Synthesis and characterisation of elastomeric composites prepared from epoxidised styrene butadiene rubber, 3-aminopropyltriethoxysilane and tetraethoxysilane

Hybrid composite materials were obtained by the reaction of epoxidised styrene butadiene rubber with 3-aminopropyltriethoxysilane, followed by in situ hydrolysis and polycondensation of tetraethoxysilane (TEOS). The hybrid films were characterised by thermogravimetric analysis, differential scanning calorimetry, swelling and stress-strain measurements, scanning electron microscopy and infrared spectrometry. Non-solubility of the films in tetrahydrofuran indicated the formation of a network, the microstructure of which varied according to the concentrations of the inorganic precursors employed. The thermal stabilities of the films were similar to that of rubber, and the mechanical stress increased considerably with the amount of silica incorporated. The most transparent films were those prepared with the lowest concentrations of inorganic precursors, whilst those obtained using larger amounts of TEOS showed distinct microscopic phases. The protocol described represents a simple method by which to bind inorganic precursors to rubbers.