Researchers at Georgia Institute of Technology have created material made from crab shells and tree fibers that could potentially replace plastic packaging used to keep food fresh, according to Georgia Tech News.
The material is created from spraying multiple layers of chitin, from crab shells, and cellulose, from trees, which then forms a film that is similar to plastic packaging.
“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,” said J. Carson Meredith, a professor in Georgia Tech’s School of Chemical and Biomolecular Engineering. “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.”
Chitin is one of the planet’s most common natural biopolymers, found in shellfish, insects and fungi.
The team created the film by hanging cellulose and chitin nanofibers in water and spraying them onto a surface in alternating layers. Once dried, the film becomes flexible, strong and transparent.
“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.
The original intention of food packaging is to preserve it longer without oxygen passing through. The researchers’ new material improves conventional plastic packaging because of the crystalline structure of the film.
“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.”
There are still more hurdles to overcome in order to make the new material abundant for all to use. A manufacturing process that maximizes economy of scale will need to be developed, methods to produce large amounts of chitin need to occur and they still need to improve the material’s ability to block water vapor.