Polymers for cement dispersing mixtures.

A modified acrylic polymer obtainable by reacting (A) a poly (acrylic acid) with endgroups from initiators and / or transfer agents chain that are inert for condensation reactions, said poly ( acrylic acid) a-1 a molecular weight of 500 to 20,000 ** ** and formula (B) or molar parts of a monofunctional polyalkyleneglycolmonoalkylether B-1 HO- (AO) r- (BO) sR 1 B-1 and / or optionally (C) p molar parts of a -aminopolialquilenglicol - - monofunctional alkyl C-1 H2N- (AO-) t- (BO-) uR 1 (C-1) i / or optionally (D) q molar parts a primary or secondary amine D-1 ** ** formula wherein R represents a hydrogen atom, a methyl group, or a mixture thereof: M representaunatomo hydrogen, an alkyl C1-C5, an alkali metal , alkaline earth metal or other di- or trivalent metal atoms, an ammonium or organic ammonium or a mixture thereof; each R 1 is independently an alkyl C1-C4. A and B represent alkylene groups with 2 to 4 carbon atoms, the mixture of (AO) and (BO) may be formed by a random addition or by a block addition, and (AO) 6 = (BO) .