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Researchers Create Biodegradable Plastic from Crab Shells, Tree Fibers

Researchers from the Georgia Institute of Technology have developed a biodegradable plastic, derived from crab shells and tree fibers, that could potentially replace petroleum-based packaging in the food and consumer-product industries.

The team created the new material by creating nanoparticle suspensions of cellulose, the fibrous material in the cell walls of plants, and chitin, a carbohydrate found in the exoskeletons of crustaceans, and spraying them onto a surface in alternating layers.

The resulting material, when dry, they said, is “flexible, strong, transparent and compostable.”

At the same time, because the layers of chitin and cellulose are oppositely charged, they remain distinct from one other, keeping out oxygen and locking in freshness—an ideal situation for perishables. 

“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 at the college’s School of Chemical & Biomolecular Engineering who described the material last month in the journal ACS Sustainable Chemistry and 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,” he added.

Should the process prove scalable, the plastic could serve as an eco-friendly alternative to conventional single-use plastics, such as carry-out bags, that are clogging up landfills, shorelines and waterways. With the amount of cellulose already available, plus a steady supply of chitin-rich byproducts left over from the seafood industry, Meredith says there’s “likely more than enough” ingredients to make the material a viable, mass-produced commodity.

Such a product might provide some measure of relief to brands and retailers that are scrambling for options in the wake of efforts to curb single-use plastics. A move by the west Indian state of Maharashtra to ban single-use plastics, for instance, prompted companies like Amazon, H&M, Pepsi and Coca-Cola to lobby for a gentler phase-in and the softening of certain norms.  

India’s prime minister, Narendra Modi, in the meantime, is pushing a broader plan to completely end the use of single-use plastic in the South Asian country by 2022, following the examples of 40 other nations that have banned, partially banned or taxed disposable plastic bags, including China, France, Italy and Rwanda.