Method for synthesizing polycarboxylate superplasticizer through RAFT method

A technology of polycarboxylic acid and water reducing agent, applied in the field of polycarboxylic acid water reducing agent, can solve problems such as few research reports, and achieve the effects of high chain transfer efficiency, simple process and mild reaction conditions

Active Publication Date: 2015-12-16
SOUTH CHINA UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the existing reports on aqueous RAFT living polymerization, there are

Method used

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  • Method for synthesizing polycarboxylate superplasticizer through RAFT method
  • Method for synthesizing polycarboxylate superplasticizer through RAFT method
  • Method for synthesizing polycarboxylate superplasticizer through RAFT method

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0050] Example 1 Preparation of polycarboxylic acid water reducing agent

[0051] (1) Add 120g of TPEG macromonomer to the reaction kettle, add 117.5g of water, heat the reaction kettle to 80°C in a water bath, and continue to stir;

[0052] (2) 14.4g of acrylic acid and 40g of water are mixed uniformly, 2.256g of BDATT is added to the mixed solution to dissolve, and the mixture is dropped for 3h at a uniform speed;

[0053] (3) Dissolve 0.5424g of azobisisobutylamidine dihydrochloride in 20g of water, and start dropping the solution in step (2) at a uniform rate into the reaction kettle of step (1) at the same time, and the dropping time is 3h;

[0054] (4) After the dripping is finished, continue the constant temperature stirring reaction for 4h;

[0055] (5) After the reaction is over, add 30% NaOH aqueous solution and 10 g of water, and cool to room temperature to obtain the polycarboxylic acid water reducing agent.

Example Embodiment

[0056] Example 2 Preparation of polycarboxylic acid water reducing agent

[0057] (1) Add 120g of TPEG macromonomer to the reaction kettle, add 137.5g of water, heat the reaction kettle to 80°C in a water bath, and continue to stir;

[0058] (2) 14.4 g of acrylic acid and 30 g of water are mixed uniformly, 2.256 g of BDATT is added to the mixed solution to dissolve, and the mixture is added dropwise for 3 hours;

[0059] (3) Dissolve 0.2282g of ammonium persulfate in 20g of water, and start dropping the solution in step (2) at a uniform rate into the reaction kettle of step (1) at the same time, and the dropping time is 3h;

[0060] (4) After the dripping is finished, continue the constant temperature stirring reaction for 5 hours;

[0061] (5) After the reaction is completed, a 30% NaOH aqueous solution is added, and the mixture is cooled to room temperature to obtain a polycarboxylic acid water reducing agent.

Example Embodiment

[0062] Example 3 Preparation of polycarboxylic acid water reducing agent

[0063] (1) Add 120g of TPEG macromonomer to the reaction kettle, add 117.5g of water, heat the reaction kettle to 80°C in a water bath, and continue to stir;

[0064] (2) 14.4g of acrylic acid and 40g of water are mixed uniformly, 1.128g of BDATT is added to the mixed solution to dissolve, and the mixture is dropped for 3h at a uniform speed;

[0065] (3) 0.1356g of azobisisobutylamidine dihydrochloride was dissolved in 20g of water, and the solution in step (2) was simultaneously dropped into the reactor of step (1) at a uniform rate, and the dropping time was 3h;

[0066] (4) After the dripping is finished, continue the constant temperature stirring reaction for 5 hours;

[0067] (5) After the reaction, add 30% NaOH aqueous solution and 10 g of water, and cool to room temperature to obtain the polycarboxylic acid water reducing agent.

[0068] figure 1 The infrared spectra of PCE prepared in this example and PCE...

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Abstract

The invention discloses a method for synthesizing polycarboxylate superplasticizer through a RAFT method. According to the method, firstly, macro-monomers A are added into a reaction kettle, water is added, water bath heating is performed till the temperature is 65-85 DEG C, and constant-temperature stirring is performed; then, a trithio ester chain transferring agent is dissolved in a mixed solution of micro-monomers B and water, the mixture is dropwise added into the reaction kettle at constant speed, and meanwhile an initiator aqueous solution is dropwise added; after all the needed matter is dropwise added, a stirring reaction lasts for 3-5 h under the continuous constant-temperature stirring condition of 65-85 DEG C; after the reaction ends, an alkali solution and water are added to adjust PH to 6-7, and the polycarboxylate superplasticizer is obtained after reaction products are cooled to room temperature. By means of the method, the molecular-structure-controllable polycarboxylate superplasticizer can be prepared, the molecular weight is controllable, the molecular weight distribution range is narrow, polymer molecule design can also be performed, and the method has great significance in research and development of the polycarboxylate superplasticizer synthetic technology.

Description

technical field [0001] The invention relates to a polycarboxylate water reducer, in particular to a method for synthesizing a polycarboxylate water reducer (PCE) using a reversible addition-fragmentation chain transfer polymerization (RAFT) method, and belongs to the technical field of concrete chemical admixtures. Background technique [0002] Water reducing agent is known as the fifth component of concrete and plays an important role in the development of concrete. Polycarboxylate superplasticizer has the application advantages of low dosage in concrete, high water reducing rate, small slump loss over time, small concrete shrinkage rate, etc., as well as the synthesis advantages of strong variability in its own molecular structure. Research hotspots at home and abroad. Many scholars are trying to analyze the molecular structure information of PCE. The molecular structure of PCE includes molecular weight, molecular weight distribution, functional groups, side chain density...

Claims

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Application Information

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IPC IPC(8): C08F283/06C08F220/06C08F2/38C04B24/26C04B103/30
Inventor 吴笑梅余文志樊粤明
Owner SOUTH CHINA UNIV OF TECH
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