Question

Explain the purpose of vulcanization of rubber.

Answer 1

Natural rubber becomes soft at high temperature and brittle at low temperatures. To improve physical properties of rubber, vulcanization is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between $373K$ and $415K$. On vulcanization, sulphur forms cross-links at the reactive sites of double bonds and thus the rubber gets stiffened.