Polymerization
is the process of formation of large molecules or macromolecules with high molecular weight from small molecules. 'Poly' means many and 'meros' means parts in Greek. The simple compounds from which these macromolecules are made are called monomers. When two monomers combine, a dimer is got. The compound is known as a trimer and a tetramer when three and four monomers combine with each other. Many monomers combine together to form a high molecular weight substance called polymer.
Today polymers have quite a significant presence in our day-today life. Proteins and carbohydrates are natural polymers. Synthetic fibers, resins, plastics, and synthetic rubber are all synthetic or manmade polymers.
A polymer obtained from any pure monomer is called a homopolymer (e.g., polyethylene). And the polymer formed when two different kinds of monomers react is called a copolymer (nylon).Kinds of Polymerization
Addition or chain polymerization
Polymerization involves addition reactions.
Example: Ethene polymerizes to form polythene.Condensation or step-reaction polymerization
Monomers react with each other with elimination of small molecules like water, methanol and ammonia to form polymers.
Example: Nylon is a condensation polymer.