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🧪 Chemistry  ·  Polymers  ·  NEET & JEE

Living polymerisation is characterised by:

Answer: No termination or transfer reactions, allowing controlled molecular weight.

  • A No termination or transfer reactions, allowing controlled molecular weight
  • B Very fast termination of every growing chain end overall in most cases
  • C A broad, uncontrolled polydispersity across the product under typical conditions
  • D Chain lengths that vary randomly with little control over distribution

Correct answer: A. No termination or transfer reactions, allowing controlled molecular weight

Explanation: In living polymerisation, chains grow without termination; it gives narrow molecular weight distributions and allows block copolymer synthesis.

Addition vs Condensation PolymerisationAddition (e.g. polythene)n (CH₂=CH₂)-[-CH₂-CH₂-]ₙ-No atoms lost - monomers just join at the double bondCondensation (e.g. Nylon-6,6)HOOC-R-COOH + H₂N-R'-NH₂-[-CO-R-CO-NH-R'-NH-]ₙ-+ n H₂OA small molecule (water here) is eliminated at EVERY linking step

Addition polymerisation simply links monomers containing a double bond with nothing left over, while condensation polymerisation joins two different monomers through a reaction (often forming an ester or amide bond) that releases a small molecule like water at each step.

Concept context

Large molecules made of repeating monomer units. Covers addition and condensation polymerisation, natural and synthetic polymers (nylon, PVC, Bakelite, natural rubber), and their real-world industrial applications.

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