Radiation shielding composites based on polyimide and Bi 2 O 3 were synthesized. Surface and physical-mechanical properties of polyimide/Bi 2 O 3 composites were studied. Bi 2 O 3 particles were modified by polymethylphenylsiloxane for the uniform distribution of filler in composites. This paper presents data on the production of composites in two ways: hot- and cold-pressing. The hot-pressing method for the synthesis of composites is preferable compared to the cold-pressing method (the density increases by 10–12%, and the Vickers microhardness by 10–20%). The results show that the introduction of Bi 2 O 3 significantly increases the thermal stability of the composites. At 680 °C, a polymer composite containing 10 wt% Bi 2 O 3 retains 9.7% of its mass, and at 60 wt% Bi 2 O 3 , retains 58.4%. The radiation-protective characteristics of the composites with respect to gamma radiation were evaluated by experimental and theoretical methods. High radiation-protective characteristics of the composites have been established in the gamma-quanta energy range of 0.1–1 MeV.

The paper presents the results of studies of the thermal stability of titanium hydride and titanium hydride containing a borosilicate framework. It is shown that the presence of chemically attached boron atoms on the surface of titanium hydride particles increases the initial dissociation temperature of titanium hydride. The phase composition and imperfection of titanium hydride crystals in the temperature range of 100-700 °C were studied. An increase in the defectiveness of the structure of a titanium hydride crystal during its heat treatment is shown. Mechanisms for modifying the surface of titanium hydride by surface assembly and the creation of a borosilicate framework have been established. It was shown that the ongoing structural-phase transformations in the borosilicate coating activate solid-phase interactions and contribute to the fixation of borosilicate. Based on the data of thermogravimetric analysis, it was shown that the modification of titanium hydride increases its thermal stability by 185 °C, shifting the onset of dehydrogenation processes to the high-temperature region from 463 °C to 649 °C.

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This study aims to address the poor thermal stability of titanium hydride. Surface microstructural observations, differential thermal analysis, and electron-probe analysis of the thermal stability and phase composition measurements of a titanium hydride fraction that was modified by the electrochemical deposition of titanium metal are presented. It is demonstrated that the metallic titanium deposited on the surface of the fraction acts as an effective trap for hydrogen diffusion into the surface layers upon thermal heating. Modification of the surface of the titanium hydride fraction by electrochemical deposition of titanium metal increased its initial temperature of dehydrogenation by 231.8 °C. The concentration of the hydride phase at the surface layer at 500 °C increased to 87.2% due to the structural redistribution of atomic hydrogen and the hydrogenation of metallic titanium at the surface layer.

This work investigates the radiation resistance of a structural material based on modified titanium hydride and a Portland cement in a flux of neutron and γ-radiation. An assessment of the geometric and physicomechanical properties is given, along with the surface structure of irradiated cement composites, and the phase composition of the main hydrosilicates of the hydrated cement matrix during its γ-irradiation. It is shown that the use of a shot of titanium hydride increases the radiation resistance of radiation shielding based on a cement matrix, in comparison with the unmodified shot. A composite based on a modified shot of titanium hydride retains its basic properties after γ-irradiation, at an absorbed dose of up to 10 MGy. At an absorbed dose of 2 MGy in the Portland cement matrix of a composite based on a modified shot of titanium hydride, the formation of suolunite hydrosilicates occurs. It was established using X-ray fluorescence that, in the titanium hydride, a redistribution of the electron density occurs at an absorbed dose of γ radiation of 5 MGy, caused by structural phase changes due to the ongoing dehydrogenation processes.

Studies have been carried out to increase the adhesive interaction between a titanium hydride substrate and a copper coating. An additional layer containing chemically active groups was created on the surface of the spherical titanium hydride by chemisorption modification. This paper discusses the results of scanning electron microscopy (SEM) using energy-dispersive X-ray spectroscopic mapping of coatings obtained on spherical granules of titanium hydride before and after adsorption modification. The mechanism of interaction of the surface of spherical granules of titanium hydride and titanium sulfate salt is proposed. It is shown that the creation of a chemisorbed layer of hydroxotitanyl and the subsequent electrodeposition of metallic copper contribute to the formation of a multilayer shell of a titanium–copper coating on the surface of spherical titanium hydride granules (≡Ti-O-Cu-) with a high adhesive interaction. Results have been given for an experimental study of the thermal stability of the initial spherical granules of titanium hydride and granules coated with a multilayer titanium-copper shell.

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The paper presents the results of studies on surface modification of finely dispersed tungsten (IV) dioxide with polyethylsiloxane from a solution of n-hexane with the aim of its compatibility and the possibility of uniform distribution in the volume of the nonpolar polyimide matrix. The energy dispersive interaction of the press powder of polyimide and highly dispersed modified WO2 in a jet-vortex mill allowed for the activation of their surface, as well as high uniformity of distribution of the filler in the polyimide matrix and excluded the possibility of the formation of agglomerates. It is shown that the use of modified WO2 increases the degree of filling of the polymer composite by 15-20% and the increase in the density of the composite by 16.0%.