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Flame-Proof Cotton Carpeting
By Jan Suszkiw
April 10, 2002
Demand for cotton-based carpeting and
rugs, a $10-billion market dominated by synthetic fibers such as nylon,
polypropylene or polyester, could improve because of a new flame-retarding
treatment developed by Agricultural Research
Cottons backseat status to synthetic fibers as a floor covering
material stems from burning characteristics that often prevent it from meeting
federal standards for surface flammability. Although numerous commercial flame
retardants are available for treating cotton, many arent cost effective
for practical use on all-cotton or cotton/polyester carpeting materials, notes
Eugene Blanchard, a chemist with ARS
Chemistry Unit in New Orleans, La.
There, he and ARS chemist Elena Graves overcame the problem by treating
cotton carpeting with nontoxic chemicals called polycarboxylic acids. They
chose the chemicals for their low cost, availability, absence of formaldehyde,
lack of toxicity and reactivity with cotton fibers to impart flame resistance.
For test purposes, scientists subject the treated carpeting to 10 wash
cycles with detergent before drying it in preparation for the methenamine pill
test. This involves placing a 12- by 12-inch carpet sample onto a 9- by 9-inch
metal frame with an 8-inch diameter hole in the center. A methenamine tablet is
then placed there and ignited. Cotton-based carpeting with a low-density cut
pile surface normally burns beyond the allowed range (to within one inch of the
holes edge). In fact, such burning often chars the samples entire
surface. On the treated carpeting, however, the flames spread is
restricted to less than one inch from the ignition point. Technically, the
flame could spread another two inches and the sample would still pass the test,
adds Blanchard, who co-published a paper in the January 2002 issue of
Use of the treatment could help U.S. cotton capture a greater share of the
carpeting market, which consumes five billion bales of synthetic fibers
A more detailed story on the research appears in the
April issue of
Agricultural Research magazine.
ARS is the U.S. Department of
Agricultures chief scientific research agency.