Broadband dielectric spectroscopy studies of glassy-state relaxations In annealed poly(2,5-benzimidazole)

摘要

A broadband dielectric spectroscopic (BDS) study of poly(2,5-benzimidazole) revealed three sub-glass relaxations and the manner in which the time scales of these local molecular motions shift with annealing temperature and time. Also issuing from the BDS studies was a trend in the degree of connectivity of charge migration pathways and conductivity with annealing temperature and time. These studies were complemented with dynamic mechanical analysis, which showed the same relaxations, and solid state ~1H and ~(13)C NMR studies that showed hydrogen bonding group mobility versus temperature. Wide angle X-ray diffraction investigations indicated an increase in chain-packing efficiency that was used to rationalize the BDS and NMR results.