نشریه علوم و فناوری رنگ
سال پنجم شماره 1 (پیاپی 15، بهار 1390)

The chitosan emulsion containing nano-particles has been prepared in a suspension form by adding drop-wise sodium polyphosphate (SPP) solution into a chitosan solution (CS). The results showed that the adsorption of C. I. Reactive Blue 19 (RB19) on chitosan emulsion was affected by contact time، initial dye concentration، pH، and temperature. For an initial dye concentration of 160ppm and 25°C in the optimum conditions (pH=4، [CS] / [SPP] =2. 85)، the chitosan nano-emulsion has much higher dye adsorption capacity. The RB19 removal in optimum condition was 60% and 100% for conventional chitosanand chitosan nano-emulsion respectively.

This research reports on the examination of enzymatic decolorization. Decolorization of Reactive Black 5 using fungal peroxidase obtained from Coprinus Cinereus was studied in a stirred tank reactor. Effect of several parameters including hydrogen peroxide concentration، pH، dye concentration and enzyme activity on the decolorization of Reactive Black 5 was investigated. Dye decolorization efficiency of 67% was achieved under continuous feeding of dye solution and stepwise addition of hydrogen peroxide and peroxidase enzyme. Under this condition، pH value، dye and hydrogen peroxide concentrations were 8. 0، 40 ppm and 96. 1 mM، respectively.

In this research، dyeing ability of the chitosan grafted-acylated wool fabrics has been studied. Acylated wool fabrics at two different solvents (dimethylsulfoxide (DMSO) and N،N-dimethyl formamide (DMF)) using succinic anhydride (SA) and grafted with chitosan have been dyed with acidic dye Polar Brilliant Red 3BN. Chitosan grafted fabrics indicated the higher K/S in comparison with the acylated and blank wool samples.

The present study describes a rapid and novel method for the synthesis of two monoazo mordant dyes. In this method، diazonium salt (ArN2 + -CrO3-SiO2) was prepared via grinding of 2-amino benzoic acid as diazo component، NaNO2، wet SiO2 and nano silica chromic acid without solvent at room temperature. The obtained diazonium salt was sufficiently stable to be kept at room temperature in the dry state. Azo dyes were prepared by coupling of (ArN2 + -CrO3-SiO2) with 1 and 2- naphthoxide as coupling components، in good to excellent yields. The analytical methods such as FT-IR، 13CNMR and 1HNMR were used for identification of two synthesized dyes. Synthesized monoazo mordant dyes were applied to dyeing wool in after chrome method. The chromaticity co-ordinations and wash fastness of samples were measured. The results showed that the hues of both dyed and mordanted samples are the same and their wash fastnesses are 3.

Produce of Persian luster ware is doing inactive since about 14. century. Many of contemporary ceramists are interested to alive the forgotten fantastic and beautiful Iranian art. This research studies different factors، which have influence of successful processing luster enamel such as temperature، thickness of unburned layer and intensity and term of reduction. The differential thermal analyses (DTA) and thermo gravimetry (TG) diagrams of raw materials shows that the best range of reduction temperature should be 500-600°C. Industrial opaque glaze is a suitable basic glaze for luster enamel and wood ofwalnut can be a helpful reduction agent to produce an acceptable luster enamel. Thickness of unfired luster layer was a important factor to realize the effect and shining of luster by different enamel composition. Between three composition (M1، M2 and M3) the best results belong to M1 and M2، which could create golden and iridescent luster.

Titanium dioxide (titania) particles were prepared by a water-in-oil emulsion system، and studied for the photodecomposition property of methylene blue. Microemulsion (ME) consisted of water، cyclohexane and a anionic surfactant such as (AOT). The smallest diameter of the particles was 28 nm in the system of cyclohexane with surfactant when the molar ratio of water to surfactant was 2. The effect of the process parameters (water/surfactant ratio، temperatures) on the final characteristics has been investigated، in terms of structural phase and particle size. Titania particles prepared in this condition were collected as amorphous powder، and converted to anatase phase at less than 500°C، which is lower than the ordinal phase transition temperature. The titania nanopowders were characterized by means of X-ray diffraction and SEM، TEM، FT-IR، and DTA. The titania calcined at 500 ºC shows the highest activity on the photocatalytic decomposition of methylene blue.

Spectral data which give valuable information، are usually represented with a high dimension according to the accuracy of instrument. During the last decades، applying mathematical methods such as Principal Component Analysis (PCA) has shown that spectral data has limited number of principal vectors. In the present study، the appropriate numbers of PC vectors for representing the spectral reflectance of natural dyes were investigated applying a set of 629 wool samples dyed with natural dyes. GFC، RMSE and color differences under two illuminants were considered to evaluate the magnitude of error. Experimental results showed that it is possible to represent the spectral data of natural dyes with almost 5 principal components with precious accuracy (GFC=0. 999). In addition، the best results were obtained when the principal vectors are extracted from the same data set (natural dyes) in comparison to other sets such as dyed polyesters or 1269 Munsell set.

In recent years، attempts have been done to replace toxic materials like chromate based pigments by phosphate pigments having less toxicity properties. However، the anticorrosive performance of zinc phosphate pigment has been proven not to be comparable to chromate type pigments. Regarding this، attempts have done to produce second generation of phosphate pigments. This study aims to investigate and compare the properties of a polyurethane coating، containing zinc phosphate (ZP: first generationpigments) and zinc aluminum phosphate (ZPA: second generation)، at different pigment volume concentrations (PVC) of each pigment. Effect of pigment type as well as PVC on the adhesion of coating to steel panels were investigated before and after 90 days immersion in 3. 5 wt% NaCl solution using pull-off test. Cathodic disbonding (CD) was done according to ASTM G8 to investigate the disbonding behavior of coatings. Results obtained in pull-off and Cathodic disbonding (CD) tests revealed that، greater adhesion loss can be observed on the samples showing lower resistance against disbonding. Evaluation of coating resistances against disbonding were examined at each of the PVCs. It was found that، the solved components of each pigment، at their optimum PVCs، can produce protective layer at coating/metal interface which lead to increase resistance of coated layer to disbonding.

Due to their periodic structures, three dimensional photonic crystals possess some useful optical properties such as wave guiding. Sandwiching these structures between multilayered polymer films improves such properties compared to those of single-layer films because they form a nano structure. In the present investigation polymethyl methacrylate and polystyrene were dissolved in proper solvents namely, acetone and cyclohexane(plus 5ml carbon tetrachloride per 95ml of cyclohexane). Solutions and suspension of nano particles were spin-casted rotationally using specially designed machine to produce a periodic structure. The optical properties of the cast films were studied using spectrophotometric techniques. It was found that cladding three-dimensional polymer films induced a color change. A color-shift from blue to green was found to be related to refraction of light amongst polymer layers. J. Color Sci. Tech. 5(2011), 69-75© Institute for Color Science and Technology.