Foam stabilizer, preparation method thereof and low-carbon cement foam concrete

Abstract

The invention provides a foam stabilizer, a preparation method thereof and low-carbon cement foam concrete, and belongs to the field of concrete building materials. The foam stabilizer is prepared from the following raw materials: an alcohol amine-containing polymer and cellulose ether in a mass ratio of (20-40): 1. The molecular weight of the alcohol amine group-containing polymer is 50000 to 60000; the preparation raw materials of the alcohol amine-containing polymer comprise alcohol amine-containing unsaturated ester, an unsaturated polyether monomer, an initiator, a reducing agent and a chain transfer agent. The alcohol amine group-containing unsaturated ester is prepared from the following raw materials: polyhydric alcohol amine, unsaturated carboxylic acid, a catalyst and a water-carrying agent. The foam stabilizer provided by the invention is high in viscosity and strong in carbon dioxide absorption capacity, and is applied to the field of preparation of low-carbon cement foam concrete, so that the low-carbon cement foam concrete does not need to be cured under the condition of specific CO2 concentration after being molded, and the strength can be improved only by standard curing; and the carbon sequestration capability of the prepared low-carbon cement foam concrete is also remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete building materials, and in particular to a foam stabilizer and a preparation method thereof, and low-carbon cement foam concrete. Background Art

[0002] Foamed concrete, an inorganic porous thermal insulation material, offers low cost, convenient construction, low bulk density, easy molding, low investment, a wide range of raw materials, and easy commercialization. Compared to organic thermal insulation materials, it offers advantages such as fire resistance, durability, and environmental friendliness. It is widely used for exterior wall and roof insulation in residential buildings, making it a popular material choice in the construction industry. However, the binder used in foamed concrete is typically ordinary Portland cement, the production of which consumes significant amounts of energy and produces large amounts of atmospheric pollutants such as carbon dioxide. Low-carbon cement, an environmentally friendly binder, consumes less energy than Portland cement and emits less CO₂. Its main mineral phases, CS (CaO·SiO₂) and C₃S₂ (3CaO·2SiO₂), react with CO₂ to harden under certain humidity conditions and can absorb up to 20% of its own weight in CO₂, resulting in significant carbon reduction and sequestration. Using low-carbon cement to replace ordinary Portland cement in foamed concrete can achieve lower carbon emissions, significantly enhancing the greenness of foamed concrete.

[0003] Patent CN114656207A discloses a foamed concrete based on calcium slag carbonization. The concrete is primarily composed of siliceous raw materials, calcium slag, lightweight aggregate, water, and foam. CO2 is used for foaming during the preparation process, and curing is carried out under CO2 conditions after forming. While reducing cement usage, the carbonization reaction of stainless steel slag and steel slag under certain environmental conditions is utilized to fix carbon, thereby achieving the goal of carbon dioxide emissions reduction. CN118125764A discloses a method for preparing foamed concrete using carbon dioxide foam. A foaming machine connected to a carbon dioxide cylinder draws in a nanoparticle foaming agent to produce an ultra-stable carbon dioxide foam. The foam stabilizer and ultra-stable carbon dioxide foam are then added to a cement slurry that has been completely carbonized with carbon dioxide and continuously stirred to produce a carbon dioxide foamed concrete slurry. After preparation, the foamed concrete is subjected to carbonization curing. However, the methods of preparing foamed concrete using carbon dioxide foam in the above-mentioned related patents still have the following problems: CO2 gas is used for foaming, and after the foamed concrete is formed, it still needs to be placed under a certain concentration of CO2 conditions for carbonation curing, which makes the process relatively cumbersome; the above patents mostly use silicate cement or ordinary silicate cement when preparing foamed concrete, and silicate cement or ordinary silicate cement itself has a low degree of carbonization reaction, resulting in limited carbon fixation capacity and low carbon fixation rate of foamed concrete.

[0004] In industrial production, a wide variety of foam stabilizers are used, including calcium stearate, zinc stearate, sodium rosinate, and animal and plant protein hydrolysates. However, these commonly used foam stabilizers have some drawbacks, such as their relatively large usage requirements. Furthermore, during the chemical foaming process, these stabilizers exhibit poor foam stability, and even slight vibrations can cause the foam to burst, thus causing significant inconvenience in the production process. Therefore, there is an urgent need to develop foam stabilizers with high foam stability and foamed concrete with simpler processing and enhanced carbon sequestration capacity. Summary of the Invention

[0005] In view of the technical problems existing in the background technology, the present invention provides a foam stabilizer and its preparation method and low-carbon cement foam concrete, aiming to solve the technical problems in the prior art of poor foam stabilization performance of foam stabilizers, complicated preparation process of foam concrete, and poor carbon fixation capacity.

[0006] In a first aspect, the present invention provides a foam stabilizer, wherein the raw materials for preparation include an alcoholamine-containing polymer and a cellulose ether in a mass ratio of (20-40):1; the molecular weight of the alcoholamine-containing polymer is 50,000-60,000; The raw materials for preparing the alcoholamine-containing polymer include alcoholamine-containing unsaturated ester, unsaturated polyether monomer, initiator and chain transfer agent; The raw materials for preparing the alcoholamine-containing unsaturated ester include polyol amine, unsaturated carboxylic acid, catalyst and water-carrying agent.

[0007] Preferably, the cellulose ether includes at least one of hydroxyethyl cellulose ether, hydroxypropyl cellulose ether, and hydroxypropyl methyl cellulose ether.

[0008] Preferably, the molar ratio of the polyol amine to the unsaturated carboxylic acid is 1:(0.5-1); the mass ratio of the catalyst to the unsaturated carboxylic acid is (0.06-0.08):1; and the mass ratio of the water-carrying agent to the unsaturated carboxylic acid is (1-1.5):1.

[0009] Preferably, the polyol amine includes at least one of diethanolamine, N-methyldiethanolamine, and diisopropanolamine; The unsaturated carboxylic acid includes at least one of acrylic acid and methacrylic acid; The catalyst includes p-toluenesulfonic acid; Aqueous agents include cyclohexane.

[0010] Preferably, the mass ratio of the unsaturated polyether monomer to the unsaturated ester containing an alcohol amino group is (12-15):1; the unsaturated polyether monomer includes methyl allyl alcohol polyoxyethylene ether.

[0011] Preferably, the initiator comprises peroxide; the chain transfer agent comprises hypophosphite; and the reducing agent comprises vitamin C.

[0012] Preferably, the mass ratio of hypophosphite to unsaturated polyether monomer is (0.04-0.1):1; the mass ratio of peroxide to unsaturated polyether monomer is (0.005-0.01):1; and the mass ratio of vitamin C to unsaturated polyether monomer is (0.003-0.005):1.

[0013] Preferably, the peroxide includes hydrogen peroxide; and the hypophosphite includes at least one of sodium hypophosphite and potassium hypophosphite.

[0014] In a second aspect, an embodiment of the present invention provides a method for preparing a foam stabilizer, comprising the following steps: (1) Preparation of unsaturated ester containing alcohol amine group: polyol amine, catalyst and water-carrying agent are mixed evenly, and then unsaturated carboxylic acid is slowly added, and the reaction is carried out at 80℃~100℃ for 6~8h. After separation and washing, unsaturated ester containing alcohol amine group is obtained; (2) Preparation of alcoholamine-containing polymer: An aqueous solution of unsaturated polyether monomer is used as a base material. An initiator and a chain transfer agent are added under stirring. Then, solution A made from the alcoholamine-containing unsaturated ester and aqueous solution B made from a reducing agent are added dropwise to the base material for reaction. The addition time is 2.5 to 3 hours, and the reaction temperature is 30 to 35°C. After the reaction is completed, the temperature is kept for 1 to 2 hours to obtain an alcoholamine-containing polymer. (3) The alcohol amine-containing polymer obtained in step (2) and the cellulose ether are dissolved in deionized water at a mass ratio of (20-40):1 to prepare a mixed solution with a solid content of 40%-60%, and stirred until uniform to obtain a foam stabilizer.

[0015] In a third aspect, the present invention provides a low-carbon cement foam concrete, wherein the raw materials for preparing the low-carbon cement foam concrete include the above-mentioned foam stabilizer.

[0016] In a fourth aspect, the present invention provides a method for preparing low-carbon cement foam concrete, comprising the following steps: (1) preparing carbon dioxide foam: mixing a foaming agent, a first sodium bicarbonate solution and the foam stabilizer to obtain a foaming liquid, placing the foaming liquid in a carbon dioxide atmosphere to obtain carbon dioxide foam; (2) Preparation of low-carbon cement foam concrete: low-carbon cement, steel slag, fly ash water, second sodium bicarbonate solution and water reducer are uniformly mixed to prepare low-carbon cement foam concrete slurry, carbon dioxide foam prepared in step (1) is added to the low-carbon cement foam concrete slurry, and low-carbon cement foam concrete is obtained through molding, demolding and curing.

[0017] Preferably, the mass concentration of the first sodium bicarbonate solution is 5%~10%; the mass concentration of the second sodium bicarbonate solution is 1%~3%; the mass ratio of the foaming agent, the first sodium bicarbonate solution and the foam stabilizer is (8~10):(160~200):(8~12); the mass ratio of low carbon cement, steel slag, fly ash, water, the second sodium bicarbonate solution, the water reducer and the carbon dioxide foam is (380~500):(55~70):(45~60):(100~130):(80~100):(1.3~2):(26~35).

[0018] Preferably, the low-calcium cement comprises the following components by mass percentage: C3S 25% to 40%, γ-C2S 20% to 50% and CS 10% to 50%.

[0019] The principle of the technical solution of the present invention is as follows: the foam stabilizer provided by the present invention is prepared by esterifying an alcoholamine and an unsaturated carboxylic acid under certain conditions to generate an unsaturated ester, and then polymerizing the unsaturated ester with an unsaturated macromonomer under the action of an initiator and a chain transfer agent to generate an alcoholamine-containing polymer, and then uniformly mixing the alcoholamine-containing polymer with cellulose ether in proportion to obtain a foam stabilizer for low-carbon cement foam concrete. Cellulose ether is a polymer compound that can increase the viscosity of a liquid. Therefore, the foam stabilizer provided by the present invention has a relatively high viscosity, and by increasing the viscosity of the liquid phase, the drainage rate of the foam is slowed, the half-life of the foam is extended, and the stability of the foam is improved. On the other hand, the alcoholamine-containing polymer generated by the polymerization reaction contains an alcoholamine group, which can promote the absorption of carbon dioxide, so that the prepared low-carbon cement foam concrete does not require carbonization curing after forming.

[0020] The mechanism by which the alcoholamine groups in alcoholamine-containing polymers absorb CO2 is as follows: the alcoholamine groups absorb CO2 to form carbamate. After absorbing a certain amount of CO2, the carbamate hydrolyzes to form bicarbonate, thereby releasing alcoholamine molecules again and continuing to absorb CO2. The specific chemical reaction equations involved are as follows: R1R2NH + CO2 R1R2NH + COO - ; R1R2NH + COO - + R1R2NH R1R2NCOO - + R1R2NH2 + ; R1R2NCOO - + H2O R1R2NH +HCO3 - .

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The foam stabilizer provided by the present invention has a large viscosity, and can slow down the drainage rate of the foam by increasing the viscosity of the liquid phase, prolong the half-life of the foam, and thus improve the stability of the foam; the present invention introduces an amine group into the foam stabilizer, and utilizes the principle of the amine group capturing carbon dioxide to promote the absorption of carbon dioxide, and applies it to the field of preparing low-carbon cement foam concrete, so that the low-carbon cement foam concrete does not need to be carbonized and cured under conditions of a specific CO2 concentration after being formed, and only needs to be cured by standard curing to obtain a significant increase in strength.

[0022] (2) The preparation method of low-carbon cement foam concrete provided by the present invention comprises the following steps: using a 5% to 10% sodium bicarbonate solution to dilute the foaming agent, and adding a certain amount of the foam stabilizer provided by the present invention. On the one hand, the solubility of carbon dioxide in a 5% to 10% mass concentration sodium bicarbonate solution is extremely low, which can avoid the foam bursting caused by the dissolution of carbon dioxide in water. On the other hand, the addition of the foam stabilizer can delay the drainage rate of the foam by increasing the liquid phase viscosity, prolong the half-life of the foam, and improve the stability of the foam.

[0023] (3) The preparation method of low-carbon cement foam concrete provided by the present invention uses a sodium bicarbonate solution with a mass concentration of 1% to 3% to prepare cement paste, which allows the low-carbon cement to react with the bicarbonate ions in the solution first, delaying the reaction time of the cement paste and the carbon dioxide in the foam, and avoiding the large-scale absorption of carbon dioxide during the mixing process of the low-carbon cement paste and the carbon dioxide foam, which leads to a large amount of foam bursting and loss of cement paste fluidity, thereby causing the foam concrete to collapse or be unable to form.

[0024] (4) The method for preparing low-carbon cement foam concrete provided by the present invention uses low-carbon cement as raw material, and its carbon emissions are much lower than those of Portland cement or ordinary Portland cement. The low-carbon cement foam concrete prepared by the present invention has a high carbon sequestration capacity. DETAILED DESCRIPTION

[0025] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the scheme. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only used as examples and cannot be used to limit the scope of protection of the present invention.

[0026] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all commercially available conventional products or commonly used in the field.

[0027] In the following application examples of the present invention, the low carbon cement comprises the following components by mass percentage: C3S2 10.6%, γ-C2S 34.5%, and CS 46.3%.

[0028] The hydroxyethyl cellulose ether, hydroxypropyl cellulose ether and hydroxypropyl methyl cellulose ether used in the following examples of the present invention all have a viscosity grade of 50,000.

[0029] The molecular weight of methyl allyl alcohol polyoxyethylene ether (HPEG) used in the following examples of the present invention is 2400.

[0030] 1. Preparation method Example 1 A method for preparing a foam stabilizer comprises the following steps: (1) Weigh 59.58 g of N-methyldiethanolamine and 36.03 g of acrylic acid in a molar ratio of 1:1, weigh 2.16 g of p-toluenesulfonic acid (6% of the mass of acrylic acid) as a catalyst, and weigh 36.03 g of cyclohexane as a water-carrying agent; N-methyldiethanolamine, p-benzenesulfonic acid catalyst, and cyclohexane water-carrying agent were added to a three-necked flask and mixed evenly. Acrylic acid was evenly added to the flask by titration. The mixture was stirred and reacted at 85°C for 8 hours. After separation and washing, an unsaturated ester containing an alcohol amino group 1 was obtained. (2) 120 g of methyl allyl alcohol polyoxyethylene ether HPEG was added to 120 g of deionized water, stirred and dissolved at 30 ° C to prepare a 50 wt% base material, and 7.2 g of sodium hypophosphite (6% of the mass of HPEG) and 0.72 g of hydrogen peroxide (0.6% of the mass of HPEG) were added at one time while stirring. 8.7 g of the unsaturated ester containing alcohol amine group 1 synthesized in step (1) (7.2% of the mass of HPEG) was prepared into a 33% aqueous solution A, and 0.4 g of vitamin C (0.33% of the mass of HPEG) was prepared into a 4% aqueous solution B. The aqueous solution A and the aqueous solution B were gradually added dropwise to the base material for reaction. The addition time was 2.5 h, the reaction temperature was 30 ° C, and the reaction was kept warm for 1 h after the reaction was completed to obtain the alcohol amine group polymer 1; (3) The alcohol amine-containing polymer 1 obtained in step (2) and hydroxyethyl cellulose ether were dissolved in deionized water at a mass ratio of 20:1 to prepare a mixed solution with a solid content of 50%, and stirred until uniform to obtain a foam stabilizer.

[0031] Example 2 The difference between this embodiment and embodiment 1 is that in step (3), the alcohol amine-containing polymer 1 obtained in step (2) and hydroxyethyl cellulose ether are dissolved in deionized water at a mass ratio of 30:1 to prepare a mixed solution with a solid content of 50%, and stirred until uniform to obtain a foam stabilizer; the remaining steps are the same as those in embodiment 1.

[0032] Example 3 The difference between this embodiment and embodiment 1 is that in step (3), the alcohol amine-containing polymer 1 obtained in step (2) and hydroxyethyl cellulose ether are dissolved in deionized water at a mass ratio of 40:1 to prepare a mixed solution with a solid content of 50%, and stirred until uniform to obtain a foam stabilizer; the remaining steps are the same as those in embodiment 1.

[0033] Example 4 A method for preparing a foam stabilizer comprises the following steps: (1) Weigh 66.5 g of diisopropanolamine and 32.43 g of acrylic acid at a molar ratio of 1:0.9, weigh 2.27 g of p-toluenesulfonic acid (7% of the mass of acrylic acid) as a catalyst, and weigh 38.92 g of cyclohexane (1.2 times the mass of acrylic acid) as a water-carrying agent for later use; Diisopropanolamine, p-toluenesulfonic acid catalyst and cyclohexane water agent were added to a three-necked flask and mixed evenly. Acrylic acid was evenly added to the flask by titration. Stirring was started and the mixture was reacted at 90°C for 7.5h. After separation and washing, an unsaturated ester containing an alcohol amino group 2 was obtained. (2) 144 g of methyl allyl alcohol polyoxyethylene ether HPEG was added to 144 g of deionized water, stirred and dissolved at 30 ° C to prepare a 50 wt% base material, and 7.2 g of sodium hypophosphite (5% of the mass of HPEG) and 0.72 g of hydrogen peroxide (0.5% of the mass of HPEG) were added at one time while stirring. 11.22 g of the unsaturated ester containing alcohol amine group 2 synthesized in step (1) (7.8% of the mass of HPEG) was prepared into a 33% aqueous solution A, and 0.55 g of vitamin C (0.38% of the mass of HPEG) was prepared into a 2% aqueous solution B. The aqueous solution A and the aqueous solution B were gradually added dropwise to the base material for reaction. The addition time was 2.5 h, the reaction temperature was 30 ° C, and the reaction was kept warm for 1 h after the reaction was completed to obtain the alcohol amine group polymer 2; (3) The alcohol amine-containing polymer 2 obtained in step (2) and hydroxypropyl cellulose ether were dissolved in deionized water at a mass ratio of 30:1 to prepare a mixed solution with a solid content of 50%, and stirred until uniform to obtain a foam stabilizer.

[0034] Example 5 A method for preparing a foam stabilizer comprises the following steps: (1) Weigh 52.5 g of diethanolamine and 34.4 g of methacrylic acid in a molar ratio of 1:1, weigh 2.75 g of p-toluenesulfonic acid (8% of the mass of methacrylic acid) as a catalyst, and weigh 50.2 g of cyclohexane as a water-carrying agent (1.46 times the mass of methacrylic acid) for later use; Diethanolamine, p-toluenesulfonic acid catalyst and cyclohexane water-carrying agent were added to a three-necked flask and mixed evenly. Methacrylic acid was evenly added to the flask by titration. Stirring was started and the mixture was reacted at 95°C for 6 hours. After separation and washing, an unsaturated ester containing an alcohol amino group 3 was obtained. (2) 156 g of methyl allyl alcohol polyoxyethylene ether HPEG was added to 156 g of deionized water, stirred and dissolved at 30 ° C to prepare a 50 wt% base material, and 13.1 g of sodium hypophosphite (8.4% of the mass of HPEG) and 1.2 g of hydrogen peroxide (0.8% of the mass of HPEG) were added at one time while stirring. 11.22 g of the unsaturated ester containing alcohol amine group 3 synthesized in step (1) (7.2% of the mass of HPEG) was prepared into a 33% aqueous solution A, and 0.55 g of vitamin C (0.35% of the mass of HPEG) was prepared into a 0.45% aqueous solution B. The aqueous solution A and the aqueous solution B were gradually added dropwise to the base material for reaction. The addition time was 2.5 h, the reaction temperature was 30 ° C, and the reaction was kept warm for 1 h after the reaction was completed to obtain the alcohol amine group polymer 3; (3) The alcohol amine-containing polymer 3 obtained in step (2) and hydroxypropyl methylcellulose ether were dissolved in deionized water at a mass ratio of 30:1 to prepare a mixed solution with a solid content of 50%, and stirred until uniform to obtain a foam stabilizer.

[0035] Application Example 1 The foam stabilizer prepared in Example 1 of the present invention is used to prepare low-carbon cement foam concrete, which specifically includes the following steps: (1) Weigh 8 parts of a plant protein foaming agent, 160 parts of a 6% sodium bicarbonate solution, and 8 parts of a foam stabilizer by weight, and mix them evenly to obtain a foaming liquid; use a foaming machine connected to a carbon dioxide gas cylinder to inhale the foaming liquid, the outlet pressure of the carbon dioxide gas cylinder is 1.5 MPa, and allow the carbon dioxide to mix with the foaming liquid to form a continuous carbon dioxide foam. By adjusting the liquid inlet valve, the foaming multiple of the foaming agent is controlled to be 20±1; (2) Low carbon cement foam concrete is prepared according to the dry density of 600 kg / m 3 The design is carried out by taking 420 parts of low carbon cement, 60 parts of steel slag, 50 parts of fly ash, 120 parts of water, 90 parts of 2% mass concentration of sodium bicarbonate solution, and 1.6 parts of water reducer, and mixing them evenly to prepare low carbon cement foam concrete paste (ternary cementitious material system consisting of low carbon cement-steel slag-fly ash); taking 30 parts of the foam prepared in step (1) and adding it to the low carbon cement foam concrete paste, placing it in a mold for molding, demoulding it after molding for 24 hours, and placing it under standard conditions (20±1℃, RH≥90%) for curing to obtain low carbon cement foam concrete.

[0036] Application Example 2 The foam stabilizer prepared in Example 2 of the present invention was used to prepare low-carbon cement foam concrete, and the specific steps were the same as those in Application Example 1.

[0037] Application Example 3 The foam stabilizer prepared in Example 3 of the present invention was used to prepare low-carbon cement foam concrete, and the specific steps were the same as those in Application Example 1.

[0038] Application Example 4 The foam stabilizer prepared in Example 4 of the present invention was used to prepare low-carbon cement foam concrete, and the specific steps were the same as those in Application Example 1.

[0039] Application Example 5 The foam stabilizer prepared in Example 5 of the present invention was used to prepare low-carbon cement foam concrete, and the specific steps were the same as those in Application Example 1.

[0040] Application Example 6 The foam stabilizer prepared in Example 2 of the present invention is used to prepare low-carbon cement foam concrete. The specific steps are different from those in Application Example 2 in that 8 parts of a plant protein foaming agent, 160 parts of a 6% mass concentration sodium bicarbonate solution, and 12 parts of a foam stabilizer are weighed by weight.

[0041] Application Example 7 The foam stabilizer prepared in Example 2 of the present invention is used to prepare low-carbon cement foam concrete. The specific steps are different from those in Application Example 2 in that 10 parts of a plant protein foaming agent, 200 parts of a 6% mass concentration sodium bicarbonate solution, and 12 parts of a foam stabilizer are weighed by weight.

[0042] Comparative Application Example 1 The difference between this comparative application example and application example 2 is that the comparative application example does not contain a foam stabilizer.

[0043] Comparative Application Example 2 The difference between this comparative application example and application example 2 is that the 6% mass concentration sodium bicarbonate solution in step (1) is replaced by water.

[0044] Comparative Application Example 3 The difference between this comparative application example and application example 2 is that step (2) does not contain a 2% mass concentration sodium bicarbonate solution.

[0045] 2. Test Method 1. Molecular weight test of alcoholamine-based polymers in foam stabilizers The molecular weight of the alcoholamine-containing polymers obtained in Examples 1 to 5 was tested using a Waters 1515 gel permeation chromatograph manufactured by Waters Corporation of the United States to determine the molecular weight and distribution of the synthesized samples.

[0046] 2. Foam settling distance and water bleeding rate test Referring to the experimental method in JC / T 2199-2013 "Foaming Agents for Foam Concrete", the carbon dioxide foam obtained in Examples 1 to 7 and Comparative Application Examples 1 to 2 was used to test the 1-hour settlement distance and 1-hour water bleeding rate.

[0047] 3. Compressive strength and carbon fixation rate test of low-carbon cement foam concrete The compressive strength and carbon fixation rate of the low-carbon cement foamed concrete prepared in Examples 1 to 7 and Comparative Examples 1 to 3 were tested. The compressive strength of the low-carbon cement foamed concrete was measured according to the method in JG / T 266-2011 "Foamed Concrete". The carbon fixation rate of the low-carbon cement foamed concrete was measured according to the carbon fixation test method for foamed concrete in patent CN 118373649A.

[0048] 3. Analysis of test results of various embodiments and comparative examples 1. Test results of molecular weight of alcoholamine-based polymers in foam stabilizers The number average molecular weights of the alcoholamine-containing polymers obtained in Examples 1, 4, and 5 are shown in Table 1 below.

[0049] Table 1

[0050] 2. Foam settling distance and water bleeding rate test results The 1-hour settling distance and 1-hour water bleeding rate results of the carbon dioxide foam obtained in Application Examples 1 to 7 and Comparative Application Example 1 are shown in Table 2 below.

[0051] Table 2

[0052] As shown in Table 2, the addition of the foam stabilizer provided by the present invention resulted in a lower water bleeding rate and settling distance for the foam. The results of Comparative Application Example 1 show that when the foam stabilizer was not added to the foaming liquid, the resulting carbon dioxide foam had an increased one-hour settling distance and water bleeding rate, but poorer foam stability. The results of Comparative Application Example 2 show that when the 6% mass concentration sodium bicarbonate solution was not added to the foaming liquid, the carbon dioxide foam obtained had the largest one-hour settling distance and water bleeding rate, but the poorest stability. This is because the solubility of carbon dioxide in a 6% mass concentration sodium bicarbonate solution is extremely low, preventing foam breakage caused by carbon dioxide dissolving in water. 3. Test results of compressive strength and carbon fixation rate of low-carbon cement foam concrete The compressive strength and carbon fixation rate test results of the low-carbon cement foam concrete prepared in Application Examples 1 to 7 and Comparative Application Examples 1 to 3 are shown in Table 3 below.

[0053] Table 3

[0054] As can be seen from Table 3, the low-carbon foamed concrete prepared using the foam stabilizer provided by the present invention has greater compressive strength and excellent carbon fixation capacity. The compressive strength and carbon fixation capacity of the foamed concrete prepared in Comparative Application Example 2 are lower than those in Application Example 2 to a certain extent. This is because unstable foam will lead to uneven pores, thereby reducing the carbon fixation capacity and compressive strength of the concrete; the compressive strength and carbon fixation capacity of the foamed concrete prepared in Comparative Application Example 3 are also lower than those in Application Example 2 to a certain extent. This is because the use of a 2% mass concentration of sodium bicarbonate solution to prepare cement paste allows low-carbon cement to react with bicarbonate ions in the solution first, delaying the reaction time of the cement paste with carbon dioxide in the foam, and avoiding the absorption of a large amount of carbon dioxide during the mixing process of the low-carbon cement paste and the carbon dioxide foam, which leads to a large amount of foam collapse and loss of cement paste fluidity, thereby causing the foamed concrete to collapse or be unable to form.

[0055] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the present invention, other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A foam stabilizer, characterized in that The raw materials for preparing the foam stabilizer include an alcohol amine-containing polymer and cellulose ether in a mass ratio of (20-40):1; the molecular weight of the alcohol amine-containing polymer is 50,000-60,000; The raw materials for preparing the alcoholamine-containing polymer include alcoholamine-containing unsaturated ester, unsaturated polyether monomer, initiator, reducing agent and chain transfer agent; The raw materials for preparing the alcoholamine-containing unsaturated ester include polyol amine, unsaturated carboxylic acid, catalyst and water-carrying agent.

2. A foam stabilizer according to claim 1, characterized in that, The cellulose ether includes at least one of hydroxyethyl cellulose ether, hydroxypropyl cellulose ether and hydroxypropyl methyl cellulose ether.

3. A foam stabilizer according to claim 1, characterized in that, The molar ratio of the polyol amine to the unsaturated carboxylic acid is 1:(0.5-1); the mass ratio of the catalyst to the unsaturated carboxylic acid is (0.06-0.08):1; and the mass ratio of the water-carrying agent to the unsaturated carboxylic acid is (1-1.5):

1.

4. A foam stabilizer according to claim 1, characterized in that, The polyol amine includes at least one of diethanolamine, N-methyldiethanolamine, and diisopropanolamine; The unsaturated carboxylic acid includes at least one of acrylic acid and methacrylic acid; The catalyst includes p-toluenesulfonic acid; The water-carrying agent includes cyclohexane.

5. A foam stabilizer according to claim 1, characterized in that, The mass ratio of the unsaturated polyether monomer to the alcoholamine-containing unsaturated ester is (12-15):1; the unsaturated polyether monomer includes methyl allyl alcohol polyoxyethylene ether.

6. A foam stabilizer according to claim 1, characterized in that, The initiator includes peroxide; the chain transfer agent includes hypophosphite; and the reducing agent includes vitamin C.

7. A method for preparing a foam stabilizer according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Preparation of unsaturated ester containing alcohol amine group: polyol amine, catalyst and water-carrying agent are mixed evenly, and then unsaturated carboxylic acid is slowly added, and the reaction is carried out at 80℃~100℃ for 6~8h, and the unsaturated ester containing alcohol amine group is obtained by separation and washing; (2) Preparation of alcoholamine-containing polymer: An aqueous solution of unsaturated polyether monomer is used as a base material. An initiator and a chain transfer agent are added under stirring. Then, solution A made from the alcoholamine-containing unsaturated ester and aqueous solution B made from a reducing agent are added dropwise to the base material to react. The addition time is 2.5 to 3 hours, the reaction temperature is 30 to 35°C, and after the reaction is completed, the temperature is kept for 1 to 2 hours to obtain the alcoholamine-containing polymer; (3) The alcohol amine-containing polymer obtained in step (2) and the cellulose ether are dissolved in deionized water at a mass ratio of (20-40):1 to prepare a mixed solution with a solid content of 40%-60%, and stirred until uniform to obtain a foam stabilizer.

8. A low-carbon cement foam concrete, characterized in that: The raw materials for preparing the low-carbon cement foam concrete include the foam stabilizer according to any one of claims 1 to 6.

9. A method for preparing low-carbon cement foam concrete according to claim 8, characterized in that: The following steps are involved: (1) preparing carbon dioxide foam: mixing a foaming agent, a first sodium bicarbonate solution and the foam stabilizer to obtain a foaming liquid, and placing the foaming liquid in a carbon dioxide atmosphere to obtain the carbon dioxide foam; (2) Preparing low-carbon cement foam concrete: low-carbon cement, steel slag, fly ash water, a second sodium bicarbonate solution and a water reducer are uniformly mixed to prepare a low-carbon cement foam concrete slurry, the carbon dioxide foam is added to the low-carbon cement foam concrete slurry, and the low-carbon cement foam concrete is obtained through molding, demolding and curing.

10. The method for preparing low-carbon cement foam concrete according to claim 9, characterized in that: The mass concentration of the first sodium bicarbonate solution is 5% to 10%; the mass concentration of the second sodium bicarbonate solution is 1% to 3%; The mass ratio of the foaming agent, the first sodium bicarbonate solution and the foam stabilizer is (8-10): (160-200): (8-12); The mass ratio of the low carbon cement, steel slag, fly ash, water, the second sodium bicarbonate solution, the water reducer and the carbon dioxide foam is (380-500): (55-70): (45-60): (100-130): (80-100): (1.3-2): (26-35).

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