Search results

The study reported here concerned production of green pigments, hydrated nickel(II) silicates and oxides, obtained by precipitation from solutions of sodium metasilicate and sodium hydroxide using nickel(II) sulphate.

The pigments were analysed using a number of techniques including scanning electron microscopy for particle surface morphology and dynamic light scattering for particle structure and the tendency of the particles to agglomerate.

The most desirable physicochemical parameters were shown by highly dispersed nickel(II) silicates precipitated in presence of the modifying agents. Silicate pigments precipitated in the presence of Rokanol K‐7 had low bulk densities, a high capacity to absorb water, dibutyl phthalate and paraffin oil within the primary particles, which is particularly noteworthy.

Due to their good dispersibility, well developed surface and appropriate coating power, coloured silicates of, e.g. chromium(III) and nickel(II) may be used as pigments and fillers for surface coatings.

The method of obtaining nickel(II) pigments developed was novel and provided a solution for problem of post‐galvanic nickel solutions.

The purpose of this paper is to obtain ZnO‐SiO₂ oxide composites of low bulk density, high homogeneity and consisting of the smallest possible particles. The optimum parameters of precipitation of ZnO‐SiO₂ oxide composites impregnated with natural latex rubber were established. The formation and impregnation the ZnO‐SiO₂ oxide composites were made to occur simultaneously.

The influence of non‐ionic surfactants added during the precipitation process on the physico‐chemical properties of the oxide systems obtained was investigated. The products were characterised by determination of bulk density, absorption capacities of water and paraffin oil, particle size distribution (applying NIBS and laser diffraction methods), as well as SEM observations of surface morphology and microstructure. Moreover, the colorimetric characteristics of the oxide composites obtained and sedimentation profiles in water were analysed. Energo‐dispersive microanalysis of the products enabled determination of the content of ZnO and SiO₂. The surface area (BET) and the size and volume of pores were also estimated.

Modification of the oxide composites with nonylphenylpolyoxyethyleneglycol ethers was found to improve the basic physico‐chemical parameters of the ZnO‐SiO₂ hybrid systems and to change the character of its surface to become more hydrophobic. The conditions in which samples with the best properties were obtained were concluded to be optimum.

Only the selected non‐ionic surfactants were applied as modifying agents of ZnO‐SiO₂.

There is a possible application of ZnO‐SiO₂ oxide composites as activators of rubber compounds and barrier materials in textiles.

The proposed method of ZnO‐SiO₂ oxide composite synthesis in the process of precipitation with simultaneous modification with non‐ionic surfactants provides products with desirable dispersive‐morphological parameters and a hydrophobic surface character.

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.