Synthesis and characterization of UV-cured poly(siloxane-urethane) elastomers containing polyethylene oxide segments - as potential membrane materials

Conductive polymeric membranes based on poly(siloxane-urethane)s (PSUR) and designed for potential application as separators in Li-ion batteries were obtained through consecutive heat and UV curing of compositions containing NCO-terminated PSUR prepolymers with both polysiloxane (SIL) and poly(ethylene oxide) (PEO) segments in the polymer chain and unsaturated diols as chain extenders. Lithium salts in the form of solutions in ethylene carbonate/dimethyl carbonate (EC/DMC) mixture were incorporated into PSUR after curing ("post-cure" method) or (in some experiments only) also before curing (in situ method). The effect of polymer structural parameters (PEO segments content, NCO/OH ratio) as well as curing conditions and method of lithium salt incorporation on mechanical and thermal properties, swelling ability and specific conductivity of the corresponding membranes were investigated. Supramolecular structure of membranes was studied using scanning electron microscopy with X-ray analysis (SEM/EDS) technique. The selected membranes were tested as potential separators in lithium batteries.