Organic-inorganic hybrid nanometer crystal nucleus early strength agent and preparation method and application thereof

Abstract

The invention relates to the field of building materials, in particular to an organic-inorganic hybrid nanometer crystal nucleus early strength agent as well as a preparation method and application thereof. The method comprises the following steps: taking acrylic acid, silane groups, unsaturated phosphate and isobutylene polyoxyethylene ether as polymerization monomers, and carrying out free radical copolymerization reaction to obtain an organic polymer; and dropwise adding a soluble inorganic calcium source aqueous solution and a soluble inorganic silicon source aqueous solution into the organic polymer under a stirring condition, adjusting the pH value, and continuously stirring to obtain the organic-inorganic hybrid nano crystal nucleus early strength agent. The nano crystal nucleus early strength agent prepared by the method has the advantages of small crystal nucleus size, high dispersion stability in a liquid phase and good early strength effect on concrete, and has no adverse effect on the later strength of the concrete. The method has a great application prospect in projects with high requirements on early strength, such as road repair, low-temperature construction and prefabricated parts.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and particularly to an organic-inorganic hybrid nanocrystalline nucleus early strength agent, a preparation method thereof and an application thereof. Background Art

[0002] In order to meet the requirements of the industrialized development of the construction industry, the research and development of new materials and new technologies for rapidly improving the early strength of Portland cement have always been important topics. Currently, in low-temperature construction and precast component production, steam curing is mostly used to achieve the rapid development of the early strength of cement-based materials. However, there are two problems with steam curing: one is the large energy consumption and CO2 emissions, which do not meet the requirements of carbon peak and carbon neutrality; the other is the thermal damage to the interior of the concrete caused by steam curing, which reduces the durability of cement concrete, thereby reducing the service life of the concrete. To reduce steam curing, energy consumption and CO2 emissions, researchers have explored methods to achieve the rapid development of the early strength of cement concrete through various means. Adding an early strength agent is one of the common means to achieve the rapid development of the early strength of concrete under normal temperature conditions. However, most traditional early strength agents have their own insurmountable defects. For example, chloride salt (CaCl2) early strength agents have a high early strength effect, but they will corrode steel bars; sulfate (CaSO4) early strength agents not only have a general early strength effect, but also have the hazard of alkali-aggregate reaction damage; the dosage of organic series (triethanolamine, triisopropanolamine) early strength agents is not easy to control, and excessive use will instead cause a retarding phenomenon. Moreover, most commonly used early strength agents will affect the long-term strength of concrete and cannot be used on a large scale in concrete.

[0003] In recent years, research has found that adding some nanomaterials, such as nano-SiO2, nano-CaCO3, carbon nanotubes and nano-calcium silicate hydrate (C-S-H), etc. to cement-based materials can significantly accelerate the hydration rate of cement, improve the early strength, and is expected to become a new type of early strength agent for cement concrete. Among them, since nano-C-S-H is a good nucleation matrix for the main hydration product calcium silicate hydrate gel in cement-based materials, it can provide additional nucleation sites for it and promote the formation of calcium silicate hydrate gel. Therefore, the early strength effect is the most obvious and has no adverse effect on the later strength of concrete. However, due to the relatively large specific surface area of nanocrystals and the large interfacial energy, they are thermodynamically unstable and tend to agglomerate with each other, which will reduce their early strength effect. Existing technologies mostly use polycarboxylate superplasticizer as a dispersant to prepare calcium silicate hydrate / polycarboxylate superplasticizer nanocomposites to solve the agglomeration problem. However, there are still problems such as long preparation time, poor dispersion stability of nanocrystalline nucleus early strength agents, and poor early strength effect.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an organic-inorganic hybrid nano-crystalline nucleus early strength agent for concrete with high dispersion stability and good early strength effect, as well as its preparation method and application. The present invention first synthesizes an organic polymer with strong adsorption and steric hindrance effects, and then fully stirs and mixes it with a soluble calcium source and a silicon source under specific conditions to obtain the organic-inorganic hybrid nano-crystalline nucleus early strength agent. The nano-crystalline nucleus early strength agent prepared by this method has the advantages of small crystal nucleus size, high dispersion stability in the liquid phase, good early strength effect on concrete, and no adverse effect on the later strength of concrete. It has great application prospects in projects with high requirements for early strength such as road repair, low-temperature construction, and precast components.

[0006] In the first aspect, the present invention provides a preparation method of an organic-inorganic hybrid nano-crystalline nucleus early strength agent, including: 1) Using acrylic acid, silane group, unsaturated phosphate ester, and polyoxyethylene isobutylene ether as polymerization monomers to carry out free radical copolymerization reaction to obtain an organic polymer.

[0007] 2) Under stirring conditions, dropwise add an aqueous solution of a soluble inorganic calcium source and an aqueous solution of a soluble inorganic silicon source to the organic polymer and adjust the pH, and continue stirring to obtain an organic-inorganic hybrid nano-crystalline nucleus early strength agent. In the present invention, an organic polymer for inhibiting the growth of nano-particles is prepared by using small monomers such as phosphate groups, silane groups, and acrylic acid, which can quickly combine with the hydrated calcium silicate generated by the reaction through Ca 2+ complexation to form a relatively large adsorption area quickly through high charge density. Then, the silane group can change the organic-inorganic binding mode to Si—O—Si chemical bonding, making the organic-inorganic combination more stable and effectively inhibiting the aggregation and growth of nano-crystalline nuclei. Compared with ordinary nano-crystalline nucleus early strength agents, the present invention can make the particle size of the nano-crystalline nucleus early strength agent smaller, the dispersion stability better, and the early strength effect stronger. When added to cement concrete, it can provide more nucleation sites for the hydrated calcium silicate gel of cement hydration products, accelerate the generation rate, significantly improve the early strength of concrete, and have no adverse effect on the growth of later strength.

[0008] In order to further improve the early strength effect of the organic-inorganic hybrid nano-crystalline nucleus early strength agent, the preparation process of the present invention is optimized as follows: Preferably, in step 1), the silane group is selected from one or more of cetyltrimethoxysilane, hexamethyldisiloxane, polydimethylsiloxane, n-butylsilane, isobutylsilane, isooctylsilane, γ-methacryloxypropyltrimethoxysilane.

[0009] Preferably, in step 1), the unsaturated phosphate ester is selected from one or more of acrylate phosphate ester, bis(2-methacryloyloxyethyl) hydrogen phosphate, 2-methacryloyloxyethyl phosphate, and phosphonic acid-β-styryl ester.

[0010] More preferably, in step 1), the mass ratio of acrylic acid, silane group, unsaturated phosphate ester, and polyoxyethylene isobutylene ether is 3.5 - 14: 2.5 - 10: 2 - 8: 55 - 225, preferably 7.9 - 9.8: 5.7 - 7.1: 4.4 - 5.5: 124 - 153. By optimizing different monomers and their dosages, the dispersing effect of the organic polymer can be better exerted, which is beneficial to improving the dispersion stability of nanocrystalline nuclei.

[0011] Preferably, using 2-methacryloyloxyethyl phosphate (MOEP), γ-methacryloyloxypropyltrimethoxysilane (KH570), and acrylic acid (AA) as comonomers, ammonium persulfate as an initiator, thioglycolic acid as a chain transfer agent, and polyoxyethylene isobutylene ether (HPEG) with a molecular weight of 2400 g / mol as a macromonomer to prepare the polyphosphate polymer. Preferably, the raw material dosages are 138.7 ± 10 g of HPEG, 4.95 ± 1 g of MOEP, 6.41 ± 1 g of KH570, 8.78 ± 1 g of AA monomer, and 0.96 ± 0.1 g of thioglycolic acid.

[0012] More preferably, in step 1), the molecular weight of the organic polymer is 30000 - 50000.

[0013] More preferably, in step 1), the reaction temperature is 70 - 90 °C, preferably 75 - 85 °C, such as 76, 77, 78, 79, 80, 81, 82, 83, 84, 85 °C, etc.; the reaction time is 1 - 8 h, such as 1, 2, 3, 4, 5, 6, 7, 8 h, etc. By optimizing the process parameters, the conversion rate of the organic polymer can be better improved, which is beneficial to the exertion of its dispersing effect on nanocrystalline nuclei.

[0014] Preferably, in step 2), the soluble inorganic calcium source (the active ingredient of the soluble calcium source aqueous solution) is selected from one or more of calcium formate, calcium chloride, calcium nitrate tetrahydrate, calcium acetate, and calcium lactate; preferably, the soluble inorganic calcium source is selected from one or more of calcium nitrate tetrahydrate, calcium formate, and calcium acetate.

[0015] Preferably, in step 2), the soluble inorganic silicon source (the active ingredient of the soluble silicon source aqueous solution) is selected from one or more of sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, potassium silicate, and tetraethyl orthosilicate; preferably, the soluble inorganic silicon source is selected from one or more of sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, and tetraethyl orthosilicate.

[0016] Preferably, in step 2), the molar ratio of the soluble inorganic calcium source to the soluble inorganic silicon source is 1.0 to 1.7:1; preferably, the molar ratio of the soluble inorganic calcium source to the soluble inorganic silicon source is 1.0 to 1.2:1. In the present invention, by optimizing the types and proportions of the soluble inorganic calcium source and the soluble inorganic silicon source, a more stable organic-inorganic hybrid structure can be further formed, thereby improving the strength performance of the concrete in the early stage.

[0017] Preferably, in step 2), the dropping time of the aqueous solution of the soluble inorganic calcium source and the aqueous solution of the soluble inorganic silicon source is 2 to 4 h; the stirring speed is 300 to 500 r / min.

[0018] Preferably, in step 2), the dropping process of the aqueous solution of the soluble calcium source and the aqueous solution of the soluble silicon source is carried out under the condition of water bath heating, the temperature is 40 to 60 °C, preferably 45 to 55 °C.

[0019] Preferably, in step 2), NaOH and HNO3 are used to adjust the pH of the solution to 11 ± 0.5. During the synthesis process of the present invention, the pH value of the solution in the reaction kettle is adjusted to the above range by NaOH and HNO3, which is beneficial to the full combination of the organic components and the inorganic components, and enables the nanocrystalline nucleus early strength agent to have high dispersion stability.

[0020] Preferably, in step 2), the temperature for continued stirring is 15 to 30 °C, and the time is 18 to 24 h, preferably 20 to 24 h.

[0021] Preferably, in step 2), the concentration of the aqueous solution of the soluble inorganic calcium source is 25 to 65%, such as 30, 40, 55, 55.5, 58.33, 60, 61.61, 62, 63, 65%, etc., and the concentration of the aqueous solution of the soluble inorganic silicon source is 10 to 50%, such as 10, 20, 25, 26, 27, 28, 28.16, 30, 40, 45.73, 50%, etc.

[0022] In the present invention, by dropping the aqueous solution of the soluble inorganic calcium source and the aqueous solution of the soluble inorganic silicon source into the organic polymer under stirring conditions, adjusting the pH, continuing to stir, and optimizing the conditions, the obtained organic-inorganic hybrid nanocrystalline nucleus early strength agent can more effectively improve the early strength of the concrete, while having no adverse effect on the later strength of the concrete, and the nanocrystalline nucleus has high dispersion stability, providing better performance improvement for the concrete material.

[0023] Preferably, the dosage of the organo-inorganic hybrid nano-early strength agent prepared by the present invention in concrete is controlled at 0.5% - 2.0% of the binder, such as 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.5, 1.6, 1.7, 1.8, 1.9%, etc. This is mainly because too low dosage cannot play a good early strength enhancing role, and too much organic component in the nano-crystal nucleus early strength agent may have a delaying effect on cement hydration, which will affect the early strength effect of the nano-crystal nucleus early strength agent.

[0024] The present invention uses a polycarboxylic acid copolymer containing phosphoric acid groups and silane groups as a dispersant. By utilizing the rapid adsorption characteristics of the phosphoric acid groups, a copolymer can be formed with the nano-crystal nuclei. At the same time, the silane groups can change the adsorption mode of the organic polymer and nano C-S-H from Ca 2+ complexation to a more stable Si—O—Si chemical bond bonding mode, effectively inhibiting the agglomeration and growth of the nano-crystal nuclei, improving the dispersion stability of the nano-crystal nucleus early strength agent, extending the storage time, and enhancing its early strength effect.

[0025] In the second aspect, the present invention provides an organo-inorganic hybrid nano-crystal nucleus early strength agent prepared by the above preparation method.

[0026] Preferably, in the organo-inorganic hybrid nano-crystal nucleus early strength agent, the mass fraction of the organic polymer is 5 - 10%, preferably 6 - 9%. In the present invention, the organic component should not be too high or too low, otherwise it is not conducive to the exertion of the early strength effect of the nano-crystal nucleus early strength agent.

[0027] In the third aspect, the present invention provides the application of the organo-inorganic hybrid nano-crystal nucleus early strength agent obtained by the above preparation method in concrete; preferably, the dosage of the organo-inorganic hybrid nano-crystal nucleus early strength agent is 0.5% - 5% of the cement binder, preferably 1% - 2%.

[0028] The beneficial effects of the present invention are at least as follows: The preparation method of the organo-inorganic hybrid nano-crystal nucleus early strength agent for concrete provided by the present invention utilizes the synergistic mechanism of phosphoric acid groups and silane groups in the organic component, which can be fully combined with the inorganic component to disperse nano-particles, effectively solving the problem of poor dispersion stability of the nano-crystal nucleus early strength agent. The average particle size of the prepared nano-crystal nucleus early strength agent is mainly distributed in 100 - 120 nm, the crystal nucleus size is stable, and the storage time is long. When applied to concrete, it can promote the hydration of cement, significantly improve the early strength of concrete, and does not affect the later strength. It is a new type of high-performance early strength agent and has great application prospects in the production of concrete precast components, winter construction, etc., providing strong technical support for the energy conservation and emission reduction of concrete. Specific Embodiments

[0029] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be described clearly and completely below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without any creative work belong to the scope of protection of the present invention.

[0030] In the ranges disclosed in the present invention, the endpoints and any values of the ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0031] In the embodiments of the present invention, where specific technologies or conditions are not indicated, they are carried out according to the technologies or conditions described in the literature in the art or according to the product specifications. For devices, instruments, reagents, etc. where the manufacturer is not indicated, they are all conventional products that can be purchased through regular channels. The experimental reagents and raw materials involved are all commercially available products, and the reagents are all analytical pure products.

[0032] In some embodiments of the present invention, the preparation of the organic-inorganic hybrid nanocrystalline nucleus early strength agent includes: dissolving the prepared organic polymer in a 1000 mL four-necked flask, placing it in a water bath at a temperature of 40 - 60 °C, adjusting the pH value of the reaction solution to 11 ± 0.5 with NaOH and HNO3, continuously stirring in the water bath with a stirring paddle, and dripping a certain concentration of soluble calcium salt solution and soluble silicate salt solution into the reaction kettle with the organic polymer prepared in step (1) as the precursor through a peristaltic pump. The dripping time is 2 - 4 h, and after the dripping is completed, continue to stir at room temperature for 18 - 24 h.

[0033] In the following examples of the present invention, the organic polymer used is prepared by using 2-methacryloyloxyethyl phosphate (MOEP), γ-methacryloyloxypropyltrimethoxysilane (KH570), and acrylic acid (AA) as copolymerization comonomers, ammonium persulfate as an initiator, thioglycolic acid as a chain transfer agent, and isobutene polyoxyethylene ether (HPEG) with a molecular weight of 2400 g / mol as a macromonomer to prepare a polyphosphoric acid polymer. The specific process is as follows: First, 138.7 g of HPEG is dissolved in 150 g of deionized water and stirred evenly, then loaded into a three-necked flask and heated to 80 °C in a water bath. 4.95 g of MOEP, 6.41 g of KH570, 8.78 g of AA monomers, and 0.96 g of thioglycolic acid are dissolved in 60 g of deionized water as dropping solution A. 3.56 g of ammonium persulfate is added to 30 g of deionized water as dropping solution B. Then, dropping solution A and dropping solution B are slowly dropped into the three-necked flask through a peristaltic pump within 4 hours and 5 hours respectively. During the entire polymerization process, the temperature in the water bath is kept constant at 80 ± 2 °C. After the dropping is completed, continue to keep warm for 1 h to complete the subsequent polymerization reaction, and an organic polymer with a solid content of 40% (molecular weight of 45000) is obtained after cooling.

[0034] Example 1 This example provides an organic-inorganic hybrid nanocrystalline nucleus early strength agent. The specific steps for preparing the organic-inorganic hybrid nanocrystalline nucleus early strength agent are as follows: First, 50 g of the organic polymer prepared in the above example is added to a 1000 mL four-necked flask, and then 105 g of deionized water is added. Then, the four-necked flask is transferred to a water bath at a temperature of 60 °C and continuously stirred with a stirring paddle at a rate of 500 r / min. 28 g of calcium nitrate tetrahydrate is dissolved in 20 g of deionized water, and 19.6 g of sodium metasilicate nonahydrate is dissolved in 50 g of water. The calcium nitrate tetrahydrate solution and the sodium metasilicate nonahydrate solution are simultaneously dropped into the four-necked flask through a peristaltic pump. The dropping time is 3 h. After the dropping is completed, continue to stir in a room temperature environment for 18 h to obtain an organic-inorganic hybrid nanocrystalline nucleus early strength agent. The mass fraction of the organic polymer in the nanocrystalline nucleus early strength agent is 8.0%.

[0035] Example 2 This embodiment provides an organic-inorganic hybrid nanocrystalline nucleus early strength agent. The specific steps of the preparation method of the organic-inorganic hybrid nanocrystalline seed early strength agent are as follows: First, add 40 g of the organic polymer prepared in the above embodiment into a 1000 mL four-necked flask, and then add 137.28 g of deionized water. Then, transfer the four-necked flask into a water bath at a temperature of 40 °C, and continuously stir with a stirring paddle at a rate of 400 r / min. Dissolve 28 g of calcium nitrate tetrahydrate in 17.45 g of deionized water, and dissolve 33.7 g of sodium metasilicate nonahydrate in 40 g of deionized water. Drop calcium nitrate tetrahydrate and sodium metasilicate nonahydrate into the four-necked flask simultaneously through a peristaltic pump. The dropping time is 2 h. After dropping, continue to stir in a room temperature environment for 24 h to obtain an organic-inorganic hybrid nanocrystalline nucleus early strength agent. The mass fraction of the organic polymer in the nanocrystalline nucleus early strength agent is 5.4%.

[0036] Example 3 This embodiment provides an organic-inorganic hybrid nanocrystalline nucleus early strength agent. The specific steps of the preparation method of the organic-inorganic hybrid nanocrystalline seed early strength agent are as follows: First, add 50 g of the organic polymer prepared in the above embodiment into a 1000 mL four-necked flask, and then add 102.75 g of deionized water. Then, transfer the four-necked flask into a water bath at a temperature of 50 °C, and continuously stir with a stirring paddle at a rate of 300 r / min. Add 28 g of calcium nitrate tetrahydrate to 20 g of deionized water, and add 19.6 g of sodium metasilicate nonahydrate to 50 g of deionized water. Drop the calcium nitrate tetrahydrate solution and the sodium metasilicate nonahydrate solution into the four-necked flask simultaneously through a peristaltic pump. The dropping time is 3 h. After dropping, continue to stir in a normal temperature environment for 24 h. The mass fraction of the organic polymer in the nanocrystalline nucleus early strength agent is 8.0%.

[0037] Comparative Example 1 Add 132.5 g of deionized water into a 1000 mL four-necked flask. Then, transfer the four-necked flask into a water bath at a temperature of 60 °C, and continuously stir with a stirring paddle at a rate of 500 r / min. Dissolve 28 g of calcium nitrate tetrahydrate in 20 g of water, and dissolve 19.6 g of sodium metasilicate nonahydrate in 50 g of water. Drop the calcium nitrate tetrahydrate solution and the sodium metasilicate nonahydrate solution into the four-necked flask simultaneously through a peristaltic pump. The dropping time is 3 h. After dropping, continue to stir in a room temperature environment for 24 h to obtain a nanocrystalline nucleus early strength agent.

[0038] Comparative Example 2 Add 50 g of ordinary polycarboxylate copolymer with a molecular weight roughly equivalent to that of the organic polymer prepared in the above step (1) into a 1000 mL four-necked flask, and then add 102.75 g of deionized water. After that, transfer the four-necked flask into a water bath at a temperature of 50 °C, and continuously stir it with a stirring paddle at a rate of 300 r / min. Add 28 g of calcium nitrate tetrahydrate into 20 g of deionized water, and add 19.6 g of sodium metasilicate nonahydrate into 50 g of deionized water. Drop the calcium nitrate tetrahydrate solution and the sodium metasilicate nonahydrate solution into the four-necked flask simultaneously through a peristaltic pump. The dropping time is 3 h. After the dropping is completed, continue to stir for 24 h at room temperature to obtain a nano-crystalline nucleus early strength agent. The mass fraction of the organic polymer in the nano-crystalline nucleus early strength agent is 8.0%.

[0039] Experimental Example 1 1. Grain size of polymer-modified calcium silicate hydrate nano-seed early strength agent Since the grain size of nano-calcium silicate hydrate has a direct relationship with its early strength effect, the grain size of nano-calcium silicate hydrate prepared in the examples and comparative examples of the present invention was investigated by a Malvern particle size analyzer. The test results are shown in Table 1.

[0040] Table 1 Time-dependent change of particle size distribution of nano-calcium silicate hydrate seed early strength agent

[0041] It can be seen from Table 1 that the organic-inorganic hybrid nano-crystalline nucleus early strength agent synthesized according to the present invention has the advantages of small particle size and high dispersion stability. After being placed for 1 year, the grain size is still only 200 - 300 nm. This is due to the fact that the phosphate groups and silyl groups in the organic polymer can quickly adsorb with the inorganic components synergistically. At the same time, the bonding mode changes from Ca 2+ complexation to a more stable Si-O-Si chemical bond bonding mode, thereby effectively inhibiting the aggregation of nano-particles through electrostatic repulsion and steric hindrance effects. In Comparative Example 1 without adding organic matter, the grain size increased significantly due to the lack of the dispersion effect of organic matter. In Comparative Example 2, the nano-crystalline nucleus early strength agent prepared with ordinary polycarboxylate copolymer had aggregation of nano-particles due to insufficient dispersion ability of the organic component. Although the particle size was small after preparation, it could hardly reach the nano-level after half a year.

[0042] 2. Influence of organic-inorganic hybrid nano-crystalline nucleus early strength agent on concrete strength The prepared nano-calcium silicate hydrate seed early strength agent was incorporated at 1.0% of the concrete binder. The concrete strength test was carried out on the organic-inorganic hybrid nano-seed early strength agent standing for 1 day and 180 days. The raw materials of the concrete are as follows:[[]] P.I 42.5 cement, S95 blast furnace slag powder, Class II fly ash, limestone aggregate (5 - 20 mm), medium sand in Zone II, water reducing agent.

[0043] The raw material formula of the concrete is shown in Table 2.

[0044] Table 2 Mix proportion of raw materials of concrete (kg / m 3 )

[0045] The strength of each concrete was tested in accordance with GB 50081 - 2019, and the results are shown in Table 3; Table 3 Influence of organic - inorganic hybrid nano - crystal nucleus early - strength agent standing for 1 d on concrete strength

[0046] Table 4 Influence of organic - inorganic hybrid nano - crystal nucleus early - strength agent standing for 180 days on concrete strength

[0047] As can be seen from Table 3, whether it is the example or the comparative example, the early strength of the concrete is effectively improved. At this time, the nano - hydrated calcium silicate crystal seed suspensions of all examples and comparative examples have good dispersibility and can play the role of crystal seed early - strength to improve the early strength of the concrete, but the early - strength effect of the nano - crystal nucleus early - strength agent without organic - inorganic hybridization is poor.

[0048] As can be seen from Table 4, after half a year of placement, the organic - inorganic hybrid nano - crystal nucleus early - strength agents of Examples 1 - 3 prepared by the present invention still show good early - strength effects, while the early - strength effects of Comparative Examples 1 - 2 basically disappear. This is mainly caused by the difference in the dispersion stability of the nano - crystal nucleus early - strength agent. The main reason is that the organic - inorganic hybrid nano - crystal nucleus early - strength agent prepared by the present invention shows excellent dispersion stability, solving the problems that nano - crystal nuclei are easy to agglomerate and not easy to store. It shows that the organic - inorganic nano - crystal nucleus early - strength agent for concrete provided by the present invention is a crystal nucleus early - strength agent with small crystal grain size, good dispersion stability and excellent early - strength effect, and has great potential for market promotion.

[0049] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various examples of the present invention.

Claims

1. A preparation method of an organic-inorganic hybrid nanocrystalline nucleus early strength agent, characterized in that It includes the following steps: 1) Using acrylic acid, silane groups, unsaturated phosphate esters, and polyoxyethylene isobutylene ether as raw materials, carrying out a free radical copolymerization reaction to obtain an organic polymer; 2) Under stirring conditions, dropping a water solution of a soluble inorganic calcium source and a water solution of a soluble inorganic silicon source into the organic polymer and adjusting the pH, and continuing to stir to obtain an organic-inorganic hybrid nano-crystal nucleus early strength agent.

2. The preparation method according to claim 1, characterized in that, In step 1), the silane groups are selected from one or more of cetyltrimethoxysilane, hexamethyldisiloxane, polydimethylsiloxane, n-butylsilane, isobutylsilane, isooctylsilane, γ-methacryloxypropyltrimethoxysilane; and / or, the unsaturated phosphate esters are selected from one or more of acrylate phosphate esters, bis(2-methacryloxyethyl) hydrogen phosphate, 2-methacryloxyethyl phosphate, phosphonic acid-β-styryl ester; and / or, the mass ratio of the acrylic acid, silane groups, unsaturated phosphate esters, and polyoxyethylene isobutylene ether is 3.5~14 : 2.5~10 : 2~8 : 55~225.

3. The preparation method according to claim 1 or 2, characterized in that, In step 1), the reaction temperature is 70~90 °C and the reaction time is 1~8 h; and / or, in step 1), the molecular weight of the organic polymer is 30000~50000.

4. The preparation method according to any one of claims 1 to 3, characterized in that, In step 2), the soluble inorganic calcium source is selected from one or more of calcium formate, calcium chloride, calcium nitrate tetrahydrate, calcium acetate, calcium lactate; and / or, the soluble inorganic silicon source is selected from one or more of sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, potassium silicate, tetraethyl orthosilicate; and / or, the molar ratio of the soluble inorganic calcium source and the soluble inorganic silicon source is 1.0~1.7:

1.

5. The preparation method according to any one of claims 1-4, characterized in that, In step 2), the dropping time of the water solution of the soluble inorganic calcium source and the water solution of the soluble inorganic silicon source is 2~4 h, and the stirring speed is 300~500 r / min.

6. The preparation method according to any one of claims 1-5, characterized in that, In step 2), the dropping process of the water solution of the soluble calcium source and the water solution of the soluble silicon source is carried out under the condition of water bath heating, and the temperature is 40~60 °C.

7. The preparation method according to any one of claims 1-6, characterized in that, In step 2), the pH of the solution is adjusted to 11±0.5 using NaOH and HNO3.

8. The preparation method according to any one of claims 1-7, characterized in that, In step 2), the temperature for the continued stirring is 15~30 °C and the time is 18~24 h.

9. An organic-inorganic hybrid nanocrystalline nucleating agent for early strength, characterized in that, Obtained by the preparation method according to any one of claims 1-8.

10. Application of the organic-inorganic hybrid nano-crystal nucleus early strength agent obtained by the preparation method according to any one of claims 1-8 in concrete; preferably, the dosage of the organic-inorganic hybrid nano-crystal nucleus early strength agent is 0.5%~5% of the mass of the binder.

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