Analysis MethodNMR study of styrene-butadiene rubber (SBR) and TiO2 nanocomposites

The chemical behavior of styrene-butadiene rubber (SBR) and of the SBR/TiO2 and photodegraded SBR/TiO2 nanocomposites was investigated through nuclear magnetic resonance spectroscopy (NMR) in the solid state with magic angle spinning (MAS). The 13C cross polarization/magic angle spinning (CP/MAS) routine spectrum allowed us to obtain information on the polymer microstructure and also to evaluate the domain mobilities. The variation contact time and the proton spin-lattice relaxation time in the rotating frame (T1ρH) were determinant factors to evaluate the dynamic molecular motion. The NMR spectrum of the nanocomposites was dislocated 5 ppm to higher chemical shift, indicating the presence of a strong interaction between the polymer chains and the TiO2 nanoparticles. The VTC experiment showed a rigid domain in the SBR/TiO2 photodegraded nanocomposite due to cross-linking reactions.