JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2010 | Volume:3 | Issue:4|Papers Count:11

This work reports the surface treatment of calcium carbonate using a silane coupling agent. To this end, a direct method was used in which different parameters including temperature, pH as well as hydrolysis method were studied. Sample characterization was performed utilizing FT-IR spectroscopy, thermal gravimetric analysis and turbidimetry. It was revealed that the coupling agent is unable to chemically attach to the surface unless a pretreatment with phosphoric acid was conducted. The amount of silane analyzed in the presence of this acid was measured to be 1.67 wt% in which 1.06 wt% was found physically bonded to the surface, while 0.61 wt% remained chemically attached. The dispersion behavior of the treated particles was studied in water and toluene using turbidimetric analysis.

In this study reactive modification of polypropylene (PP) and talc composites by powder coating waste (PCW) on a corotating twin screw extruder was studied and morphology and mechanical properties were evaluated. The morphological study of the composites showed that the use of powder coating waste improved the dispersion of talc in PP and leads to orientation of talc plates in the flow direction of the injection mold. The PP-talc composite shows high loss of mechanical properties with thermal aging in comparison with PP-talc composites which have powder coating waste (PCW). PP + Talc (20%) + PCW (20%) sample shows good resistance against to thermal aging. The improvement of thermal stability of PPTalc- PCW composites can be the result of adhering of epoxy-polyester resin of powder coating waste on talc plates and also to metals impurities. The cured epoxy –polyester resin particles were played the role of stress concentrators and decreased mechanical properties such as impact strength.

Photo-yellowing is one of the most important drawbacks for wool fabrics. Different methods have been used for decreasing the yellowing rate. One of them is covering the wool surface by ultraviolet absorbers. In this study wool fabric was treated with nano titanium dioxide and butane tetra carboxylic acid, cured and then irradiated for three hours. Yellowness variations of irradiated samples were detected by a spectrophotometer. The result of this study showed that titanium dioxide was a very suitable UV absorber and its effect depends on concentration.

In this work, extraction of a food colorant from red beet and evaluation of its stability by using UV-Vis spectrophotometry was studied. After the step of preparation of red beets, different methods of extraction (solid- liquid extraction and juicing) and effective process parameters such as pH, temperature, light and darkness were evaluated. The extraction of pigment by a juicing method is better than other and it has the most stability at temperatures less than 25°C, pH = 5 and darkness. Due to the specification of red beet pigment it has considerable potential for use in the food industry particularly in cold food products.

This paper reports the luminescence properties and colorimetry of Eu2+ activated SrMgAl2SiO7 pigments prepared via a solgel method. Effect of calcination time on pigment properties has been characterized by X-ray diffraction (XRD) and spectrophotometer. Furthermore, microstructure has been studied by Scanning Electron Microscope (SEM). By using scherrer equation, it was realized that the crystallite size of the synthesized powder increases as time of calcination increases and crystallite size of final product was estimated 30-40 nm. Investigation of luminescence properties, illustrated that Eudoped nanocrystals when exposed to 260 nm UV light, showed a uniform and relatively pure blue color that is related to the 4f7 ® 4f65d1 transition of Eu2+ in the phosphor lattice with color coordination (x = 0.187, y = 0.077). Furthermore, it was found that the color purity of the pigment increases as calcinations time increases.

A monoazo disperse dye based on naphthalimide was synthesized by using 3-(6-amino-1,3-dioxo-1H-benzo[de]isoquinoline- 2(3H)-yl) propanoic acid as a diazo component and N-ethyl-N-hydroxyethyl aniline as a coupling component. The synthesized dye was purified and characterized by FTIR, 1HNMR, DSC and UV-Vis spectroscopic techniques. The spectrophotometric characteristics of the dye were investigated in various solvents. The results showed that the synthesized dye has a positive solvatochromism. Wavelength of maximum absorption and molar extinction coefficient in acetone were 524.3 nm and 34125 l mol-1cm-1, respectively. The synthesized dye was applied to nylon, polyester and acrylic fibers and the effects of temperature, time and build up were investigated. The results showed that the synthesized dye had a good build up on nylon which gave excellent wash and rubbing fastnesses and fair light fastness.

In this study, cellulosic cotton fabrics were treated with different concentrations of nano aluminum hydroxide (ATH) dispertions. The optimum coating method of nano particles and the thermal and color characteristics of cellulosic fabrics were studied using SEM, TGA, DSC and reflectance spectrophotometry and the results were discussed. It was concluded that the ATH could be considered as a suitable envirmentaly friendly fire retardant for cotton. The results also show that the coating has only a small (if any) effect on the color coordinate values of the treated fabric.