PURPOSE: To obtain the titled porous hollow yarn composite membrane having high gas permeability and permselectivity and excellent resistance to heat and solvents and mechanical strength by depositing a plasma-polymerized membrane on the surface of a porous hollow yarn carrier membrane of poly(2,6- dimethylphenylene oxide).
CONSTITUTION: Poly(2,6-dimethylphenylene oxide) having a repeating unit shown by the formula is dissolved in a solvent such as N-methyl-2-pyrolidone while being heated and agitated. While the obtained soln. is kept at that temp., the soln. is extruded into a coagulation bath of water, etc., from a double-pipe nozzle, coagulated, then washed with water to extract the solvent and dried to obtain a porous hollow yarn carrier membrane. Then the carrier membrane is introduced into a reaction vessel under reduced pressure, glow discharge is generated while sending a polymerizable monomer such as methyltrivinylsilane, and a plasma-polymerized membrane is deposited on the carrier membrane to obtain a composite membrane.