Researchers in the College of Agriculture and Life Sciences are investigating ways to create biodegradable plastics from agricultural byproducts — such as poultry feathers and eggs — that would be comparable to petroleum-based plastics.
Biodegradable polymers created from such byproducts may add value to the poultry industry and help solve the growing environmental problem of plastic waste, according to Justin Barone, associate professor of biological systems engineering.
According to the U.S. Environmental Protection Agency, more than 29 million tons of non-biodegradable plastic waste ends up in landfills each year.
“Twelve percent of all municipal solid waste is plastics, mostly packaging, that ends up in landfills because only a fraction is recycled,” says Barone. “Once in the landfill, it doesn’t biodegrade. The challenge is how we can create a simpler plastic bag or bottle that will biodegrade.”
According to Barone, the technology to create biodegradable plastics from biomass, such as corn and soybeans, has been around for more than 70 years.
However, the recent push to increase energy production from these feedstocks has increased the value of these agricultural commodities, making products made from them more expensive.
Barone has turned his focus to the agricultural waste stream and is concentrating on developing ways to use under-utilized byproducts, such as poultry feathers or eggs that don’t pass inspection. These agricultural byproducts currently find uses in low-value animal feed or are simply disposed. Both options come at a cost to the poultry industry that is passed on to consumers.
The challenge in developing biodegradable plastics is creating a product as good as, if not better than, its petroleum counterpart, explains Barone.
“The industry is looking for a versatile product that can be used for multiple markets,” he says.
Plastics made from biomass can be made just like petroleum-based plastics. They are cheaper to manufacture and meet or exceed most properties except for water resistance and longevity. Meeting these performance requirements is a challenge, he explains.
Barone says he’s taking his lead from nature to find potential solutions to these performance requirements. He is investigating the properties of polymers created from poultry feather keratin. The protein, keratin, comprises hair, nails, and feathers and makes them hard and strong.
Barone has found that altering the amino acid structure of keratin can improve the strength and longevity of the polymer.
In addition, the viscosity can be improved with reducing agents such as sodium sulfite and lubricants such as poultry fat. The solid-state properties can also be modified using divalent transition metal ions to affect stiffness and smell. These will help the keratin polymer be processed faster, be more aesthetically pleasing, and become water resistant and stronger for increased longevity.
Barone’s current research is funded by the Poultry Protein and Fat Council of the U.S. Poultry and Egg Association.
Biodegradable plastics could be used for plant containers and mulching film.
More than 3 billion plastic containers are used by the horticulture industry each year.
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