Crosslinking of poly(vinylene fluoride) separators by gamma-irradiation for electrochemical high power charge applications

• High dose of Gamma rays (Co60) causes chain scissionof PVdF based separators.
• Irradiated membranes with different cross-linkig coagents [(Triallylisocyanurate (TAIC) and a macromonomer of ethylene oxide- propylene oxide (MEP)] showed enhanced mechanical properties compared to a pristine membrane.
• The utilization of coagents is limited to 2–5% per weight in order not to produce brittle membranes.
• Porous structure of PVdF was not destroyed by irradiation.
• This reinforcement technique allows producing thinner membranes with good mechanical properties and with low ohmic contribution to the resistivity.

Macroporous poly(vinylene fluoride) (PVdF) separators were prepared by phase inversion method and introduced to a gamma (γ) radiation with and without cross-linking agents. Triallyl isocyanurate (TAIC) and a macromonomer of ethylene oxide- propylene oxide (MEP) were used as a cross-linking agent. The resulting membranes were characterized in terms of thermal and mechanical properties. Ionic conductivities were determined in a molar solution of tetraethylammonium tetrafluoroborate (TEABF4) in acetonitrile (AN) and propylene carbonate (PC). Excellent mechanical properties (250 MPa at 25 °C) and conductivities (14 mS cm−1) were obtained for the cross-linked separator prepared with TAIC.