Effect of polyaniline-modified clay on the processing and properties of clay polyimide nanocomposites

Polyaniline modified-clay/polyimide nanocomposite (PANi-CPN) containing highly intercalated montmorillonite was synthesized by in-situ double intercalation polymerization followed by thermal imidization. The presence of PANi-clay resulted in a decrease in the poly(amic acid) (PAA) solution viscosity during polymerization, and accelerated the polymerization procedure as the solution viscosity attained the maximum value at a shorter reaction time. The extent of imidization for PAA is largely improved compared with the organo-CPN prepared in the same condition. The PANi-CPN prepared in this study showed a characteristic polyaniline (PANi) UV/Vis absorption peak between 450 and 700 nm. The Wide Angle X-ray diffraction (WAXD) patterns for PANi-CPNs cured at 70 °C show a weak peak at a very low diffraction angle, indicating the formation of highly intercalated clays. This peak disappears for the PANi-CPN cured at higher temperatures, indicating fully exfoliated clay structure. The thermo-mechanical properties of the composites increased with increasing filler concentration.