Ohio State researchers' biodegradable plastic alternative being honed for marketplace

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Ohio State researchers have developed a sustainable alternative to plastic, but it might be some time before it can be used in everyday products.

Yael Vodovotz, an OSU professor and researcher, and her team have been working on the plastic for more than 13 years and said her team is now testing ways to make it more recyclable and biodegradable.

“Unfortunately, only about 8% of the total recyclable material is actually recycled,” Vodovotz said. “It’s a habit (to recycle) and people seem to not do it.”

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PHVB, or Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), is the main polymer used. Vodovotz has bonded the polymer with rubber to form a material that is flexible and can be used in items such as bottles, films and foams. Pure PHVB is brittle and breaks, which is why the rubber compound is important.

“The point is to marry those two polymers together,” Vodovotz said. “What we’ve done is exactly that. We’re not the first ones to combine them, but we’re the first to combine it successfully by playing around with some of the material properties.”

PHVB is made through the bacterial fermentation of sugars, Vodovotz said, which makes it renewable.

She said the team is still in the process of testing the plastic’s biodegradability. Most potential partners are companies looking for different specific qualities of the plastic for their products, which makes it hard to test and find the perfect fit for each.

In the lab, pure PHBV degraded by 25% after 45 days; blended with rubber, it degraded by 12% in that time period. The team has yet to test longer than 50 days.

Vodovotz and Katrina Cornish, an OSU professor and researcher whose focus is on rubber plants, also have looked into strengthening the plastic by adding tomato peels, eggshells, coffee grounds and even invasive plants.

Xiaoying Zhao, a post-doctoral researcher at OSU who has worked on the testing and experimental design, said the next step is to partner with a business to start producing the plastic in large quantities — by the ton instead of the pound.

“What we do in a lab is good and gives us a lot of information, but we can’t scale it up or source the materials as well. We can’t put it out there in a particular application,” Vodovotz said.

Once marketable, the plastic will face competitors that are natural and degrade in a person’s lifetime, such as hemp products and plastics made using banana leaves or bamboo. Those products, however, might not be able to be produced in a large scale, said Elissa Yoder Mann, conservation manager for the Sierra Club, a nonprofit environmental organization.

Yoder Mann said the new polymer will be tricky to market because bioplastics often are labeled biodegradable but aren’t unless taken to an industrial composting center.

“The question is, if I put this plastic in my backyard, will it biodegrade?” she said.

Yoder Mann said she cautions scientists producing alternatives to plastic.

“Technology got us into this in the first place, because we thought at the time that the plastic bag would be the solution to paper bags,” Yoder Mann said. “If there’s a scientific answer, I’d be careful about it.”

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