A short introductory note on Mass Polymerization & Interfacial Polymerization

1. Mass Polymerization &
Interfacial Polymerization

2. Contents
 What is mass polymerization
 Process of mass polymerization
 Advantages of mass polymerization
 Disadvantages of mass polymerization
 Examples

3. Mass or Bulk Polymerization
Bulk polymerization or mass polymerization is carried out by
adding a soluble initiator to pure monomer in liquid
state. The initiator should dissolve in the monomer. The
reaction is initiated by heating or exposing to radiation.
 It is used for most step-growth polymers and many types
of chain-growth polymers.
 Bulk polymerizations are also difficult to stir because of
the high viscosity, associated with high-molecular-weight
polymers.

4. Process
This method involves only the monomer molecule,
an initiator and a chain transfer agent.
 carried out by adding a soluble initiator to pure
monomer (in liquid state).
 The mixture is constantly agitated & heated to
polymerization temperature.
 Once the reaction starts, heating is stopped as
the reaction is exothermic
 The heat generated is dissipated by circulating
water jacket.
 Viscosity increases results difficulty in stirring.

6. Advantages
• The system is simple and requires thermal
insulation.
• The polymer obtained is pure.
• Large castings may be prepared directly.
• Molecular weight distribution can be easily
changed with the use of a chain transfer agent.
• The product obtained has high optical clarity.

7. Disadvantages
• Heat transfer and mixing become difficult as the
viscosity of reaction mass increases.
• Heat removal is difficult.
• Hot spots may form and explosion may possible.
• Gel effect occurs.
• Removal of traces of unreacted monomer is
difficult.

8. Examples
• Methyl methacrylatestyrene,
• Polyurethanes
• polycaprolactam (Nylon 6)
• polycarbonates and polyester (PET) etc.

9. Interfacial
Polymerization

10. CONTENTS
 What is interfacial polymerization
 Mechanism of interfacial polymerization
 Advantages of interfacial polymerization
 Disadvantages of interfacial
polymerization
 Examples

11. Interfacial Polymerization
Interfacial polymerization is a type of step-growth
polymerization in which polymerization occurs at
the interface between two immiscible phases
(generally two liquids), resulting in a polymer that
is constrained to the interface.
It was first discovered by Emerson L. Wittbecker
and Paul W. Morgan in 1959 as an alternative to
the typically high-temperature and low-pressure
melt polymerization technique.

12. One phase is above the interface, and the
other phase is below. Polymerization occurs
where the two phases meet, at the interface

13. Mechanism
The most commonly used interfacial polymerization methods
fall into 3 broad types of interfaces: liquid-solid interfaces,
liquid-liquid interfaces, and liquid-in-liquid emulsion
Interfaces.
 In the liquid-liquid and liquid-in-liquid emulsion
interfaces, either one or both liquid phases may contain
monomers. There are also other interface categories, rarely
used, including liquid-gas, solid-gas, and solid-solid.
 In a liquid-solid interface, polymerization begins at the
interface, and results in a polymer attached to the surface of
the solid phase.

14.  In a liquid-liquid interface with monomer dissolved in
one phase, polymerization occurs on only one side of
the interface, whereas in liquid-in-liquid interfaces with
monomer dissolved in both phases, polymerization
occurs on both sides.

15. Schematic of the steps involved in the
interfacial polymerization of water-in-oil
microemulsion process.

16. Advantages
 Polymerization is rapid and occurs at low temperatures.
 High conversions are not necessarily required to obtain
high molecular weight
 Unnecessary to start with stoichiometric quantifiers of
reactants.
Disadvantages
 Limited to highly reactive systems
 Need appropriate choice of solvent to dissolve reactants.

17. Examples
• polyaniline
• Polypyrrole
• Poly(3,4-ethylenedioxythiophene)
• Polythiophene

19. Mashrur Wasity Shovon