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This work presents the preparation and characterization of hybrid organic-inorganic optically active poly(amide-imide)/nano-Fe 3 O 4 composites with different amount of modified Fe 3 O 4 nanoparticles as new nanocomposites by ultrasonic irradiation and characterized by Fourier transform infrared spectra, X-ray diffraction, scanning electron microscopy (SEM), thermogravimetric analysis and vibrating sample magnetometry. The surface of Fe 3 O 4 nanoparticles was modified with 3-aminopropyltriethoxyl silane because of the homogeneous distribution of nano-Fe 3 O 4 in polymer matrix, which the SEM results confirmed that the Fe 3 O 4 nanoparticles were dispersed uniformly in polymer matrix. Furthermore, as compared with pure polymer, thermogravimetric analysis data indicated an improvement of thermal stability of nanocomposites.

Homopolymerization of an optically active acrylamide having an amino acid moiety in the side chain, N-acryloyl-L-alanine (AAla) was carried out via atom transfer radical polymerization (ATRP) at room temperature using 2-hydroxyethyl-2'-methyl-2'-bromopropionate (HMB) or sodium-4-(bromomethyl)benzoate (SBB) as initiator in pure water, methanol/water mixture and pure methanol solvents. The polymerization reaction resulted in the optically active biocompatible amino acid-based homopolymer in good yield with narrow molecular weight distribution. The number average molecular weight increased with conversion and polydispersity was low. The structure and molecular weight of synthesized polymer were characterized by (1)H NMR, FT-IR spectroscopic techniques and size-exclusion chromatography.

The novel optically active poly(amide-imide) (PAI)/TiO2 nanocomposites containing fluorene moieties have been successfully synthesized through ultrasonic irradiation. The surface of nanoparticles was chemically modified with γ-aminopropyltriethoxyl silane to enhance the compatibility with polymeric matrix and to avoid the aggregation of nanoparticles. The dispersion of surface-modified TiO2 in PAI film was confirmed by the transmission electron microscope (TEM) analysis showing the well-dispersed nanosized TiO2 nanoparticles. The thermal stabilities and optical properties of PAI/surface-modified TiO2 nanocomposite films were also investigated. The thermogravimetric analysis data showed an improvement of thermal stability of novel nanocomposite films as compared to the pure polymer.

An aromatic chiral diacid monomer, 5-[4-(2-phthalimidiylpropanoylamino)-benzoylamino]isophthalic acid was synthesized in five steps under conventional heating in high yield and purity. A series of soluble, thermally stable and optically active polyamides (PA)s containing pendent groups made of phthalimide, flexible L: -alanine and benzamide sequence have been successfully synthesized under microwave irradiation. Excellent yields and very short reaction time were the main characteristics of this method. The same polymerization reactions were also carried out by conventional thermal heating and the results are compared. The resulting PAs had inherent viscosity in the range of 0.50-0.79 dL g(-1). All of the these polymers are readily dissolved in various solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide and N,N-dimethylformamide and showed glass-transition temperature above 200 degrees C. Thermogravimetric analysis demonstrated that the 10% weight-loss temperatures in nitrogen were 372 and 422 degrees C for selected two PAs. All of these polymers showed optical rotation which is due to successful insertion of L: -alanine in the structure of chiral diacid monomer.