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🧪 Chemistry  ·  Polymers  ·  NEET & JEE

The monomer of PMMA (Perspex/Plexiglas), used for lenses and lamp covers, is:

Answer: Methyl methacrylate.

  • A Methyl acrylate
  • B Methyl methacrylate
  • C Vinyl acetate
  • D Acrylonitrile

Correct answer: B. Methyl methacrylate

Explanation: PMMA (poly methyl methacrylate) is the addition polymer of methyl methacrylate, valued for its transparency and use as an unbreakable glass substitute.

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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