Positron annihilation spectroscopy in carbon black-silica-styrene butadiene rubber (SBR) composites under deformation

Positron annihilation lifetime (PAL) spectroscopy has been used to investigate microstructural properties of carbon black-silica-styrene butadiene rubber (SBR) composites. The positron annihilation lifetime shows a direct dependence on the carbon black type as well as the silica content added to the rubber compound. The effect of the tensile strain (ε=0-150%) on the positron annihilation parameters has been investigated by constructing a small load frame to permit the measurement of positron lifetime in situ. The variations in the o-Ps lifetime τ3 and its intensity I3 with deformation are discussed in the framework of free volume theories. A simple illustrative sketch for the rubber-filler matrix is proposed.