Droplet Size and Morphology for the Aqueous Two-Phase Polymerization of Acrylamide in an Aqueous Poly(ethylene glycol) Solution

A kind of polyacrylamide (PAM) latex product dispersed in an aqueous solution was successfully prepared through the aqueous two-phase polymerization of acrylamide in an aqueous solution of poly(ethylene glycol) (PEG). The effects of various polymerization parameters on the size and morphology of droplets rich in PAM. were systematically investigated. The droplet size and morphology was significantly influenced by the polymerization rate. The high polymerization rate caused the formation of stripe-shaped droplets because of the aggregation of more droplets rapidly separated from the continuous phase. At the same time, the monomer partition behavior mainly relied on the temperature, and the PEG concentration also dramatically affected the droplet size and morphology. The increase in PEG concentration not only changed the monomer partition behavior and restrained droplet aggregation but also shortened the critical PAM radical chain length and accelerated the droplet formation. Furthermore, the stirring speed was also recognized as the correlative factor that affected the droplet stability and monomer diffusion rate from the continuous phase into the droplets. The addition of salt and alcohol altered the droplet stability and the final droplet size and morphology. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116:1747-1758,2010