JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2009 | Volume:2 | Issue:4|Papers Count:9

Nowadays production of water- base resins by emulsion polymerization method is more interested because of the importance of environmental considerations. Reaction calorimetry is a powerful means for the monitoring, process control and research for the reactions kinetic. Calorimetry is able to estimate the heat of reaction and conversion using a few on-line information from the process (e.g. temperature data). Finding a useful mathematical model of process and accurate identification of its parameters is an important issue in this technique to achieve the accurate robust results. Since this models have various and complicated terms, it is important to specify the importance of each term in order to reach the simple model that had an acceptable performance. In this work, calorimetry and its applications are introduced at first, and then a reaction calorimetric model is produced for laboratory reactor of polymerization based on energy balance. Finally, this model is applied in production of poly butyl acrylate in an emulsion polymerization reactor and model accuracy is verified by the experimental data.

Windows with tinted glazing transmit the light in various colors. They can prevent from transmission of a large amount of sun's spectrum and work as a sun-control. To investigate this effect, nine Persian vernacular "Orsi"s have been chosen as case studies and the window geometry and glazing color combination of them were studied and drawn. Then the transmission from four colors of their glazings has been measured by the use of spectrophotometer and the amount of energy and daylight passing through the whole window has been calculated. The results show that the energy transmittance of the Orsi is approximately one third as much as the amounts of transmitted energy from standard float glass, if the inward emission from the glazing surface is prevented. Also some applicable methods have been suggested for the optimized light transmission for the cooling dominated regions.

The present study was carried out to investigate the potential of hardened paste of Portland cement (HPPC) as a low-cost adsorbent for the removal of Basic Red 46 from contaminated water by using batch adsorption studies. In present study HPPC has been selected as adsorbent because of the main advantages such as no sludge production, abundant availability and low-cost material. The effect of contact time, adsorbent dosage, pH, temperature and adsorbent particle size were examined in the adsorption process with HPPC. Results showed that removal of BR46 increased over 80 percent with increasing adsorbent dosage, temperature, contact time, pH and adsorbent particle size decreasing. Therefore, it may be concluded that HPPC was an efficient and economical adsorbent.

Anti-corrosive pigments are added to coatings to improve the coating resistance against corrosion. Electrochemical impedance spectroscopy (EIS) and salt spray are two common methods for evaluation of the anticorrosion performance of coatings. In this study, a mixture of aluminum flake and micaceous iron oxide pigments with different proportions were employed in epoxy based coatings and their corrosion resistances were studied with EIS and salt spray tests. The alignment of the pigments was evaluated with a scanning electron microscope (SEM). The results indicated that the alignment of the pigments is an important factor in anti-corrosive performance of the coatings and although both of the pigments individually have a considerable effect on the improvement of the anti-corrosive performance of the coatings, but when a mixture of the pigments was employed the results were better than each of them singly. The best corrosion resistance was observed in the sample which the ratio of the aluminum pigment to MIO pigment was 9 to 1.

The purpose of this work is to investigate the performance of nanofiltration membrane for separation of acid dyes. Nanomembranes have been developed by UV photografting technique. Acrylic acid was used for the modification of polysulfone ultrafiltration membrane that prepared via wet phase inversion method. The modified membrane characteristics were measured and the most suitable nanofiltration membrane was chosen for treatment of dye effluents. It was observed that selected UV-photografted membrane showed acceptable performance both in terms of flux and rejection. Acid dye retention was between 86 and 99.7% and hydraulic permeability was 7.6 L/m2 h bar. It was observed that increase of either dye molecular weight or dye charge leads to improve of dye separation that confirm the effectiveness of sieving and Donnan repulsion mechanism, respectively, in nanofiltration membranes. The influence of pH on the performance of membrane in terms of permeability and dye retention was established. It was found that by changing the pH (3, 6 and 9), membrane surface and dye have different behaviors that influence the final performance of selected nanomembrane. According to results, pH=9 of dye bath provides the best condition for dye separation.

Polyurethane thickeners are important member of associative thickeners group. The structures of these materials consist of a hydrophilic segment with hydrophobic end segments. Firstly, the effect of polyethylene glycol molecular weight was studied to investigate the influence of hydrophilic segment on performance of polyurethane thickeners. Then, the optimum molar ratio of OH/NCO was obtained for synthesizing of the thickeners.  Finally the model thickener was prepared with the suitable structure. The performance of the synthesized associative thickener was studied in water and a water-based resin. The associative thickener model showed very good thickening efficiency.

Corrosion inhibition effect of cationic surfactant DTAB (dodecyl three methyl ammonium bromide) on low carbon steel in 1M HCl was studied using weight loss method. Inhibition efficiency increased with the increase of surfactant concentration. The adsorption of the surfactant on the steel surface forms a barrier layer on the surface and it was the main reason of its inhibition effect. Effect of three long chain alcohols C7OH (1-heptanol), C12OH (1-dodecanol), C15OH (1-pentanol) on inhibition efficiency of DTAB was studied considering chain length compatibility. Also synergistic effect between surfactant and chloride ions in 1M HCl was investigated with the presence of different concentration of NaCl. The inhibition efficiency increased with the increase of NaCl concentration and reached the maximum value near 0.1 M. This composite inhibitor system containing cationic surfactant and chloride ions was efficient and low-cast for steel corrosion inhibition in HCl medium.