Researchers at the Georgia Institute of Technology in America have created a material derived from crab shells and tree fibers that has the potential to replace the flexible plastic packaging used to keep food fresh.
The new material, which is described in the journal ACS Sustainable Chemistry and Engineering, is made by spraying multiple layers of chitin from crab shells and cellulose from trees to form a flexible film similar to plastic packaging film.
“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 per cent reduction in oxygen permeability over some forms of PET, which means it could in theory keep foods fresher longer.”
Cellulose, which comes from plants, is the planet’s most common natural biopolymer, followed next by chitin, which is found in shellfish, insects and fungi. The team devised a method to create a film by suspending cellulose and chitin nanofibers in water and spraying them onto a surface in alternating layers. Once fully dried, the material is flexible, strong, transparent and compostable.
Still, there’s more work to be done. To make the new material eventually competitive with flexible packaging film on cost, a manufacturing process that maximizes economy of scale will need to be developed. Additionally, while industrial processes to mass produce cellulose are mature, methods to produce chitin are still in their infancy, Meredith said. And, more research is also needed to improve the material’s ability to block water vapor.
More information is available on the Georgia Institute of Technology website.