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Preparation method of slow-setting polycarboxylic acid water reducing agent

A technology of slow-setting polycarboxylic acid and slow-coagulation carboxylic acid, which is applied in the field of concrete water reducing agent, can solve the problems of covering up, increasing the difficulty of engineering construction, affecting the popularization and application of polycarboxylate water reducing agent, etc., and achieving good results Flow properties and retarding properties, the effect of good market application prospects

Active Publication Date: 2011-08-17
FUJIAN CONSTR ENG GRP BUILDING MATERIAL SCI & TECH DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the problem of polycarboxylate superplasticizers used in the market is that they are adaptable to cement, which shows that the slump fluidity changes greatly, which increases the difficulty of engineering construction and affects the performance of polycarboxylate superplasticizers. Promote application
Of course, compounding technology is also one of the ways to solve the problem, but the degree of solving problems by relying on compounding is limited. Compounding is also at the expense of a certain aspect of performance. Compounding will also cover up the root of the problem and hinder the development of technology.
In addition, the solution of the water-reducing agent compounded with retarder will show inhomogeneity, and sedimentation and stratification will appear after standing, which will cause great differences in the performance of cement concrete.

Method used

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  • Preparation method of slow-setting polycarboxylic acid water reducing agent

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0013] Example 1: 1) Preparation of macromonomer MPEG-MAA: Add 0.4 g of hydroquinone and 110 g of MPEG into a 250 mL three-necked flask, gradually raise the temperature to 60°C under stirring, then slowly add 10.3 g of MAA and 2.2 g of concentrated sulfuric acid. After half an hour of heat preservation, the temperature was raised to 90° C., 36 g of cyclohexane was added, and the reflux was continued for 5 hours. The cyclohexane was removed by distillation and cooled to room temperature to obtain the macromonomer MPEG-MAA. 2) Preparation of macromonomer MAH–β–CD: Add 5.675 g of β–cyclodextrin, 1.5 g of MAH and 28.6 g of DMF into a round-bottomed flask, raise the temperature to 80°C with stirring, and keep the reaction for 7 hours to obtain the macromonomer Add 70 g of distilled water to the bulk MAH–β–CD solution, distill under reduced pressure, and dry it at 80°C for later use. 3) Preparation of water reducer: first add 40 grams of deionized water to a four-necked flask, and...

Embodiment 2

[0014] Example 2: 1) Preparation of macromonomer MPEG-MAA: Add 0.5 g of hydroquinone and 110 g of MPEG into a 250 mL three-necked flask, gradually raise the temperature to 60°C under stirring, then slowly add 12.8 g of MAA and 2.2 g of concentrated sulfuric acid. After half an hour of heat preservation, the temperature was raised to 95° C., 37 g of cyclohexane was added, and the reflux was continued for 5.5 hours. The cyclohexane was removed by distillation and cooled to room temperature to obtain the macromonomer MPEG-MAA. 2) Preparation of macromonomer MAH–β–CD: Add 5.675 g of β–cyclodextrin, 2.0 g of MAH and 29.6 g of DMF into a round-bottomed flask, raise the temperature to 85°C with stirring, and keep the reaction for 7.5 hours to obtain the macromonomer Add 75 g of distilled water to the bulk MAH–β–CD solution, distill under reduced pressure, and dry it at 80°C for later use. 3) Preparation of water reducer: first add 45 grams of deionized water to a four-necked flask,...

Embodiment 3

[0015] Example 3: 1) Preparation of macromonomer MPEG-MAA: Add 0.6 g of hydroquinone and 110 g of MPEG into a 250 mL three-neck flask, heat up to 60°C under stirring, then slowly add 15.3 g of MAA and 2.2 g of concentrated sulfuric acid . After half an hour of heat preservation, the temperature was raised to 100° C., 38 g of cyclohexane was added, and the reflux was continued for 6 hours. The cyclohexane was removed by distillation and cooled to room temperature to obtain the macromonomer MPEG-MAA. 2) Preparation of macromonomer MAH–β–CD: Add 5.675 g of β–cyclodextrin, 2.5 g of MAH and 30.6 g of DMF into a round bottom flask, heat up to 90°C under stirring, and keep the reaction for 8 hours to obtain macromonomer Add 80 g of distilled water to the bulk MAH–β–CD solution, distill under reduced pressure, and dry it at 80°C for later use. 3) Preparation of water reducer: first add 50 grams of deionized water to a four-neck flask, and then make a mixed monomer with 20 grams of m...

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Abstract

The invention relates to a preparation method of a slow-setting polycarboxylic acid water reducing agent, which is implemented by carrying out free radical copolymerization reaction on allylsulfonate monomers, acrylic monomers, polyethylene glycol nono-methyl ether methacrylate macromonomers and maleic anhydride grafted beta-cyclodextrin macromonomers. The invention is characterized in that a beta-cyclodextrin side chain is introduced into a polycarboxylic acid main chain, so that the polycarboxylate water reducing agent has favorable slow setting property, micro air-entraining property and better fluidity. The obtained polycarboxylic acid water reducing agent has the advantages of stable product performance, strong adaptability to cement and favorable compatibility; and the cement paste fluidity is up to higher than 290mm (W / C=0.29), the water reducing rate of concrete is up to 30-40%, and the slump protection time is 3-5 hours. The preparation method provided by the invention has the characteristics of unique technique, excellent product performance and the like.

Description

technical field [0001] The invention belongs to the technical field of concrete water reducers, and relates to a preparation method of a slow-coagulation carboxylic acid water reducer used in concrete construction. Background technique [0002] As a new type of water reducing agent developed in the past 20 to 30 years, polycarboxylate water reducing agent has the advantages of low dosage and high water reducing rate, and its performance is better than that of lignosulfonate, melamine and naphthalene water reducing agent. It is much better and has the advantages of green and environmental protection. It is widely used in various projects and has a good application prospect. At present, the problem of polycarboxylate superplasticizers used in the market is that they are adaptable to cement, which shows that the slump fluidity changes greatly, which increases the difficulty of engineering construction and affects the performance of polycarboxylate superplasticizers. Promote ap...

Claims

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Application Information

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IPC IPC(8): C08G65/00C08F290/06C04B103/30C08B37/16C08F290/10C04B24/16
Inventor 吕生华高瑞军段建平闫小亮侯明明
Owner FUJIAN CONSTR ENG GRP BUILDING MATERIAL SCI & TECH DEV
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