Natural rubber, also called India Rubber or caoutchouc, is an elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloid produced by some plants. The plants are ‘tapped’ by making an incision in the bark of the tree and collecting the sticky, milk-colored latex sap, which is refined into usable rubber. The purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically. Natural rubber is used in many applications and products, as is synthetic rubber. It is normally very stretchy and flexible and extremely waterproof.
Natural rubber is often vulcanized, a process by which the rubber is heated and sulfur, peroxide or bisphenol are added to improve resistance and elasticity, and to prevent it from perishing. Carbon black is often used as an additive to rubber to improve its strength, especially in vehicle tires.
Other significant uses of rubber are door and window profiles, hoses, belts, matting, flooring and dampeners for the automotive industry. Gloves and toy balloons are also large consumers of rubber. Significant amounts of rubber are used as adhesives in many manufacturing industries and products, although the two most noticeable are the paper and carpet industries. Rubber is also commonly used to make rubber bands and pencil erasers. Many aircraft tires and inner tubes are still made of natural rubber due to the high cost of certification for aircraft use of synthetic replacements.