. . "tituted or unsubstituted divalent hydrocarbon residue, each R5 is the same or different and is a substituted or unsubstituted divalent hydrocarbon residue, R6 is hydrogen, a substituted or unsubstituted monovalent hydrocarbon residue or an ionic substituent, a and b are the same or different and are a value of 0 or 1, and x and y are the same or different and are a value of 0 or greater; provided" . .