D.s.c., electrical conductivity, and n.m.r. studies of salt precipitation effects in PPO complexes
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Differential scanning calorimetry (d.s.c.) and electrical conductivity measurements of poly(propylene oxide), PPO, complexed with the salts NaI and KSCN are reported. In addition, 23Na n.m.r. measurements on PPO-NaI (x = 8), both at ambient and elevated pressure (2 kbar), have been performed. The d.s.c. data clearly indicate that the salt precipitates out of the complexes at about 85°C for NaI and 60°C for KSCN. These effects are manifested by a dramatic departure of the conductivity from Vogel-Tammann-Fulcher (VTF) behaviour, and a relatively sharp drop in mobile Na+ concentration, as deduced from n.m.r. measurements, above about 80°C. High pressure n.m.r. linewidth measurements are consistent with a pressure-induced increase in glass transition temperature.
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