JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2015 | Volume:9 | Issue:3|Papers Count:9

Polyacrylonitrile (PAN) hollow fiber membranes were manufactured through the dry-jet wet spinning. Considering importance effect of structure of hollow fiber to separation performance, spinning parameters such as coagulants composition were changed to achieve suitable hollow fiber membranes. Water with different amount of glycerin was used as the bore liquid and coagulation bath. The effects of the glycerin concentration on the hollow fiber permeation and separation performance were investigated. Direct red 80 was used to measure the separation performance of hollow fiber module. Field emission scanning electron microscope (FE-SEM) was used to analyze the structure of the hollow fibers. The results proved that permeation is increased by adding glycerin to external and internal coagulation bath. In addition, hollow fibers spun in lower glycerin value would indicate lower hydraulic permeability, higher separation and higher tensile strength.

There are few remains of Prehistoric murals in Iran. So, identification of pigments that were used in them is beneficial information for study of Prehistoric painting technology and method of Iran. The present study reports some of the resuls optainted from the application of different analytical techniques to characterize three pigments of Chalcolithic site of Tal-e Mash Karim, Central Iran. The characterization of the studied paintings was carried out by means of optical microscopy (OM), scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Identification the main element of calcium and calcite crystal phase represents the white limestone for white coloring. XRD analysis and identification of hematite in red pigment, Indicated of the red ochre. Also, the FTIR analysis of black pigment indicates of application of coal ash in colors.

Present study oxidation of dyes from dye effluents by O3/H2O2 was investigated. Reactive red 198(RR198) examined as a target dye. Dye oxidation measured by spectrophotometer. The maximum removal efficiency in optimum conditions including pH=9, contact time=30 minutes, the initial concentration of dye=100 ppm, H2O2 concentration=0.005 molar, O3 concentration = 0.04 g/hr were 97.09% and 87.56% for synthetic solution and actual wastewater (wastewater from Yazdbaft textile) respectively. O3/H2O2 had good efficiency in dye removal. This method with respect to high efficiency in actual condition could be used in dye removal from various industries.

Recently, the use of nanoparticles UV-absorber to protect the artworks of cellulosic and lignocellulosic has a special place. In this study, white poplar wood samples treated with dispersions of Nano-Tio2 and Nano-ZnO at two doses of 1% and 2% was investigated. The samples were placed under accelerated aging of UV-B irradiation. Structural changes were investigated by application of spectro-colorimeter and ATR-FTIR spectroscopy. Results showed that 1% of Nano-TiO2 little ability to protect from UV-irradiation. increasing the dose of nanoparticles increases the crystallinity index and amorphous cellulose degradation in the area. Treated with Nano-ZnO reduced degradation of lignin and polysaccharides in wood, and increasing the dose of nanoparticles added ability to protect against UV-irradiation. Increase of the both nanoparticles caused reduction of the darkens and the total colour difference (DE*). Treated samples with Nano-ZnO had total colour difference less than the titanium dioxide. Generally, zinc oxide nanoparticles have better ability of titanium dioxide to protection of wood against UV irradiation.

In this research polyethylene glycol urethane acrylate was synthesized as a nonionic linear polymeric dispersant based on polyethylene glycol (PEG), isophorone diisocyanate (IPDI), hydroxyethyl methacrylate (HEMA) in presence of dibutyltin dilaurate (DBTDL) as catalyst and acetone as a solvent. The nonionic polyethylene glycol urethane acrylate dispersant was characterized by Fourier Transform Infrared (FT-IR) and Proton Nuclear Magnetic Resonance (1H-NMR) and molecular weight was measured by Gel Permeation Chromatography (GPC). Besides, the dispersants were used for dispersing of TiO2 and dispersion quality and distribution was determined by Grindometer. The results indicated that because of steric protect dispersant, suspension particle size decreased. Also dispersant with the medium molecular weight and chain length, showed a better performance on the stabilization of particles of TiO2.

In this research, batch kinetic experiments were carried out for the sorption of Reactive Red 198 onto magnetic activated carbon. Effect of pH and contact time on the adsorption process was studied. The equilibrium time decreased with agitation of solution. The experimental kinetic data were fitted to the pseudo-first order, pseudo-second order, and intra-particle diffusion models by linear and non-linear methods using Mathematica software. The results showed that non-linear method is the most appropriate method to predict the rate kinetic parameters. Also, dye adsorption kinetics followed both pseudo-second order and intra-particle diffusion models.

In this research the effect of silicon carbide nanoparticles and surface pretreatment on the mechanical properties and corrosion protection properties of the polyurethane coatings (40 μm in thickness) were studied on a low carbon steel substrate. The substrates were prepared by polishing and sand blasting methods. Dispersion of the nanoparticles in the polyurethane coating was studied by field emission scanning electron microscope (FE-SEM) image and X-ray diffraction (XRD) analysis. The physical and mechanical properties of the coatings were evaluated by pull-off adhesion, Tubular impact and pencil hardness tester. The Electrochemical Impedance Spectroscopy (EIS) and polarization tests were employed in order to investigate the corrosion resistance behavior of the coatings. The effect of nanoparticles on the chemical bonding of polyurethane were investigated using Fourier Transform Infrared Spectrometry (FT-IR) Analysis. The results of the physical and mechanical study showed that the existence of 2 wt% of nanoparticles, leads to the increase of the adhesion strength up to 50%, hardness of coating increased from 3H to 5H and impact resistance were increased about 34 %. In addition, the results of electrochemical test showed that the existence of 2 wt% of nanoparticles in polyurethane did not significantly change the corrosion resistance behavior of the polyurethane. The results of field emission scanning electron microscope (FE-SEM) image and X-ray diffraction (XRD) analysis showed that nanoparticles up to 2 wt% were well dispersed in polyurethane. Sand blasting of the specimens prior to coating increased adhesion strength up to 35%, but decreased the impact resistance in compare with polishing.

In this work, the composition of blue paints in selected miniatures of Yusof-o-Zalikha (Yusuf and Zulaikha) illustrated book related to Safavid period (Iran, 15th century) as well as the main reasons of their destruction have been investigated. The miniatures were analyzed by proton-induced X-ray emission (PIXE) and atomic force microscopy (AFM) analytical methods. It was found that the pigment of blue colors is mainly lazurite and the extender is the main cause of destruction of blue paints. PIXE analysis results showed the presence of the extenders; PbCO3 and CaCO3. The AFM images showed that dissolving the extender CaCO3 in acidic media has united small aggregation of the salt and driven these bigger aggregations to the surface, makes them visible as white spots in the surface of the miniature.

In photochromic structures based on spiropyrans, two rings of spiro moiety are perpendicular. Merocyanine form with linear and conjugated structure produces by exposure to UV irradiation. Physicochemical properties of the molecular changes owing to this isomerization, and molecule switches between colored and colorless forms. Since, chemical properties of medium is highly effective on photochromic properties and reversibility, in this study, stability and photoresponces of three azospiropyran based photochromic molecule in different organic media were studied. Also, maximum absorption and molar absorption coefficient of these photochromic dyes in different solvents were evaluated. Solvatochromic effects were studied in switching ON/OFF of the molecules.