Answer: The amorphous regions transition from glassy to rubbery state.
- A The amorphous regions transition from glassy to rubbery state
- B The crystalline regions of the polymer melt into a viscous liquid
- C Cross-linking reactions begin between adjacent chains
- D Crystallisation of the polymer chains reaches completion
Correct answer: A. The amorphous regions transition from glassy to rubbery state
Explanation: Below Tg, polymer chains are immobile (glassy); above Tg, they become mobile (rubbery). It applies to amorphous regions.
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.