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The purpose of this paper is to propose a new method of synthesis of CuO · SiO₂ oxide composite based on the reaction of precipitation from water solutions of sodium silicate and copper nitrate.

Solutions of sodium silicate and copper nitrate were used as substrates. The effects of direction of substrate supply, concentration, excess of reagents and temperature of precipitation on the physicochemical properties of the products were analysed.

A new method of synthesis of CuO · SiO₂ oxide composite based on a precipitation reaction is proposed.

Only sodium silicate and copper nitrate solutions were used.

The CuO · SiO₂ oxide composite obtained can be used as blue pigment or polymer filler.

The paper determines optimum conditions of CuO · SiO₂ oxide composite precipitation to obtain products with desired physicochemical, dispersive and structural properties.

The purpose of this paper is to characterise the electrokinetic properties of pigments supported on both unmodified and modified silica. The paper describes the preparation of hybrid pigments via adsorption of organic dyes on silica supports and determination of the zeta potential and electrophoretic mobility of the materials obtained.

The materials studied were hybrid pigments obtained as a result of adsorption of two basic dyes: C.I. Basic Red 1 and C.I. Basic Orange 14 and one acidic dye C.I. Mordant Red 3 from solutions of concentrations of 500, 2,000 and 3,000 mg/dm³ on the surface of both unmodified and modified silica supports. The agent used for modification of the silica surface was N‐2‐(aminoethyl)‐3‐aminopropyltrimethoxysilane.

The modification of the silica surface with aminosilane was found to change, significantly, the electrokinetic character of the inorganic support. This change was interpreted as being due to the ionisation of −NH₂ groups from the modifier molecule, which changes the surface charge. Electrokinetic curves of the pigment composites changed considerably as a function of the type and concentration of the organic dye adsorbed.

Only SiO2 supports (unmodified and aminosilane‐grafted) and C.I. Basic Red 1, C.I. Basic Orange 14 or C.I. Mordant Red 3 dyes adsorbed on its surface were evaluated. Other dyes could also be studied.

Measurements of the zeta potential were used to characterise the stability of colloidal dispersions of paints or dyes and to control the stability of paints on storage and their performance on painting and drying.

The paper demonstrates that the measurements of zeta potential permit determination of the optimum conditions for the use of a given pigment. The finding of the change of the zeta potential of a given pigment and so, also its application properties as a result of different functional groups in the dye or the modifying agent molecules.