نشریه علوم و فناوری رنگ
سال ششم شماره 4 (پیاپی 22، زمستان 1391)

Aluminium particles were synthesized on clay using two methods of ion exchanged and oxidation. The characteristics of the pigments were investigated by fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscope (SEM), electron dispersive X-ray spectrometer (EDS), reflectance spectrophotometer (RS) and electromagnetic transition instrument (ETI). FTIR spectra showed generation of Aluminium and clay complexes into the clay interlayer. TGA result demonstrated an improvement in thermal stability of clay-Al pigments compared with untreated particles. SEM and EDX results showed that the aluminium aggregates are presented on the surface of clay. Aluminium particles also affected the electromagnetic properties of clay particles.

In this study, the effect of Co catalyst thickness, growth time, Al- blocking layer and carrier gas (Ar) on growth of CNTs upon Si substrate using ethanol as carbon source by chemical vapor deposition (CVD) was investigated; the thickness of Co film and growth time were varied from 1 to 10 nm and 10 to 120 min respectively. Structural information of CNTs, morphology and size distribution of catalysts were studied by scanning electron microscopy (SEM) and Raman spectroscopy. It was found that grain size of Co nano-particles and density and alignment of CNTs depend on thickness of Co film. Vertically aligned CNTs have been grown on 1 and 5 nm Co films and by increasing Co thickness to 7 and 10 nm, spaghetti like structure of CNTs is observed. By increasing the growth time from 10 to 100 min, the density of spaghetti structure is increased, and results of this study show that Co poisoning and CNT burning occur for growth times more than 100 min. In absence of Al layer no CNT growth was observed and without carrier gas during ethanol feed into CVD chamber, low density of CNTs with spaghetti-like structure was seen.

Nanosized titanium dioxide has received much attention because of many applications in semiconductors, sensors, antibacterial and hygienic materials, photocatalysts and solar cells. In this study, pure and iron doped titanium dioxide nanostructured coatings were prepared by spin-coating of polymeric precursor method. Prepared samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, UV-Vis spectroscopy and atomic force microscopy. The effect of iron addition on their photocatalytic activity under visible light irradiation was investigated by the degradation of methyl orange. Results showed that for the nanostructured coating of pure titanium dioxide prepared by the above method, both anatase and rutile have been observed. While for iron doped nanostructured coatings the anatase phase has been stabilized and rutile phase has been completely excluded. Also, the addition of iron at concentrations less than 1 mole percent increases the TiO2 photocatalytic properties, while higher concentrations decrease the photocatalytic properties. These results are in good agreement wirh the predictions of the absorption edge data and X-ray diffraction pattern of samples. As a result it was found that the optimum amount of iron ions doped in nanostructured titanium dioxide coatings prepared by polymeric precursor spin coating method was determined to be 0.3 mole percent to achieve the best photocatalytic activity.

To investigate the effect of epoxy-polyester resin on mechanical and physical properties of wood-plastic composite, polypropylene, wood flour and epoxy-polyester resin were mixed by an internal mixer and molded. The epoxy-polyester resin can be cured and made cross links between chains at the mixing temperature; so it can affect the properties of the composite. The result of tensile and flexural tests revealed that introduction of epoxy-polyester resin increased tensile and flexural modulus but reduced mechanical strength as well as elongation at break. Also such a material decreased impact strength. On the other hand, epoxy-polyester resin reduced water absorption of the samples and consequently decline thickness swelling. Therefore, it reduced stresses which were produced by swelling as a result of water absorption in the sample and shrinkage after drying.

In chemical reaction engineering viewpoint, kinetic study is essential for design and optimization of chemical process and their intermediates. Kinetic parameters are utilized to scale-up of laboratorial experimental results to industrial scale data. Herein, kinetic study of Pigment Red 254 synthesis procedure in ionic liquid media has been studied. The produced pigment was followed by UV-Vis spectra during the reaction. Reaction rate equations were derived from integral method. The results confirm that the reaction has concurrence to micro-kinetics with shift order reaction.

In this study, bio-sorption of Acid Red 14 (AR14) dye has been investigated at 336 hours in a batch system by Azolla A.filiculodes species. The experiments were done for five different dye initial concentrations (15, 30, 45, 60, 75 mg/L) at different contact times, temperature ranges 25-30°C (environmental temperature) and pH equal to 7. The results showed that removal percentage of AR14 dye was reduced with initial concentration of dye and contact time rising. The highest removal capacity was reported 64.5% in initial concentration of 15 mg/L. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption isothermal models were investigated for this living species in different concentrations. Comparison of experimental results to models was illustrated that the process imitated from Dubinin-Radushkevich isotherm. In addition, survey of pseudofirst and second order kinetics models presented that the bio-sorption process was compatible to pseudo-second order kinetics equation.

At the present work, the effect of synthesis temperature and atmosphere on the magnetic and color properties of the magnetite (Fe3O4) magnetic nanparticles was studied and magnetic and colorimetric properties of them were correlated. The precipitation occurred by pH adjustment of ferrous/ferric mixed salt-solution with ammonium hydroxide addition. The synthesis was performed in the temperature range of 25°C to 80°C in ambient and nitrogen protected atmospheres. The magnetite nanoparticles were characterized by vibrating sample magnetometer (VSM) analysis. Crystallite size was calculated via reclaimed Sherrer,s formula. The magnetic properties revealed that temperature variations shows appreciable effect on magnetic properties when the synthesis is performedin ambient atmosphere but is not effective when it is performed in inert atmosphere. The colorimetric parameters were calculated in two color spaces CIEL*a*b* and CIEL*C*h°. The results showed that the color of nanopigments tend to red shade when synthesis was performed in ambient atmosphere and to black shade when synthesis was done in nitrogen atmosphere.

In this paper, the application of Chitosan-Dendrimer PPI (CS-PPI) hybrid as a biopolymer adsorbent for the decolorization of colored textile effluent containing direct dyes was reported. A Response Surface Methodology (RSM) was applied to optimize the operating variables of the decolorization process. The results from the adsorption experiments revealed that the optimal conditions for dye removal were: pH 2; dye concentration 75 mg/l; duration time 30 minutes and temperature 40 ⁰C. The dye removal values of 5555.55 mg/g and 6134.97 mg/g were achieved with DR23 and DR81, respectively. The kinetic absorption data for used direct dyes fitted well to pseudo-second order kinetic model. Furthermore, adsorption isotherm study indicated that dyes adsorption was correlated reasonably well by Langmuir isotherm model. The results from this paper demonstrated that CS-PPI can be employed as an affective biopolymer with high potential for direct dyes removal from colored textile effluents.

In this manuscript, synthesis of an acid dye by diazotization of 4-amino-9-metyoxypropyl naphthalimide with nitrosyl sulfuric acid and coupling with J-acid has been reported. The synthesized dye was purified and characterized by use of DSC, 1HNMR, FTIR and Uv-vis techniques. The synthesized dye was applied on polyamide fibers and its dyeing properties such as build up, fastness properties and color characteristics were investigated. The measured spectrophotometric attributes of dyed fibers showed that the synthesized dyestuff has a good build up and creates bluish red on polyamide fibers. In addition, assessment of fastness properties of dyed fibers showed that the synthesized dyestuff has relatively acceptable results on polyamide fibres.

In this study, attempts were made to quantify appearance perception of automotive finishes based on visual assessed data of 7 observers. To this end, three physical scales of appearance attributes, namely specular gloss, distinctness of image and orange peel were prepared using white and metallic black automotive finishes. The scales were visually evaluated under a 45/0 illumination and observation geometry by means of a grey scale technique, and observers accuracy were calculated using appropriate statistical parameters. The results showed that there seems to be a noticeable difference between the visual assessment of orange peel in comparison with specular gloss and distinctness of image. Moreover, it was found that quantification of visual perception of appearance attributes for white samples is much more difficult than black samples.