Q.What role does sulfur play in the vulcanization of rubber, and why does vulcanized rubber not become sticky in hot weather the way raw rubber does?
You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.
Start your 14-day free trial to unlock the full solution →During vulcanization, sulfur atoms react with the residual double bonds present at every isoprene unit of NEIGHBOURING rubber chains, forming short chains of sulfur atoms -- disulfide or polysulfide bridges -- that covalently cross-link the chains together into a loosely connected three-dimensional network. Raw, un-cross-linked rubber becomes soft and tacky in hot weather because warming loosens the already-weak van der Waals attractions between its untethered chains, letting them flow and stick to surfaces they touch; the reactive double bonds along the chain also make the surface somewhat chemically 'grabby'. Once sulfur has cross-linked the chains and consumed many of those reactive double bonds, the chains are held in a fixed, covalently-bonded network that cannot flow or slide the way an uncross-linked chain can, and the surface's reactive sites are largely used up -- so vulca …
Unlock everything free for 14 days
- Full step-by-step solutions
- Concept-first explanations
- Methods, shortcuts & mistakes
- PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.