JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2008 | Volume:2 | Issue:3|Papers Count:7

Electrically conductive coatings are mainly required for static charge dissipation and electromagnetic/radio frequency interference (EMI/RFI) shielding. Electrically conductive coatings are prepared by the incorporation of the metallic pigments/graphite or carbon black onto the binder. In the present investigation, a study on the correlation between electrical, percolation threshold, filler volume concentration and some other physical and mechanical properties for graphite filled epoxy coating was carried out through an examination of the filler concentration dependence of the volume resistivity and other mechanical properties. The impact strength of epoxy resin filled with graphite was also investigated. A decrease in impact strength with an increase in filler content was observed. It is found that there are two critical threshold, in plot of electrical resistivity v.s. filler volume concentration. The adhesion of the filled resin to substrate was also determined by pull-off test. A decrease in the adhesion to substrate with an increase in filler content was observed in Then to find out the correlation between filler concentration and viscoelastic behavior of the system tensile test carried out. Then for expand a theory that can explain the transfer between insulator-semiconductor and semiconductor-conductor behavior of graphite filled system images was gived by SEM and optical microscopy and also oil absorption (for determine CPVC) test carried out. All data show that formation of internal network by graphite particles and particle by particle contact of them is the reason of formation a conductive network in epoxy system.

In this study a pad-steam process for alkali treatment of polyester/cotton fabric has been developed and the effect of alkali on polyester/cotton fabric has been investigated. Caustic soda has been used as a main chemical for alkaline hydrolysis. In order to reach the required percentage of weight reduction without damaging the fiber structure and optimizing the chemicals and treatment time, certain auxiliary product such as quaternary ammonium salt which can be considered as a hydrolysis accelerating agent, besides caustic has been used. Some characteristics of alkali-treated fabric such as tenacity, crease recovery angle, bending length and water absorbency have been measured.  Finally the best process, giving the best result as far as water absorbency, handle with the lowest damaging to the physicochemical properties of the fabric has been evaluated.

In this paper, Li2Co5O10 was synthesized by a solid reaction and controlling nucleation and crystal growth time. The enamels adherence greatly increased by adding this powder as mill addition. The influence of this additive was studied by investigating chemical composition and microstructure of enamel-steel interface by using scanning electron microscopic (SEM). The distribution of Co, Fe and Si was also studied by point and line scan analysis. The results revealed that the superfine powder can change the composition and microstructure of the interface and promote the adherence of enamel to steel. Adherence of samples was examined by standard test method ASTM B916 and the optimum amount of the additive was observed to be 1.8 %wt.

In this paper, the synthesis of methyl metacrylate-butylacrylate copolymer used in water-based paints by emulsion polymerization was investigated. The synthesize planning in the case of selection of the type and ratio of the monomers, was based on the chemical structure analysis of an imported industrial resin and using the other characterization of referred resin like as particle size distribution and glass transition temperature measurement.  In the emulsion polymerization, to attain the desired final properties, the whole of system include the type and the quantity of the applied monomers and emulsifiers, reaction temperature follow with the molecular weight and Tg of produced polymer as well as the particle size distribution must be controlled.  In this research, after different synthesize, the results of the different analysis methods proved the successfulness synthesize.

This study was carried out to improve nylon 6 fiber structure and to study different properties including dyeability, moisture absorption, surface changes and color fastness using lipase enzyme. For this purpose, nylon 6 fabrics were first treated with different concentrations of lipase enzyme in water solution including 1, 2, 4 and 6% o.w.f. The dyeing process was then carried out on the treated fabrics with disperse and acid dyes. The results of color measurement on enzyme treated/dyed with these two class of dyes showed that the L* of enzyme treated samples decreased and more decrease in L* was observed with an increase in the enzyme percentage. The results of acid and disperse dyes exhaustion on treated fibers showed higher absorption of dyes on fibers. Tensile strength studies indicated that enzymatic processing decreases tenacity, modulus and elongation at break of nylon 6 fabric. Thermal studies of enzyme treated sample did not show significant changes on orientation of fiber after enzyme treatment before the temperature of 300oC. But increase in heating temperature of the sample to the range of 300-400oC showed considerable decrease in thermal degradation temperature of enzyme treated sample compared to non-treated one. The wash and light fastnesses properties of samples were measured according to ISO 105-CO5 and Daylight ISO 105-BO1, respectively. Enzyme treatment before dyeing process improves wash and light fastnesses of samples which could be the result of dyes penetration into the fibers.

In this research, color anodizing of Ti-6Al-4V alloy was done in phosphoric acid solution with concentration of 0.4 M at different voltages (10-120V) with a DC power supply. Structure of oxide layer was surveyed by X-ray diffraction. The structure of anodized layer in phosphoric acid solution with all applied voltages is consist of Ti from substrate and TiO2 (anatase). Due to change of anodizing voltages, the structure and color of anodized layer do not change. Color properties of barrier anodic oxide film has studied with DE CIE L*a*b 1976 equation. Color stability of anodized samples was survayed by immersion in the Ringer's + 150 mM H2O2 solution. It can be seen that the most stable color is the sample anodized in 50V with DE=1.57 and the sample anodized in 80V is the unstable color with DE=1.57. The maximum lightness of color is related to 20V sample and the minimum lightness is related to 50V sample.

This study illustrates the production of high-pure anthraquinone from crude anthracene that is used as the base of anthraquinone dyes. This valuable product has not been produced in Iran, and as a result of presence of carpet and textile industries in this country, it would be necessary to make such a product. In this research all anthraquinone production methods, which include the production anthraquinone was studied. It is concluded that the best method is the use of anthracene as raw material, which after purification, should be oxidized by chromium trioxide to anthrquinone. Finally, the production of anthraquinone with high purity was tried. Also high-pure anthracene was produced as a valuable intermediate product from anthracene with the purity about %40.