DYNAMIC-MECHANICAL PROPERTIES OF A NR BR BLEND AT DIFFERENT CURE LEVELS/

The purpose of this paper is to study the influence of the cure level on the dynamic mechanical properties of an elastomeric NR-BR blend com pound. Dynamic moduli were evaluated in the transition and plateau zon e, at low frequency in the range between 213 and 373 K. As far as the effects of frequency and temperature are concerned, a master curve can be obtained by shifting dynamical modulus data along the log G' axis (vertical shifts) by the factor S-T which depends On temperature follo wing an Arrhenius law. An apparent activation energy that does not dep end on the crosslinking level and is related to the carbon black netwo rk is obtained. Considering horizontal shifts, the dependence of the l oss tangent on frequency is also obtained for different degrees of vul canization.