Polymerization of N,N′-methylenebis(acrylamide) using potassium peroxydiphosphate–thiocarboxylic acid redox systems: A comparison

The kinetics of aqueous polymerization of the symmetrical nonconjugated divinyl monomer N,N′-methylenebis(acrylamide) (MBA), was studied at 35°C and at constant ionic strength under nitrogen atmosphere involving potassium peroxydiphosphate (PDP) as oxidant with three different activators thiolactic acid (TLA), thiomalic acid (TMA), and thioglycollic acid (TGA). The rate of polymerization, R_P, and rate of disappearance of peroxydiphosphate, –R_PDP have been followed while polymerization was initiated separately by the PDP–TLA/PDP–TMA/PDP–TGA redox systems. R_P for the above three systems showed first-order dependences on both monomer] and activator] and zero-order dependence on PDP]. First-order dependence on PDP] and zero-order dependences on monomer] and activators] were observed with respect to –R_PDP in the above three systems. A reaction mechanism which involves complex formation between PDP and thiocarboxylic acid, propagation through intramolecular–intermolecular reactions, degradative chain transfer reaction of the growing radical with PDP, and linear termination by the interaction of the chain radical with primary radical was proposed. The kinetic parameters for the three polymerization systems were calculated and compared. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 11–20, 1998