Highly elastic polymers. Rubber is classified as natural rubber and synthetic rubber according to raw material. By form it is divided into lump raw rubber, latex, liquid rubber and powdered rubber. Rubber is the basic raw material of the rubber industry, widely used in the manufacture of tires, hoses, tapes, cables and other various rubber products.
General-purpose rubber has better comprehensive performance and is widely used. There are mainly: ① natural rubber. Produced from the latex of the three-leaf rubber tree, the basic chemical composition of cis - polyisoprene. Good elasticity, high strength, good overall performance. ② Isoprene rubber. Full name is cis-1,4-polyisoprene rubber, high cis synthetic rubber made from isoprene, because of its structure and properties similar to natural rubber, it is also known as synthetic natural rubber. (iii) Styrene-Butadiene Rubber (SBR). Abbreviation SBR, copolymerization of butadiene and styrene. According to the production method is divided into emulsion polymerization of styrene butadiene rubber and solution polymerization of styrene butadiene rubber. Its comprehensive performance and chemical stability. ④Cis-butadiene rubber. Full name is cis-1,4-polybutadiene rubber, abbreviated BR, produced by butadiene polymerization. Compared with other general-purpose rubbers, vulcanized cis-butadiene rubber is particularly excellent in cold resistance, abrasion resistance and elasticity, less heat generation under dynamic load, good aging resistance, and easy to be used with natural rubber, chloroprene rubber, nitrile rubber and so on.
Specialty rubber refers to rubber with some special properties. Mainly: ① chloroprene rubber. Abbreviated CR, produced by the polymerization of chloroprene. Has a good overall performance, oil resistance, flame resistance, oxidation resistance and ozone resistance. However, its density is large, easy to crystallize and harden at room temperature, storage is not good, poor cold resistance. ② Nitrile rubber. Abbreviated NBR, copolymerized from butadiene and acrylonitrile. Oil resistance, aging resistance is good, can be in the air at 120 ℃ or 150 ℃ in the long-term use of oil. In addition, it also has water resistance, air tightness and excellent bonding properties. ③Silicone rubber. The main chain consists of alternating silicon and oxygen atoms, with organic groups on the silicon atom. It is resistant to high and low temperatures, ozone, and good electrical insulation. Fluorine rubber. Synthetic rubber containing fluorine atoms in the molecular structure. Usually to the copolymer containing fluorine unit of the number of fluorine atoms to indicate, such as fluoroelastomer 23, is a copolymer of vinylidene fluoride and chlorotrifluoroethylene. Fluorine rubber is resistant to high temperature, oil and chemical corrosion. ⑤ Polysulfide rubber. Polysulfide polycondensation from dihalogenated alkanes and alkali metals or alkaline earth metals. It has excellent oil and solvent resistance, but not high strength, aging resistance, processing is not good, there is a bad smell, and more with nitrile rubber and used. In addition, there are polyurethane rubber, chlorohydrin rubber, acrylate rubber and so on.