| abstract |
1. A film-forming polymeric material selected from the group consisting of (i) polymers consisting essentially of repeating units having the structure -Ar-SO2- and (ii) polymers consisting essentially of units having the structure -Ar-SO2- and units having the structure -Ar-CO-, where Ar is selected from (a) a divalent aromatic radical obtained by removal of two aromatically bound hydrogen atoms from a compound selected from the group consisting of benzene, polynuclear hydrocarbons containing not more than two aromatic rings, diphenyl, compounds having the structure <IMAGE> where Z is selected from the group consisting of -O- and -S- and where said compound contains two aromatic rings, one of said hydrogen atoms being removed from each ring, and (b) substituted derivatives of said divalent aromatic radicals in which at least one of the aromatically bound hydrogen atoms is substituted by a monovalent radical selected from the group consisting of halogen atoms, alkyl groups containing from 1 to 4 carbon atoms and alkoxy groups containing from 1 to 4 carbon atoms, at least some of the Ar units being a radical derived from said compounds of the structure <IMAGE> or said substituted derivatives thereof. |