Reinforcement of poly(amide–imide) containing N-trimellitylimido-L-phenylalanine by using nano α-Al2O3 surface-coupled with bromo-flame retardant under ultrasonic irradiation technique

•A straightforward and fast method was used for the surface modification of ANPs.•Flame retardant THCB was utilized for the modification of ANPs.•Modified ANP was improved the thermal properties of PANCs.•TEM and FE-SEM images proved that ANPs were dispersed in the PAI matrix.

By the uniform dispersion of nanoparticles into a polymer matrix, a substantial improvement of physicochemical properties can be attained. In this study, a series of poly(amide–imide)/Al2O3 nanocomposites (PANC)s based on various amounts of modified α-Al2O3 nanoparticles (ANP)s were prepared using the ultrasonic irradiation method. In the process of manufacturing the nanocomposites (NC)s, severe agglomeration of ANPs into the polymer matrix can be reduced using 2,3,4,5-tetrabromo-6-[(4-hydroxyphenyl)carbamoyl]benzoic acid as novel coupling agent. The effects of modified ANPs on the morphology and properties of the polymer matrix were studied by means of Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and thermal gravimetric analysis (TGA). The results obtained by TGA showed that the thermal stability of the NCs was improved with the addition of the small amounts of ANPs as effective thermal degradation resistant reinforcement.

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