JEE Main · 2023 · 29 Jan 2023 · Shift 2 · Polymers

An elastomer has weak intermolecular forces between its chains, which lets the material stretch and spring back, a property shown by neoprene. A fibre has strong intermolecular forces and close chain packing that give thread-forming strength, as in the polyester terylene. A thermosetting polymer hardens into a rigid, cross-linked network once heated and cannot be remoulded, which is the behaviour of urea$-$formaldehyde resin. A thermoplastic softens on heating and can be reshaped again and again, as in polystyrene. The elastomer is therefore neoprene, the fibre is polyester, the thermosetting polymer is urea$-$formaldehyde resin and the thermoplastic is polystyrene.