New Polymerization Reaction Uses Single Carbon Atoms

Irvine, Calif., Nov. 27, 2000 — UC Irvine organic chemists have developed a novel polymerization reaction using single carbon atom monomers that can be used for the synthesis of high-performance plastics.

Ethylene-propylene copolymers are among the world's most important petroleum-based plastics. Traditionally, the polymers are prepared by the polymerization of ethylene and propylene monomers. Kenneth J. Shea, UCI professor of chemistry, and graduate student researcher Xian-Zhi Zhou have discovered a new route to synthesize these important materials. With this new chemistry, Shea said, it is possible to have greater control over variables in the overall polymer structure, allowing for the construction of higher-quality, specialized products. The results appeared in the Nov. 22 issue of the Journal of the American Chemical Society.

Petroleum-based plastics are made cheaply and easily with a molecular structure featuring a chain of carbon atoms called the polymer backbone. Chemists connect other groups to this carbon backbone in order to make specific polymers. The polymer backbone is built from individual molecules called olefins, which consist of two carbon atoms bonded together. The olefins are thus united to form large, high-molecular weight molecules called polymers. Shea has taken a different approach, using building blocks that contain a single carbon atom instead of the traditional two carbon atoms. He and Zhou found that this new polymerization reaction gives greater control and allows attachment of "sticky handles"—chemical groups that permit the polymer to fasten to other molecules or surfaces—to make more advanced plastics that may have use in many consumer items.

"We took this novel approach to see if we could deviate from the standard carbon-carbon polymer structure," Shea said. "While our process is much more complex and not a competitor to already efficient methods of making polymers, our technology provides opportunities that current technology can't offer by taking a completely different approach. Because we can build more complex copolymers, our process eventually can have applications for specialized products that don't need to be produced in huge quantities."

The study was funded by the National Science Foundation.

Contact:
Tom Vasich
(949) 824-6455
tmvasich@uci.edu