Gypsum water reducing agent as well as preparation method and application thereof

The invention belongs to building material admixtures, and particularly relates to a gypsum water reducer as well as a preparation method and application thereof. The preparation method of the gypsum water reducing agent comprises the following steps: performing free radical polymerization reaction on an esterified macromonomer, acrylic acid and an ethylene glycol monovinyl polyoxyethylene ether macromonomer in the presence of a chain transfer agent and a redox initiator, the esterified macromonomer is an esterification reaction product of methoxy polyethylene glycol and 1-butylene-2, 3, 4-tricarboxylic acid, and the redox initiator is a mixture of a chain transfer agent and a redox initiator. The obtained free radical polymerization reaction product is the gypsum water reducing agent. The gypsum water reducer obtained by the method provided by the invention is small in fluidity time loss, and has great industrial application prospects. 本发明属于建筑材料外加剂，具体涉及一种石膏减水剂及其制备方法和应用。所述石膏减水剂的制备方法包括将酯化大单体、丙烯酸和乙二醇单乙烯基聚氧乙烯醚大单