Yazar "Işik N.O." seçeneğine göre listele

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    The changes on some chemical properties of artificially aged garment leathers
    (2010) Işik N.O.; Karavana H.A.
    Aging is a process of reversible and/or irreversible structural change of material, which depends on structural characteristics and environmental factors. Heat, humidity, UV radiation, chemical effects and their causes in visible and invisible damages which lead to structural deteriorations and decreases in fastness are some factors that depends on aging in leathers and leather products. In this research, Chromium (VI) and formaldehyde contents which resulted after artificial aging procedure in chrome, vegetable and semi-vegetable tanned garment leathers, caused by the chemical decomposition have been investigated. Temperature, temperature/humidity and temperature/UV radiation have been chosen as aging factors. According to the findings; in finished garment leather samples, Chromium (VI) and formaldehyde contents higher than acceptable limits and aging conditions effective on level of increase have been investigated through ISO 17228 (2005) artificial aging procedure depending on temperature, humidity and UV radiation.
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    Effects of Chromium VI stress on green alga Ulva lactuca (L.) [Yeşil Alg Ulva lactuca (L.) üzerinde krom (VI) Stresinin Etkileri]
    (2010) Ünal D.; Işik N.O.; Sukatar A.
    In order to contribute to the understanding of its response to metal stress, Ulva lactuca (L.) was treated with different concentration of chromium (VI) (0.2, 0.5, 1, and 5 mM K2CrO4), and alterations in Fv/Fm ratio (maximal photochemical efficiency of PSII) and cell viability were investigated. Significant alterations of the maximal photochemical efficiency of PSII (Fv/Fm) ratio were observed in response to the increase in chromium concentration. The Fv/Fm ratio decreased in Ulva lactuca following 2 h treatment with 1 and 5 mM Cr(VI) solution. The cell viability was decreased in cells exposed to higher Cr(VI) concentrations. Thallus cell morphology was altered in thalli exposed to chromium. A cytotoxic effect of chromium was demonstrated for the first time using acridine orange/ethidium bromide staining in macroalgae. In 1 and 5 mM of Cr(VI) treated samples, the rate of necrotic cells increased about 76.93% and 84.23%, respectively. © TÜBİTAK.
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    Leather surface refinement with application of the TiO 2 -SiO 2 -GLYMO nanocomposite and lacquer coating
    (Society of Leather Technologists and Chemists, 2018) Kaygusuz M.; Işik N.O.; Meyer M.; Aslan A.
    In the present study the effect of TiO 2 -SiO 2 -GLYMO nanocomposite on surface properties of leather was investigated. The TiO 2 -SiO 2 -GLYMO composite was prepared through the sol-gel route from tetraethoxysilane (TEOS) and titanium n-butoxide (TBO). 3-glycidoxypropyltrimethoxysilane (GLYMO) was added as coupling agent to provide a stable bond between metal oxides and leather substrate. The prepared composite was applied by spraying on the top coat of leathers in finishing. The surface properties observed by scanning electron microscopy (SEM) showed an even and homogenous coating obtained on leather by application of the composite in the presence of lacquer. The chemical structure of composite films was examined via Fourier transform infrared (FTIR) and Si-O-Ti bond and opening of epoxy rings of GLYMO were revealed. The presence of Ti and Si in the composite treated leather samples was ascertained by inductively coupled plasma optic emission spectrometer (ICP-OES). The results of the physical and fastness tests indicated that the use of TiO 2 -SiO 2 -GLYMO nanocomposite improves some performance characteristics of leather such as finish adhesion, dry and wet rubbing fastness, colour fastness to light and UV light. The results are promising for the refinement of leather surface with the application of the nanocomposite in the finishing process. © 2018 Society of Leather Technologists and Chemists. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Leather surface refinement with application of the TiO2-SiO2-GLYMO nanocomposite and lacquer coating
    (Society of Leather Technologists and Chemists, 2018) Kaygusuz M.; Işik N.O.; Meyer M.; Aslan A.
    In the present study the effect of TiO2-SiO2-GLYMO nanocomposite on surface properties of leather was investigated. The TiO2-SiO2-GLYMO composite was prepared through the sol-gel route from tetraethoxysilane (TEOS) and titanium n-butoxide (TBO). 3-glycidoxypropyltrimethoxysilane (GLYMO) was added as coupling agent to provide a stable bond between metal oxides and leather substrate. The prepared composite was applied by spraying on the top coat of leathers in finishing. The surface properties observed by scanning electron microscopy (SEM) showed an even and homogenous coating obtained on leather by application of the composite in the presence of lacquer. The chemical structure of composite films was examined via Fourier transform infrared (FTIR) and Si-O-Ti bond and opening of epoxy rings of GLYMO were revealed. The presence of Ti and Si in the composite treated leather samples was ascertained by inductively coupled plasma optic emission spectrometer (ICP-OES). The results of the physical and fastness tests indicated that the use of TiO2-SiO2-GLYMO nanocomposite improves some performance characteristics of leather such as finish adhesion, dry and wet rubbing fastness, colour fastness to light and UV light. The results are promising for the refinement of leather surface with the application of the nanocomposite in the finishing process. © 2018 Society of Leather Technologists and Chemists. All rights reserved.