PROGRESS IN COLOR, COLORANTS AND COATINGS
Year:2009 | Volume:2 | Issue:2|Papers Count:7

uniform nanostructure coating of TiO2 was prepared on 316L stainless steel by sol-gel method using Tetra-n-Butyle Titanat (TBT) as alkoxide material. 316L specimens were coated with the mentioned sol by dip coating method. The influences of preparation condition, pH of sol on TiO2 nanostructure coating were investigated. Their structural properties were examined at various calcination temperatures. The effect of drying cycle and solvent bath on crack reduction and the influence of withdrawal speed on thickness of the film was evaluated. Choosing of alcohol as a drying atmosphere could hinder the cracks formation. 400oC was desirable temperature to obtain nanoparticles from anatase phase. At this temperature it was found that TiO2 films exhibited a uniform anatase structure with particle size of about 15 nm.

In general, the evaluation of automotive coatings appearances favors (is considered preferentially) more than chemical and physical properties. Therefore, its improvement is most required. Studying appearance by means of QMS-BP technique, in which it measures some of the most important coating appearance factors, such as: the specular gloss, distinctness of image (DOI) and orange peel. In this article the influence of variation in the primer properties, such as thickness, roughness and gloss on the appearance of final coating system for two different primer types was studied. Results showed that increase in specular gloss would cause the intensification of NAP (Niveau d’Aspect Peinture) values, while increase in thickness and roughness would decrease it.

Today, natural colorants are emerging globally due to the fact that they are safer and more environmentally-friendly. Natural dyes have been employed in dyeing Persian carpet piles for many years. In this study, the dried Achillea was used for dyeing wool yarns. The Iranian wool yarn was scoured, mordanted using Cu, Sn, Al salts and then dyed with different amounts of dried Achillea powder. Taguchi statistical method was employed to find theeffective factors and results of the planned experiments, in order to optimize the dyeing factors. A L9 orthogonal array (four factors in three levels) was employed to evaluate the effects of different parameters in dyeing process. The colorimetric properties of the dyed yarns were evaluated in CIELAB system. Achillea found to have good agronomic potential as a natural dye in Iran. Dyeing with Achillea in conjunction with metal mordants showed enhancement in its fastness properties. Therefore it shows commercial capability for dyeing of wool yarns used as Persian carpet piles.

To reproduce an image, it is necessary to map out of gamut colors of the image to destination gamut. It is clear that the best color gamut mapping introduces the perceptually closest image to the original one. In this study, a new color gamut mapping is purposed by the aid of Genetic Algorithm (GA). The color difference between the original and mapped images based on SLAB formula was chosen as fitness function. The proposed algorithm was applied in CIELAB color space and special genetic operators were developed to meet the aim of gamut mapping. To increase the rate of convergence and have a faster algorithm, one of the initial population chromosomes can be obtained from the result of clipping method. The results showed that the new method introduces smaller color difference between the reproduced and original images in comparison with the common clipping method. The other advantage of the genetic color gamut mapping is that any new criterion for color image difference can be easily used as a fitness function. In addition, by this method the final colors are not restricted to the gamut surface and they may be included into the gamut.

Ultrasound-assisted extraction (UAE) was evaluated as a simpler and more effective alternative to conventional extraction methods for the isolation of curcuminoids from turmeric plant rhizomes. The turmeric samples were extracted under indirect sonication in an ultrasonic bath, and compared with the conventional methods. It was found that the yield of ultrasound-assisted extraction was approximately three times higher than the traditional method. Taguchi experimental design was employed to study the effect of pH, solvent composition and extraction time on the yield of extracted curcuminoids from turmeric. The optimum combination was determined as a solvent composition ethanol/water 70:30 (V: V), pH of 3 and an ultrasoundassisted extraction time of 15 min. The extracts were analyzed using high performance liquid chromatography (HPLC).

The corrosion inhibition performance of acetylacetonate complexes of zinc(II), manganese(II), cobalt(II) and copper(II) on the mild steel substrate in 1M H3PO4 was studied using DC polarization. It was seen that the mentioned complexes decreased corrosion rate of mild steel in phosphoric acid media due to the adsorption on metal surface. The potential of mild steel shifted toward more active potentials. The cathodic Tafel slopes increased showing that acetylacetonate complexes are cathodic inhibitors. Presence of chloride ions in the electrolyte enhanced inhibition performance of acetylacetonate complexes due to synergism. Chloride ions provided by HCl had a better performance compared to NaCl.

In this research, several series of triarylmethane dyes containing one or more terminal methoxy substituents with a variable tertiary amino groups have been used. These dyes have been applied to different substrates by using various methods including transfer printing and then their fastness properties were measured. These dyes shows exceptionally high light fastness (6- 7) on acid modified polyacrylonitrile fibres.