Preparation method of fluorine-containing shrink-reduced polycarboxylate water reducing agent

A technology of water reducer and polycarboxylate, which is applied in the field of preparation of shrinkage-reducing polycarboxylate water reducer, can solve problems such as complex synthesis process and increased engineering cost, and achieve rich sources, low gas content and surface tension, and excellent performance stable effect

Active Publication Date: 2019-01-29
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the use of these shrinkage reducing agents reduces the shrinkage of concrete to a certain extent, the engineering cost is greatly increased, and the synthesis process is complicated

Method used

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  • Preparation method of fluorine-containing shrink-reduced polycarboxylate water reducing agent
  • Preparation method of fluorine-containing shrink-reduced polycarboxylate water reducing agent
  • Preparation method of fluorine-containing shrink-reduced polycarboxylate water reducing agent

Examples

Experimental program
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Effect test

Embodiment 1

[0024] 1) Preparation of carbonyl-containing polycarboxylate superplasticizer prepolymer: 0.1mol 2-keto-3-butene, 2mol acrylic acid and 1mol allyl polyethylene glycol (800g / mol) in 0.01mol sodium persulfate , under the action of 0.03mol sodium metabisulfite and 0.005mol sodium methacryl sulfonate, keep at 50°C for free radical polymerization for 3 hours to obtain a polycarboxylate superplasticizer prepolymer containing carbonyl groups;

[0025] 2) Preparation of fluorine-containing shrinkage-reducing polycarboxylate superplasticizer: mix 1 mol of carbonyl-containing polycarboxylate superplasticizer prepolymer with 0.01 mol of Prakash reagent (TMSCF 3 ) for 10 minutes of nucleophilic substitution reaction, after the reaction was completed, the pH value was adjusted to 5 with sodium hydroxide, and water was added to obtain a shrinkage-reducing polycarboxylate water reducer with a mass concentration of 5%.

Embodiment 2

[0027] 1) Preparation of carbonyl-containing polycarboxylate superplasticizer prepolymer: 0.2mol 3-methyl-4-penten-2-one, 3mol maleic anhydride and 1mol methallyl polyethylene glycol (2500g / mol) Under the action of 0.01mol potassium persulfate, 0.03mol sodium sulfite and 0.01mol mercaptopropanol, keep at 50°C for free radical polymerization for 5 hours to obtain a carbonyl-containing polycarboxylate superplasticizer prepolymer;

[0028] 2) Preparation of fluorine-containing shrinkage-reducing polycarboxylate superplasticizer: mix 1 mol of carbonyl-containing polycarboxylate superplasticizer prepolymer with 4 mol of Prakash reagent (TMSCF 3 ) for nucleophilic substitution reaction for 20 minutes, after the reaction was completed, the pH value was adjusted to 5.5 with potassium hydroxide, and water was added to obtain a shrinkage-reducing polycarboxylate-based water-reducer with a mass concentration of 15%.

Embodiment 3

[0030] 1) Preparation of carbonyl-containing polycarboxylate superplasticizer prepolymer: 0.3mol 3-buten-2-one, 4mol fumaric acid and 1mol 3-methyl-3-butene-1-polyethylene glycol (4000g / mol) under the action of 0.05mol hydrogen peroxide, 0.1mol ferrous pyrophosphate and 0.05mol mercaptoacetic acid, keep at 30°C for free radical polymerization for 3 hours to obtain a carbonyl-containing polycarboxylate superplasticizer prepolymer ;

[0031] 2) Preparation of fluorine-containing shrinkage-reducing polycarboxylate superplasticizer: 1 mol polycarboxylate superplasticizer prepolymer containing carbonyl, and 0.01mol Prakash reagent (TMSCF 3 ) for 30 minutes of nucleophilic substitution reaction, after the reaction was completed, the pH value was adjusted to 5.5 with sodium hydroxide, and water was added to obtain a shrinkage-reducing polycarboxylate water reducer with a mass concentration of 35%.

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Abstract

The invention discloses a preparation method of a fluorine-containing shrink-reduced polycarboxylate water reducing agent. The method particularly includes: 1) preparation of a polycarboxylate water reducing agent prepolymer: under effects of an initiator, a reducing agent and a chain transfer agent, performing a redox radical polymerization reaction to a carbonyl-containing monomer, an unsaturated acid monomer and an unsaturated macro-monomer to obtain a carbonyl-containing polycarboxylate water reducing agent prepolymer; 2) preparation of the fluorine-containing shrink-reduced polycarboxylate water reducing agent: performing a nucleophilic substitution reaction to the carbonyl-containing polycarboxylate water reducing agent prepolymer with a Prakash reagent (TMSCF3) to obtain the water reducing agent. The water reducing agent can significantly reduce surface tension and improve cement dispersibility, is high in shrinkage reducing performance on the basis of high water reduction, is good in compatibility with cement, is low in gas content when being applied to concrete, can effectively improve size stability of concrete and reduce shrinkage cracking and can improve the durabilityand service life of a concrete structure.

Description

technical field [0001] The invention relates to the technical field of a polycarboxylate water-reducer for cement concrete, in particular to a preparation method of a shrinkage-reducing polycarboxylate water-reducer. Background technique [0002] Cracking of concrete due to shrinkage can lead to greatly reduced strength and durability of concrete, thereby further shortening the service life of concrete. The shrinkage and cracking of concrete, especially high-performance concrete, has attracted great attention from the engineering community. Although polycarboxylate water reducers can reduce the shrinkage of concrete to a certain extent, it is still difficult to meet the needs of the project. At the same time, polycarboxylate water reducers The high air content of the polycarboxylate superplasticizer also seriously affects the strength of the concrete, so reducing the shrinkage of the concrete and reducing the air content of the polycarboxylate superplasticizer is an urgent p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F283/06C08F220/06C08F222/06C08F222/02C08F228/02C08F212/14C08F220/58C08F220/18C08F220/14C08F220/20C04B24/16C04B24/26C04B103/30
CPCC04B24/165C04B24/2605C04B24/2647C04B24/2658C04B24/267C08F283/065C04B2103/302C08F220/1803C08F220/585C08F212/14C08F220/1808C08F220/1804
Inventor 王子明钱珊珊毛倩瑾王亚丽刘晓崔素萍姚燕
Owner BEIJING UNIV OF TECH
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