The present invention relates to copolymers which are obtainable from the free-radical copolymerization of at least (a) a monoethylenically unsaturated carboxylic acid having from 3 to 6 carbon atoms or its anhydride with (b) a reaction mixture comprising a component of the general structural formula (I) where R1, R2, R3, R4 are each independently H or C1-C4-alkyl, n and m are each independently an integer from 1 to 100 and R5 is H or methyl, to a process for preparing the inventive polymer and to its use as a scale inhibitor.