Progress in Color, Colorants and Coatings
Volume:4 Issue: 2, Summer 2011

Hydrophobically modified ethoxylated urethanes have been synthesized using polyethylene glycol, hexamethylene diisocyanate and cetyl alcohol. These types of thickeners are categorized as nonionic associative thickeners. The HEURs were prepared in two steps. Initially an ethoxylated urethane prepolymer was synthesized through a reaction between a polyethylene glycol (Mn=6000) and hexamethylene diisocyanate using the step growth polymerization technique, then modification was carried out by reaction of cetyl alcohol with the obtained prepolymer. HEURs were characterized using 1H NMR, FTIR and GPC techniques. The rheological properties of incorporated samples in different media proved the considerable thickening efficiency of the produced HEUR. Prog. Color Colorants Coat. 4(2011), 71-77. © Institute for Color Science and Technology. 1. Introduction Polymers that act as associative thickeners in water are of considerable industrial importance in paint coatings, personal care products, and oil industries because of their dramatic ability to modify rheological properties.Associative polymers are a group of thickeners used inwater-based latex systems to adjust and modify the rheology profiles. Also, they have wide applications in foods and pharmaceutical products in order to enhance oil recovery. Associative thickeners are water-soluble polymers onto which hydrophobic segments have been chemically attached, either to both ends or along the hydrophilic chain backbone. One of the most common types of associative thickeners is hydrophobically modified ethoxylated urethane (HEUR). They consist of chains with predominantly hydrophilic repeat units but also include a small fraction of hydrophobic sequences in the main chain or as its side groups [1-6]. Associative polymeric thickeners constitute a particular family of commercial organic rheology modifiers including naturally derived and synthetic compounds. HEURs belong to this class and are actually nonionic block copolymers. They can be telechelic or random block copolymers in linear or branched structures. The synthesis of modified PEO with linkers such as ethers, esters, urethanes or diurethanes was reported elsewhere [7-9]. Other research groups have worked on the structure of HEUR associative thickeners consisting of a hydrophilic segment like poly (ethylene glycol) and the hydrophobic hydrocarbon groups located at the ends of the hydrophilic segments [10-12]. At the same time, at high shear rates, high viscosity is necessary to produce a good film thickness. On the other hand, low viscosity help good flowing-out and leveling.

Acolor ink jet printing with improved water fastness property was produced using an acrylic/nano silver resin in the ink’s formulation. Introduced resin was a nano-composite (acrylic/nano silver) emulsion which was prepared via mini-emulsion polymerization of acrylate monomers in the presence of silver nano-particles. The water fastness properties of the prints were assessed by the ASTM /F2292-03 water fastness test standard. The results indicated that nano composite resin increased water fastness property of the printed paper and provided a water insoluble printed image on the paper. Furthermore, by introducing acrylic/nano-silver resin in the ink formulation, the hue of printed image was darker than plain acrylic resin. Prog. Color Colorants Coat. 4(2011), 79-83. © Institute for Color Science and Technology. 1. Introduction In the last two decades, the interest in ink-jet printing in industry has been increased; especially drop-on demand (DOD) ink jet printing system [1-6]. Ink jet printers are widely used in small business and home office applications due to their economic, low space demand, substrate independence, easy integration with existing production lines and high-quality color output. The two most popular types of DOD ink jet printers are thermal[1-3] and piezoelectric [4-5] printers. Thermal ink jet printer which is used in this research utilizes a number of resistors to eject droplets of ink through nozzles. In addition, the attention should be paid to the interaction of the ink and the print media [7]. Printing inks with ink jet printers are usually aqueous solutions and the print media are usually paper. Currently the highest possible dot resolution for commercial ink jet printers is 4800 dpi (with an ink dot diameter of less than 5.3 micron); however, the resolution of the printed image is controlled not only by the dot arrangement of the ink jet but also by the printing media. Three basic elements are important for ink jet printing quality which are as follows; printed head, ink formulation, and printing media. In case of ink formulation, dyes in some respects are superior to pigments for a number of well-known reasons. Pigment particles are significantly (about six order of magnitude) larger than dye molecules. Pigment based inks are, basically, finely ground particles suspended in a transfer medium. It is evident that, dye based inks will yield good color gamut and avoid jet.

Nano-crystalline TiO2 powders were synthesized by combustion method using metal nitrate solution and urea, glycine and citric acid fuels. Microwave irradiation was used as the heating source. X-ray diffraction, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy and Brunauer-Emmett-Teller surface area analysis were performed to characterize the prepared samples. X-ray diffraction patterns revealed that in the case of citric acid, calcination step is needed to obtain the desired phase. Moreover, the ratio of rutile/anatase phases varied from 25/75 to 0/100 as the fuel type was changed from urea to glycine and citric acid. The crystallite size of the synthesized samples was calculated by Scherrer’s formula which was revealed to be 8-15 nm. The highest surface area was observed when glycine fuel had been used. By Scanning Microscopy images, thick and thin flaky particles were detected in the case of citric acid and urea samples while a porous spongy morphology was seen when using glycine sample. The sample synthesized using urea is a better candidate for photo-catalytic functions due to a well-crystallized mixed crystalline structure (75% anatase - 25% rutile) which results in the synergistic effects of mixed anatase and rutile phases. Prog. Color Colorants Coat. 4(2011), 85-94. Institute for Color Science and Technology.

In many applications of color technology such as spectral color reproduction, it is of interest to represent the spectral data with lower dimensions than spectral space dimensions. It is more than half of a century that Principal Component Analysis (PCA) method has been applied to find the number of independent basis vectors of spectral dataset and representing spectral reflectance with lower dimensions. Recently, a new Interim Connection Space (ICS) named LabPQR was introduced, which contains three colorimetric dimensions and additional black metamer space. In the present study, the performance of PCA method in comparison to LabPQR was investigated for representation of spectral reflectance. For this end, different color data sets including Munsell, Glossy Munsell, GretagMacbethColorChecker, Esser test chart and two printing datasets were evaluated. The results show that, the performance of PCA and LabPQR, depends on the applied dataset. Based on spectral metrics such as RMS and GFC values, PCA has better results than LabPQR. Considering color difference errors, LabPQR is a better space than PCA even based on the color difference under second illuminant. Moreover, the dataset used for obtaining PQR vectors affects the representation results. For some datasets, the PQR components of the other sets perform better. However, obtaining PQR bases from the same data source, gives better results. It was found that Cohen and Kappauf-based methods performs better for all the datasets compared with unconstrained LabPQR method. Prog.

The water solubility kinetics of two synthesized mono azo naphthalimide based disperse dyestuffs in the presence of two different dispersing agents, namely Irgasol DAM and Lyoprint EV were investigated at various temperatures. An exponential equation was found to describe the dissolution process. Addition of Irgasol DAM and Lyoprint EV dispersing agents increased the dissolution rate of both synthesized dyestuffs. The dissolution of the methyl naphthalimide derived dyestuff in water as expected was more than the propylnaphthalimide derivative. The dyeing depth and the leveling properties were also higher for the methyl derivative than the propyl derivative.Prog.

Aseries of symmetrical multidentate Schiff base ligands 1–13 based on the N‚N-(4‚4-ethylenebiphenyl) bis-3-methoxysalicylideneimine with different range of color from yellow, orange, brown, cream to red has been synthesized, purified and characterized. These multidentate Schiff base ligands were used to prepare the galvanic cell of the type Ag|AgCl|NiCl2 for potentiometric determination of activity coefficients of NiCl2 in water-glucose mixtures at 298.15 K, and also to bind various transition metals as membrane sensors. Prog.

The interaction of Congo Red (CR) with a series of Alkyl trimethyl ammonium bromide (CnTAB), N-hexadecyl pyridinium bromide (CPB) and N-hexadecyl pyridinium chloride (CPC) were investigated using conductometry and UV-Vis spectroscopy technique. Job’s method was used to determine the stoichiometric ratio of dye and surfactant in ion pairs. The equilibrium constant and other thermodynamic parameters for the ion pair formation were calculated on the basis of a theoretical model using the data obtained by conductometry. It was found that an increase in temperature reduces the tendency for ion pair formation as equilibrium constants decrease with increasing temperature. The results showed that as the chain length of the CnTAB molecule in Dye/CnTAB systems was increased, the equilibrium constantswere significantly increased. Therefore, the short range as well as long range interactions is responsible for the formation of the ion pair. The importance of long range electrical forces is basically to bring the dye anion and the surfactant cation close enough to enable the action of short range interactions whose contribution represents the major part of the standard free energy change for the formation of the anionic dye–cationic surfactant ion pair. The reaction between the dye and the surfactants was revealed to be an enthalpy-driven reaction which is highly dependent on the temperature and the structures of both dye and the surfactant.