Preparation method and application of polycarboxylate superplasticizer containing phosphate groups

Abstract

The invention provides a preparation method and application of a polycarboxylate superplasticizer containing phosphate groups. The preparation method can overcome the defect that due to the chain transfer effect of the phosphate groups, the structure and molecular weight of the superplasticizer can not be accurately controlled. The preparation method includes the steps that firstly, unsaturated polyether macromonomers and unsaturated anhydride are subjected to a solution copolymerization reaction in an organic solvent to obtain a polycarboxylate superplasticizer prepolymer; then, the polycarboxylate superplasticizer prepolymer is subjected to phosphorylation modification to obtain the polycarboxylate superplasticizer, wherein the unsaturated polyether macromonomers do not contain OH, phosphorylation modification refers to that anhydride groups in the polycarboxylate superplasticizer prepolymer and a phosphorylation reagent are subjected to an amidation reaction to obtain the polycarboxylate superplasticizer containing the phosphate groups, molecules of the phosphorylation reagent contain one or more phosphate groups and amino capable of participating in the amidation reaction, and the molar ratio of unsaturated anhydride participating in the solution copolymerization reaction to the phosphorylation reagent is 1:(0.01-0.5).

Description

Technical field [0001] The invention relates to a preparation method and application of a polycarboxylic acid water reducer containing phosphoric acid groups, and belongs 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 following reinforced concrete and prestressed concrete. The third major breakthrough in concrete technology after concrete. [0003] Polycarboxylic acid water-reducing agent has become the most important product in the concrete admixture market due to its advantages such as low dosage, high water-reducing rate, good slump retention, strong molecular structure adjustment, and environmental protection. With the scarcity of natural high-quality sand and gravel and the development of green bu...

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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. Optimizing the superplasticizer with phosphoric acid group, the steps are cumbersome and the process control is difficult

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