Question

What is the utility of the vulcanization of rubber? How is vulcanization carried out?

Answer 1

Hint: Vulcanization marked the birth of the modern rubber industry. It results in cross-linking between linear chains of rubber molecules and prevents slippage of the chains as the material retains the desired elasticity. It often requires sufficiently high temperatures.

Complete step by step answer:
Rubber molecules have very few cross-links and therefore it becomes sticky and soft in summer and hard and brittle in winter. And gets dissolved in solvents.
These undesirable properties of natural rubber were overcome by American inventor Charles Goodyear.
He accidentally placed a sample of rubber mixed with sulfur and lead oxide on a hot stove. This converted rubber into a heavily cross-linked. This modifies the properties of rubber and it becomes insoluble. This process is known as vulcanization.
Thus, vulcanization is carried out to make the rubber highly cross-linked and to convert it into a thermosetting polymer from a thermoplastic.
The procedure of Vulcanization:
Vulcanization is carried out at a temperature of 140-180 degrees Celsius.
Sulfur also with some other additives is added to the rubber sample.
Some of the additives include accelerators, antioxidants, and reinforcing agents.
Accelerators permit the reaction to occur at a comparatively lower temperature and lesser time.
Antioxidants are used to increase the shelf-life of rubber by reducing its deterioration that is caused by atmospheric oxygen which breaks covalent bonds and lowers the molecular weight.
Reinforcing agents increase stiffness, tensile, and resistance to abrasion.


Note:
Charles Goodyear was not involved with the Goodyear Tire and Rubber Company.
The company was founded by Frank A. Seiberling. The founder of the company named this company so in the honor of the American inventor.
In 1851, Goodyear’s brother Nelson used sulfur to convert natural rubber into ebonite, the first thermosetting plastic.