A kind of cross-linked air-entraining water reducing agent and preparation method thereof

Abstract

The invention relates to the technical field of concrete admixtures, in particular to a cross-linked air-entraining water-reducing agent and a preparation method thereof, wherein the water-reducing agent comprises: a cross-linked air-entraining polymer, the air-entraining polymer Contains polymers or copolymers derived from monomers including air-entraining monomers, vinyl ether macromonomers. By using the cross-linked air-entraining water reducing agent provided by the present invention, air bubbles can be introduced into the concrete and the air bubbles can be stabilized and the dispersion retention of the concrete can be improved. Not only that, the introduction of the micro-cross-linked structure makes the polymer structure more stretched and the hydration film thicker. , has greater steric hindrance and better dispersibility, dispersion retention and better anti-intercalation effect, and has broad market application prospects.

Description

technical field

[0001] The present invention relates to the technical field of concrete admixtures, in particular to a cross-linked air-entraining water reducer and a preparation method thereof. Background technique

[0002] With the large-scale construction of foundation projects in my country, the requirements for the workability, strength, durability and other properties of concrete have been continuously improved, which has prompted the rapid development of concrete admixtures, especially the rapid development of polycarboxylic acid-based high-performance water reducers. . As an important component of concrete admixture, polycarboxylic acid-based high-performance water-reducing admixture has a certain air-entraining effect when added to concrete, but the quality of the introduced foam is poor, and the foam-stabilizing performance is also poor, which cannot meet the high performance requirements. The demand for concrete durability generally requires compound air-entrainin...

Examples

preparation example Construction

[0033] The invention provides a preparation method of a cross-linked air-entraining polycarboxylate water reducer, comprising the following steps:

[0034] Put vinyl ether macromonomer, reducing agent and appropriate amount of deionized water in the reactor, stir and dissolve, add the mixed solution of unsaturated acid and unsaturated ester, air-entraining monomer solution, oxidizing agent dropwise into the reactor and chain transfer agent, and adjust the temperature to 5 ~ 15 ℃ to carry out the reaction, the dropwise addition time is 0.5 ~ 1h, after the dropwise addition, the temperature is kept for 0.5 ~ 1.5h, after the reaction is completed, the temperature is lowered to room temperature, and the pH is adjusted to 6 ~ 7 with liquid caustic soda , that is, the cross-linked air-entraining retarder water reducing agent is obtained.

[0035] Wherein, the mass ratio of the vinyl ether macromonomer:monomer B:monomer C:monomer D is: 200:(1-30):(10-30):(1-10);

[0036] The oxidant...

Embodiment 1

[0049] (1) Preparation of air-entraining monomer B1: 0.1 mol of bis(hydroxyethyl) methyl dodecyl ammonium chloride, 0.115 mol of acryloyl chloride, 40 mL of 1,4 dioxane, and 0.1 mol of pyridine were placed in the reaction The product was purified by vacuum distillation and recrystallization to obtain the air-entraining monomer B1 under the condition of 15 ℃ in the reactor for 10 hours.

[0050] (2) copolymerization reaction: in parts by weight, 200 parts of 4-hydroxybutyl vinyl polyoxyethylene ether-2400, 1.5 parts of sodium formaldehyde sulfoxylate and deionized water are placed in the reactor, stirring and dissolving, to 20 parts of acrylic acid, 2 parts of 2-methacryloyloxyethyl phosphate and 3 parts of air-entraining monomer B1 mixed solution, 2 parts of hydrogen peroxide solution, 1 part of thioglycolic acid solution were added dropwise to the reactor, 5 ℃ The dropwise addition time was 45min under the conditions, the temperature was kept for 1h after the dropwise additio...

Embodiment 2

[0052] (1) Preparation of air-entraining monomer B2: 0.1 mol of octadecylbis(2-hydroxyethyl) methylammonium chloride, 0.115 mol of acryloyl chloride, 45 mL of 1,4 dioxane, and 0.1 mol of pyridine were placed In the reactor, the reaction was carried out at 15°C for 10 hours, and the product was purified by vacuum distillation and recrystallization to obtain the air-entraining monomer B2.

[0053] (2) copolymerization reaction: in parts by weight, 200 parts of 4-hydroxybutyl vinyl polyoxyethylene ether-2400, 1 part of Brüggolit FF6 and deionized water are placed in the reactor, stirring and dissolving, respectively in the reactor Add dropwise a mixed solution of 21 parts of acrylic acid, 3 parts of 2-methacryloyloxyethylphosphorylcholine and 4 parts of air-entraining monomer B2, 2 parts of hydrogen peroxide solution, 1 part of thioglycolic acid solution, and added dropwise at 10°C The time was 45 min, the temperature was kept for 1 h after the dropwise addition, and the temperat...

technical field

[0001] The present invention relates to the technical field of concrete admixtures, in particular to a cross-linked air-entraining water reducer and a preparation method thereof. Background technique

[0002] With the large-scale construction of foundation projects in my country, the requirements for the workability, strength, durability and other properties of concrete have been continuously improved, which has prompted the rapid development of concrete admixtures, especially the rapid development of polycarboxylic acid-based high-performance water reducers. . As an important component of concrete admixture, polycarboxylic acid-based high-performance water-reducing admixture has a certain air-entraining effect when added to concrete, but the quality of the introduced foam is poor, and the foam-stabilizing performance is also poor, which cannot meet the high performance requirements. The demand for concrete durability generally requires compound air-entrainin...

Examples

preparation example Construction

[0033] The invention provides a preparation method of a cross-linked air-entraining polycarboxylate water reducer, comprising the following steps:

[0034] Put vinyl ether macromonomer, reducing agent and appropriate amount of deionized water in the reactor, stir and dissolve, add the mixed solution of unsaturated acid and unsaturated ester, air-entraining monomer solution, oxidizing agent dropwise into the reactor and chain transfer agent, and adjust the temperature to 5 ~ 15 ℃ to carry out the reaction, the dropwise addition time is 0.5 ~ 1h, after the dropwise addition, the temperature is kept for 0.5 ~ 1.5h, after the reaction is completed, the temperature is lowered to room temperature, and the pH is adjusted to 6 ~ 7 with liquid caustic soda , that is, the cross-linked air-entraining retarder water reducing agent is obtained.

[0035] Wherein, the mass ratio of the vinyl ether macromonomer:monomer B:monomer C:monomer D is: 200:(1-30):(10-30):(1-10);

[0036] The oxidant...

Embodiment 1

[0049] (1) Preparation of air-entraining monomer B1: 0.1 mol of bis(hydroxyethyl) methyl dodecyl ammonium chloride, 0.115 mol of acryloyl chloride, 40 mL of 1,4 dioxane, and 0.1 mol of pyridine were placed in the reaction The product was purified by vacuum distillation and recrystallization to obtain the air-entraining monomer B1 under the condition of 15 ℃ in the reactor for 10 hours.

[0050] (2) copolymerization reaction: in parts by weight, 200 parts of 4-hydroxybutyl vinyl polyoxyethylene ether-2400, 1.5 parts of sodium formaldehyde sulfoxylate and deionized water are placed in the reactor, stirring and dissolving, to 20 parts of acrylic acid, 2 parts of 2-methacryloyloxyethyl phosphate and 3 parts of air-entraining monomer B1 mixed solution, 2 parts of hydrogen peroxide solution, 1 part of thioglycolic acid solution were added dropwise to the reactor, 5 ℃ The dropwise addition time was 45min under the conditions, the temperature was kept for 1h after the dropwise additio...

Embodiment 2

[0052] (1) Preparation of air-entraining monomer B2: 0.1 mol of octadecylbis(2-hydroxyethyl) methylammonium chloride, 0.115 mol of acryloyl chloride, 45 mL of 1,4 dioxane, and 0.1 mol of pyridine were placed In the reactor, the reaction was carried out at 15°C for 10 hours, and the product was purified by vacuum distillation and recrystallization to obtain the air-entraining monomer B2.

[0053] (2) copolymerization reaction: in parts by weight, 200 parts of 4-hydroxybutyl vinyl polyoxyethylene ether-2400, 1 part of Brüggolit FF6 and deionized water are placed in the reactor, stirring and dissolving, respectively in the reactor Add dropwise a mixed solution of 21 parts of acrylic acid, 3 parts of 2-methacryloyloxyethylphosphorylcholine and 4 parts of air-entraining monomer B2, 2 parts of hydrogen peroxide solution, 1 part of thioglycolic acid solution, and added dropwise at 10°C The time was 45 min, the temperature was kept for 1 h after the dropwise addition, and the temperat...

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