Bulk Polymerisation It is polymerization of undiluted monomer ehich is carried out by adding soluble initiator to pure monomer(in liquid) Mixture is constantly agitated and heated to polymerization temperature Once reaction starts reaction starts as heating is exothermic Heat dissipated is circulated by using water jacket Viscosity increases dramatically during conversion This method is used for polymerization of liquid state monomer Usually adopted to produce polystyrene pvc and low density poyethene

Advantages System is simple and requires thermal insulation Polymer produced is pure Large castings may be prepared Molecular weight distribution can be easily changed using chain transfer agentDisadvantages Heat transfer and mixing becomes difficult as reaction mass viscosity increases Highly exothermic Polymerization is obtained with broad molecular weight distribution, due to high viscosity and lack of heat transfer Very low molecular weights are obtained

Emulsion Polymerisation Technique is used for production of large no of commercial plastics and elastomers Solution consist of water, insoluble monomer, dispersion medium , emulsifying agent or surfactants( soap and detergent) and water soluble initiator(potassium persulphate ) Monomer is dispersed in aqueous phase , not as a discrete droplet but as a uniform emulsifier The size of the monomer droplet is about (0.5 to 10 ) depending upon the polymerization temperature and rate of reaction. Emulsion of monomer in water is stabilized by surfactant A surfactant has hydrophilic and hydrophobic end in its structure When it is put into water the surfactant molecules aggregate together to form micelles The hydrophilic end orient outward toward water and hydrophilic end orient inwards.

Disadvantages Surfactants and polymerization adjuvant difficult to remove For dry polymers water removal is an energy intensive process Designed to operate at high conversion of monomer to polymer. this can result in significant chain reaction of monomer Cannot be used for condensation ionic or Ziegler Natta polymerization