Structural, thermal and dielectric properties and thermal degradation kinetics of nylon 11/CaCu3Ti4O12 (CCTO) nanocomposites

Nylon 11/CaCu3Ti4O12 (CCTO) nanocomposites were prepared via solution casting method followed by vacuum drying and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry, thermo-gravimetry (TG) and impedance analyzer for their structural, thermal and dielectric properties. The presence of gamma-phase of nylon 11 both in the pure nylon 11 cast film as well as in the nylon 11/CCTO nanocomposites was confirmed using XRD analysis. Distribution of CCTO nanofillers into nylon 11 matrix was almost uniform according to SEM analysis. The shift in endothermic peak and new IR absorption bands indicated possible interaction between nylon 11 and CCTO. TG results showed that the composites have better thermal stability than pure polymer. Activation energies calculated using Flynn-Wall-Ozawa, Friedman, and Coats-Redfern methods further support the fact that the composites have better thermal stability. A kinetic model consisting of two parallel reactions was proposed for the thermal degradation process of nylon 11 as well as its 30 mass% CCTO nanocomposite. The proposed model was also verified by comparing the experimental and simulated conversion curves. For nylon 11/CCTO-30 mass% nanocomposite, room temperature dielectric permittivity as high as 168 at 50 Hz has been achieved indicating the possibility of using these materials for high-energy-density capacitor applications.