Photopolymerization of acrylamide in an annular flow reactor

Rates of homogeneous polymerization of aqueous solutions of acrylamide were measured in an annular flow reactor at 35°C. By independent determinations of the quantum yield for the initiation step and the light intensity, it was possible to identify reaction orders and to calculate ratios of rate constants for the polymerization process. An empirical kinetics model, based upon producing activated molecules solely from initiator (K 2 S 2 O 8 ), best fit the data. According to this model the rate is 3/2 order in monomer concentration, 1/2 order in initiator, and proportional to the 1/2 power of the intensity of absorbed radiation. The effect of monomer concentration on the induction period and tlie 3/2 order with respect to monomer indicate a complex initiation process.