Influence of Herbal Fillers Addition on Selected Properties of Silicone Subjected to Accelerated Aging

Abstract

This work aims to assess the impact of the type and percentage of powdered herbs on selected properties of silicone-based composites. The matrix was an addition cross-linked platinum-cured polydimethylsiloxane. The fillers were powdered thyme and sage, which were introduced at 5, 10, and 15 wt.%. The introduced fillers differed in composition, morphology, and grain size. The grain morphology showed differences in the size and shape of the introduced fillers. The qualitative and quantitative assessment resulting from the incorporation was conducted based on tests of selected properties: density, wettability, rebound resilience, hardness, and tensile strength. The incorporation slightly affected the density and wettability of the silicone. Rebound resilience and hardness results differed depending on the filler type and fraction. However, tensile strength decreased, which may be due to the matrix’s distribution of fillers and their chemical composition. Antibacterial activity evaluation against S. aureus proved the bacteriostatic properties of the composites. Accelerated aging in PBS solution further deteriorated the mechanical properties. FTIR and DSC have demonstrated the progressive aging of the materials. In addition, the results showed an overall minimal effect of fillers on the silicone chemical backbone and melting temperature. The developed materials can be used in applications that do not require high mechanical properties.