Chapter 31.SE, Problem 13VC

Interpretation Introduction

Interpretation:

Identify the structural class of the following polymer and also the monomer units used to make it.

Concept introduction:

In this reaction, the polymeric product formed is a polycarbonate. Polycarbonates are the compounds which are somewhat same as polyesters but contain two (-OR) groups.

Polymers can be classified into three types based on their structures:

(i) Linear polymers:

These polymers are similar in structure to a long straight chain with identical links connected to each other. The monomers in these are linked together to form a long chain. These polymers have high melting points and are of higher density.

Example of this is PVC (Poly-vinyl chloride). This polymer is largely used for making electric cables and pipes.

(ii) Branch chain polymers:

The structure of these polymers is like branches originating at random points from a single linear chain. Monomers join together to form a long straight chain with some branched chains of different lengths.

As a result of these branches, the polymers are not closely packed together. They are of low density having low melting points. Low-density polyethene (LDPE) used in plastic bags and general purpose containers are the common examples.

(iii) Cross-linked or Network polymers:

In this type of polymers, monomers are linked together to form a 3D network. These monomers are bi-functional and tri-functional in nature. These polymers are brittle and hard.

Some of the examples are: Bakelite, melamine etc.