English Abstract
Effect of Humidity on Ionic Conductivity of NBR/Polyether Electrolyte Blends with Microscale Sea-Island Phase Separation

Shigeo ASAI*2
Masao SUMITA*2
*1:Department of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology (Koganei-shi, Tokyo, Japan)
*2:Department of Chemistry and Materials Science, Tokyo Institute of Technology (Meguro-ku, Tokyo, Japan)
Nippon Gomu Kyokaishi,(2009),82(12),499-506 Original Paper in Japanese

Novel ion-conductive elastomer blends containing polyether-based solid polymer electrolyte (SPE) were prepared by the radical polymerization of oligo[(ethylene oxide)-co-(propylene oxide)] methacrylate (M(EO/PO)) monomer with LiClO4 in NBR. Obtained samples showed micro- (or nano-) scale Sea-Island phase separation, which was revealed from the TEM observation in case of NBR18/PM(EO/PO)mono-LiClO4 50/50 wt% blend, and the DC conductivity under dry N2dry) was approximately 10-8 S cm-1 at 25 . The difference in the conductivity of blend samples between dry and wet conditions was very small, whereas the conductivity of PM(EO/PO)-LiClO4 without NBR under wet condition (σwet) was 10-times higher than σdry. Moreover, the σdry of NBR43 blend sample (NBR43/electrolyte = 30/70 wt%) was higher than that of the neat electrolyte. The complex impedance measurement revealed that AC ionic conductivity of the NBR43 blend sample was 6.7 x 10-6 S cm-1 at 25 and the value was approximately 6-times higher than that of the neat electrolyte. This may be caused by accelerated ion-conduction between the electrolyte islands or on the NBR/electrolyte interface where the resistance is very small because of the electrical interactions between Li ions (or Li+-polyether complex domains) and nitrile groups of NBR.

(Received on January 29, 2009)
(Accepted on August 3, 2009)

Elastomer Blends, Solid Polymer Electrolytes, Lithium Salts, Ionic Conductivity, Morphology, Sea-Island, Phase Separation