Hybrid Taguchi–RSM optimization of tensile strength in talc-filled rtv silicone rubbers: A comparative study of RTV 48, RTV 683, and RTV M4503

Room-temperature-vulcanizing (RTV) silicone rubber is widely used in flexible engineering components where compliance, durability, and controlled mechanical performance are required. However, formulation selection remains challenging when matrix grade, catalyst content, and mineral filler loading must be optimized simultaneously. This study presents an integrated Taguchi–response surface methodology (RSM) framework to optimize the tensile behavior of talc-filled RTV silicone rubbers. Three RTV grades, namely RTV 48, RTV 683, and RTV M4503, were evaluated with catalyst contents of 2–4 wt% and talc loadings of 40–60 wt% using ISO 37:2017 tensile testing. A Taguchi L15 orthogonal array was first employed to screen the formulation effects, followed by RSM-based modeling and desirability optimization to identify the preferred formulation. The Taguchi signal-to-noise analysis identified RTV grade as the dominant factor affecting ultimate tensile strength. The RSM-ANOVA results further confirmed that the UTS model was statistically significant, with RTV grade and catalyst content as significant contributors, while talc loading showed a response-dependent effect within the investigated range. For strain energy density, the model was also significant, with catalyst content and RTV grade governing the deformation energy response. Multi-response desirability optimization identified RTV M4503 with 2 wt% catalyst and 60 wt% talc as the preferred formulation, providing a predicted UTS of 1.367 MPa, predicted strain energy density of 264.917 J/m³ , and desirability of 0.938. SEM observation of the optimized composite revealed distributed platy talc particles within the RTV matrix and provided microstructural evidence for interpreting the statistical response trends. The results demonstrate that matrix selection and catalyst control are the primary formulation levers for improving tensile performance, while talc serves as a functional filler for stiffness and formulation tuning. This hybrid experimental–statistical–microstructural approach offers a practical framework for designing talc-filled RTV silicone rubbers for flexible molds, soft tooling, damping components, sealants, gaskets, and other engineering elastomer applications.