Step Growth Polymerization

If the monomers add end to end and liberate a byproduct is called Step Growth Polymerization. Here molecular weight of monomer and repeat unit is different, bi product my H2O, CO2, NH3 etc.
When two or more reactive functional group reacts with each other is called condensation type polymerization. E.g.: Formation of polyester and Nylon 6,6.
There are two types of condensation type polymerization. They are:

  1. A-B Type.
  2. AA-BB Type.
A-B Type: A-B →B (-A.B-) A + bi-product, When two functional group react with each other and produced a bi-product is called A-B type. It is a self condensation process.
AA-BB Type: AA-BB →A (-A.B-) B, When two pair of functional group react with each other. It is not a self condensation process.