Question Constellation Sign up for free AQA · GCSE · Chemistry · Higher
Polymer structure and thermal behaviour
Explain why some polymers do not melt when heated.
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Marking points
- 1 Identifies cross-links/covalent bonds between polymer chains.
- 2 Explains that too much energy is needed to overcome these links/bonds.
Full-mark answer
These polymers have covalent cross-links between their chains. So much energy would be needed to overcome the cross-links that the polymer does not melt when heated.
Why this answer loses marks
Some polymers do not melt because their chains are simply very long.
Chain length is not the credited reason; the answer needs covalent cross-links and the energy needed to overcome them.