Studies on the Polymerization of Vinyl Toluene in Microemulsion Medium

Oil in water, vinyltoluene - SDS - water - n-pentanol microemulsions are prepared and used to study the kinetics and mechanism of polymerization reactions of vinyltoluene. Initiations are effected by using both potassium peroxodisulphate (KPS), a hydrophilic and 2,2' azobisicobutyronitrile (AIBN), a hydrophobic initiator separately. At the end of polymerization, stable polymer microlatexes are obtained. The viscosity average molecular weights ̅M_v) range from 1.5 to 3.2 × 10⁶. The R_p and ̅M_v show fractional and negative order dependence on initiator concentration respectively, but vary directly with monomer concentration. The overall activation energy of polymerization (20.4 kcal/mol) agrees with that for homogeneous vinyl polymerization.