Polycarboxylic acid water-reducing agent with high adaptability to temperature and method for preparing the same

A polycarboxylic acid water-reducing agent with high adaptability to temperature, wherein an unsaturated macromonomer D having a temperature-sensitive side chain is introduced in the polycarboxylic acid water-reducing agent during a synthesis process of the polycarboxylic acid water-reducing agent, wherein the unsaturated macromonomer D contains an unsaturated double bond, through free radical polymerization of which the macromonomer D is bonded to a backbone of polycarboxylic acid, and the unsaturated macromonomer D further contains a temperature-sensitive side chain;

• the unsaturated macromonomer D is prepared by a method comprising:
• carrying out a step-by-step addition polymerization reaction of polyethylene glycol A with a lactone or lactam monomer B to obtain an intermediate product C, and then reacting the intermediate product C with maleic anhydride to obtain the unsaturated macromonomer D containing the double bond at a terminal end and the temperature-sensitive side chain;
• and
• the polyethylene glycol A is commercial polyethylene glycol with hydroxyl at a terminal end, and has a number-average molecular weight of 1000-2000;
• in the step-by-step addition polymerization reaction of the polyethylene glycol A with the lactone or lactam monomer B, a mass fraction of the monomer B with respect to the substance A is 30-50%;
• and a molar ratio of the intermediate product C to the maleic anhydride is 1:2,
• wherein the polycarboxylic acid water-reducing agent is prepared by free radical polymerization of the unsaturated macromonomer D with temperature sensitivity, an unsaturated carboxylic acid monomer E, and an unsaturated polyether macromonomer F;
• a molar ratio of the unsaturated carboxylic acid monomer E to the polyether macromonomer F is 2.0-10.0;
• a mass of the unsaturated macromonomer D is 5-10% of a total mass of the monomer E and the monomer F;
• and
• a weight-average molecular weight of the polycarboxylic acid water-reducing agent is 20,000 to 100,000.