KINETICS AND MECHANISM OF THE AQUEOUS POLYMERIZATION OF METHACRYLONITRILE AND ACRYLONITRILE INITIATED BY POTASSIUM PERSULFATE AT 50-DEGREESIN AN INERT ATMOSPHERE OF NITROGEN GAS

The kinetics and mechanism of the aqueous polymerization of methacrylo nitrile (MAN) and acrylonitrile (AN) have been investigated experiment ally within the solubility range of monomers at 50 degrees in an unbuf fered aqueous medium and in an inert atmosphere of nitrogen gas. The r ates of polymerizations under various conditions have been followed by the conventional gravimetric method. The molecular weights of the pol ymers have been estimated from the intrinsic viscosity data and also b y the gel permeation chromatographic method as a function of monomer a nd initiator, potassium persulphate (KPS) concentrations. It has been found that the rates of polymerization (R(p)) are given by R(p) propor tional to [MAN](1.60) (+/-) (0.05) [KPS](0.50) (+/-) (0.05) and R(p) p roportional to [AN](1.46) (+/-) (0.04) [KPS](0.46) (+/-) (0.04) Both i n the MAN-KPS and AN-KPS systems, the injection of initiator late in a run increases the rate of aqueous polymerization but has no measurabl e effect on the viscosity average molecular weight ((M) over bar(v)) o f the polymers, whereas the addition of extra amount of monomer late i n a run increases both the rates of polymerization and the (M) over ba r(v). The rate of the aqueous polymerization is higher in the AN-KPS s ystem than that in MAN-KPS system, The particle size distribution has been measured. A mechanism has been suggested to explain the kinetic d ata.