Question

Discuss the main purpose of vulcanization of rubber.

Answer 1

Hint: Natural rubber gets softens at high temperature. Addition of appropriate additives increases the elasticity and flexibility of natural rubber, which gives resistance to high temperature.

Complete answer:
Vulcanisation is a chemical process which is used for converting natural rubber or its polymers into more durable materials by the addition of sulphur atom or other equivalent curatives or accelerators.the polymers are modified by the addition of additives by forming three dimensional cross-links between individual polymer chains.
There are two types of polymers on the basis of thermal effect- Thermosetting and Thermoplastic.
Thermosetting plastic is a polymer, which becomes irreversibly rigid on heating.
Thermoplastic is also a plastic polymer, it softens on heating and on cooling it becomes hard. Thermoplastic materials can be heated and cooled several times, without changing its physical or chemical properties. When these materials are heated up to their melting point, they melt into liquid.Natural rubber is a polymer of isoprene (2-methyl-1,3-butadiene).
Main purpose of vulcanization of rubber is to improve the elasticity of rubber at high and at low temperatures.Vulcanised rubber has higher tensile strength and has resistance to swelling and abrasion, and is flexible at a greater range of temperatures.In the process of vulcanization, raw rubber is heated with sulphur at a temperature of 373K to 415K , along with the addition of appropriate additives. On vulcanization, sulphur forms cross-links at the double bonds, which are the reactive sites and thus the natural rubber gets stiffened.

Note: Natural rubber is obtained by polymerization isoprene(2 methyl-1, 3-butadiene). Natural rubber is made from the latex sap of rubber trees. Natural rubber also has high tensile strength, but at high temperature, vulcanization helps the rubber to increase its stability.