Influence of thermal treatment of nano-scaled silica on interfacial adhesion properties of the silica/rubber compounding

In this work, the effect of thermal treatment on crosslink density and adhesion properties of nano-scaled silica/rubber compounding are investigated. The chemical structures and surface properties of modified silicas are studied in terms of Fourier transform-IR (FT-IR), solid-state 29Si-NMR spectroscopy, and surface free energy, respectively. Also, the mechanical interfacial properties of the silica/rubber compounding are determined by the crosslink density and tearing energy (GIIIC). As a result, it was found that the thermally treated silicas became hydrophobic in nature, due to the condensation of surface hydroxyls and the formation of siloxane bond. From which, the increase of the siloxane bond on the silica surfaces led to an improvement of the dispersion of silicas in a rubber matrix, finally resulting in improving the tearing energy in a compounding system.