Polyetherimide membrane

摘要

A membrane has a polyimide sepg. layer which comprises 50-100 wt.% repeat units of formula (I) and 0-50 wt.% repeat units of formula (II): Where: R1, R2, R3, R4 = H, CH3, CF3 or CnH2n+1, where n<10; X1 = m-phenylene (Phe'), p-phenylene (Phe), Phe-O-Phe, Phe-O-Phe', Phe-CH2-Phe, Phe-S-Phe, Phe-CMe2-Phe, Phe-SO2-Phe, Phe-O-Phe-O-Phe or Phe-CH2-CH2-Phe. Also claimed is the use of polyimide resins, prepd. by reacting 2,2-bisphthalic anhydrido-(4)-propane or its ester, amide or acid derivs. with 2,2-bis-(4-aminophenoxyphenyl)propane or its acetyl cpd., isocyanate or carbamate in a water-miscible solvent, in the prodn. of membranes.