DSC and high pressure conductivity and electrical relaxation measurements in PPO and PPO complexed with lithium salts

Abstract

Differential scanning calorimetry and high pressure electrical conductivity studies have been carried out on poly(propylene oxide) after the addition of various lithium salts. In addition, high pressure electrical relaxation measurements have been performed in the glass transition region on uncomplexed PPO. The vacuum conductivity measurements show that T 0 is 30–40°C lower than the DSC Tg. Next, it is found that both T 0 and Tg increase several K/kbar. In terms of the configurational entropy model, the isobaric data yield a reasonable value for the activation volume which is consistent with values previously reported for PEO complexed with alkali metal ions. The isothermal data yield a negative activation volume for PPO complexed with LiSCN. Finally, DSC and isothermal conductivity measurements show that neither T g nor the apparent activation volume scale directly with ion size.