Anti-mud type phosphate modified polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention discloses an anti-mud type phosphate modified polycarboxylate superplasticizer and a preparation method thereof. The method specifically comprises the following steps: performing oxidation-reduction free radical polymerization reaction on unsaturated carboxylic acid micro-monomer and unsaturated polyether macro-monomer in the presence of an initiator, a reducing agent and a chain transfer agent, thereby acquiring a carboxyl-containing polycarboxylate superplasticizer prepolymer; with diphenyl phosphoryl chloride, modifying the carboxyl-containing polycarboxylate superplasticizer prepolymer partially, thereby acquiring a phosphate based copolymerization product; after completing the reaction, regulating the pH value to 6-7 and adding water, thereby acquiring the polycarboxylate superplasticizer. According to the invention, the side chain of the polycarboxylate superplasticizer is modified into a phosphate group containing two benzene rings and the phosphoric acid functional group enters into the carminate element of the polycarboxylate superplasticizer, so that the sulfate radical resisting capacity and anti-mud capacity of the polycarboxylate superplasticizer are promoted. The introduction of the benzene rings can greatly increase the physical size of the side chain of the polycarboxylate superplasticizer and the polycarboxylate superplasticizer is unlikely to be inserted into the layered structure of clay, so that the anti-mud effect can be achieved and the intrinsic function of the polycarboxylate superplasticizer is not influenced.

Description

technical field [0001] The invention relates to the technical field of a polycarboxylate water reducer for cement concrete, in particular to a mud-resistant polycarboxylate water reducer and a preparation method thereof. Background technique [0002] Polycarboxylate superplasticizers are more and more widely used in concrete engineering because of their excellent properties such as high water reducing rate, good slump retention, low dosage, strong molecular structure adjustability, and environmental protection. However, a large number of engineering examples and studies have shown that compared with traditional naphthalene-based, melamine-based and sulfamic acid-based water-reducers, polycarboxylate-based water-reducers are more sensitive to the clay content of aggregates. The mud in the mixture will absorb the polycarboxylate superplasticizer. With the increase of the mud content, the water reducing and dispersing ability of the polycarboxylate superplasticizer will be seve...

AI Technical Summary

Problems solved by technology

This method is used for straight-chain condensation water reducers, and its water reduction rate and retention are relatively poor compared to comb-shaped polycarboxylate water reducers

[0005] Chinese patent document CN 105418857 A reports a preparation method of a phosphate-based polycarboxylate water reducer, which is to firstly carry out unsaturated polyether macromonomer, unsaturated carboxylic acid ester, and unsaturated alcohol in an organic solvent. Copolymerization reaction to obtain polycarboxylate superplasticizer prepolymer, then phosphorylate and modify the polycarboxylate superplasticizer prepolymer, and then in the presence of acidic aqueous solution, make the carboxylate on the phosphorylated modified product The group is hydrolyzed, and the organic solvent is removed, and finally neutralized to obtain the polycarboxylate water reducer containing phosphate groups, but the production process of this invention is complicated, and the conversion rate is not high, the production cost is high, and a large amount of organic Solvent, not conducive to large-scale production and application

This method has a long reaction time, harsh industrial conditions, low esterification yield, and high initial investment in industrial production equipment.

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