İlkay Özaytekin

Synthesis and Characterization of PVA/Calix[4]arene Fibers

In this study, both boron-doped and -undoped poly(vinyl alcohol)/Calix[4]arene fibers were prepared by using an electrospinning technique. Obtained fibers were characterized by FT-IR, DSC, and SEM techniques. The DSC results show that the degradation of the boron-doped fibers started at much higher temperatures. This result indicates the addition of boron increased the thermal stability of the fibers. SEM pictures show that both of the fiber samples are nonbeaded with diameters ranging from 0.5 to 1 µm. The fiber diameters are not homogeneous and uniformly distributed for boron-undoped samples.

Synthesis of a Novel m-Substituted Poly(phenoxy-imine) and Investigation of its Fluorescence and Some Properties

Oxidative polycondensation of 3-((2-phenylhydrazono)methyl)phenol (3-PHMP), a new m-substituted poly(phenoxy-imine), was studied using oxidants such as sodium hypochlorite, air (O2) and hydrogen peroxide in an aqueous alkaline medium under various polymerization conditions. The macromolecular structure and optical properties of the polymer were characterized with elemental analysis, Size Exclusion Chromatography (SEC), Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR), absorption and fluorescence spectroscopy techniques. As a result of fluorescence measurement, the fluorescence lifetime of poly(3-PHMP) in DMF was calculated as 2.88 ns (χ2= 1.12). An electrochemical property the monomer and polymer were also studied using Cyclic Voltammetry (CV) technology. According to the CV measurements, the electrochemical band gaps (Eg′) of 3-PHMP and poly(3-PHMP) were found to be 2.64 and 1.94 eV, respectively. Electrical conductivity of the polymer was measured by the four-point probe technique. The electrical conductivity of poly(3-PHMP) was found to be ∼3.2 × 10−2S/cm. Thermo Gravimetric Analysis (TGA) revealed poly(3-PHMP) to be stable against thermo-oxidative decomposition. In addition, the in vitro antimicrobial activities of the synthesized compounds were tested on various microorganisms.

Synthesis and Properties of Poly(benzoxazole)s Prepared from Aromatic Dihydroxamoyl Chlorides

In this study, a new synthesis of polybenzoxazoles was studied by reacting 3,31-dihydroxy-4,41diaminobiphenyl with various p-aromatic dihydroxamoyl chlorides in N,N-dimethylformamide under a nitrogen atmosphere at both room temperature and 150 3C. The polymers were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, liquid chromatography/mass spectrometry, thermogravimetric analysis and the elemental analysis. Direct current conductivity of HCl acid-doped polybenzimidazole pellets was measured by applying a constant voltage of 5 V. The results of this study are discussed herein.