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.