- Harvard researchers have developed plastic made of shrimp shells, silk
- So-called "shrilk" can be hard or flexible
- Substance is also biodegradable
Shrimp: It's not just for surf-and-turf anymore.
In fact, thanks to research at Harvard University, the little crustaceans may be the next thing in plastic.
In experiments with the material in shrimp shells, called chitosan, and material from silk, known as fibroin, researchers at Harvard's Wyss Institute for Biologically Inspired Engineering put the two together at a nano level. The result was a material they call "shrilk" -- a substance that's both remarkably malleable and incredibly sturdy.
"It actually feels like a huge beetle shell, or cuticle," says Don Ingber, the director of the Wyss Institute.
"(It) can be very strong in terms of tensile strength. If you wet them they can actually get more flexible," he adds. "We can get the range of different properties of plastics by changing how we fabricate these."
Though the word "plastic" applies to any moldable solid, it's come to be associated with materials made out of petrochemicals. That's both a blessing and a curse. Plastics are made in such quantity that they're both inexpensive and versatile, yet most aren't biodegradable.
Indeed, the infamous Pacific trash vortex -- the large area of garbage suspended in the Pacific Ocean -- is primarily made up of plastic debris, which has killed fish and wildlife and wreaked havoc on local ecosystems.
Shrilk, on the other hand, is fully biodegradable, says Ingber -- a necessity if the product is to succeed.
"In the middle of the Atlantic and Pacific there's continents of plastic floating that fish are getting entangled in and dying. We can't keep going on like this," he says. "I think many people are searching for replacements for plastics that would have the properties of plastic but be fully biodegradable. This may not solve all the problems but we feel like it's a first step."
The current challenge for shrilk is to make it cost-effective. There's plenty of raw material, says Ingber -- the seafood industry has so much shrimp shell discard "that they have to pay to get it cleared away sometimes" -- but there's still a ways to go.
"We need to work with real manufacturers who know what the design challenges are and the durability and the cost," says Ingber. "The materials exist, the manufacturing processes exist, it really just requires it to be integrated into the pipeline."
The researchers say there is plenty of room for growth. Literally, in fact: the material in shrilk makes excellent fertilizer.
"They are so rich in nutrients that you could put seeds in them, just in the broken down material, and a plant will grow," says Ingber.
Perhaps, a new part of the plastics industry will as well.