The invention of nylon marked a new era in the fashion industry. The first fully synthetic fibre to be mass-produced, nylon led the way in usurping natural fibres as the material of choice throughout the second half of the 1900’s. A polymer with numerous applications, it can be found today in outdoor gear, toothbrush bristles and guitar strings, as well as in clothing.
Before the advent of nylon, the only ‘synthetic’ fibre on the market was rayon. Marketed as a cheap alternative to silk, rayon occupied a grey area between synthetic and natural fibres, being derived from the cellulose in wood pulp. However, despite being a fraction of the cost of silk, rayon ultimately made a poor substitute fibre as it lacked the tensile strength and durability of real silk. Thus, by 1926, executives at the DuPont Company, one of the leading companies in rayon research, began looking at funding research into new synthetic fibres.
In 1928, the man who would be instrumental in nylon’s development, Wallace H. Carothers, joined DuPont’s research team. He focused his research on polymerisation, in which small molecules chemically bond to produce long chains. At the time, polymers were not well understood, with scientists disagreeing about their shape and nature. Carothers’ work helped define the structure of polymers as long chains made of repeated units – the definition taught to GCSE chemistry students around the country to this day.
The first polymer produced by Carothers’ research group was a polymeric ester – an example of what we now know as ‘polyester’. This polyester was produced in 1930 by combining a dialcohol with a diacid. Some of its properties were certainly useful: threads of the polyester could stretch to 4 times their original length. However, some of its other properties were less commercially viable, as it had a very low melting point and was extremely brittle. Nevertheless, this crucial first breakthrough, relatively early into the research process, proved to the team that they were looking in roughly the right direction.
However, despite the initial successes, another four years passed without any meaningful progress. The biggest problems lay in polyester’s low melting point and high solubility in water. During this time Carothers left the project, but was convinced to re-join in 1934 by Elmer Bolton, DuPont’s new chemical director. He re-focused his research into polyamides as opposed to polyesters, and later that year, his team produced the first nylon from an aminoethyl ester. This new polymer retained the same stretch-and-recovery properties as the polyesters previously produced but had a much higher melting point.
Finally, on 28th February 1935, Dr. Gerard Berchet, a member of the DuPont research team, reacted hexamethylene diamine with adipic acid in a condensation polymerisation reaction. The water formed during the reaction was then distilled, leaving behind the polymer which would be known as Nylon 6,6. The two 6’s in the name are due to the two monomers (the original small molecules the polymer was made from) each containing 6 carbon atoms.
The nylon reaction:
(n+1) H2N-(CH2)6-NH2 + (n+1) HOOC-(CH2)4-COOH –> H2N-(CH2)6-NH[CO(CH2)4-COHN-(CH2)6-NH]nOC-(CH2)4-COOH + (n+1) H2O
By autumn of 1935, Carothers’ team had managed to form their new polymer into threads which could be knitted or woven to form textiles. Nylon’s invention was officially made public in October 1938, with DuPont choosing to make stockings from the ‘miracle material’. However, nylon’s first commercial application was in toothbrush bristles, previously made from boar hair, which had become increasingly rare following the Japanese invasion of Manchuria in 1937. It was only in May 1940 that nylon stockings were officially launched across the US, marketed as stockings which were more durable than silk and would not run.
Instantly popular, nylon stockings quickly replaced silk as the material of choice in stockings and hosiery. However, the industry took a hit with the entry of the USA into WW2. Nylon production quickly shifted towards aiding the war effort, being used mainly in parachutes, but also in ropes, life rafts and mosquito netting. This left the domestic market without nylon, to the extent that black-market prices for nylon stockings were astronomical – one seller made $100,000 from stockings produced from a diverted nylon shipment. Women unable to afford black-market prices instead made do by drawing thin lines on their legs to imitate stocking seams when they went out.
Following the end of WW2, DuPont immediately switched back to producing nylon stockings to meet the massive consumer demand. This demand was so great that newspapers reported on ‘nylon riots’, in which thousands of women lined up outside stores to compete for limited pairs of stockings. It was not until 1946 that DuPont managed to produce enough stockings to meet demand.
However, by this point, nylon was no longer the only synthetic fibre on the market. DuPont’s success had led to a greater understanding of the properties of polymers and synthetic fibres, and how to manipulate them. The result of this was that, by the 1950’s, several other alternatives were on the market, including lycra, various polyesters, polyamides and acetates. Each version was marketed as ‘unique’ by their respective manufacturers, flooding the fashion industry with easily-cared-for, cheap and ultimately disposable clothing.
The invention of nylon and its introduction into fashion undoubtedly was a great scientific step forward. Carothers’ research helped lead to a ‘plastic revolution’, in which a greater understanding of polymers resulted in them becoming an everyday household item. However, the introduction of synthetic fibres has also resulted in a growing amount of plastic pollution around the world, and the same properties which made nylon so desirable in the 1940’s have made polymers some of the hardest materials to safely dispose of in the present.