The invention relates to a method for preparing pH-responsive comb-structure polycarboxylic acid through terminal group functionalization. According to the method, with a pH-responsive
monomer, unsaturated halogenated
hydrocarbon, a small
carboxylic acid momonomer and the like as raw materials, a polycarboxylate material is prepared through self-
polymerization first, then substitution and then copolymerization; namely, with the pH-responsive
monomer as a reactant, a terminal group-functionalized pH-
responsive polymer chain is produced through the self-
polymerization under the actions of an initiator and a terminal group functionalizing agent, then a
substitution reaction is performed on the terminal group-functionalized pH-
responsive polymer chain and the unsaturated halogenated
hydrocarbon to obtain a pH-responsive
macromonomer, and finally a copolymerization reaction is performed on the pH-responsive
macromonomer and the small
carboxylic acid momonomer under the action of the initiator to obtain a comb-structure
polymer which uses polycarboxylic acid as a main chain and has a
side chain with a pH-responsive function. By the method, the process is high-efficiency and energy-saving, the conversion rate of a product is high, the
functional modification of the polycarboxylic acid is successfully achieved through introduction of the pH-
responsive polymer side chain by a terminal group functionalization method, an excellent characteristic of inhibiting shrinkage of
cement mortar is shown, and the market competitiveness and the application prospect are very good.