GARBAGE GIVES GREEN POLYMER

Circuit boards from chicken feathers, plastic from soybean8212;scientists are turning over the trash can to find materials from which to produce environment friendly polymers.

Carbon dioxide. Orange peels. Chicken feathers. Olive oil. Potato peels. E. coli bacteria. It is as if chemists have gone Dumpster diving in their hunt to make biodegradable, sustainable and renewable plastics. Most bioplastics are made from plants like corn, soy, sugar cane and switch grass, but scientists have recently turned to trash in an effort to make so-called green polymers, essentially plastics from garbage.

Geoff Coates, a chemist at Cornell, one of the leaders in the creation of green polymers, pointed to a golden brown square of plastic in a drying chamber. 8220;It kind of looks like focaccia baking, doesn8217;t it?8221; Coates said. 8220;That8217;s almost 50 percent carbon dioxide by weight.8221;

Coates8217; laboratories occupy almost the entire fifth floor of the Spencer T. Olin Laboratory at Cornell, and have a view not only of Cayuga Lake and the hills surrounding Cornell, but of a coal power plant that has served as a kind of inspiration. It was here that Coates discovered the catalyst needed to turn CO2 into a polymer.

With Scott Allen, a former graduate student, Coates has started a company called Novomer, which has partnered with several companies, including Kodak, on joint projects. Novomer has received money from the Department of Energy, New York state and the National Science Foundation. Coates imagines CO2 being diverted from factory emissions into an adjacent facility and turned into plastic.

The search for biocomposite materials dates from 1913, when a French and a British scientist filed for patents on soy-based plastic. 8220;There was intense competition between agricultural and petrochemical industries to win the market on polymers,8221; said Bernard Tao, professor of agricultural and biological engineering at Purdue.

Much of the early research on bioplastics was supported by Henry Ford, who believed strongly in the potential of the soybean. One famous 1941 photo shows Ford swinging an ax head into the rear of a car to demonstrate the strength of the soy-based biocomposite used to make the auto body. But soy quickly lost out to petrochemical plastics. 8220;In those days you had a lot more oil around, and you could dig it up all year round,8221; Tao said. 8220;You didn8217;t have to wait until the growing season.8221;

And there was another problem: permeability. The soy plastic was not waterproof. 8220;Petroleum is biologically and relatively chemically inert, 8220; Tao explained. 8220;Most living systems require water.8221;
Fossil fuels 8212;inexpensive, abundant and water resistant8212; quickly dominated the plastics market. Now, agriculture-based plastics are back in the running, and with the type of catalysts developed by Coates and others, a whole new array of polymers has become commercially viable.

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Choosing carbon dioxide as a feedstock for a polymer was not an obvious choice. It was what Coates called 8220;a dead molecule8221;. 8220;CO2 has almost no reactivity,8221; he said, 8220;and that8217;s why it8217;s used in fire extinguishers.8221; So what made him choose carbon dioxide? 8220;It8217;s abundant and cheap. We picked it for environmental and economic reasons, not for its reactivity.8221;

Richard Wool, a University of Delaware chemist, works with a material even less glamorous than orange peels: chicken feathers. Wool and his graduate students designed a composite made from soybeans and the down of chicken feathers. After seeing the composite, a Tyson Foods engineer approached Wool, offered him two billion pounds of chicken feathers, and an unlikely partnership was born. Despite the madcap premise, Professor Wool used the material to design a circuit board he said is a lighter, stronger, cheaper product with high-speed electronic properties. In short, the feathers allow extra air flow and do not expand like plastic when heated, so the hotter temperatures that come with higher speeds are less problematic.

Wool is also working with olive oil and other high-oleic oils to create rubber, paint and what he calls biocompatible adhesives; he envisions making bandages that would work more like skin.
NONNY DE LA PENANew York Times