Which of the following polymers can have strong intermolecular forces?
(i) Nylon
(ii) Polystyrene
(iii) Rubber
(iv) Polyesters
The answer is the option (i, iv). Polyamides (Nylon) and Polyesters (terylene) have high tensile strength and modulus due to strong intermolecular forces like H-bonding. This leads to close packing in the chain resulting in crystalline nature. That is why they are used as thread forming fibres.