The dependence of the properties of polyurea greases on the composition of the dispersion medium was investigated. Synthetic lubricating fluids of different chemical natures and mixtures of these fluids were used as the dispersion medium. Lubricants on a mixed base have better lubricant properties than lubricants based on the individual synthetic fluids.

UDC 541.183 N. V. Borisenko, I. Ya. Sulim, and L. I. BorisenkoThe chemisorption of Zr(acac) 4 and the formation of nanoparticles of ZrO 2 on the surface of silica were studied by IR spectroscopy, thermogravimetry, thermal and X-ray phase analysis. The composition was established and the hydrolytic and thermal properties of ºSiOZr(acac) 3 groups were investigated.Chemical reactions of metal (M) chlorides and oxochlorides with surface hydroxyl groups are widely used for the formation of nanoparticles of metal oxides in silica matrices. The most completely studied is the chemisorption of metal chlorides on the surface of silica with subsequent hydrolysis and condensation. However, the hydrogen chloride, evolved during the reaction, interacts with the SiO-M bond leads to restrictions in the conditions of the modification process. Therefore in recent years researchers have paid considerable attention to the modification of SiO 2 with metal acetylacetonates [1]. As a result of the chemical transformations of the modifying compounds nanoparticles of metal oxide in the surface layer of silica. In this case the chemisorption of the metal on the silica surface is an intermediate but very important stage. The formation and stability of the adsorbed complexes, the chemisorption processes proceeding with the participation of silanol groups of the silica surface, the structural-adsorption characteristics of the silica matrix, the thermal and hydrolytic properties of the surface compounds have a considerable influence on the structure of the surface oxides in the M x O y /SiO 2 nanocomposites.Gas phase modification of SiO 2 with zirconium compounds, ZrCl 4 in particular, and also subsequent hydrolysis, dehydration, and phase condensation has been previously studied in detail [2][3][4][5]. We have established [5] that the SiO-Zr bond underwent hydrolysis at temperatures above 400°C. Zirconium dioxide, formed as a result of subsequent modification of the silica surface (chemisorption of ZrCl 4 , hydrolysis, dehydration), has a crystal structure which depends on the temperature of calcination. The average size of the crystallites of ZrO 2 , formed on the surface of pyrogenic silica, increased from 46 to 109 nm with increasing numbers of stratification from 1 to 4. The tetragonal modification of ZrO 2 is stabilized by pyrogenic silica, inhibiting its transition to the monoclinic form on heating to 1000°C. An analogous effect was observed by the authors of [6] on introducing calcium cations and silicate ions into ZrO 2 . On calcining silica containing zirconium to a temperature of 1500°C the monoclinic modification is formed along with the tetragonal form [4].It should be noted that the chemisorption of zirconium acetylacetonate has not been investigated previously. The present work is associated with the chemical reaction of Zr(acac) 4 with the SiO 2 surface and also the formation of nanoparticles of ZrO 2 in a silica matrix.In this work highly dispersed pyrogenic silica (HDS), mark A 300 (Kalush Pilot Plant of the Chemical Insti...

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