16.1 Introduction

A polymer is a macromolecule, made up of many smaller repeating units called monomer. Polymers have high molecular weight in the range of several thousand or even higher. The first synthetic organic polymer polyvinylchloride was synthesized in 1838 by accidentally. Later, polystyrene was discovered in 1839.

16.2 Classification

Polymers can be classified into a number of ways which are described below.

Polymers can be divided into four types depending on its skeletal structure.

• A linear polymer is represented by a chain with two ends.
• A cyclic polymer have no chain ends and show properties that are entirely different from their linear counterparts.

• Branched polymers have side chains, or branches, of significant length which are bonded to the main chain at branch points, and are characterized in terms of the number and size of the branches

• Network polymer or cross-linked polymer have three dimensional structures in which each chain is connected to all others by a sequence of junction points and other chains. But it does not contain any main chain when compare with branched polymer.

Similarly, polymers can be classified into four categories based on the forces of attraction between polymer chains are thermoplastic polymers, thermosetting polymers and elastomers.