July 23 (UPI) -- Scientists at the Georgia Institute of Technology have developed a new material made from crab shells and tree fibers. Researchers hope the material will serve as a more sustainable replacement for flexible plastic packaging used to keep food fresh.
"The main benchmark that we compare it to is PET, or polyethylene terephthalate, one of the most common petroleum-based materials in the transparent packaging you see in vending machines and soft drink bottles," J. Carson Meredith, a professor of chemical and bimolecular engineering at Georgia Tech, said in a news release. "Our material showed up to a 67 percent reduction in oxygen permeability over some forms of PET, which means it could in theory keep foods fresher longer."
To make an eco-friendly plastic wrap, scientists looked to nature's two most common natural biopolymers: cellulose, sourced from plants, and chitin, found in shellfish, insects and fungi.
Researchers suspended the cellulose and chitin nanofibers in separate water solutions and sprayed them in alternating layers onto a substrate before allowing them to dry. The fibered layers formed a strong but flexible material.
"We had been looking at cellulose nanocrystals for several years and exploring ways to improve those for use in lightweight composites as well as food packaging, because of the huge market opportunity for renewable and compostable packaging, and how important food packaging overall is going to be as the population continues to grow," Meredith said.
Because chitin nanofibers are positively charged and celluloses nanocrystals are negatively charged, researchers realized the duo might make for ideal partners in a new composite material. The novel fibrous interface prevents gas from penetrating the materials.
"It's difficult for a gas molecule to penetrate a solid crystal, because it has to disrupt the crystal structure," Meredith said. "Something like PET on the other hand has a significant amount of amorphous or non-crystalline content, so there are more paths easier for a small gas molecule to find its way through."
Researchers described their new material this week in the journal ACS Sustainable Chemistry & Engineering.
Though the new material's performance and environmental impact is superior to PET, researchers will need to find ways to economically scale up production before food manufacturers agree to adopt the technology.