FILM FOR REINFORCING ELECTROLYTE MEMBRANE OF SOLID POLYMER FUEL CELL

摘要

Disclosed is a biaxially oriented film which is suitable as a reinforcing member for electrolyte membranes of solid polymer fuel cells. The biaxially oriented film exhibits excellent hot water resistance in high-temperature high-humidity environments in which the film is used, and can maintain reinforcing effects for a long time. Specifically disclosed is a biaxially oriented film for reinforcing electrolyte membranes of solid polymer fuel cells, which is characterized in that (i) the film is mainly composed of a syndiotactic polystyrene; and (ii) the Young's modulus of at least one of the lengthwise direction or the widthwise direction is not less than 4500 MPa but not more than 8000 MPa.