Preparation method of viscosity-reducing mud-resistant polycarboxylic acid water reducing agent

Abstract

The invention belongs to the field of concrete water reducing agents, and particularly relates to a preparation method of a viscosity-reducing mud-resistant type polycarboxylic acid water reducing agent, which comprises the following steps: uniformly mixing trifluoroacetic acid and a catalyst, adding an enol compound into a mixed solution, carrying out reflux reaction, and after the reaction is completed, distilling and collecting a product to prepare a viscosity-reducing functional monomer I; dissolving a polyether monomer and a benzylidene nitrile compound in water to form a water phase system, dissolving a reducing agent and a chain transfer agent in water to serve as a solution A, and dissolving a carboxyl small monomer and a viscosity-reducing functional monomer I in water to serve as a solution B; and adding an initiator into the water-phase system, then dropwise adding thesolution A and the solution B into the water-phase system, completely reacting at a certain temperature, preserving heat and curing for 2-4 hours, and finally adjusting the pH value to be neutral, thereby obtaining the viscosity-reducing and mud-resistant polycarboxylate superplasticizer. The viscosity-reducingmud-resistant type water reducing agent prepared by the invention can obviously reduce the use dosage of the water reducing agent and prolong the slump retaining time of concrete. The viscosity-reducingmud-resistant type water reducing agent has an excellent viscosity reduction effect, reduces the plastic viscosity of concrete and improves the construction performance of concrete.

Description

technical field [0001] The invention belongs to the field of concrete water reducers, and in particular relates to a preparation method of a viscosity-reducing and mud-resistant polycarboxylate water reducer. Background technique [0002] With the development of the concrete field and the national infrastructure industry, various concrete admixtures are used to improve the performance and physical properties of concrete. The most widely used admixture is the water reducer, and its total consumption accounts for more than 80% of the total admixture. The polycarboxylate superplasticizer (PCE) invented in the early 1980s, as a new type of comb-type superplasticizer, means a milestone in the progress of concrete technology. Although PCE has the advantages of small dosage, high water-reducing rate, and good slump-retaining performance, and its practical application is becoming more and more extensive, there are still some aspects that need to be improved. Among them, PCE has str...

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Problems solved by technology

[0003] At present, the development of functional polycarboxylate superplasticizers has become the consensus of researchers in the industry. In recent years, mud-resistant and viscosity-reducing polycarboxylate superplasticizers have attracted a large number of scholars to conduct related research. For example, in CN110563891A, polyether large orders Polymer, unsaturated carboxylic acid, functional monomer, initiator, chain transfer agent and olefin containing ester functional group are reacted under the action of initiator to prepare a water reducing agent with both viscosity reducing and anti-sludge functions. The product has certain anti-sludge effect, but only phosphates are used as functional monomers, and the anti-mud and viscosity-reducing effects are very limited

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