| abstract |
PURPOSE:To obtain a gas separation membrane having high heat resisting and mechanical properties, method for forming a membrane therefrom being simple, an asymmetrical hollow yarn membrane being easily forming therefrom, handling thereof being easy, by using polyalylate of aromatic condensed ring represented by a specific formula as a material for forming a membrane. CONSTITUTION:Terephthalic acid dichloride or isophthalic acid dioxide are reacted with 9,9-bis(4-hydroxyphenyl)fluorene in 1,2-dichloroethane to obtain polyalylate, comprising either (a) or (b), or a mixture of (a) and (b) represented by the general formulas, wherein R: H, Ch3, C2H5; which is used as a material for membranes. The polyalylate is dissolved into a solvent such as N-methyl pyrrolidone etc., to prepare a raw liquid for producing membranes, whereby wet hollow yarn membranes are formed by wet type membrane forming method. By removing solvent from said wet hollow yarn membranes and drying them, gas separation membranes are obtained, which are effective as oxygen-enriching membranes to supply oxygen-enriched air even at high temperatures, and hydrogen separation membranes having high heat resisting properties. |