Commerical vulcanisation of rubber involves

Commercial vulcanization of rubber primarily involves the use of sulphur to create cross-links between polymer chains. Discovered as the first cure system, sulphur vulcanization remains the most extensively used method in the industry [t1][t8]. During this process, sulphur atoms form strong chemical bridges (cross-links) that transform raw rubber from a plastic, tacky material into a durable, thermoset elastomer with improved structural and physical properties [t2][t8]. While other elements like selenium and tellurium can technically cross-link rubber, they are typically reserved for specialized applications rather than standard commercial processes [t3][t5]. Carbon, often in the form of carbon black, is frequently added to rubber compounds, but it serves as a reinforcing filler to improve tensile strength and wear resistance rather than acting as the primary vulcanizing agent [t6][t7]. Therefore, sulphur is the essential element for commercial vulcanization.

Sources

1. [1] https://www.sciencedirect.com/topics/engineering/sulfur-vulcanization
2. [2] https://core.ac.uk/download/pdf/11933071.pdf
3. [3] https://pmc.ncbi.nlm.nih.gov/articles/PMC9916552/