فهرست مطالب

Progress in Color, Colorants and Coatings - Volume:11 Issue:1, 2018
  • Volume:11 Issue:1, 2018
  • تاریخ انتشار: 1397/01/08
  • تعداد عناوین: 6
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  • M. Shahidi *, Gh. Golestani Page 1
    In the present work, four polymeric nanocomposite PNC coatings were prepared with different concentrations of yttrium aluminum garnet nanoparticles YAG-NPs in polyvinyl butyral PVB matrix. The corrosion protection of the PNC coatings applied on the carbon steel surface was investigated in 1.0 M HCl solution by electrochemical impedance spectroscopy EIS. The YAG-NPs were synthesized by pulse electrochemical method. The formation of YAG-NPs was confirmed through XRD and SEM analysis. The EIS data obtained from the coated samples both without and with YAG-NPs samples were fitted with an equivalent circuit containing two time constants. The protection efficiency values of the PNC coatings were calculated from EIS data. The PNC coating containing 0.025 wt YAG-NPs as the efficient coating showed the best corrosion protection in HCl solution for immersion times up to 28 days.
    Keywords: YAG Nanoparticles, Polyvinyl Butyral, Protection Efficiency, Electrochemical Impedance Spectroscopy (EIS)
  • R. Salehi, F. Dadashian*, E. Ekrami Page 9
    The present study aims at investigating the potential of activated carbon AC prepared from waste cotton fiber for the removal of Acid Dyes from aqueous solutions. The prepared activated carbon was characterized by pore structure analysis, Fourier transforms infrared spectroscopy FTIR. Batch adsorption studies were carried out and the effect of experimental parameters such as pH, initial dye concentration and contact time on the adsorption was studied. The results revealed that the produced activated carbon has developed porous structure, fibrous shape, predominantly amorphous structure. The kinetic data obtained at different concentrations were investigated using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The experimental data were found to conform to the pseudo-second-order kinetics with good correlation. The obtained equilibrium data were best fitted to the Freundlich model. Finally, according to the thermodynamic parameters obtained, it was found that adsorption process was spontaneous and exothermic in nature.
    Keywords: Activated carbon, Adsorption, Dye Removal, Waste cotton fiber
  • M. Sadeghi-Kiakhani *, S. Safapour Page 21
    This study presents a novel method for eco-friendly dyeing of cotton fabrics with direct dyes. Cotton fabric modified with chitosan-poly propylene imines dendrimer CS-PPI, and its dyeing and fastness properties were investigated using three direct dyes. The impacts of important factors, i.e., CS-PPI concentration, dye concentration, dyeing time, dyeing temperature, and salt concentration were investigated and optimized. Results showed that cotton treatment with optimum CS-PPI concentration 15 owf significantly improved dye up-take and decreased effective dye concentration required to obtain the more color depth. Also, optimum dyeing time and temperature were reduced ~50 and ~20˚C, respectively. Moreover, salt was eliminated from cotton dyeing process with direct dyes and “salt-free dyeing” was therefore developed. Colorimetric and color fastness data emphasized that this treatment had no negative effect on the hue and color fastness properties of dyed samples. So, it was concluded that this new eco-friendly process can help to save considerable amount of time, energy, chemicals, and dyeing costs, and also can remedy the associated dyeing effluent problems from dyeing of cotton with direct dyes.
    Keywords: Cotton fabric, Modification, Chitosan-dendrimer hybrid, Salt-free Dyeing, Direct dyes
  • B. Ghobadi Jola, B. Shirkavand Hadavand, Kh. Didehban, A. Mirshokraie* Page 33
    Cationic waterborne polyurethane as a new dispersing polymer was synthesized by using relatively hydrophilic polyols. Dispersing cationic polyurethane (DCPU) nanocomposites were prepared using isophorone diisocyanate (IPDI), polyethylene glycol (PEG) with different molecular weights (Mn=200, 400, 600,and1000 g/mol), N-methyl diethanolamine (MDEA), dibutyltin dilaurate (DBTDL) and different percentages of nanoclay (1, 3, and 5%). The aim was to study the effect of polyol molecular weight and weight percentage of nanoclay on the extent of polarity, polymer flexibility, dispersibility of nanocomposite in aqueous phase, thermal stability and rheological behavior of the polymer. FT-IR and 1H-NMR spectroscopy, Contact angle and thermal and rheometric analyzes were used to characterize the synthesized polymer and related nanocomposites. The results revealed that by increasing the molecular weight of polyethylene glycol, the following changes will be observed in the produced polymeric nanocomposites: particle size reduction, increase in dispersibility, contact angle, thermal stability and viscosity, as well as increase in semi-plasticity and elasticity properties of nanocomposites.
    Keywords: Cationic polyurethane dispersion, Contact angle, Nanoclay, Polyethylene glycol, Rheological properties, Thermal stability
  • M. Hosseinnezhad *, S. Moradian, K. Gharanjig, Sh. Rouhani, M. Ataeefard Page 47
    In this paper we studied preparation of working films of dye-sensitized solar cells using screen printed method. The organic dye based on phenoltiazine with cyanoacrylic acid as the electron donor group utilized as photosensitizer. Fluorine-doped thin oxide FTO coated glass is transparent electrically conductive and ideal for use in dye-sensitized solar cells. FTO glass was coated by screen printed method and investigated the effect of fabrication´s parameters. The influence of the squeegee printing angle of 37°, 55° and 65° on the dye-sensitized solar cells performance was investigated in order to assess changes in the status of the power conversion efficiency. The Conversion efficiency for 37°, 55° and 65° are 2.71 and 1.96 and 1.58, respectively. When using the FTO glass for working electrode preparation, a low squeegee angle gives a porous thick film, which is ideal for dye absorption.
    Keywords: Organic dye, Dye-sensitized solar cells, Screen printing, working electrode, Power conversion efficiencies
  • E. Yarahmadi, Kh. Didehban, M. Shabanian, M.R. Saeb* Page 55
    Epoxy is a versatile resin used in different fields such as coatings, colors, colorants, and composites. Adding nano-scale fillers/additives to the epoxy has valued epoxy coatings for engineering applications, and opened the time of advanced epoxy-based nanocomposite coatings. In the present work, graphene oxide GO was chemically functionalized with starch, as a natural polymer, and added to the epoxy/amine system. Differential scanning calorimetry was utilized to assess the cure kinetics of neat epoxy and its composites containing pristine and starch-functionalized GO GO-St. Cryofractured surfaces of epoxy/GO and epoxy/GO-St nanocomposites are detected by scanning electron microscopy. Overall, the results are indicative of appropriateness of surface functionalization of GO by starch for high-performance coating applications. Hindered cure observed in the case of epoxy/GO was conquered by the attachment of starch to GO; moreover, tree-like fracture was responsible for higher fracture resistance due to starch.
    Keywords: Epoxy Coatings, Graphene Oxide, Natural polymer, Surface functionalization, Cure kinetics