Preparation of functional polystyrene copolymers through nitroxide mediated polymerization and their applications as surface modifiers for BaTiO ₃ nanoparticles

Polystyrene copolymers containing maleic anhydride or maleic acid functional groups with controlled architectures were prepared through nitroxide mediated polymerization and applied to BaTiO ₃ nanoparticles as polymeric surface modifiers. Effective surface modification effect of BaTiO ₃ nanoparticles with the copolymers were observed, as evidenced by TGA, SEM, EDX and FT-IR. Modified BaTiO ₃ nanoparticles exhibited improved dispersion in toluene, suggesting that the amphiphilic copolymers acted as dispersants. Through the addition of the surface modifier, the viscosity of the BaTiO ₃/epoxy pastes decreased and the dielectric constants of the resulting nanocorn-posite films increased. Molecular weight and number of functional groups of the copolymers were important factors to ascertain good processability and high dielectric constants of the composite.