Question

Novlac, the linear polymer used in paints is

• A. copolymer of 1,3-butadiene and styrene
• B. obtained by the polymerization of methyl methacrylate
• C. initial product obtained in the condensation of phenol and formaldehyde in the presence of acid catalyst
• D. obtained by the polymerization of caprolactam
• E. copolymer of melamine and formaldehyde

Hint:

Think of Novolac as "Unfinished Bakelite." It's the linear, paint-friendly version before the heavy cross-linking turns it into a hard plastic.

Answer 1

The Correct Option is C

Concept: Novolac is an important intermediate in the production of Bakelite, one of the oldest synthetic polymers.
• Reaction: It is formed by the condensation reaction of phenol with formaldehyde.
• Conditions: When the ratio of formaldehyde to phenol is low and an acidic catalyst is used, a linear polymer is formed.
• Properties: Novolac is a thermoplastic, linear chain polymer used primarily in the manufacture of varnishes and paints.

Step 1: Analyze the formation of Phenol-Formaldehyde resins. The reaction starts with the formation of ortho and para hydroxymethylphenol derivatives. These then condense to form linear chains. This linear product is Novolac.

Step 2: Distinguish from Bakelite. If Novolac is further heated with formaldehyde, it undergoes cross-linking to form an infusible solid mass called Bakelite. Thus, Novolac is the "initial" linear product described in Option (C).