NEWS OF THE WEEK In 1992, the parties to the Montreal Protocol on Substances That Deplete the Ozone Layer amended the treaty to require a freeze on production of methyl bromide at 1991 levels by 1995. World production in 1990 amounted to about 63,000 metric tons, according to UNEP. In the U.S., where the Clean Air Act requires that ozone-depleting substances be banned completely, the Environmental Protection Agency has set a phaseout date for methyl bromide of Jan. 1, 2001 (C&EN, Feb. 1,1993, page 23, and Nov. 22,1993, page 23). Producers and users vehemently oppose this ban. They argue that the lack of readily available substitutes will disrupt growth, shipping, and storage of important foods like tomatoes, strawberries, and citrus fruits. And they contend data
on methyl bromide sources and sinks are so sketchy it is inappropriate to conclude that synthetic methyl bromide endangers the ozone layer. In their Science paper, Stein Manô and Meinrat O. Andreae of the Max Planck Institute for Chemistry in Mainz, Germany, conclude that biomass burning may be as large a source of methyl bromide as pesticide use. They measured the concentration of methyl bromide in smoke plumes from fires in savannahs, chaparral, and boreal forests. From the ratio of methyl bromide to carbon dioxide in the smoke and from estimates of the amount of carbon dioxide given off each year from biomass burning, they calculate that such fires can account for 10 to 50% of total methyl bromide emissions. Pamela Zurer
A nonstick material that is not wetted by solvents nor bound by adhesives is headed for consumer and industrial use. Plans to commercialize the material—a water-based, cross-linked, fluorochemical coating—are now being formulated by 3M. The first detailed description of the material's surface properties has just appeared in Nature [368,39 (1994)]. Last September, 3M received a license from Dow Chemical for commercial development and marketing of the material. The coating was discovered at Dow about eight years ago by polymer chemist Donald L. Schmidt and coworkers, who obtained U.S. patents for it in 1990 and 1991 (Nos. 4,929,666 and 5,006,624). The work described in Nature was carried out by Schmidt and several Dow coworkers— tics, paper, and textiles—would be ex- polymer chemist Charles E. Coburn, surface scientist Benjamin M. DeKoven, and empt from the ban. 'The most immediate impact will be analytical chemists Gregg E. Potter and to stop the export of about 5,500 tons of Gregory F. Meyers—together with physspent lead-acid batteries and lead waste icist and materials scientist Daniel A. from batteries," Browner notes. The U.S. Fischer of the National Institute of Stansends these wastes to 33 countries for dards & Technology. lead recycling. One objective of banning The material is a clear coating that can export of recyclable hazardous wastes is be applied by spraying or brushing. The to create demand for an expanded U.S. best properties are obtained when it is recycling industry. cured with moderate heat, but it also According to EPA, the U.S. exported cures at ambient temperatures. Its crossabout 145,000 tons of hazardous wastes in linked structure makes it very durable. 1993, less than 0.1% of those generated. And as a waterborne coating, it is enviAbout 90% of that went to Canada and ronmentally benign, with low volatile Mexico, with much of it recycled. Mexico, organic compound emissions. for instance, does not permit import of The coating is made by copolymerizwastes from the U.S. just for disposal. The ing acrylate or methacrylate esters of fluU.S. chemical industry does not export oroalkyl alcohols with carboxylate-funcmuch hazardous waste for disposal, notes tionalized vinyl monomers. The resultFrederick C. McEldowney, associate di- ing copolymer spontaneously organizes rector of international issues at the Chem- itself on surfaces in aqueous solution, ical Manufacturers Association. with the perfluorinated alkyl groups CMA agrees with the tenets of the Basel aligned in parallel and pointing away Convention, but McEldowney says the from the surface. Then, the copolymer is Clinton principles seem to go beyond cross-linked with an oxazoline-based what the convention requires. CMA is polymer to form the coating. concerned that banning export of recycla'The basic novelty of what's done is ble wastes will discourage legitimate busi- we were able to chemically cross-link ness deals and could actually lead to less the material to lock the orientation of recycling. For example, U.S. firms regular- perfluoro groups at the surface," says ly send spent metal catalysts to Europe for DeKoven. The perfluorinated groups regeneration, but fear this might be account for the material's nonwetting stopped under the Clinton proposal. "We and nonstick properties. are hoping this will be covered under the In the Nature paper, the Dow reexemption for recyclable metals," McEl- searchers report using the National Syndowney says, "but we are not sure." chrotron Light Source at Brookhaven NaDavid Hanson tional Laboratory to study the surface
U.S. seeks to curtail hazardous waste exports The Clinton Administration last week recommended that Congress adopt a set of principles severely restricting export of hazardous wastes to countries outside North America. The Administration wants the principles included in legislation to implement the Basel Convention, the first major international agreement to address the import and export of hazardous and other wastes. The Senate approved the convention in August 1992, but Congress must enact legislation to implement its provisions to make the U.S. a full party to the convention. Carol M. Browner, Administrator of the Environmental Protection Agency, discussed the new principles at the general assembly of the Global Legislators Organization for a Balanced Environment, held in Washington, D.C. "We believe the U.S. must set an example for the world by taking responsibility for our own waste," she says. "We have more than enough capacity here. There is no good reason for sending our waste overseas. Citizens in other countries should not be asked to bear the burden of U.S. pollution." If passed as presented, the law would ban exports of all hazardous wastes, including incinerator ash, to countries outside North America, with limited exceptions. For example, recyclable hazardous wastes going to members of the Organization for Economic Cooperation & Development would be phased out over five years. Wastes the Administration calls safe and recyclable—such as plas6
MARCH 7,1994 C&EN
Uses for nonwettable, nonstick coating probed
