70 Years of “Miracle Fiber”

nylonThis October marks the month 70 years ago when the U.S. chemical giant DuPont announced "one of the most significant developments in the history of industrial research":  nylon. It was, they said, as strong as steel and fine as a cobweb.

The invention of nylon, dubbed the "miracle fiber," was among the first of a series of revolutionary synthetic products. A cheap alternative to natural fabrics, nylon offered a material that could be stained, machine-washed, and re-used countless times.

Its numerous applications-from violin strings to jungle gym ropes to automobile tires-have provided countless benefits. But at the same time, the material's simplicity has encouraged a culture of consumerism, and its production has been a significant source of pollution.

Nylon's first application was in socks. The material first proved itself as a cheap alternative to silk in women's stockings, and demand quickly outpaced production. Rations during World War II forced women to abandon their nylon stockings cold turkey; the fiber was needed for parachutes, tires, tents, ropes, and ponchos. Many of the wealthy turned to the black market, although some made their sacrifices: actress Betty Grable sold a pair of nylons for $40,000 in a war-effort fundraiser.

After the war, nylon production expanded for the clothing, carpeting, and automobile industries as the U.S. economy boomed. In 1969 it went to the Moon, in the astronauts' space suits and the flag they planted on the surface.

Nylon, however, has a history of environmental concerns. Manufacturing all nylon products depends heavily on large amounts of crude oil. Another main ingredient is the chemical adipic acid. Producing the acid was once the largest source of industrial nitrous oxide (N2O), a greenhouse gas. Efficient pollution controls have reduced adipic acid emissions 61 percent between 1990 and 2006, according to the U.S. Environmental Protection Agency. But the chemical still accounts for 5-8 percent of global human-caused emissions of N2O.

Another concern is that nylon cannot be melted down and used again, so recycling nylon requires it to be broken down into its constituent chemicals.

But many nylon products, such as carpets and tires, are still reused in different forms. DuPont, Evergreen, and BASF Corporation have built nylon-carpet recycling facilities in North America and Europe. While the purification and remanufacturing processes do create some waste, this system (which recycles 25 million kilograms of carpet annually) is nearly a closed loop.

More than half the tires discarded in California are patched up for further driving or shredded to become products such as insulation, playground cushioning, and mulch. A Connecticut public health study, however, warned in 2007 that tire crumbs could release carcinogenic chemicals into the air and ground water.

In 1970, nylon accounted for about 40 percent of the world's synthetic fibers. Since then, polyester-cheaper although less durable-has taken over. Nearly 4 million tons of nylon were made in 2005, mostly in the United States and more recently in China. Whereas almost 30 million tons of polyester were produced in 2004, according to Textiles Intelligence. Overall nylon production appears to be falling about 0.35 percent each year.

Polyester, however, also consumes significant oil during production. Yet a Cambridge University study found that polyester materials consume less life-cycle energy than organic apparel, which require frequent washings at high temperatures, tumble-drying, and ironing.

Nylon filaments, on the other hand, are growing in demand for tire production as China and India purchase more cars.