CN108250370B - Polycarboxylic acid and its use in cement - Google Patents

Abstract

The invention relates to a polycarboxylic acid and application thereof in cement. The polycarboxylic acid provided by the invention has a comb-shaped structure and is formed by randomly copolymerizing a first monomer A, an unsaturated carboxylic acid monomer B and a functional monomer C, wherein the first monomer is selected from at least one of an unsaturated polyether monomer and an unsaturated polyester monomer, and the molar ratio of the monomers is A: b: c is 1: (8-50): (0-5). The polycarboxylic acid provided by the invention can be used as a dispersing agent, can be greatly prolonged and can effectively control the retention of cement slump and fluidity without bleeding under the condition of not doping a retarder, and the engineering requirements are met.

Description

Polycarboxylic acid and its use in cement

technical field

The present invention relates to a polycarboxylic acid and its use in cement.

Background technique

Concrete is one of the widely used materials in the world, of which cement is an important component as a cementitious material. Cement can be divided into: 1) General cement, cement commonly used in general civil construction projects, mainly refers to: six types of cement specified in GB175-2007, namely Portland cement, ordinary Portland cement, slag silicate Salt cement, pozzolanic Portland cement, fly ash Portland cement and composite Portland cement; 2) Special cement refers to cement with special purpose, such as Grade G oil well cement, road Portland cement; 3 ) characteristic cement: refers to a certain kind of cement with outstanding performance. Such as: fast-hardening Portland cement, low-heat slag Portland cement, expanded sulfoaluminate cement, aluminophosphate cement and phosphate cement. Although there are many kinds of cement, Portland cement is mainly used in China and the world, which is collectively referred to as Portland cement abroad.

As a new kind of energy saving and environmental protection, sulfoaluminate cement has gradually received more and more attention. Due to its excellent properties such as early strength and fast hardening, high strength, high impermeability, high frost resistance, corrosion resistance, low shrinkage or even no shrinkage, it has been used in some cement mortars or concretes that require special properties. Such as repair plugging, grouting, marine concrete, etc. At the same time, since the production of sulfoaluminate cement uses low-grade bauxite, gypsum and limestone as raw materials, it is fired into clinker composed of anhydrous calcium sulfoaluminate and dicalcium silicate. The sulfate phase is ground finely. The production process has the advantages of low energy consumption and low emissions. It has a large space for application promotion.

However, it is well known that many properties such as strength and durability of cement mortar or concrete depend on the water-cement ratio, that is, the ratio of mixing water consumption to cement consumption. The lower the water-cement ratio, generally the higher the strength and the better the durability. However, the reduction of the water-cement ratio simultaneously reduces the workability, fluidity, etc. of the mortar or concrete. Therefore, water reducing agent, as a dispersant with dispersed cement particles, has become an indispensable component in the mixing ratio of modern concrete or mortar. The addition of a small amount of water reducing agent can greatly improve the fluidity of mortar or concrete and reduce water consumption. In particular, polycarboxylate superplasticizers have become the main varieties of cement concrete superplasticizers due to their high water-reducing rate (25-40%), diversification of molecular structure and easy regulation and control.

However, most of the polycarboxylate water reducers currently available in the market are designed for Portland cement. Unlike Portland cement, sulfoaluminate cement is mainly composed of anhydrous calcium sulfoaluminate, gypsum and other silicate phases. It has the characteristics of fast hydration speed and fast setting time. At the same time, the particle surface properties of cement particles and hydration product phases are different, resulting in the inability of traditional polycarboxylate water reducers to be successfully used in sulfoaluminate cement systems. The main problems presented are insufficient dispersibility, low initial fluidity or slump, large admixture, and poor flow retention or slump retention in concrete. To this end, this patent invents a polycarboxylate water reducing agent specially used in sulfoaluminate system. When mixed into sulfoaluminate cement mortar or concrete, it has excellent properties such as small dosage, good dispersibility and good slump retention.

SUMMARY OF THE INVENTION

In view of the defects in the prior art, the present invention provides a polycarboxylic acid and the application of the polycarboxylic acid as a dispersant in cement, especially sulfoaluminate cement. Without adding retarder, the polycarboxylic acid provided by the present invention can greatly prolong and effectively control the maintenance of cement slump and fluidity as a dispersant, without bleeding, and meets engineering requirements.

In a first aspect, the present invention provides a polycarboxylic acid, which has a comb-shaped structure and is formed by random copolymerization of a first monomer A, an unsaturated carboxylic acid monomer B and a functional monomer C, wherein, The first monomer is selected from at least one of unsaturated polyether monomer and unsaturated polyester monomer, and the molar ratio of each raw material is A:B:C=1:(8～50):(0～ 5), preferably, A:B:C=1:(9~30):(0~5), more preferably, A:B:C=1:(9~30):(0.01~5), More preferably, A:B:C=1:(9~30):(0.5~4).

According to some embodiments of the present invention, the structure of the unsaturated polyester monomer is shown in formula (1),

in:

A represents an alkylene group having 2 to 4 carbon atoms;

B represents an alkylene group having 2 to 4 carbon atoms and different from A;

R ¹ and R ² each independently represent H or an alkyl group having 1 to 5 carbon atoms, preferably a methyl group;

R ³ represents H or an alkyl group having 1 to 4 carbon atoms;

X represents an alkylene group having 0 to 5 carbon atoms;

m represents an integer from 0 to 200, preferably 20 to 140;

n represents an integer from 0 to 200, preferably 20 to 140;

m+n>10.

According to some embodiments of the present invention, the structure of the unsaturated polyether monomer is shown in formula (2),

in:

E represents an alkylene group having 2 to 4 carbon atoms;

F represents an alkylene group having 2 to 4 carbon atoms and is different from E;

R ⁴ and R ⁵ each independently represent H or an alkyl group having 1 to 5 carbon atoms, preferably a methyl group;

R ⁶ represents H or an alkyl group having 1 to 4 carbon atoms;

Y represents an alkylene group having 0 to 5 carbon atoms;

p represents an integer from 0 to 200, preferably 20 to 140;

q represents an integer from 0 to 200, preferably 20 to 140;

p+q>10.

Preferably, the molecular weight of the unsaturated polyether monomer is 2000-8000, preferably 2000-5000. According to one embodiment, the unsaturated polyether monomer is HPEG-4000.

Preferably, the molecular weight of the unsaturated polyester monomer is 2000-8000, preferably 2000-5000.

According to some embodiments of the present invention, the unsaturated carboxylic acid monomer is selected from at least one of acrylic acid (AA), methacrylic acid, itaconic acid, fumaric acid and maleic acid (anhydride).

According to some embodiments of the present invention, the functional monomer is sodium allyl sulfonate (ALS), N,N-dimethylacetylacetamide (DMAA), 2-acrylamido-2-methylpropane Sulfonic acid (AMPS), sodium p-styrenesulfonate (SSS), N,N,N-trimethyl-3-(2-methallylamido)-1-propylamine chloride (MAPTAC, CAS number: 51410-72-1), at least one of 3-methacryloyloxypropyltrimethoxysilane (KH570) and styrene (St).

A second aspect of the present invention provides the use of the polycarboxylic acid as a dispersant in mortar or concrete with sulfoaluminate cement as the main cementitious material.

According to some embodiments of the present invention, the dispersant does not contain any other adjuvants.

According to some embodiments of the present invention, the dispersant is not used concurrently with the retarder.

According to some embodiments of the present invention, the mixing amount of the dispersant in the sulfoaluminate cement is 0.1-2.0 wt %, preferably 0.5-1.5 wt %.

The present invention has the following beneficial technical effects: the polycarboxylic acid provided by the present invention, as a dispersant for sulfoaluminate cement, has an improved water-reducing and dispersing effect, and can be greatly extended and effectively controlled without mixing a retarder. The maintenance of slump and fluidity without bleeding meets engineering requirements.

Description of drawings

Figure 1 shows the initial dispersion effect at different dosages for the SAC1 cement system with unsaturated carboxylic acid (AA) and macromonomer (HPEG) molar ratios of 10 and 12.

Figure 2 shows the initial dispersion effect of different dosages when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (HPEG) is less than 8 or greater than 50 for SAC1 cement system.

Figure 3 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (HPEG) is 10 and 12, under different dosages (0.002 means the dosage is 0.2wt%, 0.005 means the dosage is 0.5wt%, 0.01 means the dosage is 1wt%, 0.015 means the fluidity retention is 1.5wt%).

Figure 4 shows for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (HPEG) is less than 8 or greater than 50, the fluidity retention at different dosages.

Figure 5 illustrates the fluidity retention of the copolymerized functional monomer dispersant to the SAC1 system when the unsaturated carboxylic acid is AA and the macromonomer is HPEG at a dosage of 0.5 wt%.

Figure 6 illustrates the fluidity retention of the copolymerized functional monomer dispersant to the SAC1 system when the unsaturated carboxylic acid is AA and the macromonomer is HPEG at a dosage of 1.5 wt%.

Figure 7 illustrates the fluidity retention of different dispersants to the SAC2 system when the unsaturated carboxylic acid is AA and the macromonomer is HPEG at a dosage of 1.5 wt%.

Figure 8 illustrates the fluidity retention of different dispersants to the SAC2 system when the unsaturated carboxylic acid is AA and the macromonomer is HPEG at a dosage of 2.0 wt%.

Figure 9 illustrates the initial dispersion effect at 1.5% wt dosage for SAC1 cement system with unsaturated carboxylic acid (MA) and macromonomer (HPEG) molar ratios of 10 and 12.

Figure 10 illustrates the fluidity retention at different dosages for the SAC1 cement system with unsaturated carboxylic acid (MA) and macromonomer (HPEG) molar ratios of 10 and 12.

Figure 11 illustrates the initial dispersion effect at different dosages for the SAC1 cement system with unsaturated carboxylic acid (AA) and macromonomer (TPEG) molar ratios of 10 and 12.

Figure 12 illustrates the fluidity retention at 1.5% wt dosage for the SAC1 cement system for unsaturated carboxylic acid (AA) and macromonomer (TPEG) molar ratios of 10 and 12.

Detailed ways

The present invention will be described in detail below with reference to the examples, but the present invention is not limited by the following examples.

The invention adopts an aqueous solution free radical copolymerization method to synthesize the polycarboxylic acid.

The raw materials used in the examples and comparative examples were obtained commercially unless otherwise specified, and were analytically pure.

The unsaturated polyether monomer HPEG was purchased from Liaoning Aoke Chemical Co., Ltd., with a molecular weight of 4000.

The unsaturated polyester monomer TPEG was purchased from Liaoning Aoke Chemical Co., Ltd., with a molecular weight of 4000.

PCE is a common polycarboxylate water reducer on the market.

Example 1

Synthesis of PCE4000-10: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g of H with a mass concentration of 30% ₂ O ₂ was added to the three-necked flask. 9g AA and 24g water were mixed uniformly to prepare dropwise A, and 0.204g 3-MPA, 0.125gVc and 25g water were mixed uniformly to prepare dropwise B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 29.8%.

Example 2

Synthesis of PCE4000-12: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g of H with a mass concentration of 30% ₂ O ₂ was added to the three-necked flask. 10.8g AA and 24g water were mixed uniformly to prepare dropwise A, and 0.241g 3-MPA, 0.147gVc and 25g water were mixed uniformly to prepare dropwise B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 28.9%.

Example 3

Synthesis of PCE4000-16: Weigh 150g of water and 80g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.77g of H with a mass concentration of 30% ₂ O ₂ was added to the three-necked flask. 23.04g AA and 50g water were mixed uniformly to prepare drop A, and 0.505g 3-MPA, 0.308gVc and 30g water were mixed uniformly to prepare drop B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 28.4%.

Example 4

Synthesis of PCE4000-22: Weigh 150g of water and 80g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 1.04g of H with a mass concentration of 30% ₂ O ₂ was added to the three-necked flask. 31.68g AA and 70g water were mixed uniformly to prepare drop A, and 0.684g 3-MPA, 0.417gVc and 35g water were mixed uniformly to prepare drop B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 28.6%.

Example 5

Synthesis of PCE4000-25: Weigh 150g of water and 80g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 1.18g of H with a mass concentration of 30% ₂ O ₂ was added to the three-necked flask. 36.00g AA and 75g water were mixed uniformly to prepare drip A, and 0.773g 3-MPA, 0.471gVc and 40g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 29.1%.

Example 6

Synthesis of PCE4000-30: Weigh 150g of water and 80g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 1.41g of H with a mass concentration of 30% ₂ O ₂ was added to the three-necked flask. 43.20g AA and 90g water were mixed uniformly to prepare drip A, and 0.921g 3-MPA, 0.562gVc and 40g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 28.6%.

Example 7

Synthesis of PCE4000-50: Weigh 82.00g of water and 50.00g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 1.45g of 30% mass concentration The H ₂ O ₂ was added to the three-necked flask. 45.00g AA and 95.00g water were mixed uniformly to prepare drip A, and 1.35g 3-MPA, 0.58gVc and 45.00g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 29.9%.

Example 8

Synthesis of PCE4000-10 (TPEG): Weigh 82g of water and 50g of TPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g of 30 % H ₂ O ₂ was added to the three-necked flask. 9g AA and 24g water were mixed uniformly to prepare dropwise A, and 0.204g 3-MPA, 0.125gVc and 25g water were mixed uniformly to prepare dropwise B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.0%.

Example 9

Synthesis of PCE4000-12 (TPEG): Weigh 82g of water and 50g of TPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g of 30 % H ₂ O ₂ was added to the three-necked flask. 10.8g AA and 24g water were mixed uniformly to prepare dropwise A, and 0.241g 3-MPA, 0.147gVc and 25g water were mixed uniformly to prepare dropwise B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.1%.

Example 10

Synthesis of PCE4000-10-DM-2: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g for mass concentration 30% H ₂ O ₂ was added to the three-necked flask. 9g AA, 2.48g DMAA and 33g water were mixed uniformly to prepare dripping A, and 0.241g 3-MPA, 0.147gVc and 25g water were mixed uniformly to prepare dripping B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.0%.

Example 11

Synthesis of PCE4000-10-MA-2: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g for mass concentration 30% H ₂ O ₂ was added to the three-necked flask. 9g AA, 5.55g MAPTAC and 40g water were mixed uniformly to prepare drip A, and 0.241g 3-MPA, 0.147g Vc and 25g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 28.1%.

Example 12

Synthesis of PCE4000-10-AM-2: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g for mass concentration 30% H ₂ O ₂ was added to the three-necked flask. 9g AA, 5.18g AMPS and 40g water were mixed uniformly to prepare drip A, and 0.241g 3-MPA, 0.147g Vc and 25g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.0%.

Example 13

Synthesis of PCE4000-10-VPA-2: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g for mass concentration 30% H ₂ O ₂ was added to the three-necked flask. 9gAA, 2.7gVPA and 33g water were mixed uniformly to prepare drip A, and 0.241g 3-MPA, 0.147gVc and 25g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 29.8%.

Example 14

Synthesis of PCE4000-10-St-0.5: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.33g for mass concentration 30% H ₂ O ₂ was added to the three-necked flask. Mix 9g AA and 30g water to prepare dropwise A, mix 0.21g 3-MPA, 0.130gVc and 25g water to prepare dropwise B, and use 0.65gSt as dropwise C. Add dropwise A, dropwise B and dropwise C into the three-necked flask at a constant speed through a peristaltic pump. The dropwise addition time of dropwise A is 3h, the dropwise addition of B is 3.5h, and the dropwise addition time of dropwise C is 3.5 hours. for 3h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 26.7%.

Example 15

Synthesis of PCE4000-10-Si-0.5: Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.33g for mass concentration 30% H ₂ O ₂ was added to the three-necked flask. 9g AA, 1.55g KH570 and 30g water were mixed uniformly to prepare drip A, and 0.21g 3-MPA, 0.130g Vc and 25g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 28.8%.

Example 16

Synthesis of PCE4000-10 (MA): Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.31g of 30 % H ₂ O ₂ was added to the three-necked flask. 12.25g MA and 30g water were mixed uniformly to prepare drop A, and 0.29g 3-MPA, 0.12gVc and 25g water were mixed uniformly to prepare drop B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.1%.

Example 17

Synthesis of PCE4000-12 (MA): Weigh 82g of water and 50g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.37g of 30 % H ₂ O ₂ was added to the three-necked flask. 14.70g MA and 35g water were mixed uniformly to prepare dropwise A, and 0.34g 3-MPA, 0.15gVc and 30g water were mixed uniformly to prepare dropwise B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.1%.

Comparative Example 1

Synthesis of PCE4000-5: Weigh 82.00g of water and 50.00g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 0.17g of 30% mass concentration The H ₂ O ₂ was added to the three-necked flask. 4.50g AA and 20.00g water were mixed uniformly to prepare drip A, and 0.16g 3-MPA, 0.07gVc and 25.00g water were mixed uniformly to prepare drip B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 29.9%.

Comparative Example 2

Synthesis of PCE4000-60: Weigh 82.00g of water and 50.00g of HPEG, dissolve and mix evenly, pour into a three-necked flask in a constant temperature water bath, stir with a stirring paddle at a constant speed of 150rpm and heat up to 65°C, weigh 1.73g of 30% mass concentration The H ₂ O ₂ was added to the three-necked flask. 54.00g AA and 110.00g water were mixed uniformly to prepare dripping A, and 1.62g 3-MPA, 0.69gVc and 50.00g water were mixed uniformly to prepare dripping B. Dropwise A and dropwise B were added dropwise to the three-necked flask through a peristaltic pump at a constant speed, the dropwise addition time of dropwise A was 3h, and the dropwise addition of B was 3.5h. After the dropwise addition was completed, the temperature was kept for 1 h. After the reaction, the actual solid content test was carried out, and the test result was 30.0%.

Table 1

Performance Testing

Referring to GBT "Concrete Admixture Homogeneity Test Method", under the condition of 0.35 water-cement ratio, the initial fluidity and retention of the net paste of Comparative Example 1-2 and Example 1-17 were measured, and two kinds of sulfur-aluminum The acid salt cement is represented by the codes SAC1 and SAC2 respectively, and the components of SAC1 and SAC2 are shown in the table below. The test results are shown in Figures 1-12.

Table 2 Chemical composition of two sulfoaluminate cements. (wt.%)

Figure 1 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (HPEG) is 10 and 12, the initial dispersion effect at different dosages is better than that of commonly used water reducers on the market.

Figure 2 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (HPEG) is less than 8 or greater than 50, the initial dispersion effect is poor at different dosages.

Figure 3 illustrates the retention of fluidity at different dosages (0.2%, 0.5%, 1.0% and 1.5%) for the SAC1 cement system with a molar ratio of unsaturated carboxylic acid (AA) to macromonomer (HPEG) of 10 and 12. The properties are better than the commonly used water reducers on the market.

Figure 4 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (HPEG) is less than 8 or greater than 50, the fluidity retention is poor at different dosages.

Figure 5 shows that at 0.5% dosage, when the unsaturated carboxylic acid is AA and the macromonomer is HPEG, the fluidity retention of the copolymerized functional monomer dispersant to the SAC1 system is better than that of the commonly used water reducers on the market.

Figure 6 shows that at 1.5% dosage, when the unsaturated carboxylic acid is AA and the macromonomer is HPEG, the fluidity retention of the copolymerized functional monomer dispersant to the SAC1 system is better than that of the commonly used water reducers on the market.

Figure 7 shows that under the dosage of 1.5%, when the unsaturated carboxylic acid is AA and the macromonomer is HPEG, the fluidity retention of different dispersants to the SAC2 system is better than that of the commonly used water reducers on the market.

Figure 8 shows that under the dosage of 2.0%, when the unsaturated carboxylic acid is AA and the macromonomer is HPEG, the fluidity retention of different dispersants to the SAC2 system is better than that of the commonly used water reducers on the market.

Figure 9 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (MA) and macromonomer (HPEG) is 10 and 12, the initial dispersion effect at 1.5% dosage is better than that of commonly used water reducers on the market.

Figure 10 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (MA) and macromonomer (HPEG) is 10 and 12, the fluidity retention at different dosages is better than that of commonly used water reducers on the market.

Figure 11 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (TPEG) is 10 and 12, the initial dispersion effect under different dosages is better than that of commonly used water reducers on the market.

Figure 12 shows that for the SAC1 cement system, when the molar ratio of unsaturated carboxylic acid (AA) and macromonomer (TPEG) is 10 and 12, the fluidity retention at 1.5% dosage is better than that of commonly used water reducers on the market.

Although the invention has been described in detail, modifications within the spirit and scope of the invention will be apparent to those skilled in the art. Furthermore, it is to be understood that the various described aspects, parts of the various embodiments, and various features recited may be combined or interchanged in whole or in part. In each of the above-described embodiments, those referring to another embodiment may be appropriately combined with other embodiments, as will be understood by those skilled in the art. Furthermore, those skilled in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the present invention.

Claims (8)

1. the purposes of a polycarboxylic acid as a dispersant in mortar or concrete with sulfoaluminate cement as main cementitious material, the polycarboxylic acid has a comb-shaped molecular structure, and is composed of the first monomer A, non- Saturated carboxylic acid monomer B and functional monomer C are randomly copolymerized, wherein the first monomer is selected from at least one of unsaturated polyether monomers and unsaturated polyester monomers, and the The molar ratio is A:B:C=1:(22-25):(0~5), The structure of the unsaturated polyester monomer is shown in formula (1),

in: A represents an alkylene group having 2 to 4 carbon atoms; B represents an alkylene group having 2 to 4 carbon atoms and different from A; R ¹ and R ² each independently represent H or an alkyl group having 1 to 5 carbon atoms; R ³ represents H or an alkyl group having 1 to 4 carbon atoms; X represents an alkylene group having 0 to 5 carbon atoms; m represents an integer from 0 to 200; n represents an integer from 0 to 200; m+n>10; The structure of the unsaturated polyether monomer is shown in formula (2),

in: E represents an alkylene group having 2 to 4 carbon atoms; F represents an alkylene group having 2 to 4 carbon atoms and is different from E; R ⁴ and R ⁵ each independently represent H or an alkyl group having 1 to 5 carbon atoms; R ⁶ represents H or an alkyl group having 1 to 4 carbon atoms; Y represents an alkylene group having 0 to 5 carbon atoms; p represents an integer from 0 to 200; q represents an integer from 0 to 200; p+q>10; The functional monomer C is sodium allyl sulfonate, N,N-dimethylacetylacetamide, 2-acrylamido-2-methylpropanesulfonic acid, sodium p-styrene sulfonate, N,N , at least one of N-trimethyl-3-(2-methacrylamido)-1-chlorinated propylamine, 3-methacryloyloxypropyltrimethoxysilane and styrene. 2 . The use according to claim 1 , wherein, in structural formula (1), R ¹ and R ² are methyl groups; m represents an integer of 20-140, and n represents an integer of 20-140. 3 . The use according to claim 1, characterized in that, in structural formula (2), R ⁴ and R ⁵ are methyl groups; p represents an integer of 20-140, and q represents an integer of 20-140. 4. The use according to any one of claims 1-3, wherein the unsaturated carboxylic acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid at least one. 5. The use according to claim 1, characterized in that the dispersant does not contain any other adjuvants. 6. The use according to claim 1 or 5, characterized in that the dispersant is not used simultaneously with the retarder. 7 . The use according to claim 1 , wherein the amount of the dispersant in the sulfoaluminate cement is 0.1-2.0 wt %. 8 . 8 . The use according to claim 7 , wherein the mixing amount of the dispersant in the sulfoaluminate cement is 0.5-1.5 wt %. 9 .

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