Abstract
Dispersion polymerization of styrene and butyl methacrylate copolymer was studied using the 2,2-azobisisobutylronitrile (AIBN) and polyvinylpyrrolidone (PVP) as the initiator and stabilizer respectively. The factors that influence the dispersion polymerization were investigated, such as the stabilizer concentration, monomer ratio, initiator concentration and solvent. For coloration of the uniform-sized polymer beads, pigments were also used. In order to predict the nucleation of the polymer microphases, which is critical to control the diameter of the beads, the Flory-Huggins theory was used to calculate the Gibbs free energy of the polymer solution for quantitatively analysis of the critical chain length of the growing chain during dispersion polymerization. The results were in good agreement with that reported in the literature [8]. In addition to the calculation of the critical chain length, we used AFM to investigate the particle growth in dispersion polymerization. For coloration, spherical and narrow-sized polymer beads were obtained by adding pigment during the polymerization with the right amount of stabilizer. The effect of the stabilizer on colored dispersion polymerization, however, is different from that without the pigment particles. Dispersion of the pigments during polymerization appears to be of critical importance for the success of the polymerization.