Study of kinetics and nucleation mechanism of dispersion copolymerization of methyl methacrylate and acrylic acid

Dispersion copolymerization of methyl methacrylate (MMA) and acrylic acid (AA) was carried out in an ethanol/water media with 2,2′-azobisisobutyronitrile (AIBN) as the initiator and poly (N-vinylpyrrolidone) as the stabilizer in the presence of ethylene glycol dimethylacrylate (EGDMA) as the crosslinking reagent. The kinetic characteristics of the dispersion copolymerization of MMA and AA were investigated. It was proposed that there were two nucleation mechanisms in the dispersion copolymerization of MMA and AA: homogeneous nucleation and heterogeneous nucleation. Furthermore, the effects of reaction parameters such as monomer compositions, AIBN concentrations, or reaction temperatures on the polymerization rates of the mini-emulsion-nucleated dispersion copolymerization and the partitioning of carboxyl group in the particles and media were also studied.