NMR, DSC, DMA, and High Pressure Electrical Conductivity Studies in PPO Complexed with Sodium Perchlorate

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Abstract
Audio frequency electrical conductivity, DSC, DMA, and 23Na 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 which are about 72°C higher than the “central” 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 290–380 K and at pressures up to 0.65 GPa from 315–370 K. From a VTF analysis is found to be about 0.09 eV, and is found to be about 45°C below the “central” glass transition temperature which is the same behavior observed previously for PPO complexed with lithium salts and for the α relaxation in uncomplexed material. In addition, it is found that the vacuum activation volumes for the electrical conductivity and the α relaxation are approximately the same when compared relative to . The 23Na NMR measurements reveal the presence of both bound and mobile sodium species, where the bound species constitutes only about 20% of the total sodium at temperatures below , and is no longer observable above about 80°C. In addition the mobile23Na resonance becomes motionally narrowed above . The NMR results combined with conductivity data imply that ion motion is controlled by large scale segmental motions of the polymer chains.

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