| abstract |
A polymethaphenylene isophthalamide based polymer porous film having excelle nt gas permeability and resistance to heat, and a satisfactory pore structure, which may be produced by a method comprising casting a dope of polymethaphenylene isophthalamide onto a support and coagulating it in a coagulation bath. The porous film may contain an inorganic whisker and may form a composite porous film together with another thermoplastic polymer fil m. |