| abstract |
The present invention relates to polymer membranes on the basis of polyviidene fluoride (PVDF), a process for the production thereof and their use for ultrafiltration. The membranes are produced according to known techniques from homogeneous solutions containing 5 to 30% by weight of PVDF and 0.01 to 30% by weight of sulfonic acids and/or their salts, obtainable by sulfonation of the polyetheretherketones of formula (I) and/or subsequent neutralization of the sulfonic acids. The membranes are then treated with methanolic solutions containing 0.1 to 5% by weight of the above-mentioned sulfonic acids and/or their salts. This process supplies membranes having excellent hydrophilic properties, high thermal and mechanical stabilities and high trans-membrane flows. n n --(--O--p--C.sub.6 H.sub.4 --O--p--C.sub.6 H.sub.4 --CO--p--C.sub.6 H.sub.4 n n --) n -- (I) |