The effect of the types of carbon black on the physicomechanical, dynamic mechanical, and dielectric relaxation spectra in chlorobutyl vulcanizates was studied. The primary relaxation (a transition, the glass transition) was studied by dynamic mechanical analysis as a function of temperature (-60 to +100 degrees C) and by positron annihilation lifetime spectroscopy (-70 to +100 degrees C). Irrespective of the type of carbon black that was used, all composites showed glass-transition temperatures in the range of -29 to -33 degrees C, which was explained on the basis of the relaxation dynamics of polyisobutylene chains in the vicinity of the fillers. The secondary relaxation (alpha* or beta relaxation) was studied using dielectric relaxation spectra in the frequency range of 100-10(6) Hz. The nonlinear strain dependent dynamical parameters (Payne effect) were also evaluated at dynamic strain amplitudes of 0.07-5%. The nonlinearity in the tan 8 and storage modulus was explained by the concept of filler-polymer interactions and the interaggregate attraction (filler networking). (c) 2006 Wiley Periodicals, Inc.