Ester polycarboxylic acid water reducing agent with chitosan for concrete and method for preparing ester polycarboxylic acid water reducing agent

The invention provides an ester polycarboxylic acid water reducing agent with chitosan for concrete and a method for preparing the ester polycarboxylic acid water reducing agent. The ester polycarboxylic acid water reducing agent is a polymerization product with the chitosan and comprises, by weight, 0.02-12.6% of the chitosan, 4-65% of poly-oxyalkylene ester unsaturated macromonomers, 1-40% of unsaturated carboxylic acid and/or unsaturated acid anhydride, 0.02-8% of unsaturated carboxylic acid derivatives and/or unsaturated ether and 25-94% of water. Polymerization reaction is carried out on the chitosan, the poly-oxyalkylene ester unsaturated macromonomers, the unsaturated carboxylic acid and/or the unsaturated acid anhydride, the unsaturated carboxylic acid derivatives and/or the unsaturated ether and the water to obtain the ester polycarboxylic acid water reducing agent. The ester polycarboxylic acid water reducing agent and the method have the advantages that the method is simple, and the ester polycarboxylic acid water reducing agent is low in production cost; the ester polycarboxylic acid water reducing agent is high in water reducing ratio, phenomena of easiness in separation and bleeding of the concrete can be obviously improved, slump loss of the concrete can be reduced, and obvious effects of improving the later strength of the concrete can be realized.