What Is Synthetic Rubber Definition Types Preparation Methods and Key Uses
Synthetic rubber is defined as any artificial elastomer. It is usually derived from the polyene monomers additional polymers and unless the synthetic rubber gets disclosed as a polysulfide rubber, and the laminates containing such a layer can be classified with additional polymers.
About Elastomer
Elastomer is described as the material with the mechanical property that can undergo much more elastic deformation, under stress compared to most of the materials and still return to its previous size without any permanent deformation. Synthetic rubber also serves as a substitute for natural rubber in several cases, especially when the improved material properties are needed.
History of Synthetic Rubber
The motor vehicles expanded use, especially the motor vehicle tires, starting in the 1890s, created an increased demand for rubber. Also, in 1909, a team headed by Fritz Hofmann working at the Bayer laboratory in Elberfeld, Germany has succeeded in the polymerization of Isoprene, which is the first synthetic rubber.
By 1940, the United States was effectively stockpiling natural rubber, doubling its normal imported quantity of around a half million tons a year. And, in 1941, Japan occupied South-East Asia by cutting off the natural rubber supplies to the United States. In the first response to its supply crisis, the U.S. government has ordered planting tens of thousands of acres of guayule. This shrub, which thrives in the western parts of the United States and Mexico, also has rubber latex. It also has the disadvantage of rubber yielding only with difficulty; the plant should be ground up and extracted, hence requiring a constant supply of new plants.
By the end of this war, petroleum served as the base for synthetic rubber, since it would present in the postwar years. Whereas the manufacturing process of petroleum usage was more complex, but on average, petroleum chemical was also cheaper, and the progress was rapid. B.F.Goodrich has done his early work in synthesis and became the largest successive producer of synthetic rubber during the war. The U.S. firms built 51 synthetic rubber factories in the period between 1942 and 1945. During that period, production has increased from 24,640 tons of synthetic rubber to more than 784000 tons from 1942 to 1945.
Synthetic Rubber vs Natural Rubber
Let us look at the major differences between Synthetic rubber and Natural rubber.
In November 1948, natural rubber became freely available at a lower price. Also, it remains to be seen if synthetic rubber, on uniformity and quality basis will continue to be voluntarily consumed under the present price relationship of natural rubber and synthetic rubber.
Other synthetic rubber examples can be listed as follows:
chloroprene, which is prepared by the polymerization of 2-chlorobutadiene
polyisoprene, which is prepared by the polymerization of synthetic isoprene
nitrile rubber, which is made from 2-propenenitrile and butadiene or cyanobutadiene
A considerable lag is there between the time of purchase to the time of consumption and prices may substantially vary in that period. Also, the test will come when the less priced natural rubber becomes more readily available and starts to enter into quantity consumption in the manufacturing establishments.
A widely used elastomer for external sheets like roof coverings is chlorosulphonated polyethylene or Hypalon. A new class of synthetic rubber is described as the thermoplastic elastomers that are moulded easily unlike conventional N.R. vulcanized rubber.
Their structure can be stabilized by cross-linking by the crystallites either in the case of SBS block copolymers or in the case of polyurethanes or by amorphous domains. Silicone rubber is defined as an inorganic polymer which is resistant to both very low and higher temperatures and can be widely used for catheters and also for other medical devices or equipment. However, its tensile strength is low compared with other synthetic rubbers.
Different Types of Synthetic Rubber
The different types of synthetic rubber are Buna rubbers, butyl rubbers, and neoprene, and they are generally developed for specialized applications having specific properties. Butadiene rubber and styrene-butadiene (where both are Buna rubbers) are generally used in tire production.
Uses of Synthetic Rubber
Let us look at the uses of synthetic rubber as listed below:
Synthetic rubber can be preferred over natural rubber for a few uses if the price differential is not greater.
The transport industry is one of the largest users of rubber for tire production.
Rubber can also be used by the construction industry in hoses, tubes, elevator belts, seismic bearings, and more.
Industries that produce consumer goods make use of rubber in making erasers, good footwear, sports items, and more.
Polyisoprene synthesis is given as the artificial rubber that has the same properties as those of the natural rubber in the chemical composition of ingredients which is used in its manufacture.
FAQs on Synthetic Rubber Chemistry Structure Preparation and Applications
1. What is synthetic rubber in chemistry?
Synthetic rubber is an artificial elastomer produced by the polymerization of petrochemical monomers such as butadiene or styrene. Unlike natural rubber (polyisoprene from latex), synthetic rubber is manufactured through controlled chemical reactions to achieve specific properties. It consists of long-chain polymers that exhibit elasticity due to their flexible molecular structure and cross-linking. Common examples include styrene-butadiene rubber (SBR) and neoprene, widely used in tyres, seals, and industrial products.
2. How is synthetic rubber made?
Synthetic rubber is made by the addition polymerization of unsaturated hydrocarbon monomers such as butadiene. The process typically involves:
- 1. Selection of monomers like 1,3-butadiene (C4H6) or styrene.
- 2. Initiation using free-radical or coordination catalysts.
- 3. Chain propagation forming long polymer chains.
- 4. Termination and recovery of the polymer.
For example, polymerization of butadiene can be represented as:
n CH2=CH–CH=CH2 → (–CH2–CH=CH–CH2–)n. The resulting polymer is then processed and vulcanized to improve strength and elasticity.
3. What is the difference between natural rubber and synthetic rubber?
The main difference between natural and synthetic rubber is that natural rubber is obtained from latex, while synthetic rubber is chemically manufactured from petrochemicals.
- Natural rubber: Polymer of isoprene (cis-1,4-polyisoprene), obtained from rubber trees.
- Synthetic rubber: Man-made polymers like SBR, neoprene, or Buna-N.
- Natural rubber has better tensile strength, while synthetic rubber offers better chemical and heat resistance.
- Synthetic rubber properties can be tailored by changing monomers and catalysts.
Both are elastomers, but synthetic rubber provides greater control over performance in industrial applications.
4. What are the types of synthetic rubber?
The main types of synthetic rubber include SBR, Buna-N, neoprene, and butyl rubber.
- Styrene-butadiene rubber (SBR): Used in car tyres.
- Buna-N (NBR): Copolymer of butadiene and acrylonitrile, resistant to oils.
- Neoprene: Polymer of chloroprene, resistant to heat and chemicals.
- Butyl rubber: Copolymer of isobutylene with isoprene, used in inner tubes.
Each type differs in monomer composition and chemical resistance, making them suitable for different industrial and commercial uses.
5. What is styrene-butadiene rubber (SBR)?
Styrene-butadiene rubber (SBR) is a copolymer of styrene (C8H8) and 1,3-butadiene (C4H6) widely used in tyre manufacturing. It is formed by free-radical emulsion polymerization. The simplified reaction is:
m CH2=CH–CH=CH2 + n C6H5–CH=CH2 → SBR copolymer
SBR provides good abrasion resistance and aging stability, making it one of the most important synthetic rubbers in the automotive industry.
6. What is vulcanization of synthetic rubber?
Vulcanization is the process of heating rubber with sulfur (S) to form cross-links between polymer chains, improving strength and elasticity. During vulcanization:
- Sulfur atoms form bridges between double bonds in the polymer.
- Elasticity, tensile strength, and durability increase.
- Rubber becomes more resistant to heat and chemicals.
This chemical cross-linking converts soft, sticky rubber into a tough, elastic material suitable for tyres and industrial products.
7. Why is butadiene used in making synthetic rubber?
Butadiene is used in synthetic rubber because it contains conjugated double bonds that readily undergo addition polymerization to form elastic polymers. The structure CH2=CH–CH=CH2 allows 1,4-addition, producing flexible chains with residual double bonds for vulcanization. Its availability from petroleum cracking and its ability to form strong, elastic materials make it a key monomer in SBR and Buna rubber.
8. What is Buna-N rubber?
Buna-N is a copolymer of 1,3-butadiene and acrylonitrile (CH2=CH–CN) known for its oil and fuel resistance. It is produced by emulsion polymerization and contains polar –CN groups that improve resistance to hydrocarbons. Buna-N is widely used in fuel hoses, gaskets, and seals because it maintains flexibility in contact with petroleum products.
9. What are the uses of synthetic rubber?
Synthetic rubber is used in tyres, seals, hoses, footwear, and industrial products due to its durability and chemical resistance.
- Automobile tyres (mainly SBR).
- Conveyor belts and gaskets.
- Oil-resistant seals (Buna-N).
- Electrical insulation and protective gloves.
Its properties such as abrasion resistance, elasticity, and heat stability make it essential in modern manufacturing and polymer chemistry applications.
10. Is synthetic rubber a polymer?
Yes, synthetic rubber is a polymer formed by linking many small monomer units into long chains through polymerization. It is classified as an elastomer, meaning it can stretch and return to its original shape. The repeating structural unit, such as (–CH2–CH=CH–CH2–)n in polybutadiene, gives the material its characteristic elasticity and flexibility.
