INVERSE EMULSION POLYMERIZATION OF ACRYLAMIDE AND SALTS OF ACRYLIC-ACID

Kinetics of the persulfate-initiated inverse emulsion polymerization o f acrylamide and acrylic acid sodium and ammonium salt have been inves tigated. Rate orders with respect to the initiator, the monomers and t he emulsifier were determined for all three monomers. Influences of th e change of concentration of the individual components of the polymeri zation system on molecular weight and particle size of the resulting p olymers were described. Overall activation energies of polymerizations were determined. Results of the kinetics measurements for the non-ion ic acrylamide and the ionic salt of acrylic acid were compared. Depend ence of the polymerization rate R-p on the concentration of components in the polymerization system can be expressed for all three mononers by the following equation: R-p = [I](0.5) [M](1.5) [E](0.1). These kin etic data are in good agreement with the supposed mechanism of polymer ization. The almost sesquimolecular rate order with respect to the mon omer proves to the participation of the monomer on the initiation reac tion. This fact also explains the reason of the unusually low polymeri zation temperature of 40 degrees C. The persulfate-initiated inverse e mulsion polymerization of acrylic monomers takes place as a solution p olymerization in microparticles. (C) 1997 Published by Elsevier Scienc e Ltd.