New hydrogel dressings containing the herbal medicinal substance "Alkhydin", obtained from the Kirghiz (Alhagi kirghisorum Schrenk), grown in Kazakhstan, were obtained by radiation irradiation of the initial reaction mixture (IRM). Poly-<br />N-vinylpyrrolidone (PVP) with a molecular weight (MM) of 1 ppm was used to prepare hydrogel dressings as the main gelling polymer for IRM, agar-agar and lowmolecular polyethylene glycol MM = 600 were used as auxiliary substances. The main regularities of the formation of the three-dimensional structure of PVP under conditions of irradiation of IRM are investigated. It is shown that with increasing PVP in IRM, as well as irradiation dose, the yield of gel fraction increases and the degree of swelling decreases. Obviously, these effects are due to an increase in the degree of cross-linking of the polymer network formed. For the obtained hydrogel dressings containing the herbal medicinal substance Alkhydin, cytotoxic effects on the culture of mouse embryonic fibroblasts obtained by primary trypsinization were studied. The results obtained in this case testify to the absence of a cytotoxic effect on the cell culture. In conditions "in vivo" in rats using the model of thermal skin burn, the wound healing effect of hydrogel dressings with "Alkhydin" was studied. It is shown that such bandages show a pronounced wound-healing effect. This is evidenced by a higher rate of reduction in the area of the burn wound treated with a hydrogel dressing compared to the control.
The mechanism of formation of slightly crosslinked composite hydrogels based on natural agar-agar polysaccharide, synthetic polymers for medical purposes – poly-N-vinylpyrrolidone (PVP) and low-molecular plasticizers (polyethylene glycol PEG-400 and glycerin) synthesized by electron irradiation was considered from the point of view of analyzing their mechanical characteristics under various types of applied efforts. It is established that the synthesis conditions and the component composition of the initial mixture determine the formed structure of the hydrogel compositions and their mechanical properties. A new interpretation of the formation of the structure of composite hydrogels in the presence of various plasticizers is given. A detailed analysis of the deformation curves of composite hydrogels is presented taking into account the elastic-elastic, highly elastic and forced-elastic states.
A systematic study of the synthesis of hybrid composite materials based on synthetic (poly-N-vinylpyrrolidone) and natural (agar-agar) macromolecules in the presence of plasticizers (PEG-400, glycerin) and mineral filler bentonite has been performed by the method of electron irradiation. The methods of X-ray diffraction analysis and SEM showed that the structure of the resulted hybrid compositions is defined as an interpenetrating network with the distributed intercalated particles of mineral component inside its volume. It has been established that mechanical properties of the hybrid composition are determined mainly by the struc-tural organization of the interpenetrating polymer network, formed during electron irradiation of the initial polymer mixture in the presence of plasticizers, as well as by the conditions for intercalation of polymer seg-ments into the interpacket layers of the mineral matrix. During the process of crazing of the sample under ten-sion the shear stress is concentrated in the central part of the sample from the periphery of the fastening. It is shown that the degree of swelling for hybrid composition strongly depends on concentration of a low molecu-lar plasticizer in the polymeric interpenetrating network, which can easily impregnate into the interplanar lay-ers of bentonite.
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