In this study, to investigate the effect of nanoparticles titanium (TiO 2 ) on the properties of polymers such as thermal stability, optically active poly(amide-imide)/TiO 2 -citric acid nanocomposites (PAI/TiO 2 -CA NCs) were synthesized by ultrasonic irradiation. The surface modification was essential for decreasing of the agglomeration of and improving of their compatibility with polymer matrix. So, the surface of TiO 2 nanoparticles was modified with citric acid. The resulting modified were characterized with FT-IR, XRD, TEM, FE-SEM and TGA techniques. Next, PAI as a polymer matrix was synthesized from the polymerization reaction of N , N ? -( pyromellitoyl)-bis-L-leucine diacid with 4,4?-diaminodiphenylmethane by using of triphenyl phosphite and tetra-n-butylammonium bromide as a green media. Finally, NCs containing different amount of modified TiO 2 were synthesized under ultrasonic method as a fast, low cost and green way. The obtained NCs characterized by FT-IR, TGA, XRD, FE-SEM and TEM analyses. TGA results confirmed that the heat stability of the NCs was improved compared to the pure polymer. The FE-SEM and TEM results indicated that the modified with CA were dispersed homogenously in polymer matrix. Poly(vinyl alcohol) (PVA) is a water-soluble polymer, highly biocompatible and nontoxic. In the other investigation, the surface of the TiO 2 was modified with PVA. PVA has many hydroxyl groups, which can react with the OH groups of TiO 2 via hydrogen banding and reduce aggregation of . Then, NCs containing PAI synthesized and various amounts of TiO 2 with PVA were synthesized by ultrasonic irradiation. The resulting NCs were characterized by several techniques including FT-IR, XRD and their morphology were investigated by FE-SEM and TEM as well as these results showed that the are uniformly dispersed in the of PAI matrix. The thermal properties of nanocomposites were studied by TGA.
