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Kardar P.,Institute for Colour Science and Technology
Pigment and Resin Technology | Year: 2016

Purpose - The purpose of this work was to prepare a catalyst-free microcapsules as self-healing agent in an automotive clearcoat to improve the scratch resistance of coatings. Design/methodology/approach - In this research, microcapsule with isophorone diisocyanate (IDPI) core and polyurethane shell were prepared and used in self-healing coatings. Microcapsules synthesised were characterised by thermal gravimeter and infrared spectra. The microcapsules were dispersed in an acrylic-melamine clearcoat, and the scratch resistance was evaluated. Findings - The triplex product and the formed polyurethane bonds were confirmed by thermal gravimeter and infrared spectra. In addition, smooth spherical particles with a diameter of 1.5 to 1.7 micronmeters were observed by a scanning electron microscope. The microcapsules dispersed in an acrylic-melamine clearcoat increased the scratch resistance of coatings. Also, the self-healing feature of those coatings was proved. Research limitations/implications - The size of microcapsules can affect its dispersion in the clearcoat and consequently affect the properties of the cured films. Practical implications - The self-healing coatings are interested for many industries such as building and automotive industries. The reported data can be used by the formulators working in the R&D departments. Social implications - Self-healing systems are considered as one of the smart coatings. Therefore, the developing of its knowledge can help to extend its usage to different applications. Originality/value - The application of microcapsules in the coating as healing agents is a great challenge, which has been hardly investigated so far. In the current research, the effect of polyurethane-IDPI microcapsules in an automotive clearcoat as a self-healing coating was investigated. © Emerald Group Publishing Limited.

Gharagozlou M.,Institute for Colour Science and Technology | Naghibi S.,Islamic Azad University at Shahreza
Materials Science in Semiconductor Processing | Year: 2015

Abstract Vitamin B12 (VB12) was applied to modify TiO2 nanoparticles (NPs) for the first time. TiO2 NPs were synthesized via sol-gel method. In the next step, as-synthesized NPs were modified by VB12. Fourier transform infrared (FTIR) spectroscopy demonstrated the formation of primary bonds between NPs and VB12. Thermogravimetric analysis (TGA) was also utilized to calculate the proportion of NPs to VB12. The percentage of VB12 gained was -20 wt%. The band gap value decreased from 3.27 (TiO2) to 3.20 eV and the photocatalytic degradation of Rhodamine B (RB) solution diluted in VB12-TiO2 NPs. The photoluminescence (PL) intensity increased from 3 to 6 cd. This is because the total pore volume raised about 18% by modifying TiO2 NPs; therefore, the photogenerated charge-carrier recombination rate increases by the VB12 loading. © 2015 Elsevier Ltd. All rights reserved.

Soleimani-Gorgani A.,Institute for Colour Science and Technology | Taylor J.A.,Colour Synthesis Solutions Ltd.
Coloration Technology | Year: 2011

A novel blue cationic reactive dye (dye1) based on an azo benzothiazole derivative and possessing an acrylamido reactive group, was synthesised and evaluated on dyeing Coloursafe modified nylon6.6 at optimum pH. Benzothiazole quaternary dye was chosen as a target as this is known to be very strong chromophically. Evaluation of the technical properties of dye1 showed that it fixed efficiently to nylon under acidic dyeing conditions. As it was necessary to prove that fixation occurs via a covalent bond, the dyeing properties of a non-reactive cationic dye, (CI Basic Blue41), on dyeing nylon6.6 at optimum pH were evaluated. CI Basic Blue41 was similar in structure to dye1 and would be capable of forming an ion-ion bond with the fibre. Evaluation of the technical properties of dye1 proved that, in all cases, its fixation efficiency and build-up properties were far better than that of CI Basic Blue41. © 2011 The Authors. Coloration Technology © 2011 Society of Dyers and Colourists.

Soleimani Gorgani A.,Institute for Colour Science and Technology | Shakib N.,Islamic Azad University at Tehran
Coloration Technology | Year: 2013

The current commercial application of ink-jet reactive inks to cotton fabrics requires pretreating with pad liquor containing a thickener, urea and alkali prior to printing. In this study, attempts have been made to develop a reactive ink-jet print in a single-phase process by adding an organic salt to the ink formulation and hence removing the need to pretreat fabrics. This approach utilises inks containing both a reactive dye, in this case Procion Red H-E3B, and an organic salt such as sodium formate, sodium acetate, sodium propionate or tri-sodium citrate. The behaviour of a novel reactive ink formulation for ink-jet printing on to cotton fabric was evaluated at different pH vlaues. The results at optimum pH indicated that printed non-pretreated fabrics with ink containing organic salts exhibited a higher level of reactive dye fixation than printed pretreated fabric containing no organic salt ink. The yielded prints demonstrate excellent colour fastness to washing and dry/wet crocking properties. The light fastness of the printed fabrics was improved by adding an organic salt to the ink formulation. © 2013 The Authors. Coloration Technology © 2013 Society of Dyers and Colourists.

Hajy Alimohammadi M.,Tarbiat Modares University | Javadian S.,Tarbiat Modares University | Gharibi H.,Tarbiat Modares University | Tehrani-Bagha A.R.,Institute for Colour Science and Technology | And 2 more authors.
Journal of Chemical Thermodynamics | Year: 2012

The aggregation behavior of the cationic Gemini surfactants C mH2m+1N(CH3) 2(CH2)S (CH3)2 N C mH2m+1,2Br- with m = 12, 14 and s = 2, 4 were studied by performing surface tension, electrical conductivity, pulsed field gradient nuclear magnetic resonance (PFG-NMR), and cyclic voltammetry (CV) measurements over the temperature range 298 K to 323 K. The critical micelle concentration (CMC), surface excess (max), mean molecular surface area (Amin), degree of counter ion dissociation (α), and the thermodynamic parameters of micellization were determined from the surface tension and conductance data. An enthalpy-entropy compensation effect was observed and all the plots of enthalpy-entropy compensation exhibit excellent linearity. The micellar self-diffusion coefficients (Dm) and intermicellar interaction parameters (kd) were obtained from the PFG-NMR and CV measurements. These results are discussed in terms of the intermicellar interactions, the effects of the chain and spacer lengths on the micellar surface charge density, and the phase transition between spherical and rod geometries. The intermicellar interaction parameters were found to decrease slightly with increasing temperature for 14-4-14, which suggests that the micellar surface charge density decreases with increasing temperature. The mean values of the hydrodynamic radius, Rh, and the aggregation number, Nagg, of the Gemini surfactants' m-4-m micelles were calculated from the micellar self-diffusion coefficient. Moreover, the Nagg values were calculated theoretically. The experimental values of Nagg increase with increases in the chain length and are in good agreement with both previous results and our theoretical results. © 2011 Elsevier Ltd. All rights reserved.

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