Preparation method and application of polycarboxylate water reducer containing phosphate group

Abstract

The invention provides a preparation method and application of a polycarboxylate water reducer containing a phosphate group. According to the preparation method, the defects that the structure and the molecular weight of the water reducer cannot be accurately controlled due to the chain transfer action of the phosphate group can be overcome. The preparation method comprises the steps that an unsaturated polyether macromonomer, unsaturated carboxylic ester and unsaturated alcohol are subjected to a copolymerization reaction in organic solvent to obtain a polycarboxylate water reducer pre-polymer; phosphorylated modification is performed on the polycarboxylate water reducer pre-polymer; on the condition that an acid aqueous solution exists, a carboxylic ester group on a product obtained after phosphorylated modification is hydrolyzed, and the organic solvent is removed; neutralization is performed to obtain the polycarboxylate water reducer containing the phosphate group; the unsaturated polyether macromonomer does not contain hydroxyl, phosphorylated modification is achieved through the step that an alcoholic hydroxyl group in the polycarboxylate water reducer pre-polymer and a phosphate esterification reagent are subjected to an esterification reaction, and the using amount of the phosphate esterification reagent is sufficient to completely esterify the alcoholic hydroxyl group in the polycarboxylate water reducer pre-polymer.

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 CN104311752A 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 phosphine-containing monomers into the molecular chain of the water reducer. , containing silicon groups, to prepare a polycarboxylate water reducer with high water reducing rate, good slump retention, and conducive to the early strength development of concrete. Problems of low 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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