JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2014 | Volume:7 | Issue:4|Papers Count:11

This study was aimed to investigate the effects of wood surface quality on adhesion strength of some clear coats. The wood samples were prepared from three species consist of walnut (Juglans regia), beech (Fagus orientalis) and sycamore (Platanus orientalis) which had 8% moisture content and were 300×100×10 mm in diameter. Samples were sanded with 100-160-180 and 100-160-360 grit size. Samples’ surface were covered with a clear coat in two separate process which was sealer-clear and sealer-clear & acid catalyzed lacquer. The results showed the surface roughness had significant effect on the adhesion strength of coating on the wood surface. The highest adhesion strength was obtained in samples that were sanded by 180 grit sandpaper in all three species. Finally, the highest adhesion of coating samples was found in sycamore samples finished with sealer-clear & acid catalyzed coat and sanded by 180 grit sandpaper.

In this study, wood containing printing paper was coated by latex with nanoclay and PCC loading for printing improvement at two and four levels, respectively. Scanning electron microscope images confirm partial filling and covering of cavities on the surface of base paper by the coating. Rheological behavior and viscosity of two types of color pigment are quite different and PCC would be better because of lower preparation costs. Results showed that the printing paper coating reduced roughness, porosity and water absorption, so printability and dimensional stability of paper would improve in web offset printing. There is significant difference between gloss and print density of coated paper and control at a=0.01. Apparently, coated paper with PCC showed better print quality than the control. Printing with IGT tester revealed that no picking occurred on coated paper contrary to the control that could be critical for print quality and linting problem on the press rolls.

Self doped polyaniline-clay nanocomposite was synthesized via copolymerization of aniline and 3-amino benzene sulfonic acid with ammonium peroxydisulfate in ScCO2 in the presence of Cloisite 30B nano-clay. Self doped polyaniline was sunthesized in the same procedure. The synthesized self doped polyaniline and self doped polyaniline-clay nanocomposite were added into the epoxy and zinc rich epoxy coatings, separately. Corrosion protective properties of synthesized products were analyzed via determination of water vapor transmission and determining free corrosion potential (Ecorr.) and electrochemical impedance spectroscopy. Results revealed that the best protective performances were achieved by using self doped polyaniline-clay nanocomposite.

One of the most ZnO applications is in paint industry as pigment, specially in white thermal control coatings used on satellites. In this paper, the effects of the process variables on ZnO size and morphology is studied. The experiments were carried out based on the design of experiments using Taguchi method. The parameters were zinc nitrate solution concentration, potassium hydroxide solution concentration, the pH of initial solution, temperature and reaction time. The ZnO structures were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The analysis of variance showed that among the parameters studied, temperature and potassium hydroxide solution concentration have the most significant effects on ZnO properties and amount of produced powder. The zinc nitrate solution concentraton should be always lower than potassium hydroxide solution concentration. The optimum sample was prepared according to the best levels of each factor, 1m zinc nitrate solution, 4m potassium hydroxide solution, the pH equals to 12.5, temperature of 170oC and reaction time of 14 h. The powder yield from a 100 mL autoclave was about 3.1 g and its purity was about 97%. The yield of ZnO powder by hydrothermal method was 94%.

In this research, the effect of electropolishing treatment on the roughness and luminosity of aluminum foil and quality of blue color after dyeing on anodized film was investigated. For this purpose, the effect of solution composition (Perchloric acid: ethanol with volume ratio 1:5, 1:6 and 1:7), voltage (5-25 volt) and electropolishing duration (2-9 min) were studied. Atomic force microscopy (AFM) and Photoshop were used to study on surface coating. The AFM results showed that electropolishing under optimal conditions (2 min, 15 volt, Perchloric: ethanol with volume ratio 1:5) have good effect on surface quality, so that Rz value for anodized sample after dyeing of 34.35 nm were reduced to 1.50 nm by electropolishing pretreatment.

Current study tries to explore the possibility of acceleration in recognition and remedy process of heart disease and continues electrocardiogram signal acquisition. The electrical resistance shows a range around 0.1  W/sq, which sounds quite proper for ECG signal acquisition. The quality of acquired signal from printed sensors in two forms of square and circle compared with the standard Ag/Agcl electrode using commercial electrocardiogram from derivative II in sitting situation. The comparison of acquired ECG signal data led to the consideration of small circular fabric sensor for better performance and the least disturbance regarding to homogeneity and attenuation in electric field scattering.

Illumination/observation geometries have an effective role in visual assessments of geometric attributes such as gloss, distinctness of image, orange peel of automotive paints. In this research, gloss, distinctness of image and orange peel of an automotive paint were investigated under three different illumination/observation conditions namely, directional, diffuse and combination of the two (i.e. directional plus diffuse) usually achieved in a standard light cabinet. For each condition, the visual assessments were carried out at various viewing geometries. For this purpose, three scales, i.e. specular gloss, distinctness of image and orange peel were prepared for a black automotive finish. These scales were separately evaluated visually under various illumination/viewing conditions by a panel of 8 observers. The statistical parameters showed that the visual perception of gloss under directional lighting/viewing geometry of 38o/7o along with visual perception of distinctness of image and orange peel observed in a standard light cabinet with a 45o /0o geometry gave the most reasonable results as the performance of observers in such set ups induced average stress values of less than 8%.

Illumination/observation geometries have an effective role in visual assessments of geometric attributes such as gloss, distinctness of image, orange peel of automotive paints. In this research, gloss, distinctness of image and orange peel of an automotive paint were investigated under three different illumination/observation conditions namely, directional, diffuse and combination of the two (i.e. directional plus diffuse) usually achieved in a standard light cabinet. For each condition, the visual assessments were carried out at various viewing geometries. For this purpose, three scales, i.e. specular gloss, distinctness of image and orange peel were prepared for a black automotive finish. These scales were separately evaluated visually under various illumination/viewing conditions by a panel of 8 observers. The statistical parameters showed that the visual perception of gloss under directional lighting/viewing geometry of 38º/7 º along with visual perception of distinctness of image and orange peel observed in a standard light cabinet with a 45º /0º geometry gave the most reasonable results as the performance of observers in such set ups induced average stress values of less than 8%.

Polypropylene is a thermoplastic polymer which is not a paintable polymer. Some intrinsic characteristics such as hydrophobicity, non polar structure, high crystallinity and steric orderness make it difficult for a polymeric coating to adhere on the polypropylene surface. To overcome such disadvantage, a rout was designed in which nano organic particles based on polyesteramide and nano inorganic particles (nanoclay) were used to modify polypropylene. Dendritic polymers possess a micellar core-shell spherical structure that are covalently bonded together and are able to be used as dispersing agent for nanoclay in polymeric matrices. The obtained samples underwent various experiments to assess the modification process and its effect on the physical, mechanical and structural properties. Thermal, morphological and rheometrical experiments revealed that different structures with intercalate and exfoliated order have been obtained. Mechanical tests also declared that the modification process has been useful. Finally measurements of contact angle cleared that in samples containing inorganic and organic nano particles, paintability has been improved.