Vulcanising rubber mainly makes it stronger , tougher, and more useful while reducing some of its original softness and flow.

Quick Scoop: Key Property Changes

When rubber is vulcanised (heated with sulfur), these changes are observed:

  • Elasticity increases (it stretches and springs back better over a wide range of temperatures).
  • Tensile strength and tear strength increase (it becomes much stronger and less likely to tear).
  • Hardness increases (it becomes firmer, not as soft and sticky as raw rubber).
  • Plasticity decreases (it no longer flows or deforms permanently as easily as before).
  • Elongation at break generally decreases (it cannot stretch absurdly long like raw rubber before breaking, but it becomes more usefully elastic).
  • Permanently set deformation on compression decreases (better shape retention under load).
  • Heat resistance improves (it can withstand higher temperatures without melting or becoming tacky).
  • Chemical and solvent resistance improve (less soluble; it mostly only swells in solvents, does not dissolve).
  • Air and water permeability decrease (better sealing properties).
  • Aging resistance improves (less cracking and degradation over time due to oxygen, light, and heat).
  • It becomes harder, elastic, and more resistant to temperature changes overall.

In simple exam-style form, you can write:

On vulcanisation, rubber becomes harder, stronger, more elastic, less plastic, less soluble (only swells in solvents), more resistant to heat, chemicals, and aging, and shows decreased air and water permeability.

Information gathered from public forums or data available on the internet and portrayed here.