Synthesis and kinetic studies of TiO2/polystyrene composite particles by emulsion polymerization

AbstractIn the presence of titanium dioxide (TiO2) nanoparticles, emulsion polymerization of styrene with sodium dodecyl sulphate (SDS) as an emulsifier and potassium persulphate as an initiator was investigated in detail. It was shown that SDS concentration influences the morphology of the composite particles in higher degree. Moreover, the effects of operating variables such as emulsifier concentrations, initiator concentration, monomer concentration, and polymerization temperature on the kinetic features were also examined. The kinetic data showed that at conditions studied, the rate of polymerization over interval II was proportional to the 0.68 power of the initial emulsifier concentration, to the 2.2 power of the initial initiator concentration and to the 1.6 power of the initial monomer‟s concentration. The initiator concentration has a dominant effect on the rate of the polymerization. The appropriate conditions for polymerization were obtained when emulsifier concentration of 6.5×10-3 mol·L-1, initiator concentration of 4.4×10-3 mol·L-1, the polymerization temperature of 75 °C and the initial monomer‟s concentration of 0.288 mol·L-1 were used. The polymerization rate obtained is more favorable than that of the conventional emulsion approach. The experimental results can be reasonably ascribed to the nucleation mechanism of “TiO2/SDS” micelles in the emulsion polymerization of styrene.