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The paper presents an original approach to the synthesis of polycalciumorganyl silsesquioxanes through the reaction of polyorganyl silsesquioxanes [RSiO1.5]n (where R is an ethyl and phenyl radical) with sea urchin skeleton under the conditions of mechanochemical activation. The novelty and practical significance of the present study lies in the use of an available natural raw source as a source of calcium ions to initiate the reaction of calcium silicate formation and create a matrix for the formation of a porous inorganic composite framework. The thermal stability of the introduced silicates, i.e., the ability to maintain a porous structure at high temperatures, is key to the production of an ordered porous material. The reaction scheme was proposed to be based on the interaction of calcium carbonate with the siloxane bond. FTIR, XRD, GPC, and TGA were used to study the composition and structure of the obtained materials. The cross-sectional area of the polymer chain and the volumes of the coherent scattering regions of the polymers obtained were calculated from the XRD data. To prepare the composites, the sea urchin skeleton was further modified with polycalciumorganyl silsesquioxanes in a toluene solution. To remove the sea urchin skeleton, the obtained biomimetic composites were treated with hydrochloric acid. The results of the morphological and surface composition studies are reported. The method proposed in the paper could be of fundamental importance for the possibility of obtaining structured porous composite materials for a wide range of practical applications, including for the purpose of creating a composite that may be a promising carrier for targeted delivery of chemotherapy agents. [ABSTRACT FROM AUTHOR]

This paper considers the results of an examination of painted pottery from prehistoric sites of the Prmor'ye region (Southern Russian Far East) in the northwestern part of the Sea of Japan basin. Red-painted and black-painted ceramic wares occur here only in the remains of the Yankovskaya archaeological culture dated to the 1st mil. BCE. Red painting appears as a colored surface coating, and black painting is represented by very simple drawn patterns. Until recently painting decorations have not been intentionally studied. The objects of our investigation are a small series of red-painted and black-painted ceramic fragments originated from archaeological sites. The methods of optical microscopy, SEM-EDS, and Raman spectroscopy were applied to the study of research materials. As a result, the data on characteristics of texture and composition of red and black paints were obtained. Both were determined to be pre-firing paints. Red paint is a clayish substance mixed with natural ochre pigment containing the hematite coloring agent. Black paint is carbon-based. Black carbon and burnt bone are recognized as colorants. The presented materials are new evidence of pottery paint technologies in prehistoric Eurasia. [ABSTRACT FROM AUTHOR]

The paper presents a method of obtaining functionally graded material (FGM) of heterogeneous (layered) type based on joined metals Cr-Ti-Fe-Co-Ni-Cu using spark plasma sintering (SPS) technology. The structure, elemental and phase composition of FGM obtained on the basis of joined metals with different values of the temperature coefficient of linear expansion (CTLE) were studied by SEM, EDS and XRD methods with regard to the phase states of the alloy system. Based on the Vickers microhardness data, the evaluation of the mechanical characteristics of FGM in the whole sample body and locally at the contact boundaries of the joined metals was carried out. The results of the study are new and represent a potential for FGM, as well as functionally graded coatings (FGC), which have special physical, chemical and mechanical properties and are highly demanded for the manufacture of structures and products for industrial applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]