[Chemistry Class Notes] on Synthetic Rubber Pdf for Exam

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.