According to the U.S. Environmental Protection Agency, more than 29 million tons of non-biodegradable plastic waste ends up in landfills each year. Justin Barone, associate professor of biological systems engineering at Virginia Tech, is investigating ways to create biodegradable plastics from agricultural byproducts such as poultry feathers and eggs that would be comparable to petroleum-based plastics. He presented the research on March 29 at the 233rd American Chemical Society National Meeting in Chicago, Ill.
"Twelve percent of all plastic packaging ends up in landfills because only a fraction is recycled," said Barone. "Once in the landfill, it doesn't biodegrade. The challenge is how can we 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 or agricultural waste, such as poultry feathers or eggs that don't pass inspection. These agricultural wastes currently find uses in low-value animal feed or are simply disposed. Both come at a cost to the poultry industry that is passed onto 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."
Plastics made from biomass are made just like petroleum-bas ed 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, Barone explains.
Barone is 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, is a major component of 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.