No abstract

No abstract

This paper studied the effect of additives of 0.5–20 wt.% synthetic CaSiO3 wollastonite on the thermodynamic, mechanical, and tribological characteristics and structure of polymer composite materials (PCM) based on ultra-high-molecular weight polyethylene (UHMWPE). Using thermogravimetric analysis, X-ray fluorescence, scanning electron microscope, and laser light diffraction methods, it was shown that autoclave synthesis in the multicomponent system CaSO4·2H2O–SiO2·nH2O–KOH–H2O allows one to obtain neeindle-shaped nanosized CaSiO3 particles. It was shown that synthetic wollastonite is an effective filler of UHMWPE, which can significantly increase the deformation-strength and tribological characteristics of PCM. The active participation of wollastonite in tribochemical reactions occurring during friction of PCM by infrared spectroscopy was detected: new peaks related to oxygen-containing functional groups (hydroxyl and carbonyl) appeared. The developed UHMWPE/CaSiO3 materials have high wear resistance and can be used as triboengineering materials.

No abstract

No abstract

BY1,. M. AVKHUTSKII (a), R. L. DAVIDOVICH (a), L. A. ZEMNUKHOVA (a), P. S. GORDIENEO (a), V. URBONAVI~IUS (b), and J. GRIGAS (b) The dynamics of the (NH,),SbF, crystal lattice showing the superionic phase transition is studied in a broad temperature interval by NMR and NQR methods, together with electrophysical and calorimetrical properties. The investigations establish the ionic state of the axial fluorine atom in relation to equatorial atoms in the [SbF,I2-complex. The successive phase transitions are revealed and the mechanism of phase transitions is elucidated. The phase transitions are caused by the reorientation movements of NH, and [SbF,IZ-groups. The paper also describes the influence of water solution inclusions in the crystal on the superionic phase transition.Es wird die Dynamik des Kristallgitters mit den Methoden der NMR, NQR, sowie auch die elektrophysikalischen und kalorimetrischen Eigenschaften von (NH,),SbF,-Kristallen, in denen ein superionischer Phasenubergang gefunden wird, in einem breiten Temperaturintervall nntersucht. Die Ionenbindung des axialen F-Atoms ist vie1 starker als die Ionenbindung der aquatorialen P-Atome der [SbF,]2--Gruppe. Es wird eine Phasenubergangsfolge in diesen Kristallen gefunden und ein Mechanismus dieser Phasenubergange vorgeschlagen. Die Phasenubergange werden durch Drehung von NH,-und [SbF,I2--Gruppen vernrsacht. Es wird auch der EinfluB der im Kristall befindlichen Wasserlosnngsinklusionen auf den superionischen Phasenubergang diskutiert.

The use of titanium dioxide is so diverse that varies from food to heavy industry and it is the main substance in the titanium industry. Over 90% of the world's mined titanium concentrates are processed to produce pigments. The sources for the production of titanium dioxide are the typically used titanium-containing ores including minerals rutile, ilmenite, and others. The volume of world production of titanium dioxide pigment exceeds 5 million tons per year and it is carried out in two ways: sulphate and chlorine (in approximately equal volumes). The changed approach to the green production processes requires the improvement of existing technologies and the development of new methods for processing titanium-containing raw materials. The authors have experimentally confirmed the high efficiency of complex, waste-free processing of titanium-containing raw materials developed by hydrofluoride. Creating pigment production on the basis hydrofluoride method will meet not only the domestic needs but also offer thepigment for export, as its parameters will surpass those of the best world analogues.

No abstract