Question

what is the role of sulphur on vulcanisation or rubber ​

Answer 1

Rubber is made up of hydrocarbon chains, basically carbon and hydrogen. These chains slide over one another and get tied to one another which leads to natural rubber being sticky.

Now when we vulcanize rubber by using sulphur, the sulphur reacts with these chains and forms disulphide (or similar) bonds. These new bonds join two of the hydrocarbon chains together. In this manner a mesh like network is formed which is stronger than the separate hydrocarbon chains in natural rubber. All of this comes about by the formation of the disuphide (or trisulphide or ...) bonds.