Preparation method and application of polycarboxylate water reducer containing phosphate groups

Abstract

The invention provides a preparation method and application of a polycarboxylate water-reducer containing phosphate groups. The preparation method can avoid the disadvantage that the structure and molecular weight of the water-reducer cannot be accurately controlled due to the chain transfer effect of the phosphoric acid group. . The preparation method is to first carry out copolymerization reaction of unsaturated polyether macromonomer, unsaturated carboxylic acid ester, and unsaturated alcohol in an organic solvent to obtain a polycarboxylate water-reducer prepolymer, and then make the polycarboxylate water-reducer The prepolymer is phosphorylated and modified, and then in the presence of an acidic aqueous solution, the carboxylate group on the phosphorylated and modified product is hydrolyzed, and the organic solvent is removed, and finally neutralized to obtain the phosphate group-containing Polycarboxylate superplasticizer, in which the unsaturated polyether macromonomer does not contain hydroxyl groups; phosphorylation modification is to esterify the alcoholic hydroxyl groups in the polycarboxylate superplasticizer prepolymer with phosphoric acid esterification reagents Reaction; the amount of the phosphoric acid esterification reagent is enough to completely esterify the alcoholic hydroxyl group in the polycarboxylate superplasticizer prepolymer.

Description

technical field [0001] The invention relates to a preparation method and application of a phosphate group-containing polycarboxylate water reducer, belonging to the technical field of concrete admixtures. Background technique [0002] The addition of chemical admixtures can greatly improve the durability, workability, applicability, economy and strength of concrete, and provide a strong guarantee for the quality of large-scale projects. Therefore, its wide application is known as the successor to reinforced concrete and prestressed concrete. The 3rd major breakthrough in concrete technology after concrete. [0003] Polycarboxylate superplasticizer has become the most important product in the current concrete admixture market due to its advantages such as low dosage, high water reducing rate, good slump retention, strong molecular structure adjustability, and environmental protection. With the scarcity of natural high-quality sandstone and other material resources and the de...

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Problems solved by technology

[0010] Chinese patent document CN 104311752 A reports a preparation method of a polycarboxylate water reducer. Some unsaturated phosphine-containing and silicon-containing monomers are added to the raw materials for synthesizing the water reducer, thereby introducing some Containing phosphine and silicon groups, a polycarboxylate superplasticizer with high water reducing rate, good slump retention, and early strength development of concrete is prepared to overcome the ubiquity of polycarboxylate superplasticizers in machine-made sand. Problems of low water reducing rate and poor slump retention

Therefore, in the copolymerization reaction of water reducer involving unsaturated monomers containing phosphoric acid groups, there is the possibility of changes in the structure and molecular weight of the water reducer, and the structure and molecular weight of the water reducer cannot be accurately controlled. To optimize the water reducing agent of the group, the steps are cumbersome and the process control is difficult

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