Browsing by Author "Kamaci, M"

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    Synthesis of Novel crosslinked Poly(azomethine-urethane)s: Photophysical and thermal properties
    Avci, A; Kamaci, M; Kaya, I; Yildirim, M
    This paper describes synthesis, photophysical, electrochemical and thermal properties of some new flexible crosslinked poly(azomethine-urethane)s. Synthesis procedure includes two main steps: The first one is the synthesis of a polyurethane prepolymer (TP) using toluene-2,4-diisocyanate and 2,4-dihydroxy benzaldehyde, and the second step is the synthesis of resulting flexible crosslinked poly(azomethineurethane) derivatives by conventional polycondensation reaction of TP with different aliphatic diamines. Diamines with various chain lengths (6-12 methylene numbers) were used to obtain various resulting polymers with different physical properties. Photophysical properties of the flexible crosslinked poly(azomethine-urethane)s were investigated using photoluminescence (PL). PL results showed that the flexible crosslinked poly(azomethine-urethane)s exhibited multicolor emission behavior. A linear relationship was observed between the excitation energies and the obtained emission maxima. This characteristic enabled adjusting the PL color at the desired scale. Thermal and morphological properties of the polymers were also investigated using TG-DTA, DSC and AFM techniques. (C) 2015 Elsevier B.V. All rights reserved.
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    New Poly(azomethine-urethane)s Including Melamine Derivatives in the Main Chain: Synthesis and Thermal Characterization
    Kaya, I; Yildirim, M; Kamaci, M; Avci, A
    Up to date, only a few kinds of poly (azomethine-urethane)s (PAMUs) derived from aromatic hydroxy compounds were obtained and studied with thermal degradation steps. Novel PAMUs were prepared using the hydroxy-functionalized Schiff bases derived from melamine and toluene-2,4-diisocyanate. Schiff base prepolymers were synthesized by the condensation reaction of melamine with 4-hydroxybenzaldehyde and 2hydroxy-1-naphtaldehyde. Characterization was made by UV-Vis, FTIR, NMR, and SEC techniques. Thermal characterizations of the novel PAMUs were carried out by TG-DTA and DSC techniques. Thermal decomposition steps at various temperatures were also clarified and the physical changes of the synthesized PAMUs with exposing to the thermal degradation steps were displayed. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3027-3035, 2011
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    Synthesis and thermal characterization of novel poly(azomethine-urethane)s derived from azomethine containing phenol and polyphenol species
    Kaya, I; Yildirim, M; Avci, A; Kamaci, M
    Oligophenol-based poly(azomethine-urethane)s (PAMUs) were newly synthesized in two steps. At the first step, the prepolymers including the phenol and oligophenol based-Schiff bases were prepared by a condensation reaction of o-dianisidine with 4-hydroxybenzaldehyde/3-ethoxy-4-hydroxybenzaldehyde, and the polycondensation reactions of the corresponding Schiff bases in an aqueous alkaline media. At the second step, the PAMUs were obtained by copolymerization of the prepolymers with toluene-2,4-diisocyanate (TDI) under an argon atmosphere. The structures of the obtained compounds were confirmed by FTIR, UV-vis, H-1 NMR, and C-13 NMR, and size exclusion chromatography (SEC) techniques. The synthesized compounds were also characterized by TG-DTA and DSC analyses. Thermal decomposition steps at various temperatures were clarified by FTIR analyses of the degraded products. The physical changes to the synthesized PAMUs after exposing them to the thermal degradation steps are displayed.
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    The crosslinked poly(azomethine-urethane)s containing o-hydroxyazomethine: Tunable multicolor emission, photophysical and thermal properties
    Kamaci, M; Avci, A; Kaya, I
    This article presents synthesis, photophysical, electrochemical, thermal, and morphological properties of the crosslinked polyurethanes (CLPUs). CLPUs were synthesized in two main steps. In the first step, aldehyde functionalized polyurethane prepolymer was synthesized using 2,4-dihydroxy benzaldehyde and hexamethylene diisocyanates. In the second step, the prepared prepolymer was converted to the crosslinked polyurethane derivatives using different diamines via condensation reaction. Diamines with various chain length and side-group substitutions were used as crosslinker. Photophysical properties of the crosslinked polyurethanes were investigated using UV-vis and photoluminescence (PL) spectra techniques. Fluorescence measurements showed that CLPUs exhibited multicolor emission behavior. Additionally, a linear relationship is determined between the excitation energies and the obtained emission maxima and, this property allows tuning the PL color by changing the source light energy on the desired scale. (C) 2015 Elsevier B.V. All rights reserved.