question_answer

Differentiate the following pairs of polymers based on the property mentioned against each. (i) Novolac and bakelite (structure). (ii) Buna-S and terylene (intermolecular forces of attraction).

Answer:

                (i) Novolac is a linear but bakelite is a cross- linked polymer of phenol and formaldehyde. For structures refer to pages 15/14-15/15. (ii) Terylene contains ester functional groups which are polar in nature. Therefore, the intermolecular 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 :