Preparation method for synthesizing ultra-slow-release polycarboxylate superplasticizer from high-activity polyether

Abstract

The invention discloses a preparation method for synthesizing an ultra-slow-release polycarboxylate superplasticizer from high-activity polyether. The preparation method comprises the following steps:S1, uniformly mixing unsaturated carboxylic acid monomers, unsaturated carboxylic acid monobasic ester, unsaturated carboxylic acid dibasic ester, a chain transfer agent and deionized water to obtaina material A, and uniformly mixing a reducing agent and deionized water to obtain a material B; S2, adding deionized water and a high-activity polyether monomer into a reaction kettle, and carrying out stirring and dissolving at normal temperature; S3, adding an assistant into a solution obtained in the step S2 at 10-20 DEG C, carrying out stirring, starting to dropwise add the material A and thematerial B, and carrying out a curing reaction after the dropwise addition is finished; and S4, adding alkali liquor to adjust a pH value to obtain the ultra-slow-release polycarboxylate superplasticizer. The ultra-slow-release polycarboxylate superplasticizer prepared by the invention has a good slump maintaining function, and can continuously release carboxyl groups with a dispersing function in an alkaline cement paste environment, so a concrete mixture can maintain plasticity for a long time, slump maintaining time can reach more than 3 hours, and the demand for long-distance transportation and construction of concrete is met.

Description

technical field [0001] The invention belongs to the technical field of building material production, and in particular relates to an ultra-slow-release polycarboxylate water reducer and a preparation method thereof. Background technique [0002] As a new type of high-performance water reducer, polycarboxylate water reducer has the advantages of low dosage, high water reducing rate, small slump loss, strong molecular structure adjustability, no chlorine and low alkali, green and environmental protection, etc. Become one of the important components in modern concrete and construction mortar. However, there are still many problems in practical application, especially affected by factors such as cement changes, high-quality sand and gravel mud, long-distance transportation and high-temperature construction, etc., problems such as rapid loss of concrete slump and poor workability have appeared. , Seriously affect the construction and quality of the project. [0003] In order to...

AI Technical Summary

Problems solved by technology

At present, most slow-release polycarboxylate superplasticizers are synthesized with vinyl alcohol 4C (methallyl polyoxyethylene ether HPEG) and 5C (prenyl polyoxyethylene ether TPEG) macromonomers, which are subject to Influenced by the low reactivity of unsaturated double bonds, the polymerization reaction generally needs to be carried out under high temperature conditions. Although the redox agent initiation system realizes normal temperature polymerization, the reaction time is 3-5h, the production cycle is long, and the energy consumption is high.

[0004] Patent CN102503226B discloses a high-slump-retaining polycarboxylate water-reducer with slow-release effect and its preparation method, which introduces acrylamide monomers and (meth)acrylate monomers into polycarboxylates as slump-retaining aids. In the main chain of the acid molecule, the obtained water reducer has excellent slump retention performance, and the slump is basically not lost within 3 hours, but the reaction needs to be carried out at 60-80°C, the polymerization reaction time is as long as 5-7 hours, and the production energy consumption is too high ; Patent CN107325235A discloses a normal-temperature synthesis process of a slow-release polycarboxylate superplasticizer with a reaction temperature of 10-35°C. Compared with the traditional synthetic process of a slow-release polycarboxylate superplasticizer, the production method Simple and easy to operate, but because it is synthesized by monocarboxylic acid hydroxyalkyl ester, the sustained release time is relatively short, and affected by the reactivity of polyether macromonomers, there are also problems of long reaction time and high production energy consumption

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