Differentiate between the following pairs of polymers based on the property mentioned against each :
(i) Novolac and Bakelite (Structure)
(ii) Buna-S and Terylen (Intermolecular forces).

Explanation

(i) Novolac is a linear but bakelite is a cross -linked polymer of phenol and formaldehyde.
(ii) Terylene contains ester functional groups which are polar in, therefore , the intermoleuclar forces of attraction involved in terylene are strong dipoe-dipole interactions as shown below:

Buna-S , on the other hand, does not have polar functional groups. It has only non - polar hydrocarbon chains and hence has only weak van der Waals forces of attraction as shown below :