TECHNOLOGY UPDATE A pollution-preventing wrinkle in fabric finishing Clothing pretreated with an environmentally benign process to make it wrinkle-free may be available as early as next spring. Instead of the formaldehyde used in conventional treatments, the new process employs a combination of nontoxic chemicals that increases fabric durability, a University of Georgia researcher reported at an American Chemical Society meeting in March. Charles Yang, professor at the University of Georgia-Athens, in the Department of Textiles, discovered the new process in 1997 in response to concerns about formaldehyde. The compound is found on almost all of the no-iron cotton and cotton-blend products currently on the market, said John Turner, senior chemist at Cotton, Inc., a research organization sponsored by cotton growers. The new process uses a combination of three carboxylic acids—citric acid and two different polymers of maleic acid—to promote the fabric's cellulose fibers to form permanent cross-linkages that result in wrinkle resistance. It was licensed to two companies, Callaway Chemical and FMC, in 1998. They formed a joint venture called Callaway FMC to commercialize the process, which is now being marketed to fabric and garment companies. The new no-iron fabric finish is the most attractive alternative to formaldehyde on the market, Turner said. "The OSHA standard on formaldehyde in the workplace has necessitated a move away from formaldehyde, toward no formaldehyde where economically feasible," explained Jerry Tew, technical director of the American Association of Textile Chemists and Colorists, a nonprofit organization. EPA regulates formaldehyde as a hazardous air pollutant, and emissions of the compound are publicized through the Toxics Release Inventory. A small amount of formaldehyde is
continuously released by all wrinkleresistant fabrics treated with the chemical. The popularity of wrinkle-free finishes has been increasing steadily since the early 1990s, according to Tew. Formaldehyde is used on 40% of men's casual slacks, and 50-60% of men's dress shirts, as well as on bed sheets and draperies, estimated David Shank, product development manager with Callaway FMC. Both formaldehyde and carboxylic acid finishes are baked onto the fabric they are used to treat. Because they force the fibers into a fixed matrix, mese cross-linking treatments make fabric vulnerable to breakage, Shank said. Yang believes that the cross-linking induced by the formaldehyde reaction's catalyst "is more severe" than that from the catalyst used in the carboxylic acid reaction. This gives Yang's process, which Callaway FMC calls Crosslink, "moderately better" strength retention, he said. Despite the fact that Yang's new process currently costs approximately twice as much as formaldehyde-based finishes, Shank said that fabric and clothing apparel companies are generally not daunted by the cost. Fabric finishing represents a small percentage of a garment's ultimate cost, he stressec
Attempting to activate the market for coal waste Scientists at the Pennsylvania State University presented a new way to use wastes from coal-fired power plants at the March American Chemical Society meeting. Preliminary studies show that the new process can transform unburned carbon residues into highquality activated carbon. The research project's goal is to find an economically appealing alternative to disposing the waste from coal-fired power plants in landfills, said Mercedes Maroto-Valer, the research associate at Penn State's Energy Institute who devised the new process. Until utilities began using low-
NOx burners in response to Clean Air Act regulations mandating air emissions reductions, this waste consisted mostly of fly ash that cement manufacturers could reuse. The increased amount of unburned carbon in the waste from plants using low-NOx burners renders unseparated fly ash unusable by the cement industry, however. The major appeal of the Penn State Technology would be to offset the cost of separating the carbon from the ash, said Joseph J. Battista, senior engineer for research and development at GPU/Genco, one of Pennsylvania's largest utilities. Power plant operators currently do not have a great incentive to invest in separation equipment, he said. To date, only three power plants use separation equipment, MarotoValer said. An EPA report on wastes from the combustion of fossil fuels that was released in late March indicates that more stringent requirements for creating composite-lined landfills to hold coal-fired power plant wastes are likely to drive utilities' costs up. This could give utilities an added incentive to consider new alternatives to disposing in landfills, said Dean Golden, senior project manager for the Electric Power Research Institute. It is possible that utilities could use any activated carbon they generate to help remove mercury from the plant emissions, he said. Activated carbon generally is made from coal or wood. Three recent reports peg the U.S. market for activated carbon filters, which are used to remove pollutants from liquids and gases, as growing 3-5% annually, said a spokesperson for Calgon Carbon Corp., the world's largest manufacturer of granular activated carbon. Traditionally, carbon is activated by a two-step process, MarotoValer said. Because coal burned at the nation's 450 power plants already has been ignited at 1200-1300 °F, the unburned carbon wastes can bypass the first devolatilization step, she explained. —KELLYN S. BETTS
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