The invention relates to polymers in a solid state which may be obtained by reaction of at least one polymer, produced from at least one monomer, selected from unsaturated mono- or di-carboxylic acids, or analogues of unsaturated mono- or di-carboxylic acids and optionally at least one ethylenically-unsaturated monomer with at least one polymer which is terminated at one end by terminal groups which are non-reactive under normal reaction conditions and hydroxy- or amino-functionalised at the other end thereof and, optionally, at least one amine. The invention further relates to polymers in a solid sate which may be obtained by the reaction of at least one monomer, selected from unsaturated mono- or di-carboxylic acids or analogues of unsaturated mono- or di-carboxylic acids in the presence of a radical initiating agent with at least one monomer, selected from the group of unsaturated esters or amides of a polymer, terminated at one end by terminal groups which are non-reactive under normal reaction conditions and hydroxy- or amino-functionalised at the other end thereof, with optionally at least one ethylenically unsaturated monomer. The production and use of solid polymers as dispersants and fluidising agents in cement systems is also disclosed.