To improve retention of slump of concrete while keeping normal setting characteristics by including a polyimide or polyamide skeleton unit substituted with a hydrophilic side chain having hydrophilic side chain of a grafted oligomer or polymer binding to amide and/or (thio)ester.
A polysuccinimide obtained by reacting maleic acid with ammonia is reacted with a nucleophilic monomethoxypolyethylene glycol, amine or thiol and the reaction product is treated with an alkali hydroxide to provide a polymer dispersant of the formula [X is H, etc.; R is 1-6C alkyl ether, etc.; Q is 0, etc.; (p) is 1-300; R1 is a hydrocarbon group, etc.; Y is a hydrophobic hydrocarbon group, etc., which acts as a deforming agent] containing a polyimide or polyamide skeleton unit substituted with hydrophilic side chain having a hydrophilic side chain of a grafted oligomer or polymer binding to amide and/or (thio)ester at at least certain ratio.
LU RUNHAI
BROWER LYNN E
SHENDY SAMY M
PACKE-WIRTH RAINER
GAO HONG
