Abstract
Dielectric relaxation in steady shear flow was studied at 297 K and in the range of frequency f from 1 to 1000 kHz for bulk cis-polyisoprene (cis-PI) with the weight average molecular weight of 16,200. At zero shear rate γ, the loss maxima due to the normal and segmental mode processes were found at log f=3.2 and 7.6, respectively. At 1 kHz near the loss maximum frequency for the normal mode process, ε′ and ε″ were independent of shear flow. In the range satisfying γ>10 s-1 and log f>4, ε′ increased but ε″ decreased with increasing γ. The results were inconsistent with the theory proposed by Peterlin and Reinhold.
