Bioplastic Made from Shrimp Shells may be Sustainable Material of the Future
Researchers have developed a method for the large-scale manufacture of everyday objects like toys and cellphone cases using a plastic derived from shrimp shells.
Objects created from this bioplastic, the researchers report, have the same properties as many other synthetic plastics, but do not come with the same environmental costs.
Rather than using plant material such as cellulose to develop the plastic, the Harvard teams' bioplastic is derived from chitosan, which is derived from the natural polymer chitin, one of the most abundant organic materials on Earth.
The hardy shells of shrimp and other crustaceans are composed of chitin.
According to the Wyss Institute, the majority of the world's available chitin comes from discarded shrimp shells. But bioplastics engineers have been unable to develop complex, three-dimensional shapes using chitin-based materials until now.
Wyss Institute researchers developed a new way to process chitin so it can be used to fabricate large, 3D objects with complex shapes that can be created with traditional plastic casting and molding methods.
To illustrate the usefulness of their chitin bioplastic, the researchers made a chess set.
"You can make virtually any 3D form with impressive precision from this type of chitosan," said Wyss postdoctoral fellow Javier Fernandez.
Fernandez and his colleagues tinkered fabrication process to enable chitin, which can be quite weak, to be able to withstand the plastic molding process to make useful materials.
"Depending on the fabrication method, you either get a chitosan material that is brittle and opaque, and therefore not usable, or tough and transparent, which is what we were after," said Fernandez.
After several trials, Fernandez and his collaborators, including Wyss Institute Founding Director Don Ingber, honed in on a method of creating a viable liquid chitosan plastic base that could withstand the casting and injection molding process.
"There is an urgent need in many industries for sustainable materials that can be mass produced," Ingber said. "Our scalable manufacturing method shows that chitosan, which is readily available and inexpensive, can serve as a viable bioplastic that could potentially be used instead of conventional plastics for numerous industrial applications."
If returned to the earth, the chitosan bioplastic breaks down releasing nutrients that efficiently support plant growth, as seen in the video below.