Bulk polymerization
Bulk polymerization or mass polymerization is carried out by adding a soluble radical initiator to pure monomer in liquid state. The initiator should dissolve in the monomer. The reaction is initiated by heating or exposing to radiation. As the reaction proceeds the mixture becomes more viscous. The reaction is exothermic and a wide range of molecular masses are produced. Bulk polymerization is carried out in the absence of any solvent or dispersant and is thus the simplest in terms of formulation. It is used for most step-growth polymers and many types of chain-growth polymers. In the  case of chain-growth reactions, which are generally exothermic, the heat evolved may cause the reaction to become too vigorous and difficult to control unless efficient cooling is used. Advantages and disadvantages. Bulk polymerization has several advantages over other methods, these advantages are: Disadvantages: For reducing the disadvantages of bulk polymerization, the process can be carried out in a solution. This is known as solution polymerization. Classification. There are two main types of Bulk Polymerization: