Researchers at Harvard's Wyss Institute have developed a new process for the large-scale manufacturing of everyday objects — from cell phones to food containers and toys — using a fully degradable bioplastic made from shrimp shells.
The Institute says the objects display many of the same properties as those created with synthetic plastics, but are more eco-friendly — even more so than most bioplastics on the market today in that they create no threat to trees or competition with the food supply.
The majority of bioplastics are made from cellulose, a plant-based polysaccharide material. The Wyss Institute team developed its bioplastic from chitosan, a form of chitin, a powerful natural polymer and the second most abundant organic material on the planet. Chitin is a long-chain polysaccharide that makes up the durable shells of shrimps and other crustaceans, armor-like insect cuticles, tough fungal cell walls — and even flexible butterfly wings.
Today, most of the world’s available chitin comes from discarded shrimp shells, and is either thrown away or used in fertilizers, cosmetics or dietary supplements, for example. However, material engineers have not been able to fabricate complex three-dimensional (3D) shapes using chitin-based materials — until now.
The Institute team developed a new way to process the material so that it can be used to fabricate large, 3D objects with complex shapes using traditional casting or injection molding manufacturing techniques. The chitosan bioplastic also breaks down when returned to the environment within about two weeks, and releases nutrients that support plant growth.
The innovation shows the potential of using bioinspired plastics for applications that require large-scale manufacturing, the Institute says. The next challenge is for the team to continue to refine their chitosan fabrication methods so that they can take them out of the laboratory, and move them into a commercial manufacturing facility with an industrial partner.
Speaking of bioplastic innovation, an Italian biotech firm called Bio-on has developed a bioplastic called PHA (Polyhydroxyalkanoate), made from agricultural processing waste materials, which is completely biodegradable in water and soil and can be used as a substrate for electric circuits. When combined with suitable nanofillers, the polymer can act as an electricity conductor, with the potential of replacing plastics in most electronics. This could go a long way in helping to reduce the world’s mounting e-waste problem.
Much of the world’s plastic ends up as e-waste from discarded electronics, which totals more than 50 million tons annually. In 2013, a record amount of e-waste (620 million pounds) was recycled by the consumer electronics industry.