MINNEAPOLIS — The future of corn-based plastics is good news for the environment and for Minnesota corn growers, according to University of Minnesota Chemical Engineering and Materials Science professor Frank Bates.
That's the gist of why the Minnesota Corn Growers Association came to the Center for Sustainable Polymers at the University of Minnesota.
Projects like the one headed by Bates are detailed in an ebook titled "The Expanding Role of Corn" recently released by the corn growers. All of the projects included in the book were financially supported by corn check-off funds. The program, which Minnesota corn farmers invest nearly $4 million each year, is focused on identifying new ways to use corn and increasing demand.
"While petroleum-based plastics could sit in a landfill for thousands of years, the corn-based counterpart breaks down quickly in composting or prolonged exposure to sunlight, addressing a major issue with plastics," the book states.
The work on corn-derived plastics that Bates' research team does at the university is associated with the Center for Sustainable Polymers.
The center at the University of Minnesota is one of six in the country funded by the National Science Foundation. The Minnesota center was awarded a $20 million grant renewal this past summer.
Bates said there are about 20 faculty members at all the centers who are principle investigators "pursuing a variety of avenues for exploring how to make polymers (plastics) most sustainable."
Bates' group is focused on enabling one of the most prevalent sustainable plastics, called polylactide, or PLA.
The Minnesota-headquartered company NatureWorks, a joint venture between Cargill and Dow Chemical, started the production of PLA in 2001 and is the biggest producer of PLA in the world.
"This turns out to be a big success story for the state of Minnesota," said Bates of NatureWorks.
Bates said that PLA, which can be made from corn sugar, is "particularly attractive because that plastic can be composted after it's used." Some commonly used products that contain PLA are utensils, plates and cups.
"When thrown in a compost heap at a commercial compost facility, it can be broken back down into basically water and ultimately carbon dioxide,” Bates said.
What Bates' team works on with PLA is making the material a more perfect plastic, which he said it currently is not. He said it has a tendency to be brittle, which makes it unsuitable for many products.
"We are investigating ways to make this material tougher and to have applications that are going to be more broadly based," said Bates.
According to CSP Senior Investigator Chris Ellison, food areas at the U use clear to-go containers made from PLA. Those containers are brittle to the touch.
“We want to find that additive that allows these plastics to go beyond the student union because it has the properties people want," said Ellison.
Bates said that when you look worldwide at the business of polymers, which is mostly just a few plastics, "the size of that business is now more than $500 billion a year in sales."
"It's one of the biggest industries in the world," said Bates. "Those are important materials that have a tremendous impact on standard of living."
However, without change, today's plastic products will be around for decades or centuries.
"It's a technical challenge that we need to embrace," said Bates. "And wouldn't it be great for the corn growers if we did that with their corn?"