1 Polymerization kinetics of chain growth polymerization Brazel & Rosen Initiation (2 mechanisms) Propagation Termination (2 mechanisms)
2 Initiation Benzoyl peroxide (BPO) 2,2’-azobis(isobutylnitrile) (AIBN)
3 Association/Attack of monomer Polystyrene (PS) Rate of initiation:
4 Rates of propagation & termination Assume constant rate of propagation reaction, k p Termination: combination or disproportionation
5 Polymerization & DP Rate of polymerization Degree of polymerization Disproportionation Combination
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 Statistical approach to DP p= (N/N o ) -1 = Carother’s Eqn. Weight average DP: PDI: