The raw materials to make rubber can be natural or synthetic.
- 32 million metric tons of rubber are produced annually 75% 75%
and of that amount two-thirds are synthetic.
Natural rubber is made from liquid tree sap, latex, that comes from a variety of trees and plants. Most of the latex comes from the Hevea brasiliensis tree.
Synthetic rubber is made by linking polymer molecules together. These are mainly polymers synthesised from petroleum by-products.
Both natural and synthetic rubber are processed to turn it into a usable product. The processes vary according to the intended use of the final product. Chemicals are added to the rubber to make it stable. Without this, the rubber would get brittle if it got cold or become sticky during high temperatures.
To make rubber strong and durable, it goes through a heat-treatment phase known as vulcanisation. The heat creates extra bonds or cross-links between the rubber molecules to make it stronger. In this process, rubber chemicals also play a key role by making it more durable and less energy-intensive. After vulcanisation, any imperfections are removed from the rubber and it is then shaped or moulded into the final product.