Effect of the structure of the Zinc-based curing activator on the mechanical behavior of rubber nanocomposites

The crosslink density and distribution inside the polymer matrix affect the mechanical properties of rubber nanocomposites (NCs). Since the catalytic activity of zinc has a central role in the formation of crosslinks, this study focuses on the effect that the structure of the catalytic sites and their localization inside the polymer matrix have on the mechanical behavior of rubber materials. To do this, a new highly efficient activator, Zn@SiO2 based on zinc single sites anchored onto the silica surface, is used as double function filler, acting as both activator and reinforcing filler. The mechanical properties of rubber NCs prepared with Zn@SiO2 are compared to NCs conventionally cured with ZnO particles. The results suggest that localizing the catalytic sites at different distance from the filler particles dispersed in the rubber matrix is a promising tool to control the crosslinking density and distribution, which means tuning the mechanical properties of rubber NCs.