Ferrous-bromate redox as initiator of aqueous vinyl polymerization

Ferrous-bromate redox is a very efficient initiator for the aqueous polymerization of a number of vinyl monomers. With methylmethacrylate, polymerization takes place in dark and at temperatures starting from 0 °C onwards. Bromate, ferrous and monomer exponents are respectively 0.51, 0.43 and 1.32 and the overall activation energy is 7.47 Kcal/mole. Neutral salts depress the polymerization rate, while an emulsifier increases it. p_H of the medium has not much influence on the polymerization rate upto the value of 2.32. However, at p_H 1.39, rate is somewhat depressed. Endgroups incorporated are hydroxyl and bromine totalling to an average of one per chain. Based upon these findings suitable mechanisms of initiation and termination have been proposed.