1. 1 Polymerization kinetics of chain growth polymerization Brazel & Rosen 9.4-9.6 Initiation (2 mechanisms) Propagation Termination (2 mechanisms)

2. 2 Initiation Benzoyl peroxide (BPO) 2,2’-azobis(isobutylnitrile) (AIBN)

3. 3 Association/Attack of monomer Polystyrene (PS) Rate of initiation:

4. 4 Rates of propagation & termination Assume constant rate of propagation reaction, k p Termination: combination or disproportionation

5. 5 Polymerization & DP Rate of polymerization Degree of polymerization Disproportionation Combination

6. 6 Polymerization kinetics of step growth polymerization Degree of polymerization –Number of repeat units in macromolecule –Statistical approach Random nature of chain growth N o : N: p:

7. 7 Statistical approach to DP p= (N/N o ) -1 = Carother’s Eqn. Weight average DP: PDI: