A series of novel poly(amide–imide)/ZnO nanocomposites with modified ZnO nanoparticles contents was prepared by ultrasonic irradiation. For this purpose, surface of ZnO nanoparticle was modified with 𝛾-aminopropyltriethoxysilane as a coupling agent. Then the effect of surface modification on dispersion of nanoparticles, thermal stability and UV absorption property of the obtained nanocomposites were investigated. The resulting novel nanocomposites were characterized by several techniques. Field emission scanning electron microscopy and transmission electron microscopy analyses of the nanocomposites were performed in order to study the dispersion of nanofillers in the polymer matrix. According to thermogravimetry analysis results, the addition of ZnO nanoparticles improved thermal stability of the obtained nanocomposites. Since the resulting nanocomposites contain phenylalanine amino acid and ZnO, they are expected to be biocompatible as well as biodegradable.

Deliberately inorganic nanoparticles (NP)s in polymer matrices significantly affect their characteristics and therefore their applications, but key factor to achieve the expected efficiency is well dispersion of the NPs in polymer matrix. The work presented here deals with the polymerization of amino acid-based monomer to synthesize optically active poly(ester-imide) (PEI) with hydroxyl terminated groups, using tosyl chloride/pyridine/𝑁,𝑁-dimethylformamide system as a condensing agent. The synthesized polymer was used for the preparation of bionanocomposite (BNC) containing modified titanium dioxide (TiO₂) NPs using ultrasonic irradiation. With the aim of 𝛾-amidopropyl-triethoxylsilicane as a coupling agent, the surface of nanoscale TiO₂ was modified to decrease aggregation of the NPs in polymer matrix. The obtained PEI/TiO₂ BNCs were characterized with fourier transfer infrared (FT–IR), thermogravimetric analysis, field emission scanning electron microscopy (FE–SEM), X-ray diffraction and transmission electron microscopy (TEM) techniques. Morphology study of resulting PEI/TiO₂ BNCs by FE–SEM and TEM analyses demonstrated that the hydroxyl-terminated polymer chains reduced aggregation of the NPs and thus lead to better dispersion of the NPs in the polymer matrix.

In a single-step, rapid microwave-assisted process, multi-walled carbon nanotubes were functionalized by 𝑆-valine amino acid. Formation of amino acid on nanotube surface was confirmed by Fourier transform-infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, field emission scanning and transmission electron microscopy techniques. The surface-modified nanotubes showed better chemical stability in common solvents such as 𝑁,𝑁-dimethylacetamide. The effects of amino acid functionalization of multiwalled carbon nanotubes on the properties of nanotube/poly(amide–imide) nanocomposites were investigated. The functionalized carbon nanotubes (5–15 wt%) were dispersed homogeneously in the poly(amide–imide) matrix, while the structure of the polymer and the nanotubes structure were stable in the preparation process as revealed by microscopic observations. The properties of nanocomposites were characterized extensively using the aforementioned techniques. The composite films have been prepared by casting a solution of precursor polymer containing 𝑆-valine-functionalized carbon nanotubes into a thin film and its tensile properties were examined. The Young’s modulus (elastic modulus) and tensile strength of the composite films were greatly improved by the incorporation of modified nanotubes.

Ascorbic acid has been covalently linked to multi-walled carbon nanotubes (MWCNTs). The structures of the functionalized MWCNTs were characterized with Fourier-transform infrared spectroscopy. Thermogravimetric analysis results also demonstrated the presence of organic portions of the functionalized MWCNTs. Polymer composites based on a nanostructured poly(amide–imide) (PAI) were fabricated by an ex situ technique with 5, 10 and 15% loading by weight. Composite films were made by the solvent casting method. The thermal stabilityof the composites increased with even a small amount of modified MWCNT added. Tensile tests were conducted and depicted an increase in the elastic modulus with increasing MWCNTs content. X-ray diffraction study of thecomposites also indicated that the composites incorporated MWCNTs in the polymer chain.