synopsisPolymerization of methyl acrylate in IIClo4 and HNO3 was studied in the temperature range 10-15"C. The kinetics of the polymerization were found to be very simple, involving initiation and termination by cobaltic ions. Kinetic studies on polymerization of acrylonitrile in HCI04 and HN03 revealed that water oxidation, and monomer oxidation were side reactions as in the case of methyl methacrylate. Experimental evidence favored the simultaneous initiation by Co3+ and CoOH2+ species. I n HzSOI, certam unusual features were encountered. At low [Co3+], linear termination as well as termination by mutual combination occurred. Another interesting aspect was that cOs04' initiated at low [Co3+]. The rates of polymerization and rates of cobaltic ion disappearance were measured with respect to changes in [MI, [Co3+], [H+], temperature, etc. The variousrat,e constants were evaluated.This was unlike the case of other monomers in HzSO~.

synopsisPolymerization of methyl methacrylate initiated by cobaltic ions in perchloric, nitric and sulfuric acids was studied in the temperature range 15-25°C. In all three acids, water oxidation occurred as a side reaction. In HC10, and HNOa media monomer oxidation was shown to be an additional complicating, feature. Rates of cobaltic ion disappearance, monomer disappearance, and chain lmgths of polymers were measured with variations in [MI, [Co3+], [H+], initially added [Co*+], and temperature. In HClOl and HNO, experimental results favored simult&neous initiation by Co3 + and CoOH2+ species, while in HPSO4, Co3+ ions alone were the active entities. An appropriate kinetic scheme to fit all the experimental observations is proposed. The various rate constants were evaluated.

No abstract

No abstract