High Ion Conducting 3D Network Poly(Ethylene Oxide)
Date
1996-08-10
Authors
Perera, K. S.
Dissanayake, M. A. K. L.
Bandaranayake, P. W. S. K.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya, Peradeniya
Abstract
Studies of ionic conductivity in polymers complexed with divalent or trivalent cations are useful for understanding the parameters related to conductivity in polymers. In the present work a calcium salt has been selected since it is less hygroscopic than corresponding alkaline salts when dissolved in poly (ethylene oxide) network. The polycondensation between ex, ro - diol-poly (ethylene glycol), H(OCH2CH2).,OH with average MW 1000 and 3-chloro-2- chloromethyl-l-propane was done in the presence of excess KOH. The average molecular weight of the linear polycondensate determined by gel permeation chromatography was about 20,000. Cross-linking of linear polycondensate was done by free-radical polymerization using dibenzoyl peroxide as initiator to obtain a thin film of 3D network polymer. Membranes of 11 mm diameter were cut from the completely dried films. To prepare samples of different O/Ca ratio, calcium trifluoromethyl-sulphonate Ca(CF3S03h salt was dissolved in a small amount of acetonitrile and the membrane was put to absorb the whole solution. It was possible to prepare sample with O/Ca ratio from 8 to 100. Then the membranes were dried under vacuum at 90°C for one day. The electrical conductivity of membranes was measured under vacuum by a complex impedance technique in the temperature range from 90°C to room temperature. The maximum conductivity was obtained for O/Ca=25 which is about 2.0 x }O"4 S em" at 75°C and 1.0 x 10.5 S em" at room temperature. Polymers synthesized in this method have glass transition temperatures below room temperature and hence, give a very high ionic conductivity and have very good mechanical properties due to three dimensional link
Description
Keywords
Physics , Ionic conductivity , Poly(Ethylen Oxide)
Citation
Proceedings of the Annual Research Sessions, August 10,1996, Uninversity of Peradeniya, Peradeniya, Sri Lanka, pp 151