STRUCTURE, THERMAL BEHAVIOR, AND ANTIBACTERIAL ACTIVITY OF POLYSTYRENE/HYDROXYAPATITE FILM COMPOSITES

Abstract

The most important area of modern materials science is the preparation and study of the properties of polymer composite materials containing micro- and nanoparticles of inorganic fillers. The introduction of such particles into a polymer matrix increases its mechanical strength and thermal stability, changes its electrical and gas barrier properties, and promotes the appearance of biological activity. The listed properties of the obtained composites depend on the characteristics of both the initial polymer and the filler. In this work, a powder of the natural ceramic mineral hydroxyapatite (HAP), which is a promising filler for polymeric materials, is characterized using a number of physicochemical methods. Size distributions of hydroxyapatite particles and quantitative characteristics of the porous structure were obtained by granulometric analysis and low-temperature sorption-desorption of nitrogen vapor. It has been established that the powder under study can be classified as a mesoporous material with a highly developed surface. The specific surface area of HAP, the total specific pore volume, the average pore size, and the fractal dimension of the porous material were determined. The pore size distribution is monomodal with a peak at 4 nm. Mechanical dispersion using o-xylene was used to immobilize hydroxyapatite particles in a polystyrene (PS) matrix, and PS/HAP composite film materials were obtained. The results of a study of X-ray scattering by polystyrene and composite films with different hydroxyapatite content are presented. It has been established by differential scanning calorimetry that PS/HAP composites are characterized by two glass transition temperatures, which correspond to relaxation transitions in the “soft” and “hard phases”. Studies of the biological activity of the synthesized PS/HAP composite materials have been carried out, and their antibacterial action against gram-positive bacteria Staphylococcus aureus Rosenbach 209-P has been established for the first time.