Sponsor Area

Polymers

Question
CBSEENCH12009398

How are the following prepared?
(a) Dacron    (b) Bakelite.

Solution
(a) Dacron is obtained by heating terephthalic acid with ethylene glycol at 425–475 K. It is a condensation polymer.


(b) Bakelite is a condensation polymer. It is obtained by treating phenol with formaldehyde in the presence of an acidic or basic catalyst.

The condensation of o-hydroxy benzyl alcohol or p–hydroxy benzyl alcohol gives a linear polymer called ‘Novolac’.

On further heating with formaldehyde ‘novolac’, undergoes cross-linking to form an infusible solid called bakelite.