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Progress in Color, Colorants and Coatings - Volume:8 Issue: 4, Autumn 2015

Progress in Color, Colorants and Coatings
Volume:8 Issue: 4, Autumn 2015

  • تاریخ انتشار: 1394/09/28
  • تعداد عناوین: 6
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  • S. Rouhani, M. Hosseinnezhad* Pages 259-265
    In azo dye is used as photosensitizers in Dye-sensitized solar cells. Azo dyes are economically superior to organometallic dyes because they are color variation and cheap. The spectrophotometric evaluation of an azo dye in solution and on a TiO2 substrate shows that the dye forms J-aggregation on the nanostructured TiO2 substrate. Oxidation potential measurements for used azo dyes ensured an energetically permissible and thermodynamically favorable charge transfer throughout the continuous cycle of photo-electric conversion. The performance of dye-sensitized solar cells based on azo dyes has been studied. The results illustrate that the dye containing acetic acid and sulfonic acid as the acceptor group gave the maximum conversion efficiency of 3.52% and 3.17% in the presence and absence of anti-aggregation agent, respectively.
    Keywords: Dye, sensitized solar cells Sensitizers Photovoltaic materials Conversion efficiencies Azo dye
  • A. Hatam, M. Dehghani Firouzabadi *, H. Resalati Pages 267-281
    This study investigates preparation of melamine formaldehyde/montmorillonite nanocomposite coatings and evaluates its abrasion resistance property as a new material for wood based panel products. The ultrasonicated MF resin/clay blends with different clay loadings were applied in the form of coatings to the saturated decorative paper to prepare thermoset prepregs. Morphology and structure of nanocomposite coatings were characterized using X-ray diffraction and field emission scanning electron microscopy (FE-SEM). Then viscoelastic properties of resultant prepregs were investigated using DMTA method. Tensile test was also employed to determine tensile modulus and toughness of different prepregs. To evaluate abrasion resistance property of cured nanocomposite coatings, Taber abrasion test was performed on panels laminated with prepregs. The results showed that although modulus of storage (stiffness) and tensile strength of intercalated nanocomposite containing 4 % clay was lower than those of exfoliated nanocomposite at 1% clay, its toughness and abrasion resistance property was amazingly better. The results of Taber abrasion test suggest the contribution of nanocomposite morphology rather than stiffness and strength in improving the abrasion resistance property in MF/montmorillonite nanocomposites. It was also found that there must be a relation between clay intercalated morphology in the nanocomposite structure and improvement of its toughness property. However, further research is needed to gain an in-depth understanding on its affecting mechanism. Prog. Color Colorants Coat. 8 (2015), 267-281 © Institute for Color Science and Technology.
    Keywords: Montmorillonite Melamine Formaldehyde Nanocomposite Morphology Abrasion Resistance
  • M. Mahdavian*, M.M. Attar, F. Shiran Pages 283-294
    Adsorption of benzimidazole, 2-methylbenzimidazole and 2aminobenzimidazole on mild steel in 3.5% NaCl solution was studied using density function theory (DFT) calculations. In this regard, charge transfer resistance (Rct) and double layer capacitance (Cdl) obtained by electrochemical impedance spectroscopy (EIS) were used to calculate surface coverage and to build prediction models. When prediction models were only based on quantum chemical parameters of imidazoles, the most effective parameters were frontier orbital energies meaning that dominant mechanism of adsorption was chemisorption. However, models based on imidazoles and iron quantum chemical parameters revealed that the most effective parameter is dipole moment meaning that dominant mechanism of adsorption is physisorption. Prediction models based on inhibitor-Fe(OH)2(H2O)4 and inhibitor-Fe(OH)3(H2O)3 systems presented dipole moment and electron donating power as the most effective parameters for θR and θC based calculations, respectively. Such a behavior could be attributed to chemical interaction of inhibitors with Fe(OH)2(H2O)4 and Fe(OH)3(H2O)3 on the mild steel surface resulting in a porous thick layer which could not effectively block the surface but could decrease double layer capacitance.
    Keywords: Adsorption EIS Corrosion Inhibitor Corrosion Product Quantum Chemistry
  • Sh. Pashapour Yeganeh, M. R. Kalaee* Pages 295-307
    The effect of different parameters including: nano silica content, curing temperature, type of hardener, and flash-off time on mechanical and optical properties of polyurethane (PU) based clearcoat was investigated via standard Taguchi L9 method. Dispersion of nano silica in the resultant nanocomposites was explored by scanning electron microscopy (SEM). SEM images showed a fine dispersion through the nanocomposites at different loadings. All PU nanocomposites showed gloss in the range of 91-94 which confirms that the presence of nano silica did not have an adverse impact on optical properties. Moreover, the most significant factor contributing to the hardness of the samples was the nano silica content. It was shown that high amount of nano silica (5 wt%) reduced the hardness of clearcoats due to interrupting curing process. The clearcoats performance after carwash test indeed showed that sample containing 2% nano silica cured at 85oC with a mixture of hardener (50% biuret, 50% trimer) after flash-off time of 5 min had the optimum physical and optical properties. Prog. Color Colorants Coat.
    Keywords: Polyurethane Clearcoat Nano silica Taguchi method
  • M. Hosseinnezhad, S. Moradian*, K. Gharanjig Pages 309-315
    In this paper we sensitized two new organic dyes (Dye 1 and Dye 2) based on indoline with indoxyl as the electron donor group. We used acrylic acid and cyanoacrylic acid as the electron acceptor anchoring group in Dye 1 and Dye 2, respectively. The proposed dyes were sensitized from carbazole as the starting material by standard reactions and characterized by different techniques such as melting point, FTIR, 1HNMR, elemental analysis and UV-Visible spectroscopy after purification. Spectrophotometric measurements of the synthesized dyes in solution and on a TiO2 substrate were carried out in order to assess the changes in the status of the dyes. The wavelength of maximum absorption for Dye1 and Dye 2 in solution are 551.5 nm and 558 nm and on TiO2 films are 576 nm and 585 nm, respectively. Finally, the proposed dyes were used as sensitizer in a dye solar cell structure and their photovoltaic properties were also investigated. The Conversion efficiency for Dye 1 and Dye 2 were 1.03% and 1.45%, respectively.
    Keywords: Indigo Dye, sensitized solar cells Sensitizers Photovoltaic materials Conversion efficiencies Photocurrent, photovoltage curves
  • A. Mohammadi*, F. Golshahi Pages 317-327
    In the present study, five naphthalene-based azo dyes were obtained using classical azo coupling reactions. The structure of the dyes was characterized and confirmed by the UV-Vis, FT-IR, 1H NMR and 13C NMR analyzes. The solvatochromic behavior of the dyes was studied in a set of 10 solvents with different polarity and considerable results were obtained. The dyes were applied as disperse dyes to polyester fiber and their dyeing properties were evaluated. The fastness properties of the dyed fabrics such as wash, light and rubbing fastness degrees were measured by standard methods. Additionally, the prepared dyes were evaluated for antioxidant activity by ferric reducing antioxidant power method.
    Keywords: Azo dye Solvatochromism Polyester fiber Dyeing Antioxidant activity