But those aren't the strongest plastics. So Grewell is working with a team of Iowa State researchers to reinforce the plastics with nanoclays, pieces of clay that are just 10 to 20 billionths of a meter thick.
It's not easy to work with those tiny pieces of clay. They tend to stick together in clumps because of electrostatic forces, said Michael Kessler, an Iowa State assistant professor of materials science and engineering who's also working on the project. Those clay platelets need to be separated and mixed evenly throughout the plastic to be much good as a reinforcing agent.
The researchers are turning to high-powered ultrasonics ?high-frequency sound waves too high for human hearing ?to separate and disperse the platelets. It's a technology Grewell knows a lot about: he worked 12 years in research and development for the Branson Ultrasonics Corp. of Danbury, Conn. He has used ultrasonics to freeze strawberries, process rice and handle many other applications.
The researchers are also using microcellular foaming technologies from Trexel Inc. of Woburn, Mass., to mold and extrude the plastics. The processing technology is expected to enhance the biodegradable plastics while allowing the researchers to use less base material to make the plastics.
Grewell said the potential applications for plastics from crop proteins include disposable wraps for hay bales, po
Source:Iowa State University