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A solid polymeric material that can repair its own cracks when heated--without the need for the additional monomer or catalyst required in previous self-healing polymers--was developed by Fred Wudl of UCLA and coworkers [Science, 295, 1698 (2002); C&EN, March 4, page 35]. The new polymer could be useful in electronic components that tend to crack from repeated cycling. The first biodegradable thermoplastic shape-memory polymers were reported by Andreas Lendlein of mnemoScience, Aachen, Germany, and Robert Langer of MIT [Science, 296, 1673 (2002); C&EN, April 29, page 24]. Shape-memory polymers transform from a temporary initial shape into a different permanent shape. The new polymers could find use in medical devices. A novel family of biomimetic arylamide polymers that could potentially be used to endow surfaces with antibacterial properties was developed by Michael L. Klein, William F. DeGrado, and coworkers at the University of Pennsylvania [Proc. Natl. Acad. Sci. USA, 99, 5110 (2002); C&EN, June 10, page 36]. A method for designing stable nanostructured blends of polyethylene and polyamide with unique properties not seen in classical blends of the two polymers was reported by Ludwik Leibler of the School of Industrial Physics & Chemistry, Paris, and coworkers [Nat. Mater., 1, 54 (2002); C&EN, Sept. 9, page 12]. A technique for using ruthenium-catalyzed ring-opening metathesis of cis-cyclooctene to make high-molecular-weight cyclic polyethylenes was developed by Robert H. Grubbs and coworkers at Caltech [Science, 297, 2041 (2002); C&EN, Sept. 23, page 19]. It addresses problems encountered with previous methods. And Jos T. F. Keurentjes and coworkers at Eindhoven University of Technology, the Netherlands, prepared high-molecular-weight polymers in high-pressure liquid carbon dioxide using ultrasound-induced chemical reactions [Science, 298, 1969 (2002); C&EN, Dec. 9, page 10]. The study broadens the range of sonochemical reactions and could lead to new organic-solvent-free industrial processes.
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Chemical & Engineering News |
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