Enhancing Thermal, Viscoelastic, and Mechanical Properties of Silicone Rubber Matrix through Reinforcements for Use as a Medical Implant

The use of silicone rubber as an implant is limited due to its weak properties. In this study, the impact of various reinforcements, such as TiO2 or SiO2 nanoparticles, carbon, or polypropylene fiber micro reinforcements, on the mechanical, thermal, and viscoelastic properties of silicone rubber composites with RTV-4125 matrix was investigated. The composites were evaluated through several tests, including tensile, compression, FTIR, TGA, DMTA, and water adsorption tests. It was found that the composites' tensile strength and compressive stress were increased by adding reinforcements, with the most significant impact on tensile strength observed for SiO2 and the most notable effect on compressive stress at a strain of 0.5 observed for polypropylene fiber. Moreover, the water absorption of the matrix was increased with the addition of reinforcements, with the highest increase observed for Titania nanoparticles. TGA analysis showed that all composites had higher thermal stability than the plain matrix, with the highest degradation temperature observed for the SR-C fiber composite and the highest degradation rate observed for SR-TiO2. Additionally, DMTA analysis revealed that TiO2 nanoparticles considerably decreased the glass transition temperature of the matrix (%28.5), while the other reinforcements had a negligible effect on this temperature. The introduction of reinforcements had a positive impact on the mechanical, thermal, and viscoelastic properties of silicone rubber composites, and the findings of this study can contribute to the development of new and improved silicone rubber composites for implant applications.