OLIGOMERIC AND POLYMERIC AROMATIC PHOSPHONIC ACIDS, THEIR BLENDS, PROCESSES FOR PREPARING THEM AND USES AS POLYELECTROLYTES

The present invention relates to halogen-free, oligomeric or polymeric phosphonic acids made up of units of the general formula (I) -[(O)m-{R1(X)n(Y)o}pR1(X)q]r-[(O)s-R5(X)t]v-(I), where: X is -P=O(OH)2, Y is carbonyl or sulfonyl, R1, R5 are, independently of one another, divalent or polyvalent, substituted or unsubstituted, heteroatom-free or heteroatom- comprising aromatic radicals, m, o, s are each, independently of one another, 0 or 1, n, q, t are each, independently of one another, 0 or an integer from 1 to 8, with n and s not simultaneously being 0, r, v are each, independently of one another, from 0 to 1, with the sum of r and v being from 0.95 to 1.05, and p is 0 or an integer >=1, where the radicals X are substituents on R1 and R5 and the radicals Y are parts of polymer or oligomer chain, to a process for preparing these compounds and also to halogen-free mixtures comprising one or more compounds of the general formula (I) and a nitrogen-free solvent having a boiling point of >150° C.