Solution polymerization of acrylamide using potassium persulfate as an initiator: kinetic studies, temperature and pH dependence

The kinetics of the radical polymerization of acrylamide in aqueous solution using potassium persulfate as initiator has been investigated by the gravimetric technique. Up to 94% conversion was obtained. The rate of polymerization was governed by the expression at 55°CRpo=k[K2S2O8]0.5[M]01.26 The order with respect to initiator was consistent with the classical kinetic rate equation, while the order with respect to monomer was greater than unity. The effects of temperature and pH on the polymerization rate were also investigated. An overall activation energy of 45.1±0.1 kJ/mol was obtained over the temperature range 35–55°C. It was found that the rate of conversion increased with increasing polymerization temperature, while the polymerization rate was insensitive to the change of pH value when monomer and initiator concentrations, and temperature were all kept constant.