Anti-cracking shrinkage-reducing type polycarboxylate superplasticizer and preparation method thereof

A technology of water reducing agent and polycarboxylic acid, which is applied in the field of anti-cracking and shrinkage polycarboxylate water reducing agent and its preparation, which can solve the problem of reducing the surface tension of the solution inside the cement slurry void, reducing the feasibility of industrial production, and lacking market competitiveness and other problems, to achieve excellent dispersion and retention effect, excellent crack resistance and shrinkage reduction performance, and safe and reliable preparation process

Active Publication Date: 2021-05-14
JIANGSU CHINA RAILWAY ARIT NEW MATEIRALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Represented by Japan and the United States, some shrinkage reducers such as alcohols, ethers, and alcohol amines were reported in the early stage. Such shrinkage reducers have no water-reducing effect, and the required dosage is high, and they will also have side effects of reduced strength in the later stage. , which limits their use
For domestic research, patent CN103724567A discloses a shrinkage-reducing polycarboxylate water reducer and its preparation method. The preparation method is free radical polymerization after esterification. surface tension, but the esterification reaction used in it needs to be carried out at a high temperature for a long time, which also greatly reduces the feasibility of industrial production; A shrinkage-reducing water-reducer prepared by free-radical polymerization of polyoxyethylene / polyoxypropylene polydimethylsiloxane maleate and a shrinkage-reducing water-reducer and a synthetic method thereof, and the dispersion of the shrinkage-reducing water-reducer to concrete The impact on the slump retention performance is small, but the 28-day shrinkage rate is smaller than the relative benchmark, which lacks market competitiveness

Method used

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  • Anti-cracking shrinkage-reducing type polycarboxylate superplasticizer and preparation method thereof
  • Anti-cracking shrinkage-reducing type polycarboxylate superplasticizer and preparation method thereof
  • Anti-cracking shrinkage-reducing type polycarboxylate superplasticizer and preparation method thereof

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Experimental program
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Embodiment 1

[0034] 1) Preparation of anti-cracking and shrinkage-type water reducing agent prepolymerization product: 1 mol of gallic acid and 4 mol of acetic anhydride were stirred and reacted at 50°C for 3 hours under the catalytic condition of concentrated sulfuric acid (0.2 mL), washed with water, and then mixed with allyl chloride at room temperature. Reaction 24h, obtain gallic acid derivative unsaturated small monomer; Gained small monomer (0.3mol), acrylic acid (3mol) in 50mL methanol and ammonium persulfate (0.1mol), sodium bisulfite (0.1mol) and 2-mercaptopropionic acid (0.08mol) acted together, and carried out free radical polymerization at 20°C for 4 hours to obtain a prepolymerized product;

[0035] 2) Add sodium hydroxide to the obtained prepolymerization product to make the pH of the solution 7 to 8, remove the protecting group and then evaporate the solvent; continue to add terminal halogen group modified polyether (1mol, M w =1000g / mol) of 120mL acetonitrile / water (v / v=1 / ...

Embodiment 2

[0040] 1) Preparation of anti-cracking and shrinkage type water reducing agent prepolymerization product: 1 mol of gallic acid and 4 mol of acetic anhydride were stirred and reacted at 50°C for 3 hours under the catalytic condition of concentrated sulfuric acid (0.2mL), washed with water, and then mixed with allyl bromide at room temperature. Reaction 24h, obtain gallic acid derivative unsaturated small monomer; The obtained small monomer (0.3mol), methacrylic acid (3.5mol) in 50mL acetone and hydrogen peroxide (0.15mol), sodium sulfite (0.08mol) and 3- Mercaptopropionic acid (0.07mol) acted together and carried out free radical polymerization at 30°C for 3.5 hours to obtain a prepolymerized product;

[0041] 2) Add potassium hydroxide to the obtained prepolymerization product to make the pH of the solution 7 to 8, remove the protecting group and then evaporate the solvent; continue to add terminal halogen group modified polyether (1mol, M w =800g / mol) of 120mL acetonitrile / wa...

Embodiment 3

[0046]1) Preparation of anti-cracking and shrinkage-type water reducing agent prepolymerization product: 1 mol of gallic acid and 4 mol of acetic anhydride were stirred and reacted at 50°C for 3 hours under the catalytic condition of concentrated sulfuric acid (0.2 mL), washed with water, and then mixed with allyl chloride at room temperature. React for 24h to obtain unsaturated small monomers of gallic acid derivatives; the resulting small monomers (0.3mol), acrylamide (4mol) in 50mL ethanol with potassium persulfate (0.1mol), sodium pyrosulfite (0.12mol) and 2 -Mercaptopropionic acid (0.08mol) acted together, and carried out free radical polymerization at 30°C for 4.5 hours to obtain a prepolymerized product;

[0047] 2) Add triethylamine to the obtained prepolymerization product to make the pH of the solution 7 to 8, remove the protecting group and then evaporate the solvent; continue to add halogen-modified polyether (1mol, M w =3500g / mol) in 120mL of acetonitrile / water (v...

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Abstract

The invention discloses an anti-cracking shrinkage-reducing polycarboxylic acid water reducer and a preparation method thereof. The weight-average molecular weight (Mw) of the anti-cracking shrinkage-reducing polycarboxylic acid water reducer is 10,000-100,000, and the structural formula of the anti-cracking shrinkage-reducing polycarboxylic acid water reducer is shown in the specification. The preparation method comprises the following steps: (1) introducing an unsaturated double-bond structure on the structure by taking gallic acid as a raw material to prepare a gallic acid derivative unsaturated small monomer, carrying out free radical copolymerization reaction on the water reducing agent prepolymer and carbonyl-containing unsaturated acid and derivative monomers thereof to obtain a water reducing agent prepolymer; (2) introducing a hydrophilic polyether side chain on the gallic acid derivative of the prepolymerization product to prepare the shrinkage-reducing polycarboxylic acid water reducer with excellent performance. The anti-cracking shrinkage-reducing type polycarboxylate superplasticizer prepared by the preparation method disclosed by the invention is good in stability and suitable for being stored under various extreme weather conditions; the dispersing effect in concrete is good, the shrinkage reducing effect is excellent, and cracking conditions caused by various types of shrinkage can be obviously controlled and retarded.

Description

technical field [0001] The invention relates to the field of polycarboxylate water-reducer for concrete, in particular to an anti-crack and shrinkage-reducing polycarboxylate water-reducer and a preparation method thereof. Background technique [0002] Polycarboxylate superplasticizers are now widely used in projects such as railways, bridges and houses. In terms of these infrastructure constructions, the market has higher and higher requirements for additives. However, due to unavoidable factors, concrete is prone to cracking during early hardening and later use, which affects its durability. At present, a series of protective measures have appeared on the market to deal with the cracking of concrete, such as improving the adhesive material components, adding expansion agents, mixing synthetic fibers, and formulating specific curing techniques for specific environments. However, from a comprehensive point of view, adding concrete shrinkage reducer is the simplest and most ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G81/02C04B24/32C04B103/30
CPCC08G81/025C04B24/32C04B2103/302
Inventor 卢通钱珊珊王学川赵旭彭荩影屈浩杰于鹏程郑春扬
Owner JIANGSU CHINA RAILWAY ARIT NEW MATEIRALS CO LTD
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