Harvard researchers have created a new type of manufacturing material that serves as a sustainable alternative.
Just say the word “plastic” and it can set off the eco-conscious alarm bells in anyone’s head. After all, plastics make up an alarming percentage of the world’s wastes and plastics that end up in landfills take thousands of years to degrade, not to mention the amount of plastic that end up in the world’s oceans and become a constant threat to marine life.
To help solve these problems, bioplastics were developed as an alternative. Bioplastics are made from cellulose, a plant-based polysaccharide, but still do not fully degrade in the environment and have limited uses.
Taking this one step further, researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering have developed a new type of fully biodegradable bioplastic that is made from chitosan, a material extracted from shrimp shells. Chitosan, a form of chitin, is a long-chain polysaccharide responsible for the hard shells of shrimps and other crustaceans.
Most of the world’s chitin comes from discarded shrimp shells that either end up as trash or used in fertilizers, dietary supplements, and cosmetics. Up until now no one has ever been successful in producing three-dimensional and complex shapes using the material.
The research team, led by Founding Director Don Ingber, M.D., Ph.D. and Postdoctoral Fellow Javier Fernandez, Ph.D., was able to develop a way to process chitosan so that it can be used to create large 3D objects using conventional casting or injection-molding techniques. The new process makes it possible to mass-produce objects that are as sturdy as items made with synthetic plastics like toys, food containers, or cell phones.
In a press release, Ingber said,
There is an urgent need in many industries for sustainable materials that can be mass produced. 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.
The new type of bioplastic is fully biodegradable and not only degrades in the environment within two weeks but also releases nutrients that help plant growth. In another experiment, the research team grew a California Blackeye pea plant in soil that had chitosan bioplastic over three weeks to demonstrate how the material can encourage plant growth.