Polymerization of acrylamide inverse microemulsion initiated directly by UV radiation

Combining the microemulsion polymerization with UV direct initiation, an efficient method for polymerization of AM with high polymerization rate and conversion, low polymerization temperature, high purity of product and simple radiation equipment was developed. In the absence of initiator and under UV radiation, the polymerizations of AM inverse microemulsion system with high monomer content and low emulsifier content were successfully accomplished at low temperature (24̃30 °C) and PAM with high purity and high limiting viscosity [?] was obtained. The polymerization rate was fast and the conversion reached to higher than 85% in 30 minutes. Based on the abundant experimental results, the reasonable polymerization mechanisms were proposed as follows: the AM participated in the initiation reaction and the main initiation locus was the emulsifier layer. Rp and [η] were weakly influenced by temperature due to the low apparent activation energy of the reaction (Ea = 12.98 kJ/mol). The polymerization kinetics of Rp was expressed as the following: Rp = [I _UV]^0.4972[M]^1.5048[E]^-0.5731. The Rp order with respect to [M] is equal 1.5048 which confirms the conclusion that the monomer participated in the initiation reaction.