Patent ID: 6630271
Filing Date: 2003-10-07
Classification: C08F,H01M,Y02E

Abstract:
A vinylidenfluoride (VDF) copolymer for preparing electrolyte polymers, wherein VDF is copolymerized with perfluoroalkylvinylethers of formula (II):CXY&boxH;CZORf â€ƒâ€ƒ(II) wherein:Rf is a perfluoroalkyl group having from 1 to 3 carbon atoms; X, Y and Z equal to or different from each other are selected from F, Cl or H; wherein the amount of perfluoroalkylvinylether monomers (II) is in the range 2-5% by moles; wherein the copolymer has a melt flow index (MFI), measured at 230Â° C. according to the ASTM D-1238 method under a 10 kg load, in the range 0.1-100; said VDF copolymers obtained by emulsion polymerization at 75-120Â° C., in the presence of organic initiators; said electrolyte polymers having an ionic conductivity higher than about 10âˆ’3 S/cm, wherein the conductivity is maintained after thermal aging cycles at temperatures up to 80Â° C.