A short fragment of a polyamide chain (three repeat units, end groups shown) is drawn. It is a fibre. Which statement about the forces between neighbouring chains, and the resulting class, is correct?

ADipole forces between ester groups; a thermosetting polymer
BCovalent crosslinks between chains; a thermosetting polymer
CHydrogen bonding between N-H and C=O of neighbouring chains; a fibre
DOnly weak van der Waals forces; an elastomer

Answer: C

The fragment is nylon 6 with many amide groups. The N-H of one chain hydrogen-bonds to the C=O of a neighbouring chain, giving strong, regular intermolecular attraction, which is characteristic of fibres. Weak van der Waals forces would give an elastomer, and a thermosetting polymer requires covalent crosslinks, which are not present here.

Practice Polymers More on Repeat unit and classification from drawn monomers

Previous questionNext question

A short fragment of a polyamide chain (three repeat units, end groups shown) is drawn. It is a fibre. Which statement about the forces between neighbouring chains, and the resulting class, is correct?

Answer: C

More questions on Repeat unit and classification from drawn monomers