnesota Alumni Association


Green Chemistry

Powered by a $20 million grant renewal, U of M researchers hope to invent the next generation of sustainable plastics.

Illustration Credit: Mengxin Li


At the time this famous word of advice about the future was offered to the aimless Benjamin Braddock in the 1967 film The Graduate, the audience was very much in on the joke: Viewers knew Braddock, a child of the counterculture who had just graduated from a nameless East Coast college, wasn’t going to sell his soul to any industry, much less one that stamped out synthetic, prefabricated products.

Fifty years later, that line has more ominous overtones as the world tries to grapple with the challenges of a global dependence on a material that is both revolutionary convenience and environmental nightmare. That’s because the properties that make plastics so useful in daily life also mean they take hundreds of years to decompose. If plastics aren’t recycled—an increasingly complicated proposition as hundreds of U.S. cities scale back or even cancel their plastics recycling programs—the items end up in landfills and waterways, causing severe ecological damage.

Part of the reason cities no longer actively recycle this material comes from the fact that China formerly purchased up to 70 percent of the world’s plastic waste. When the Chinese government recently said it would no longer do that, that unwanted waste shifted to countries such as Malaysia. CNN reported in April that the Malaysian government is now cracking down on plastics recycling in their country because unlicensed operators, operating illegally, cannot safely recycle that material. Another factor that affects the market for recycled plastic is that when oil prices are low—the material from which most plastic is produced—making new plastic is cheaper than recycling waste.

Today, roughly 8 million metric tons of plastic waste flow into the oceans every year from coastal regions, according to the University of Georgia’s National Center for Ecological Analysis and Synthesis. That’s the equivalent of five grocery bags of plastic trash placed on every foot of coastline around the world. What’s more, the University of California, Santa Barbara estimates that about 40 percent of plastic packaging  is used just once and then thrown away.

These sobering statistics have led to a variety of initiatives, including worldwide bans on everything from plastic bags and straws to polystyrene containers.

At the U of M, researchers have been seeking a more effective solution since the late 1990s. They have shown enough success that this past August, the National Science Foundation (NSF) renewed a $20 million grant to the NSF Center for Sustainable Polymers (CSP) in the College of Science and Engineering to discover the next generation of environmentally friendly plastics.

“Plastics are so useful and so inexpensive, and can have an amazing array of properties, including fibers that are as strong as steel with half or less than half the weight,” says Marc Hillmyer, director of the Center and a McKnight Presidential Endowed Chair in the Department of Chemistry. In many cases, these properties have actually contributed to sustainable technologies, including lighter and more fuel-efficient cars. They’ve also given rise to food and medical equipment packaging that keeps us safe from life-threatening pathogens.

Hillmyer and his team’s goal is doing the detailed work needed to sustainably develop new plastics where the “end life” is of equal importance to the product’s usefulness. They conduct basic research on polymers, or the molecules that make up plastics. “We do the down-in-the-chemical-weeds research to really try to uncover tomorrow’s molecules that will allow us to have materials with all the great attributes of the plastics we know and love, without the environmental consequences,” he says. “How can we make materials that are more easily recycled or that can be composted or rapidly degraded if they do get into the environment?” 

To that end, U of M and Cornell University researchers have partnered to develop new polymers that will allow the two most common plastics—isotactic polypropylene and polyethylenes—to no longer need to be separated during the recycling process. The hope is that this breakthrough will have a significant impact on the recycling industry because it will provide new pathways for recycled materials.

CSP researchers have also employed microbial engineering to develop sustainable flexible foam polymers, which are used in household items, including chair cushions and pillows. (A graduate project determined that the foam can be chemically recycled back to its starting material.) Researchers have also invented a new technology that produces isoprene—used to make automobile tires—from renewable feedstocks.

While this kind of in-depth scientific research has always been a staple of academia, businesses such as Bell Labs or IBM also used to pursue such research. Today, however, Hillmyer says that as industry moves to prioritizing shorter-term goals, the research needed to develop and grow breakthrough technologies is almost entirely the province of universities—although companies and corporations do provide funding sponsorships for it.

“[Industry] understands that this basic science is really going to be critical for their future,” he says. “I think that that’s why we have to partner with industry as best we can, in order to make these things happen.”

Powered by the grant renewal, Hillmyer is eyeing solutions for plastic packaging, specifically food packaging, which often can’t be recycled because it’s been contaminated.

“To have a food packaging that protects your chicken from bacteria [but] can then go in the compost bin with your food scraps would be important,” says Hillmyer. “While I have ideas for how this can be done, doing it in a low-cost way is a really tall order. That’s where I think our research will play a role in trying to understand how we can do it in a practical way.”

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