The surface modification of CuO nanoparticles with a flame retardant coupling agent and their influence on the thermal stability of poly(amide-imide)/CuO nanocomposites

The present work reports the fabrication and characterization of the thermally stable poly(amide-imide)/CuO nanocomposites. For this purpose, a biodegradable and optically active poly(amide-imide) was synthesized through polycondensation reaction under green media. Subsequently, the surface of CuO nanoparticles was modified with 2,3,4,5-tetrabromo-6-[(4-hydroxyphenyl) carbamoyl] benzoic acid as a new coupling agent to increase their dispersity. The modified nanoparticles were characterized by different methods. The results of Fourier-transform infrared spectra confirmed that the modifier was successfully grafted on the surface of nanoparticles. Finally, the different amounts of modified CuO nanoparticles (2, 4, and 6 wt%) were dispersed in the poly(amide-imide) matrix via sonochemical reaction. The obtained nanocomposites were studied by Fourier-transform infrared, X-ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and transmission electron microscopy. The data obtained by Fourier-transform infrared demonstrated the possible incorporation of CuO nanoparticles in the poly(amide-imide) matrix. Field emission scanning electron microscopy and transmission electron microscopy analyses showed that CuO nanoparticles were homogeneously distributed in the polymer matrix. The combination of nanoparticles and poly(amide-imide) can lead to the improvement in thermal stability property of the resulting nanocomposites.