COMPARATIVE EVALUATION OF BISMUTH- AND TIN-BASED ORGANOMETALLIC CATALYSTS IN THE SYNTHESIS OF BIO-COMPATIBLE SILICONE-BASED OSTEOPLASTIC COMPOSITES

JYIRQX

Abstract

The study compared the effectiveness of three organometallic catalysts—tin(II) 2-ethylhexanoate (EGO), bismuth(III) 2-ethylhexanoate (CAT 22), and bismuth(III) neodecanoate (CAT 20A)—in the formation of osteoplastic composites based on SKTN-G hydroxyl-containing siloxane rubber and Aerosil A-175. Bismuth catalysts were found to provide a significantly higher curing rate: at a concentration of 4 parts by weight and room temperature, the curing time was 7 min 8 sec for CAT 20A, 12 min 52 sec for CAT 22, and 48 min for EGO. Increasing the temperature to 40°C accelerates the process by 2–4 times, confirming the high thermal sensitivity of the systems. CAT 20A exhibits the most balanced characteristics—in terms of curing speed, structural homogeneity, and thermomechanical stability. Physicochemical analysis of aqueous extracts revealed that all composites have similar pH (6.0) and refractive index (1.331–1.332) values, indicating the absence of significant component leaching and high chemical stability of the materials. These results allow us to recommend bismuth catalysts, particularly CAT 20A, for the development of technologically advanced, fast-curing, and chemically inert osteoplastic composites suitable for further biomedical research.