Inelastic neutron scattering from filled elastomers

Inelastic neutron scattering experiments are powerful techniques for evalua ting local molecular dynamics. These methods are especially sensitive to hy drogen atoms containing motions. An overview of these experimental techniqu es is presented. Neutron filter analyzer and time-of-flight spectroscopy me thods are used to characterize the local dynamics of polymers in the presen ce and absence of fillers. Of particular interest is the comparison between bound rubber attached to the filler surface and the pure, unbound rubber. A commercial synthetic polyisoprene containing approximately 100% cis-1,4 i somers was compounded with three different carbon blacks: N299, G299 (graph itized N299), and N762. Soxhlet extraction on each of the samples was perfo rmed so that corresponding samples containing purely bound rubber with fill er were obtained. The filter analyzer and time-of flight spectra show disti nct differences between the bound and pure rubber as well as differences ba sed on carbon black type. Correlation of the spectral differences to the ty pe of carbon black and initial concentration of carbon black are discussed.