From liquid laundry detergent packaged in cardboard to compostable plastic cups, consumer products these days are increasingly touting their sustainable and renewable origins.
Now researchers at Georgia Institute of Technology 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 July 23 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 percent 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.
“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.
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