CBSE Class 8 Answered

Natural rubber becomes soft at high temperature and brittle at low temperature. 

In order to improve the properties of natural rubber, the process of vulcanisation is carried out.

Vulcanization of rubber is a process of improvement of the rubber elasticity and strength by heating it in the presence of sulphur at a temperature range between 373K to 415K.

This results in three-dimensional cross linking of the chain rubber molecule bonded to each other by sulphur atoms.This process was invented by Charles Goodyear.

Advantages of vulcanization: 

• It makes rubber quite resistant to the action of organic acids.
• It makes rubber resistant to wear and tear.
• The elasticity of rubber increases and it remains unaffected over a wide range of temperature.
• It makes rubber resistant to the attack of air.