By Scout Nelson
Corn-based plastics known as PLA polymers are gaining attention for their role in the growing biodegradable plastics market. These materials are made from corn and offer new opportunities beyond traditional uses in food and fuel industries. However, scientists face a key challenge. They must ensure that these plastics remain strong and durable during use yet break down quickly after disposal.
Many existing PLA products require special industrial composting conditions to fully degrade. These conditions include controlled temperature, moisture, and active microorganisms. To address this issue, researchers at the University of Minnesota’s Center for Sustainable Polymers are working on improving PLA performance and decomposition.
The research, supported by the Minnesota corn checkoff, is led by professors Chris Ellison and Marc Hillmyer. Their team is experimenting with adding small amounts of acidic compounds to PLA. These additives create shorter polymer chains, which help speed up decomposition through a process called hydrolysis.
“When the polymer chain is processed by microorganisms upon hydrolysis, it does not leave toxic byproducts behind,” Ellison said. “It becomes lactic acid and then ultimately (breaks down into) into biomass, CO2, and water.”
Even a very small number of additives, less than one percent, can significantly improve how quickly the plastic breaks down. Researchers are carefully testing different blends to ensure that the plastic does not degrade while still in use.
One promising application is a mulch film used in agriculture. This film helps retain soil moisture for crops like fruits and vegetables. Ideally, it should break down within one growing season to avoid waste in fields.
“You’d like the plastic to degrade in a single growing season, because you don’t want to be plowing in the spring and digging up a bunch of plastic,” Ellison said. “There, the PLA is exposed to the sun, and to the other elements. So, we have a tall task. Our research is focused on understanding how we can control the process of degradation, to tailor it to these different applications.”
Another challenge is that PLA is often mixed with other materials like PBAT and thermoplastic starch. Scientists are testing whether the new additives work well in these blends.
Ellison said, “We want to see if our additives work with these other materials in the same way they work with PLA. All three materials intersect with a whole range of agricultural applications. We’re trying to understand our additives and how they perform in these different blends. Obviously, we’re really focused on PLA because corn is used in its manufacture, but the markets for the various blends are all really important in agriculture too.”
The research will continue for three years. Scientists hope to bring these improved plastics into real-world products with help from local companies.
Photo Credit: gettyimages-d-keine
Categories: Minnesota, Crops, Corn, Education