Material · Synthetic

Nylon

The first fully synthetic fibre — stronger than silk, and the material that proved a laboratory could out-perform an organism.

Nylon was the first commercially successful wholly synthetic fibre, announced by DuPont in 1938 as made from coal, air and water, and it changed what people expected a laboratory to be able to do. Silk stockings were a luxury; nylon ones were not, and five million pairs sold on the first day they were available.

It is a polyamide, and the amide links between its units are the same chemical linkage that joins amino acids into protein. That is not a coincidence of naming — nylon is strong for the same reason silk and wool are, because those links hydrogen-bond to their neighbours and hold the chains together.

Uses

Rope, parachute canopy, tyre cord, carpet, hosiery, fishing line, and — because it is tough, slippery and self-lubricating — gears, bearings and cable ties.

The engineering use follows from a property the textile use does not care about: nylon slides against itself and against metal with unusually low friction, so a small gear can run dry where a metal one would need oil. Most low-load plastic gearing is nylon or acetal.

Its standing weakness is water. Nylon absorbs several per cent of its weight in moisture, and that changes its dimensions and softens it, which is why a nylon part is specified with a humidity condition and a nylon rope stretches when wet.

History

Its first mass market was hosiery and its second was the Second World War, which took the entire supply for parachutes, rope and tyre cord within two years of the first stocking going on sale. The stockings became a symbol of the shortage and then of the peace.

Wallace Carothers, who led the work, established in the process that polymers really are long covalently bonded chains rather than aggregates of small molecules — a question that was genuinely open when he began, and which nylon settled by demonstration.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

contains

Carbon — element · the chain between the links
Hydrogen — element · including the amide hydrogens that bond to the next chain along, which is where the strength comes from
Oxygen — element · in the amide link
Nitrogen — element · the element that makes it a polyamide — the same linkage that joins amino acids into protein, which is why nylon is strong for the same reason silk is

is produced by

Polymerisation — process · condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from

is used as

Textiles — application · the first synthetic fibre, and still the one chosen where abrasion and repeated loading matter — rope, webbing, carpet

is an alternative to

Polyethylene terephthalate — material · as a fibre: nylon resists abrasion and repeated loading better, polyester resists sunlight and stretching better, and that division has held for sixty years
Silk — material · the most deliberate substitution in the history of materials — DuPont set out to make a synthetic silk, and nylon was announced as exactly that
POM — material · the two engineering plastics for small moving parts. Acetal holds its dimensions in humid air and nylon absorbs water and swells; nylon is tougher and wears better against abrasive contamination

belongs to the group

Plastic — material · the first synthetic fibre, and an engineering plastic in its own right

Sources

Wikidata
Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
Material World
Our own writing

Where it comes from, and what it becomes

Follow Nylon back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

Nylon → is produced by (condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from) → Polymerisation → takes as input (as vinyl chloride, which is why more than half of PVC's weight is salt rather than oil) → Chlorine → is produced by (at the anode) → Chlor-alkali electrolysis → takes as input (as the brine the cell electrolyses, and as the source of the hydrogen that comes off the cathode) → Water → is sourced from (by desalination, where energy is cheap and coastline available — the only route that adds fresh water rather than moving it) → Seawater
Nylon → is produced by (condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from) → Polymerisation → takes as input (as tetrafluoroethylene, which is where a substantial share of industrial fluorine chemistry ends up) → Fluorine → is produced by (electrolysis of potassium bifluoride, which is molten and conducts — there is no chemical oxidant strong enough to displace fluorine from a compound, so electricity is the only route and always has been) → Molten salt electrolysis → takes as input (after concentration, as one of the two routes to lithium chloride) → Lepidolite
Nylon → is produced by (condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from) → Polymerisation → takes as input (as vinyl chloride, which is why more than half of PVC's weight is salt rather than oil) → Chlorine → is extracted from (by electrolysis of brine, which yields chlorine and sodium hydroxide together) → Halite
Nylon → is produced by (condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from) → Polymerisation → takes as input (as tetrafluoroethylene, which is where a substantial share of industrial fluorine chemistry ends up) → Fluorine → is extracted from (the only significant source; hydrofluoric acid is made from it and everything fluorinated follows) → Fluorite
Nylon → is produced by (condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from) → Polymerisation → takes as input (as vinyl chloride, which is why more than half of PVC's weight is salt rather than oil) → Chlorine → is produced by (at the anode) → Chlor-alkali electrolysis → takes as input (the largest single use of salt, and the process the whole chlorine and caustic soda industry rests on) → Salt → is produced by (in the solar route — the same process, read from the other end) → Brine evaporation
Nylon → is produced by (condensation polymerisation of a diamine with a diacid, which is where the two numbers in nylon 6,6 come from) → Polymerisation → takes as input (as vinyl chloride, which is why more than half of PVC's weight is salt rather than oil) → Chlorine → is produced by (at the anode) → Chlor-alkali electrolysis → takes as input (as brine; the salt is the feedstock for both products at once) → Halite

These are the most distinct paths back. Nylon can be traced through others besides.

Downstream — what it becomes

Nylon → is used as (the first synthetic fibre, and still the one chosen where abrasion and repeated loading matter — rope, webbing, carpet) → Textiles