Question
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.
(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.
