A new kind of intermediate hybrid nanocomposites (NCs) composed of poly(amic acid) (PAA) and surface modified ceria nanoparticles (NP)s had been prepared by sono-chemical assisted synthesis. The PAA containing pendent benzamide units had been synthesized by the reaction of 3,5-diamino-N-(4-hydroxyphenyl) benzamide and benzene-1,2,4,5-tetracarboxylic dianhydride through polycondensation reaction. The structure of the prepared PAA was studied by spectroscopic techniques. The surface modifications of ceria NPs were achieved by using hexadecyltrimethoxysilane. Results of FTIR analysis demonstrated that the aliphatic chains have been covalently bonded to the surface of the CeO2 NPs. PAA/CeO2 NCs with different contents including 4, 8, and 12 wt% of CeO2 NPs was prepared by using sonochemical method. Characterization with FTIR, powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) confirmed the success in synthesis of NCs with well dispersion properties. XRD analysis results showed that the obtained NCs displayed the crystalline nature of ceria NPs and the amorphous character of PAA matrix. The particles size of ceria NPs in NCs are about 50-70 nm as characterized by FE-SEM, TEM, and AFM analyses. This work demonstrates the application of intermediates as new matrices for preparation of hybrid nanostructures. (C) 2015 Society of Plastics Engineers