It was found that modification of the surface of nickel-plated hollow glass microspheres with N-oxide-Cl-alkyldimethylamine causes overcharging of their surface and as a result improves wetting of particles of the solid phase with acrylic latex water-emulsion paint. The conductive paint coatings are characterized by high electrical conductivity. The paint developed can be used to protect people and equipment from electromagnetic radiation.Conductive paint, similar to ordinary pigmented paint systems, is a suspension of a solid in a binder. Carbon black, graphite, industrial carbon, metal powders (silver, nickel, copper, etc.), and plated particles -core pigments (French patent application No. 2621328) are usually used as conductive fillers in paints [1,2]. Thermoplastic resins (epoxy, phenol-formaldehyde, polyurethane, acrylic, organosilicon) or water-emulsion latex dispersions are used as film-forming binders.Hollow glass microspheres coated with a layer of metal could be of special interest for fabricating conductive materials [3]. They do not settle in the polymer binder; they reduce the threshold concentration of filler at which the polymer binder acquires conductive properties; they significantly reduce the cost of fillers made from precious metals. In fabricating composite materials, it is necessary to take into consideration not only the nature of the filler and polymer but also their reaction on the interface, since the physicochemical properties and quality of filled materials are determined by adsorption of the polymer on the surface of the solid phase [4].We investigated the possibility of creating conductive paints based on nickel-plated glass microspheres for applying coatings on different surfaces.An acrylic latex-based water-emulsion paint was used as the binder and nickel-plated hollow glass microspheres (NHGM) with a bulk density of 0.5 -0.7 g/cm 3 were used as the conductive filler [3].The physicomechanical indexes of these conductive paints and the coatings made from them were determined by standard methods (viscosity according to GOST 8420-74, drying time according to GOST 19007-73, hardness with the TML pendulum instrument according to GOST 5233-89, and adhesion and compatibility with the painted surface acceding to GOST 15140-78 and GOST 29318-22, respectively).The liquid compositions were prepared by mixing 5 -20% 2 NHGS with 80 -95% binder. The finished paints were applied by pouring on wood, concrete, and brick. The viscosity of the paint according to a VZ-4 viscometer at 20 ± 2°C was 80 sec and the drying time of the coatings at room temperature was 2 -2.5 h.The electric resistance of the coatings was measured with a combined ShCh-4300 instrument. The resistivity of the coatings was calculated with the equation:where r v is the resistivity, W × cm; R is the overall resistance of the coating, W; h is the width of the coating, cm; t is the thickness of the coating, cm; l is the distance between electrodes, cm. The thickness of the conductive coating was measured with a MT-41NTs magnetic th...
It is established that nickel-plated hollow glass microspheres can be used as conducting and heat-insulating fillers for paintwork material serving as a basis for coatings with low resistivity and good heat-insulating properties.One of the most important properties of conducting paintwork materials (PM) is their ability for conducting electric current, which makes it possible sometimes to use them instead of metals. Conducting fillers usually applied in PM are soot, graphite, technical carbon, as well as metal powders [1]. PMs based on metal powders have higher conductivity than, for instance, PMs with a carbon filler [2]. However, metal fillers have an essential disadvantage: their high sedimentation rate causes stratification of paint and a nonuniform distribution of the filler in the paint coat layer.Therefore, metallized core pigments, i.e., particles of silica, mica, or inorganic fiber coated with a metal layer, are of obvious interest for the production of conducting paint materials. Core pigments have the following advantages over metal powders:-they have no sedimentation in a polymer binder; -they decrease the threshold concentration of filler under which the polymer binder acquires conducting properties;-they are significantly less expensive than fillers made of precious metals.Spherical hollow glass particles covered with a metal layer are of special interest as core pigments. Their industrial production has become possible as a consequence of advances in plasma technology and engineering [3]. Such core pigments have low volume density (0.1 -0.3 g/cm 3 ), relatively high specific compressive strength (20 -38 MPa), good adhesion to polymer binders, and good heat-insulating properties [4]. Therefore, metallized hollow microspheres can be successfully used not only as conducting PM fillers but as heat-insulating fillers as well.The purpose of the present study is studying the possibility of application of metallized glass microspheres as conducting and heat-insulating PM fillers. To produce metallized core pigments, we used industrial hollow glass microspheres MS-VP-A9 dressed with g-aminopropyl-triethoxysilane (TU 6-11-367-75). Glass spheres constitute easily friable powder consisting of spheroid glass particles of size 30 -80 mm with wall thickness 0.5 -2.0 mm. The volume density of glass spheres is equal to 0.16 -0.21 g/cm 3 .Before nickel plating, glass spheres were sensitized in a tin chloride solution and then activated in 0.5% palladium chloride solution. The reduction of nickel was carried out at a temperature of 82 -84°C and pH = 4.5 -5.5 in a solution containing (g/liter): 6 nickel chloride, 8 sodium hypophosphite, 10 sodium acetate. To ensure the stability of the process, the solution was thermostatically controlled while stirring glass spheres. The level of pH was measured by a pH-340 meter with a glass electrode. Nickel plating lasted 40 min. The volume density of glass spheres after nickel plating was equal to 0.5 -0.7 g/cm 3 . The x-ray phase analysis of samples was performed on a DRON-3 pla...
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