SYNTHESIS AND PROPERTIES OF BIOACTIVE SPHERICAL MATERIALS FOR THE TiO2–SiO2/СаO/МgO SYSTEM

Abstract

Bioactive spherical materials based on Tokehm-200 cationic exchange resin were obtained. The framework of the biomaterial is represented by TiO2-SiO2 and the inner part is filled with Ca2+ or Mg2+. Tokem-200 is a weakly acidic porous cationite based on acrylic-divinylbenzene with grain size of 0.315-1.600 mm. Carboxylic cationite Tokem-200 is highly selective to Ca2+, Mg2+ ions, which makes it promising for creating biomaterials, since calcium (magnesium) ions are one of the building materials of bone tissue. The synthesis of bioactive spherical materials for the TiO2-SiO2/CaO/MgO system consists of four stages. First stage: aggregate-stable sols were synthesized from alcohol solutions based on tetraethoxysilane and tetrabutoxytitanium (orthophosphoric acid was used as a catalyst). Maturation of the sols occurs within three days. The second stage: immersion of Tokehm-200 cationite in calcium (magnesium) salt solution for saturation (Tokehm-200 samples with Ca2+/Mg2+). The third stage: after pre-drying of Tokehm-200 samples with Ca2+/Mg2+ immersion in aggregate-stable salt. The fourth stage: temperature treatment of the obtained samples. To obtain homogeneous material thermal treatment conditions (drying at 60 ºС) were set: annealing at 150, 250, 350 ºС for 30 min each and at 600 ºС for 6 h. After the stepwise heat treatment the framework is uniformly fixed on the cationite without cracks and splits on its surface, which is favorable for practical application. It was found that at a ratio of samples Tokem-200 with Ca2+ and applied ash and Tokem-200 with Mg2+ and applied ash 1:1 highly porous loose particles are formed on the surface. The addition of magnesium ions increases the bioactivity of the obtained materials.