Natural rubber
Latex tapped from a tree and cured with sulfur — a material that returns to its shape after enormous deformation, which almost nothing else does.
Natural rubber is a polymer collected as latex from the bark of a tapped tree, and it does something very few materials do: it stretches to many times its length and returns, repeatedly, without permanent deformation. That elasticity comes from long coiled molecules that straighten under load and recoil when released.
Untreated it is nearly useless — sticky in heat, brittle in cold. Vulcanisation with sulfur links the chains together and fixes both faults at once, and everything rubber is used for dates from that discovery rather than from the material itself.
Uses
Tyres take most of it, and for the largest and most heavily loaded — aircraft and earthmoving tyres — natural rubber remains preferred over synthetic for its resistance to heat build-up and tearing.
Beyond that it goes into seals, hoses, belting, anti-vibration mounts, gloves and footwear. Synthetic rubbers have taken much of the volume, but they have not displaced natural rubber where fatigue resistance is what matters.
History
Rubber's industrial history is inseparable from its colonial one. The species is native to the Amazon, and the extraction of wild rubber there was carried out under coercion severe enough to become an international scandal.
Seed taken to British colonies in Asia established the plantation industry that supplies most rubber today, and shifted production away from its origin entirely — one of the clearest cases of a material's supply chain being redrawn by transplanting the organism that makes it.
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.
is an input to
- Vulcanisation — process · untreated latex rubber, sticky in heat and brittle in cold
is an alternative to
- Styrene-butadiene rubber — material · the substitution the Second World War forced. SBR wears and ages better; natural rubber has higher tear strength and builds up less heat, which is why truck and aircraft tyres still use a great deal of it
- EPDM — material · EPDM displaced natural rubber from every outdoor sealing application within about a decade, on weathering alone
- Silicone rubber — material · silicone works from −60 °C to 200 °C and does not perish; natural rubber is several times stronger and tougher at room temperature
- Butyl rubber — material · for anything that must hold gas: butyl is roughly ten times less permeable, which is why the tubeless tyre has a butyl liner and not a natural rubber one
- Polyurethane — material · cast polyurethane outlasts rubber by a wide margin in abrasion — which is why skateboard and industrial roller wheels changed to it and did not change back
is commonly confused with
- Silicone rubber — material · both called rubber and chemically unrelated — silicone's backbone contains no carbon at all
was succeeded by
- Styrene-butadiene rubber — material · in passenger tyre treads, under wartime supply pressure rather than on merit — and the substitution held afterwards because SBR wears better
belongs to the group
- Rubber — material · the original, and still unmatched for tear strength and heat build-up
is a source for
- Rubber — material · for the rest, and it is a plantation crop rather than a petrochemical
is used in
- Pencil — object · the eraser, and Priestley noted in 1770 that caoutchouc rubbed out pencil marks, which is where the English name came from
Sources
- Material WorldOur own writing
- Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)