Perfluoroalkyl sulfide, sulfone, polysulfone and polysulfide diols

A polyurethane having a molecular weight of from about 3,000 to 30,000 which consists of or contains repeating units of the formula V ##STR10## wherein R.sub.x is hydrogen or methyl,

• R.sub.5 is aromatic, aliphatic or cycloaliphatic
• R.sub.1 is a direct bond, a linear or branched alkylene of up to 6 carbon atoms, alkyleneoxyalkylene of up to 6 carbon atoms, alkylenethioalkylene of up to 6 carbon atoms, alkyleneoxy of up to 6 carbon atoms, alkenyleneoxyalkylene of up to 6 carbon atoms, alkylenethioalkyleneoxyalkylene of up to 9 carbon atoms, carbonamidoalkylene where the alkylene moiety contains up to 6 carbon atoms and the amido nitrogen is unsubstituted or further substituted by lower alkyl, sulfonamidoalklyene wherein the alkylene moiety contains up to 6 carbon atoms and the amido nitrogen is unsubstituted or further substituted by lower alkyl;
• carbonamidoalkylenethioalkylene wherein the carbonamidoalkylene moiety is as defined hereinabove and the thioalkylene moiety contains up to 6 carbon atoms, or sulfonamidoalkylenethioalkylene wherein the sulfonamidoalkylene moiety is as defined hereinabove and the thioalkylene moiety contains up to 6 carbon atoms, d is 0or 1,
• D is an alkylene group with 2 to 10 carbon atoms, a dialkylene ether group with 4 to 10 carbon atoms, or pentaerythritol diacetate or dipropionate, and
• R.sub.F is a monovalent, perfluorinated, alkyl or alkenyl, straight, branched or cyclic, organic radical having 3 to 20 fully fluorinated carbon atoms, which radical can be interrupted by one or more divalent oxygen or sulfur atoms, and each R.sub.F radical is the same or different.