In this investigation, a series of novel chiral and biodegradable poly(amide-imide)s (PAI)s based on different amino acids were synthesized. For this purpose at first pyromellitic dianhydride, trimellitic anhydride and amino acids (S-valine, L-leucine, L-methionine, L-isoleucine) have been used for the preparation of optically active diacids. The diamine was prepared from 2-amino thiazole and 3,5-dinitro benzoyl chloride by iron oxide hydroxide catalyst and hydrazine monohydrate is restored and aromatic diamine is formed. Finally, the prepared diacids reacted with aromatic diamine 3,5-diamino-N-(thiazole-2-yl)benzamide via direct polycondensation by using tetra-n-butylammonium bromide/ triphenyl phosphite as condensing agent under conventional heating in order to prepare thermally stable and optically active PAIs. The use of ionic liquide as solvent and catalyst for polyamidation reaction eliminate the need of volatile and toxic solvents. The chemical structure of polymers was confirmed by FT-IR, 1 H-NMR, 13 C-NMR spectroscopy, X-ray diffraction (XRD), elemental analysis and specific rotation. Thermal properties of polymers were studied by TGA curves and morphology were investigated by field emission scanning electron microscopy (FE-SEM). In other part of the project, nanocomposites containing hydrophilic TiO 2 nanoparticles were prepared, for compatibility with polymer matrix the nanoparticles, TiO 2 nanoparticles were treated with coupling agent of ?-aminopropyltriethoxysilane (KH550). Then PAI/TiO 2 nanocomposites were synthesized under ultrasonic irradiation conditions. The resulting nanocomposites were characterized by different techniques including FT-IR, XRD, FE-SEM and transmission electron microscopy (TEM). TGA confirmed that the heat stability of the composite was improved. TEM results indicated that the TiO 2 nanoparticles were dispersed homogenously in the polymer matrix. In modified TiO 2 , the organic chains of coupling agent can fulfill steric hindrance between inorganic nanoparticles and prevent their aggregation. The last section, biological and biodegradability properties of synthetic polymers were investigated.
