Q57 of 57 Page 225

Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the structural similarities between such polymers? Bakelite, urea-formaldehyde resin, polythene, polyvinyls, polystyrene.

Polythene, polyvinyl and polystyrene soften on heating and harden on cooling. Such polymers are called thermoplastic polymers.

These possess intermolecular forces of attraction whose strength lies between the strength of intermolecular forces of elastomers and fibers.


These polymers are linear or slightly branched long-chain molecules.





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