Polymerisation and condensation

The process which involved union of two or more molecules of the same compound, without the elimination of a small molecule such as H₂O, NH₃ or alcohol, etc., resulting in the formation of new compound whose molecular mass is simple multiple of the original compound is called polymerization. The new compound formed is termed polymer (Greek : poly + meros = many parts). The original simple compounds from which polymers are made are called monomer.

Characteristics of Polymerisation

i) it is generally a reversible reaction, i.e., the polymer can be converted easily into original compound.

ii) No portion of reacting molecules is eliminated in any form.

iii) No new C-C and C-N linkages are formed.

iv) Polymer and the monomer both have the same empirical mass and formula but the molecular mass of the polymer is simple multiple of the molecular mass of the monomer.

v)The monomer usually consists of a multiple bond (double or triple)in its molecule.

Alkenes, acetylenes and aldehydes undergo polymerization reactions. The polymer may be straight chain or cyclic.