Rubber is a highly elastic polymer material with reversible deformation. It is elastic at room temperature and can produce large deformation under the action of a small external force. After removing the external force, it can be restored to its original state. Rubber is a completely amorphous polymer, its glass transition temperature (T g) is low, the molecular weight is often large, more than hundreds of thousands.
Rubber is divided into natural rubber and synthetic rubber two kinds. Natural rubber is made from rubber tree, rubber grass and other plants extracted gum after processing; Synthetic rubber is made by polymerization of various monomers. Rubber products are widely used in all aspects of industry and life.
The origin and application characteristics of universal rubber
General-purpose rubber has good comprehensive performance and is widely used. The main products are: (1) natural rubber, made from the latex of Hevea triloba, and the basic chemical composition is cis-polyisoprene. Good elasticity, high strength and comprehensive performance. (2) isoprene rubber, the full name is cis-1, 4-polyisoprene rubber, isoprene made of high-grade synthetic rubber, because of its structure and performance and natural rubber similar, it is also known as synthetic natural rubber. ③ Styrene butadiene rubber, SBR for short, from butadiene and styrene copolymerization. According to the production method, it is divided into emulsion polymerization styrene butadiene rubber and solution polymerization styrene butadiene rubber. Its comprehensive properties and chemical stability are good. ④ butadiene rubber, the full name is cis-1, 4-polybutadiene rubber, referred to as BR, by butadiene polymerization system. Compared with other general rubber, vulcanized butadiene rubber has excellent cold resistance, wear resistance and elasticity, less heat under dynamic load, good aging resistance, easy to be used with natural rubber, neoprene rubber, nitrile rubber and so on. ⑤ Chloroprene rubber, referred to as CR, from the polymerization of chlorobutadiene system. Good comprehensive properties, oil, fire, oxidation and ozone resistance. But its density is large, easy to crystallize and harden at room temperature, poor storage, poor cold resistance
The origin and application characteristics of special type rubber
Special rubber refers to rubber with some special properties. The main ones are: ① Nitrile rubber, NBR for short, copolymerized by butadiene and acrylonitrile. Good oil resistance and aging resistance. It can be used for a long time in 120℃ air or 150℃ oil. In addition, it also has water resistance, air tightness and excellent bonding properties. ② Silicone rubber, the main chain consists of alternating silicon and oxygen atoms, with organic groups on silicon atoms. High and low temperature resistance, ozone resistance, good electrical insulation. (3) fluorine rubber, synthetic rubber containing fluorine atoms in the molecular structure. It is usually expressed by the number of fluorine atoms in the fluorine-containing unit of the copolymer, such as fluororubber 23, which is a copolymer of vinylidene fluoride and trifluoroethylene chloride. Fluoroelastomer is resistant to high temperature, oil and chemical corrosion. (4) polysulfide rubber, by dihalogenated alkane and alkali metal or alkali earth metal polysulfide condensation. Has excellent oil resistance and solvent resistance, but the strength is not high, aging resistance, processing is not good, there is a smell, and more nitrile rubber and use. In addition, there are polyurethane rubber, chlorol rubber, acrylic rubber and so on.
Post time: Feb-06-2021