Siberian Federal University

The results of the synthesis of microcrystalline hydroxyapatite (HAp) and the effects of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) additives on its microstructural characteristics and phase composition are presented. X‑ray diffraction analysis revealed that the hydroxyapatite sample consists of Ca5(PO4)3(OH) and Ca3(PO4)2 phases. The addition of polyvinylpyrrolidone affected the thermal stability of hydroxyapatite. In turn, this led to the formation of Ca3(PO4)2 and γ‑ Ca2P2O7 phases. The addition of polyvinyl alcohol did not affect the thermal stability of hydroxyapatite. The Hap/PVA samples consist of the Ca5(PO4)3(OH) phase. The qualitative composition of the samples was determined by infrared spectroscopy. The Ca/P elemental ratio in the samples was determined using energy-dispersive analysis: 1.4 for Hap/PVP, 1.37 for Hap/PVA, and 1.27 for HAp samples. The Ca/P ratio of 1.4 for Hap/PVP sample was found the closest to stoichiometric one. Scanning electron microscopy revealed that the polymer complexing agents affected the surface morphology of the hydroxyapatite particles. Electrospun fibers containing HAp were randomly oriented