We are surrounded by polymers around us, starting from toothbrushes to automobile decors, toys, paints, etc our lives wouldn’t be easy without the application of polymers.
Have you ever wondered what polymers are?
How they are formed? What’s the chemistry behind it? We shall discuss the elementary concept of polymer and on what basis they are categorized.
The word “Polymer” comes from two Greek words ‘poly‘ which means many and ‘mer‘ which means units.
Therefore polymer means many units, in simple terms polymers, are macromolecules with high molecular mass (in order 1000000u), and they are formed by the repetition of structural units.
These structural units are called monomers, these when joined in a large scale through covalent bonding form polymers.
This process of formation of polymer from the respective monomer is called polymerization.
Classification of polymers is done; based on the source (Natural or Synthetic), based on the mode of polymerization (Step growth or chain growth), based on structure (linear, cross-linked or branched), and based on texture.
Properties of polymers vary with the type of polymerization it undergoes, there two of polymerization reactions:
Addition polymerization or chain-growth polymerization and Condensation polymerization or step-growth polymerization.
In the case of chain-growth polymerization reactive species (free radical) reacts with the monomer breakage and formation of bonds takes place resulting in the formation of the polymer.
On the other hand in step-growth polymerization, the polymer is obtained from condensation reaction.
Also, they classified based on the physical property, commonly used terms “Thermoplastics” and “Thermosets“, thermoplastics are soft when heated and become hard on cooling whereas thermosets soften on heating and can be molded but they harden permanently.
The most commonly used thermoplastics are nylon6, polythene and commonly seen and used thermosets are melamine, billiard balls, household dishes.
For any questions please comment below | Go to the Next Chapter-3 Polymerization