Preparation method of three-arm block polycarboxylic acid water reducing agent

A technology of polycarboxylic acid and water reducing agent, applied in the field of concrete admixtures, can solve the problems of destroying the reaction system and incomplete reaction, and achieve the effects of strong affinity, simple and controllable reaction conditions, and high yield

Inactive Publication Date: 2018-09-28
UNIV OF JINAN
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method prepares the star-shaped RAFT chain transfer agent by esterification reaction, which is a reversible reaction, and generally the reaction is not complete, and the generation of by-product water destroys the reaction system

Method used

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  • Preparation method of three-arm block polycarboxylic acid water reducing agent

Examples

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Embodiment 1

[0031] (1) Preparation of the three-arm chain transfer agent: In the reactor, add 5 mol glycerol, 30 mL THF and stir until it dissolves, then add 15 mol KOH, heat to 40°C and react for 12 h, so that KOH reacts Cool to room temperature after thorough; add 15mol CS 2 After raising the temperature to 40°C, react for 2 h, then add 20 mol benzyl bromide dropwise at a rate of 6 drops / min, and react at room temperature for 24 h. After the reaction is finished, the reaction solution is precipitated in water to obtain the three-arm chain transfer agent.

[0032] (2) Preparation of three-arm block polymer I: Add 1 mol of three-arm chain transfer agent obtained in step (1), 0.25 mol of initiator and prenol polyoxyethylene ether (molecular weight 1200 ) 25 mol, dissolved in 50 ml tetrahydrofuran (DMF) and mixed, and reacted at 55°C for 20 h under nitrogen atmosphere after deoxygenation. After the reaction, the reaction solution was precipitated in petroleum ether to obtain the three-arm...

Embodiment 2

[0035] In this example, the three-arm block polycarboxylate superplasticizer (marked as PC2) was prepared in the same manner as in Example 1, the only difference being that CS in step (1) 2 The amount is 20 mol.

Embodiment 3

[0037] In this example, a three-arm block polycarboxylate superplasticizer (marked as PC3) was prepared in the same manner as in Example 1, except that the reaction time in step (2) was 12 h.

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Abstract

The invention discloses a preparation method of a three-arm block polycarboxylic acid water reducing agent. The preparation method comprises that triol, an alkali, CS2 and benzyl bromide in a molar ratio of 1: 3-4: 2-5: 2-7 undergo a reaction to produce a three-arm chain transfer agent, under the action of the three-arm chain transfer agent and an initiator, isoamyl alcohol polyoxyethylene ether and acrylic acid undergo an RAFT polymerization reaction to produce a three-arm block compolymer, and the compolymer is treated to form the three-arm block polycarboxylic acid water reducing agent. Thewater reducing agent has a controllable chemical structure, controllable molecular weight, narrow molecular weight distribution, simple processes, a high water-reducing rate and good moisture retention effects, can obviously improve concrete fluidity, has low sensitivity to mud, can meet higher construction requirements and has broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures, in particular to a preparation method of a novel polycarboxylate superplasticizer. Background technique [0002] Polycarboxylate superplasticizer in the traditional sense is a polymer formed by free radical polymerization of unsaturated monomers containing carboxyl groups and unsaturated monomers containing other functional groups. It is a random copolymer. Its molecular structure is comb-shaped, and it has the characteristics of high water reducing rate, small change in slump over time, and good adaptability to different types of cement. [0003] Water reducer is an important concrete admixture and one of the important products in the pillar industry of new building materials. The water reducing agent not only greatly improves the mechanical properties of high-strength concrete, but also provides a simple and easy construction process. Relying on the development and application of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B24/26C08F2/38C08F287/00C08F220/06C04B103/30
CPCC04B24/2605C04B2103/302C08F2/38C08F287/00C08F220/06
Inventor 李梦霞王相国裴梅山
Owner UNIV OF JINAN
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