Science: Unscrambling Nylon

A process to make new nylon out of old was announced last month by Du Pont. This challenge to the wartime nylon shortage, with drives for old nylon, should mean that many of the 200 million pairs of nylon hose made during the past three years will be converted into parachute cloth, tapes and harness, glider tow ropes, other military goods.

In the Du Pont process old nylon is put into a hot solution. The nylon (a synthetic chemical made from adipic acid and a base related to ammonia called hexamethylene-diamine) dissolves like sugar in hot tea. On cooling, the adipic acid crystallizes out and is purified, while the diamine remains in solution and can be purified by distillation. The two white crystalline chemicals resulting from this unscrambling of nylon fiber are then recombined and polymerized to form the long, tenuous molecules that give nylon its strength and elasticity. This new liquid nylon, identical with the original substance, can be squeezed out into the types of fiber needed for war uses.