Review of positron annihilation spectroscopy studies of rubber with carbon black filler

Positron annihilation lifetime spectra have been measured for rubber polymers with carbon black (CB) fillers as a function of temperature, sulfur concentration, type of CB fillers and type of polymer. The purpose of the study is to understand how the CB fillers and other components of the vulcanized composite affect the positron lifetime in polymer materials. The polymer samples to be studied include natural rubber (NR) with different sulfur concentration, Sn-SSBR either unloaded or loaded with CB N115 or N762, both vulcanized and unvulcanized Duradene 706 samples. The results show that CB fillers have no effect on the ortho-positronium lifetime but decrease the intensity of ortho-positronium; and the decrease in intensity depends on the type of CB. On the other hand both ortho-positronium lifetime and intensity decrease as a function of sulfur concentration.