Question

Which among the following polymers is obtained first by formation of salt by neutralization and then by step growth polymerisation?

• A. Polyester
• B. Nylon-6
• C. Nylon-6,6
• D. Novolac

Hint:

Nylon-6,6 is prepared via condensation of a diamine and a dicarboxylic acid through a salt intermediate.

Answer 1

The Correct Option is C

Step 1: Understand the process mentioned in the question.
The question refers to a polymer formed first by salt formation through neutralization, followed by step growth (condensation) polymerisation.
Step 2: Identify the polymer formed via salt formation.
In the preparation of Nylon-6,6, hexamethylenediamine reacts with adipic acid to form a salt known as nylon salt.
Step 3: Polymerisation step.
This nylon salt on heating undergoes step growth polymerisation with elimination of water to form Nylon-6,6.
Step 4: Eliminate other options.
(A) Polyester: Formed directly by condensation, not via salt formation.
(B) Nylon-6: Prepared by ring opening polymerisation of caprolactam.
(D) Novolac: A phenol–formaldehyde resin formed without salt formation.
Step 5: Conclusion.
Nylon-6,6 is obtained by salt formation followed by step growth polymerisation.