نشریه علوم و فناوری رنگ
سال چهارم شماره 3 (پیاپی 13، پاییز 1389)

In this paper, dissolution of a monoazo disperse dye based on naphthalimide containing carboxylic acid in the presence of anionic and nonionic dispersing agents was reported. In this respect, the effect of various parameters such as temperature, time, and concentration of dispersing agents on dissolution of the dye in water containing dispersing agents were evaluated. The results showed that with increasing the concentration of both anionic and nonionic dispersing agents, temperature andtime of dissolution of the dye was increased. In all cases, dissolution of the dye in the presence of anionic dispersing agent is better than nonionic type. The kinetic study of the dissolution of the dye in the presence of both anionic and nonionic dispersing agents at various temperatures and different concentrations of dispersing agents represented that the rate of dissolution of dye in aqueous dispersing agents are fitted with exponential equation and the rate of dissolution of dye in water containing anionic dispersing agent is more than nonionic type. The measurement of dissolution rate of the dye in both dispersing agents showed that the rate of dissolution of dye decreased with increasing of the time. J. Color Sci. Tech. 4(2010), 133-142© Institute for Color Science and Technology.

In order to have the better properties of each component, the use of fabrics prepared from natural and synthetic fibres blends are common. The well known method for the dyeing of this kind of fabrics is either the use of reactive-disperse dye or reactive/disperse dyes blend. For the dyeing of cotton component of the substrate with reactive dyes, the use of alkali is necessary. Since the addition of alkali during the dyeing process could cause unlevel dyeing and also it is time consuming, the dyeing of cotton fabric with selected reactive dyes under neutral condition was investigated. In this method, a mild alkali pretreatment of a selected reactive dye is done before dyeing stage in which the sulphato ethyl sulphone group of the dye is converted to the vinyl sulphone group. So, the role of alkali during dyeing process is performed before the dyeing process starts.The results obtained from the measurement of exhaustion and fixation percentages in dyeing of cotton/polyester substrate with selected reactive dye pretreated in optimised condition/disperse dye showed E%=94%, F%=84% for C.I. Reactive Blue 21 / C.I.Disperse Red 167 and E%=89%, F%=81% for C.I. Reactive Black 5 / C.I. Disperse Red 167. J. Color Sci. Tech. 4(2010), 143- 149© Institute for Color Science and Technology.

In the present study the treatment efficiency of O3 and UV+O3 processes were compared for the oxidation of simulated dyebath effluent containing a mixture of C.I. Reactive Red 120 (RR-120) and various dye auxiliaries. The color, COD and TOC removalrates were assessed for different processes. The effects of solution pH, initial dye concentration and presence of sodium hydroxide and sodium carbonate on rates of decolorization were studied. The rate of decolorization decreased by increasing of the initial dye concentration and addition of sodium hydroxide. No change in decolorization was observed by addition of sodium carbonate. The experimental results showed that ozonation combined with UV irradiation (9-watt low-pressure mercury lamp) was slightly more efficient than ozonation alone in COD removal with no change in color removal kinetics. At an initial pH of 6.2, bulk temperature of 25°C, ozone dosage of 55 g/m3 and initial dye concentration of 800 mg/L, the TOC removal efficiency of RR-120 reached 27% and 36% after 90 min for O3 and UV+O3 processes respectively. J. Color Sci. Tech. 4(2010), 151-160© Institute for Color Science and Technology.

In this research, microencapsulated -carotene powder has been prepared by gelatin using spray drying method. Ability of gelatin for encapsulating of -carotene was examined. Suitability of -carotene powder was investigated for using in aqueous media. Prepared emulsion had the average particle size of 2.83 microns caused stability of emulsion. Microencapsulated - carotene particles had spherical shape with smooth and some dented surfaces. Microencapsulated -carotene powder had high -carotene content which is suitable for food industry. Microencapsulation efficiency was 42.7% which was increased up to 50.8% by increment of the gelatin concentration. The cold water solubility of the microencapsulated powder was 73% and the powder was stable in water and did not show phase separation after 14 days. J. Color Sci. Tech. 4(2010), 161-167© Institute for Color Science and Technology.

This investigation aims to show some effects of nano alumina particles in an acrylic resin that is used as a protective coating against wear. The loads of nano alumina in samples are 3, 5, 7, 9, 11 percentage “based on solid” and a sample without nano alumina marked as reference. Liquid samples were examined by a rheometer to observe effects of nano alumina particles on viscosity then a turbidity instrument was utilized to observe transparency changes of clear coats that contains diverse amount of nano alumina. By means of a Taber abrasion, wear index of samples were achieved; afterward micro hardness used to consider the effects of nano alumina in hardness of samples.Adding nano alumina does not impart significant alternation in viscosity. Turbidity results show haziness in higher load percentage of nano alumina. Wear index of samples in high weight fractions dropped dramatically. Micro hardness of cured samples does not differ significantly. J. Color Sci. Tech. 4(2010), 169-174© Institute for Color Science and Technology.

In this work, the effect of coating parameters such as deposition time, voltage (field intensity), frequency and the liquid medium on deposit mass and deposition quality in alternating field electrophoresis (ACEPD) is investigated. For this purpose, suspensions of SnO2 nanoparticles in pure acetone were prepared. In order to investigate the coating quality (pattern), stereo optical microscopy was used and the coating process was performed on two parallel gold electrodes with a gap of 500 micron. Deposit mass measurements showed that the variation of deposit mass vs. deposition time and voltage follows theoretical relations. On the other hand, the deposit mass decreases at higher frequencies. The deposit pattern in each frequency is allocated to that frequency and does not change over longer deposition times. At last, the deposit mass in pure acetone was much more that the pure ethanol and distilled water due to the higher value for dielectric constant to viscosity ratio of pure acetone. So, it is possible to obtain wide variety of deposition quality by changing the electrophoretic deposition parameters. J. Color Sci. Tech. 4(2010), 175-182© Institute for Color Science and Technology.

Sodium dodecyl sulfate (SDS) was used as an accelerating reagent to replace nitrite in phosphating bath. Effect of this surfactant on the morphology and anticorrosive performance of phosphate coating on AZ31 magnesium alloy was studied. The light grey phosphate coating was formed on AZ31 magnesium alloy from the zinc phosphating bath containing sodium dodecyl sulfate at temperature of 45-50 ºC and in about 5 minutes. SEM and EDX were utilized to investigate the morphology and elemental compositions of the phosphate coatings. In addition, DC polarization was used to reveal the anticorrosive resistance of phosphate coatings. Results showed that, using SDS as an accelerating reagent to replace nitrite in phosphating bath has caused a more uniform formation of hopeite phase at different directions. In addition, a denser and less permeable coating can be obtained at this conditions. The corrosion resistance of phosphate coatings was superiorly improved using higher SDS concentration in the phosphating bath. J. Color Sci. Tech. 4(2010), 183-189© Institute for Color Science and Technology.