Effects of silica content on the durability of rubber compounds described by (Ultra) Small-Angle X-ray Scattering

This study used (U)SAXS to investigate how filler hierarchical structures and cavitation properties change under strain in rubber compounds with different silica content. The results were then compared to the macroscopically observed crack behavior of the samples. A critical threshold was identified around 21 vol.% of silica. The combined mechanical tests and (U)SAXS analysis revealed that increasing silica concentration accelerates cavity formation and crack propagation, most likely due to the amplification of local stresses, ultimately leading to premature compound failure. These findings highlight the importance of optimizing silica content to enhance the mechanical stability and longevity of rubber compounds. • (U)SAXS reveals the influence of silica content on cavitation in rubber compounds. • Simultaneously the structure of the silica filler network is probed. • Cavitation and filler changes were studied in situ using a custom tensile stretcher. • Overpassing a critical silica concentration accelerates compound failure. • Observed cause for cavitation is a rise in local stresses due to strain amplification.