NMR(Nuclear Magnetic Resonance), DSC(Differential Scanning Calorimetry), DMA, and High Pressure Electrical Conductivity Studies in PPO (Poly(Propylene)Oxide) Complexed with Sodium Perchlorate

摘要

Audio frequency electrical conductivity, DSC, DMA, and 23 Na NMR measurements have been carried out on Parel 58 elastomer complexed with sodium perchlorate. (As Parel 58 is primarily poly(propylene oxide), it will be referred to as PPO.) The DSC and DMA measurements yield similar values for Tg which are about 72 C higher than the central Tg for uncomplexed PPO. In addition, the DSC studies show that the sodium perchlorate is insoluble above about 140 C. The conductivity measurements have been carried out in vacuum over the temperature range 290-370K. From a VTF analysis Ea is found to be about 0.09 eV and T0 is found to be about 45 C below the central glass transition temperature which is the same behavior observed previously for PPP complexed with lithium salts and for the alpha relaxation in uncomplexed material. In addition, it is found that the vacuum activation volumes for the electrical conductivity and the alpha relaxation are approximately the same when compared relative to the 23Na NMR measurements reveal the presence of both bound and mobile sodium species, the relative concentrations of which change by about a factor of ten over the temperature range -90 to +90 C. In addition the mobile 23Na resonance becomes motionally narrowed above Tg. The NMR results combined with the conductivity data imply that ion motion is controlled by large scale segmental motions of the polymer chains.