Preparation method of hyperbranched polycarboxylic acid containing copolymer cement dispersant

A preparation method of hyperbranched polycarboxylic acid containing copolymer cement dispersant, characterized in that Monomer A, B and C undergo the free radical copolymerization in the aqueous medium, wherein the molar ratio of Monomer A, Monomer B and Monomer C shall conform to:

• B/A=2˜10, C/(A+B+C)=0.02˜0.08, where
• Monomer A is expressed by General Formula (1):
• Where, R1 is hydrogen atom or methyl;
• X1O, CH2O, CH2CH2O;
• m is the average addition mole number of epoxy ethane, which is an integer from 5 to 200.
• Monomer B is expressed by General Formula (2):
• Where, R2 represents H or COOM;
• R3 represents H or CH3;
• M represents H, Na, K or NH4;
• Monomer C is expressed by General Formula (3):
• Where, R4 is hydrogen atom or methyl;
• X2═O, CH2O, CH2CH2O;
• Y═CH2, CH2CH2, CH(CH3), CH2CH2CH2, CH(CH3)CH2, C(CH3)2;
• n is the average addition mole number of epoxy ethane, which is an integer from 5 to 200.