(393bg) Multifunctional Epoxy Nanocomposites

Three different kinds of nanofillers, polyaniline (PANI), barium titanate (BaTiO₃) and BaTiO₃ nanoparticles coated with PANI layer are applied to enhance the dielectric permittivity of epoxy resin. The conductive BaTiO₃-PANI polymer nanocomposites (PNCs) were synthesized by a surface initiated polymerization (SIP) method, the amino group of PANI can react with epoxy monomer and improve the dispersion of the BaTiO₃ nanoparticle in epoxy resin. For all the series of samples, mechanical property, rheological property, thermal stability, electrical conductivity and dielectric property are systematically studied. It is observed that all three nanofillers can help to increase the real permittivity of epoxy resin, however, at same loading, the increment resulted from the BaTiO₃-PANI polymer nanocomposites is much higher than the increment caused by the other two and the mechanism of the difference are analyzed theoretically. In addition, reduced viscosity is found in the Rheology test based on liquid samples, at lower loading liquid epoxy samples with both PANI and BaTiO₃ nanoparticles has lower viscosity than pure epoxy, however, at higher loading, the viscosity increases with the loading increase. PANI as the soft nanofillers can also increase the conductivity of matrix, for epoxy with PANI nanocomposites, both nanoshpere and nanofiber are applied to explore the morphology effect, at same loading, epoxy with PANI nanofibers has lower volume resistance than epoxy with nanospheres, which is resulting from the contact resistance and a 3-d variable range hopping (VRH) electron transport mechanism.