Investigation of the effects of different additives on rheological, mechanical and microstructural properties in vinyl methyl silicone rubbers

Vinyl methyl silicone (VMQ) rubbers are an integral part of the automotive industry and turbocharger technology and contribute significantly to these systems with their efficiency and reliability in this field. These silicone-based materials offer exceptional heat resistance, oil and fuel resistance, superior sealing properties and resistance to environmental factors. VMQ rubbers play a critical role in turbocharger applications to provide optimum performance and long shelf life. The general properties of rubber compounds are affected not only by the nature of the elastomers but also by the properties of other additives to form the final product. Therefore, the selection of white additives affects the viscosity, curing properties and mechanical properties of the components, which is very important for the extrudability of the material. These additives also impact the vulcanization process, causing changes in the final properties of the material. This study aims to investigate the effects of three different additives on the rheological, mechanical and microstructural properties of rubber compounds. In this sense, the focus was on three different additives: silica-kaolinite mixture (SK), amorphous silica (AS) and wollastonite (W). These additives were added to VMQ rubber at 10, 20 and 30% by weight to determine the most suitable mechanical properties. The rheological analysis results obtained showed that silica had a positive effect on the viscosity and dimensional stability properties of the mixtures. AS material increased the viscosity modulus of the mixtures, making VMQ/AS composites more durable. On the other hand, SK and W additives negatively affected the rheological behaviour of VMQ/SK and VMQ/W composites, causing the viscosities of the mixtures to decrease. When the mechanical test results were evaluated, an increase in the durability of the mixtures was generally observed, except for the VMQ/AS composite. As a result, the type of filler plays a critical role in shaping the rheological and mechanical properties of VMQ rubber mixtures. This study will contribute to the creation of an important database for the optimization of special rubber mixture formulations for industrial applications.