Dielectric Relaxation of cis-Polyisoprene Chains in Oligo- and Polybutadiene Matrices: Matrix Effects on Mode Distribution and Relaxation Time

Abstract

The dielectric behavior of dilute cis-polyisoprenes (PI) chains was examined in matrices of oligo- and polybutadiene (B) chains of various molecular weights MB. The PI chains had type-A dipoles parallel along their contour so that their global motion was dielectrically detected. Specifically, the matrix effects were examined for the dielectric mode distribution as well as for the longest and second longest relaxation times, τ1,e and τ2,e. τ1,e and τ2,e were determined from dielectric loss (e‘‘) peak frequencies for PI chains without and with (symmetrical) inversion of the type-A dipoles. These relaxation times were compared at an isofrictional state: For this purpose, the relaxation times for the PI chains in short matrices of MB 9K. As done by Colby et al. (Macromolecules 1987, 20, 2226), those ζ-correction factors were determine...