Rh(III) AND Ir(IV)-CONTAINING FILMS BASED ON CHITOSAN AND AGAR-AGAR: DYNAMICS OF CHANGES IN PHYSICAL AND CHEMICAL PROPERTIES; [ДИНАМИКА ИЗМЕНЕНИЯ ФИЗИКО-ХИМИЧЕСКИХ СВОЙСТВ Rh(III) И Ir(IV)СОДЕРЖАЩИХ ПЛЕНОК НА ОСНОВЕ ПРИРОДНЫХ ПОЛИСАХАРИДОВ]

Films based on natural polysaccharides are already widely used in coordination chemistry, medicinal chemistry, environmental chemistry, and pharmaceuticals. The wide range of applications of these materials is due to their high environmental friendliness, biocompatibility and biodegradability. To determine the possibility of using these materials, it is necessary to characterize their physicochemical properties. Chitosan-agar films were obtained by casting from solution with glycerol as plasticiser. The films contain Rh3+ and Ir4+ cations in different ratios of polymer matrix and metal cations. The materials were characterised by IR spectroscopy, differential thermal and thermogravimetric analysis (DTA and TGA), and scanning electron spectroscopy (SEM). In this paper, the dynamics of changes in mechanical properties (short-term strength (N/mm2) over a period of two months from the date of production of the material have been considered. It was proven that the nature of the metal center affects the mechanical properties: rhodium-containing samples are characterized by higher short-term tensile strength than the corresponding iridium-containing ones. The behavior of materials in aqueous solutions is also an important characteristic for determining the possibility of using films. The dynamics of the swelling behavior was studied in water as well as in salt buffer solution (pH=7.2). In buffer solution, the films undergo less swelling than in distilled water. The degree of material swelling with inclusion of rhodium(III) cations is higher than that of films with the same ratio of polymer matrix and iridium(IV) cations. When materials are stored under standard conditions, not only mechanical properties, but also the degree of swelling of the samples change. Over time, the values fall regardless of the composition of the samples under study. © (2024), (Ivanovo State University of Chemistry and Technology). All rights reserved.