Question

Question: Polycarbonates are a class of thermoplastic polymers that are used in the plastic lenses of eyeglasses and in the shells of bicycle helmets. A polycarbonate is made from the reaction of bisphenol A (BPA) with phosgene:

Phenol (C6H5OH) is used to terminate the polymer (stop its growth).

1. Draw the structure of the polycarbonate chain formed in the above reaction.
2. Is this reaction a condensation or an additional polymerization?

Short answer

1. The structure of the polycarbonate chain formed
2. Reaction is the condensation reaction

Step-by-step solution

To draw the structure of the polycarbonate chain

The polycarbonate formed by the condensation polymerization of BPA and phosgene is shown in the figure below.

In the polymerization reaction, a nucleophilic attack of the hydroxyl group on the carbonyl carbon of phosgene occurs, resulting in the release of the chloride anion. In the second step, deprotonation occurs, where HCl is formed.

hence the structure of the polycarbonate chain formed

To find Is this reaction a condensation or an addition polymerization

It needs to be determined by the reaction of bisphenol with phosgene condensation or an additional polymerization.

The reaction is the condensation reaction. An addition reaction is when the polymers are formed by the addition of monomers, and there are no by-products. In the condensation reactions, polymers are formed by releasing smaller molecules.

Hence the reaction is the condensation reaction.