Neoprene

Neoprene is polymerised chloroprene, and the chlorine on the chain is what distinguishes it. It gives moderate resistance to oil — better than natural rubber, well short of nitrile — good weather and ozone resistance, and genuine flame retardancy: neoprene is self-extinguishing, which almost no other elastomer is.

It is the generalist. It does nothing outstandingly and very little badly, which is why it survived seventy years of more specialised rubbers being developed around it.

The wetsuit is foamed neoprene, and its insulation comes from nitrogen bubbles rather than the polymer. That is worth stating because the material is popularly understood the other way round.

Compounded and vulcanised like other rubbers, though metal oxides rather than sulfur do the crosslinking. Extruded, moulded and calendered into sheet.

Foamed sheet for wetsuits is made by blowing the compound with nitrogen during cure and laminating it to nylon or polyester jersey on one or both faces — the fabric is there for tear strength and abrasion, because foamed neoprene alone tears easily.

Wetsuits, and by extension laptop sleeves, drink holders and orthopaedic supports, which use the same laminated foam for reasons of feel and cost rather than insulation.

Industrially: gaskets and hose, vibration mounts and bridge bearings, conveyor belting, cable jacketing, adhesives — contact adhesive is largely neoprene in solvent — and the gloves used where a moderate chemical barrier is needed and latex allergy is a concern.

Announced by DuPont in 1931 as DuPrene, following work by Wallace Carothers and Arnold Collins, and renamed neoprene in 1937 when the company decided to sell the material to manufacturers rather than sell finished goods. It is the first synthetic rubber to succeed commercially anywhere.

Carothers went on to invent nylon in the same laboratory, which makes that group responsible for both the first synthetic rubber and the first synthetic fibre within five years.

The wetsuit follows in the early 1950s, developed independently by Hugh Bradner and by Jack O'Neill, and it is what put the material's name into ordinary language.

Vulcanised and therefore not remeltable. Wetsuits are a recognised waste problem — a laminate of foamed rubber and synthetic jersey that cannot be separated economically — and take-back schemes grind them into mats and flooring.

Most neoprene is still made from butadiene via chloroprene, a route with a well-documented occupational health record: chloroprene monomer is classified by IARC as probably carcinogenic to humans, and communities near production sites have been the subject of significant regulatory attention in the United States. Limestone-derived and plant-derived alternatives to petrochemical neoprene now exist and are used by parts of the wetsuit industry.