Optimization of the Composition of Silicone Enamel by the Taguchi Method Using Surfactants Obtained from Oil Refining Waste

The aim of this work is to optimize the composition of a two-component silicone enamel consisting of an aluminum pigment and a polyphenylsiloxane polymer to obtain the maximum dispersion of the pigment in the coating. The following products were used as surfactants: AS-1, PEPA, and Telaz. To assess the effect of surfactants on the dispersion of the pigment, computer-optical microscopy was used. The results of the studies showed that all the studied surfactants cause an improvement in the dispersion of the pigment. According to the degree of influence on the dispersion of the pigment, surfactants can be arranged in a row: PEPA > Telaz > AS-1. When the PEPA content in the enamel is 0.25 g/dm3, a decrease in the diameter of the pigment particles by 46% (from 26 to 14 microns) is recorded, with an increase in their specific amount by 2 times (from 258 to 550 pcs). Optimal enamel compositions allow a reduction in the corrosion rate by 11 times (from 0.6 to 0.053 mm/year) and improvement to the decorative properties of coatings (roughness, gloss, etc.). The effectiveness of the AS-1 product (obtained from oil refining waste) as a dispersant additive in silicone enamel has been proven.

Thermal insulation coating based on water-based polymer dispersion

For Russia, due to its long winter period, improvement of thermal insulation properties of envelope structures by applying thermal insulation paint and varnish coating to its inner surface is considered perspective. Thermal insulation properties of such coatings are provided by adding aluminosilicate microspheres and aluminum pigment to their composition. This study was focused on defining the effect of hollow aluminosilicate microspheres and aluminum pigment on the paint thermal insulation coating based on water-based polymer dispersion and on its optimum filling ratio. The optimum filling ratio was determined using the method of critical pigment volume concentration (CPVC). The optimum filling ratio was found equal to 55%.

Coloration of aluminum pigment using SiO2 and γ-glycidoxypropyltrimethoxysilane with dichlorotriazine reactive dye

Purpose The purpose of this paper is to colour aluminium pigment to the highest chroma using SiO2 and organic silane with dichlorotriazine reactive dye and investigate its reaction mechanism, chemical stability and thermal properties to improve its applicability in surface coatings. Design/methodology/approach Aluminium pigment was encapsulated by the catalysed sol-gel method using SiO2, followed by modification with γ-glycidoxypropyltrimethoxysilane (GPTMS). Purified reactive dye (1-Amino-4-[3-(4,6-dichlorotriazin-2-ylamino)-4-sulfophenylamino]anthraquinone-2-sulfonic acid (X-BR)) was covalently immobilized onto modified SiO2 to obtain coloured aluminium pigment. The reaction mechanism, chemical stability and thermophysical properties were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope and thermogravimetric analyses (TGA). Findings The results showed that X-BR was covalently attached to modified Al/SiO2 with maximum colour grafting of 95 per cent when the dosage of GPTMS and X-BR per weight of modified Al/SiO2 was 25 and 15 per cent, respectively, at pH 8.5 and a temperature of 40°C. The coloured aluminium pigment had good chemical stability with excellent anti-migration properties in many solvents. Research limitations/implications The organic silane used required a careful control of pH to ensure maximum colour grafting efficiency meanwhile other silanes with amine groups could also be used effectively with different kinds of colorants besides reactive dyes. Practical implications The method used is less cumbersome and provides a simple route to preparing coloured aluminium pigment. Originality/value The use of organic-inorganic SiO2/γ- GPTMS with purified reactive dye to covalently colour aluminium pigment to the highest chroma is novel and will help advance the frontiers of knowledge on coloration of aluminium pigments.