How does vulcanization improve the properties of rubber?

Vulcanization is a chemical process that transforms raw rubber—which is naturally a viscous liquid that becomes sticky when warm and hard when cold—into a durable, elastic solid.12

By heating rubber with sulfur, the process creates chemical cross-links or bridges between the long-chain polymer molecules. This molecular network provides several key improvements:12

• Enhanced Stability: The cross-links prevent the molecules from flowing, ensuring the rubber remains elastic and resilient across a wider range of temperatures.12
• Increased Strength: Finished rubber exhibits higher tensile strength and improved resistance to abrasion.1
• Chemical Resistance: The interlinked structure prevents the material from dissolving in solvents, allowing it to merely swell instead. It also improves resistance to swelling and general deterioration.21

In modern manufacturing, this process—often called curing—is frequently supplemented with accelerators, carbon black, and zinc oxide to further refine these physical properties.1