How is nylon made?

Nylon is a well-known synthetic polymer (derived from the Greek words ’poly’ meaning ’many’ and ’meros’ meaning ’parts’).

It was invented by Wallace Carothers, and first brought to the public’s attention in October 1938.

Creative Commons Image PopTopLady via Flickr
Nylon thread [Image: Pop Top Lady under CC-BY-ND licence]

Soon after its introduction it was used to make parachutes, ropes and tents during the Second World War, as well as nylon stockings and toothbrushes.

It’s a strong synthetic fibre, which resists abrasion. Nylon doesn’t shrink or stretch through washing, but it is degraded by ultraviolet light.

Nylon is made when the appropriate monomers (the chemical building blocks which make up polymers) are combined to form a long chain via a condensation polymerisation reaction.

The monomers for nylon 6-6 are adipic acid and hexamethylene diamine. The two molecules are combined to create the polymer and water (H₂O) is produced as a by-product.

The water is removed from the production process as its continued presence stops the creation of more polymer.

The polymer chain can be made up of over 20,000 monomer units, connected together via an amide group, which contains a nitrogen atom.

The nylon molecules are very flexible with only weak forces, such as hydrogen bonds, between the polymer chains, which tend to tangle randomly. The polymer has to be warmed and drawn out to form strong fibres.

If you would like to know more about the synthesis of organic compounds, The Molecular World is an Open University course that introduces these fundamental ideas.