Natural rubber though useful has some problems associated with its use. These limitations are discussed below:
1. Natural rubber is quite soft and sticky at room temperature. At elevated temperatures
(> 335 K), it becomes even softer. At low temperatures (< 283 K), it becomes brittle.
Thus, to maintain its elasticity, natural rubber is generally used in the temperature
range of 283 K-335 K.
2. It has the capacity to absorb large amounts of water.
3. It has low tensile strength and low resistance to abrasion.
4. It is soluble in non-polar solvents.
5. It is easily attacked by oxidizing agents.
Vulcanization of natural rubber is done to improve upon all these properties. In this
process, a mixture of raw rubber with sulphur and appropriate additive is heated at a temperature range between 373 K and 415 K.
