نشریه علوم و فناوری رنگ
سال نهم شماره 4 (پیاپی 34، زمستان 1394)

In this study, α-Fe2O3 nanoparticles (α-Fe2O3 NPs) and its composite with wood sawdust (α-Fe2O3/SD NC) were synthesized using co-precipitation method and then were used as adsorbents for dye removal from aqueous solution. Reactive Red 195 (single azo dye) was used as a test probe in this study. Adsorption studies were carried out in batch system. In order to find out the optimum removal conditions, the effect of some important parameters such as pH, initial concentration dye, contact time, temperature, adsorbent dosage and etc onto sorption capacities of the adsorbent were investigated. Equilibrium adsorption data were treated using Freundlich and Langmuir equations. The results indicated that the adsorption capacity of α-Fe2O3 and α-Fe2O3/SD nanocomposite for dye removal were 59.17 and 29.67 mg/g, respectively. Pseudo first and Pseudo second order kinetics were used for kinetic investigation. The results showed that sorption process follows the Langmuir isotherm and Pseudo-second-order kinetic model for α-Fe2O3. The isotherm studies revealed that the equilibrium adsorption data obtained for α-Fe2O3/SD adsorbent fitted better with Freundlich model and the adsorption kinetics is also followed by the Pseudo-first order model.

Nowadays, auxiliaries are playing a very important role in improving textile dyeing and printing conditions. In the present study, cotton/polyester fabric was padded with beta-cyclodetrin (β-CD) and after printing with disperse-reactive dyes, samples were treated with TiO2 nanoparticle to improve their self-cleaning properties. The effect of β-CD on properties of printed fabric and scanning electron microscope surface image, their self-cleaning and antimicrobial properties were studied. According to the results, increasing concentration of β-CD could reduce color strength (K/S) of the samples and their water absorption time whilst water spreading area and value of the retained water were increased. β-CD showed a very limited effect on improving antimicrobial activity of goods.

Material identification of historical objects has a great importance for better understanding and reproduction process of ancient arts as a basic prior to applying the appropriate conservation method. In this research an inscription related to Ansarin house of Tabriz was studied. It has used in open air space under environmental factors which has caused to structural and visual decays. The aim of the study was identification of pigments and ink of script and ornaments by application chemical spot tests, polarized light microscopy, SEM-EDX and FTIR spectrometry. Results have indicated the use of carbon ink in inscription and ultramarine blue (Lapis lazuli), white lead, red lead (minium), massicot (litharge) with chalk as filler and copper alloys as golden pigment. Corrosion products of copper alloys such as carboxylates, appears as a green layer on golden areas.

This research describes a double layered dye sensitized solar cells by using organic dyes based on indoline. Spectrophotometric evaluations of the mixtures of dyes in solution and on a TiO2 substrate were carried out in order to assess changes in the status of the dyes. Additionally, electrochemical properties of each mixture of dyes were investigated. Oxidation potential measurements for all of mixture ensure a thermodynamically favorable charge transfer to the TiO2 conduction band. Finally, dye sensitized solar cells are fabricated in order to determine the photovoltaic behaviour and conversion efficiencies of each mixture.

In this study, natural colorants of hawthorn fruit, Crataegus elbursensis were extracted using ultrasonic energy. The effect of extraction variables such as solvent type, time, temperature, pH, and crude dye concentration was optimized through one-factor at a time method. Optimum extraction conditions of dye concentration 10 g/L, ethanol/water ratio of 4/1 V/V, temperature 50 ˚C, time 30 minutes, and pH 4 were obtained. Moreover, comparison of extraction data obtained by two conventional and ultrasonic extraction methods demonstrated that using ultrasound, extraction time and temperature were reduced and the amount of natural dye extracted was enhanced.

Products need to have high quality as well as acceptable appearance. Due to the extremely high expressive quality of the colors in the products, knowledge and understanding of the visual element is considered very difficult and yet critical step in the product design. The systematic design of sports shoes is the first step to success in global industry competition and the color element in shoes is considered a critical role in design and customers attraction, and the preferenced colors for this product in various segments of society should be identified. Given the importance of this issue, this paper investigates the effect of color preferences on product preferences with the moderating role of age, gender and education. The research methodology is of descriptive_survey type and data were collected from 400-person with different ages, gender and education in Tehran city. The conceptual model consists of three main variables. To test the hypotheses, the chi-square test, Friedman and regression were used. Results showed that age, gender and education have moderating impact on the relationship between color preferences and product preferences. Color preferences are also significantly related to product preference.

Despite the widespread applications of conductive polymers, their usage has been limited due to their poor processability. Emulsion polymerization to produce stable nanoparticles in water, solve to some extent the difficult process of these polymers. In this study, synthesis of polyaniline by inverse emulsion polymerization method along with chemical, physical and structural aspects is discussed. Synthesize of conductive polyaniline is carried out using oxidizing agent of benzoyl peroxide in a non-polar solvent, a functionalized protonic acid as dopant/ emulsifier and hydrochloric acid to improve the product conductivity. In order to optimize efficiency and conductivity of synthesized polyaniline, the effect of synthesis conditions such as reaction time, type and concentration of reactants were investigated. Synthesizing in optimum condition, minimum resistance value for a produced polyaniline was about 8.29 Ω. Beside conductivity, morphology and other properties of polyaniline has been investigated by FT-IR, SEM, DSC and DLS analysis.

The main purpose of this study is to achieve a formula to estimate the lifetime of hand-knotted woolen carpets based on changes in the appearance and color of carpet using statistical techniques. Thickness loss of surface pile yarns (TL), color difference index of pile yarns (E), tuft size index (TS) and evenness of texture index (ET) were considered as representative of the appearance characteristics. Eighteen hand-knotted woolen carpet samples (symmetric knot) with different structural specifications were produced. The carpet samples were subjected to 4000, 8000 and 12000 drum revolutions using a Hexapod tumbler tester and functional properties of samples were investigated in original and worn out carpet samples with standard methods and image processing technique. At first the effective variables selected by using multivariate test, and then multivariate analysis of variance was used for evaluating the significance of obtained models. Optimal separate equations of the functional properties on hand-knotted carpets were determined through multivariate multiple regression method. Reverse model of wear factor can be considered as a proper equation to predict the lifetime of carpets.

Ultraviolet and visible radiations are absorbed by fluorescent materials at short wavelengths and re-emitted at longer wavelengths. Spectral curve of fluorescent material consists of true and fluorescent reflection. The common Kubelka-Munk color model describes the reflectance of a translucent sample without considering fluorescence component; so, true spectral reflection of fluorescent materials should be separated from fluorescence emission. To this aim, there are some methods such as filter application to reduce fluorescence component, polychromatic and monochromatic spectrophotometers and computational methods to eliminate or decrease the fluorescence effect. At present study, to separate the true reflectance component from the fluorescence emission, the total spectral radiance factor of the fluorescent dyes was compared with the reflectance of the substrate through all visible wavelengths and exciting, crossover and emission region were determined. Accordingly, the total radiance factor curve can be separated into two parts of true and fluorescence reflection with considering of the Kubelka–Munk theory for the true reflectance part, simply and without any especial equipment.