The chemistry concerned with the sonochemical-assisted synthesis of CeO2/poly(amic acid) nanocomposites

A series of new poly(amic acid) (PAA) surface-modified cerium oxide (CeO2) nanocomposites were prepared by sonochemical-assisted method. In the first step, treatment of the surface of CeO2 nanoparticles with hexade-cyltrimethoxysilane as a surface modifier was achieved. In the second step, the partially surface-treated nanoparticles were incorporated into PAA by different weight from 4% to 12%. PAA was synthesized by polycondensation reaction of benzophenone tetracarboxylic dianhydride and 3,5-diamino-N-(4-hydroxyphenyl) benzamide in N-methyl-2-pyrrolidone. The chemical structure of PAA was confirmed by H-1 NMR and FTIR spectroscopy. The polymer had an inherent viscosity of 0.38 dL/g. Three PAA/CeO2 nanocomposite formulations were prepared from the PAA matrix and the 4, 8, and 12 wt% of surface modified nanoparticles of cerium oxide. Characterization with FTIR, powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy confirmed the successful synthesis of nanocomposites with good dispersion of nanoparticles in the polymer matrix. Both field emission scanning electron microscope and transmission electron microscope analyses showed that the cerium oxide was well dispersed in the PAA matrix; it was dispersed in the PAA matrix on a nanometer scale. Moreover, the thermal and topological properties of PAA and nanocomposites were also investigated, respectively.