Preparation method and application of nano composite material based on polymer intercalation hybridization and anti-dispersion cement paste

Abstract

The invention discloses a preparation method and application of a nano composite material based on polymer intercalation hybridization and anti-dispersion cement paste, and the preparation method comprises the following steps: dispersing hydrotalcite powder in deionized water to form a stable suspension; dropwise adding a polycarboxylate superplasticizer monomer into the suspension, and adjusting the pH value to 7-8; adding an initiator to carry out in-situ polymerization reaction for 6-8 hours at the temperature of 40-60 DEG C under the protection of nitrogen; and drying and grinding the reaction product to obtain the PCE-LDH nano composite material. According to the invention, an in-situ intercalation polymerization method is adopted to construct a nano composite additive with a nano container function, the slow release of the water reducing agent can be realized, when the nano composite additive is applied to anti-dispersion slurry, the water reducing agent locked between hydrotalcite layers at the initial stage can avoid the viscosity competition with a flocculating agent, and the stability of a system is ensured; the polycarboxylate superplasticizer is controllably released from hydrotalcite layers in the later stage, so that the fluidity loss caused by a flocculating agent can be effectively counteracted, and the filling compactness and the final mechanical strength of the slurry are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a preparation method and application of a nanocomposite based on polymer intercalation hybridization and an anti-dispersion cement paste. BACKGROUND

[0002] When concrete is poured in underwater or flowing water environment, the traditional cement paste is easily washed and diluted by water flow, leading to component separation and strength drop, and forming quality defects. The anti-dispersion cement paste significantly improves the cohesiveness of the paste and the anti-washing ability in water by adding special anti-dispersion agent, ensures the stable suspension of cement particles, and realizes the underwater self-leveling and self-compacting construction. Its application is the key technology to ensure the quality and durability of underwater pile foundation, tunnel sinking pipe, hydraulic structure repair and other engineering, and is very important to improve the safety and reliability of building structure.

[0003] The traditional anti-dispersion cement paste is mainly composed of Portland cement, anti-dispersion agent, mineral admixture and aggregate. Among them, the anti-dispersion agent is the core functional component, and water-soluble polymers such as polyacrylamide (PAM) or cellulose ether are often used. Through the bridging and adsorption of the polymer chain, the cohesiveness of the paste in water is enhanced, and the dispersion of cement particles is inhibited. Mineral admixtures (such as fly ash and silica fume) can improve the microstructure of the paste and improve the long-term durability. Qiyanhai et al. developed a CIS material with adjustable initial and final setting time (initial setting time 13-65 s, final setting time 30-255 min) and high water flow retention rate (retention rate >80% at 1.2 m / s flow rate, up to 92.3% under the best ratio), and realized the volume expansion of the paste (chemical expansion 3.28%-4.8%, physical expansion 16.48%-32.27%) through the bias expansion control technology, and applied it to the sudden gushing water treatment. Zeng et al. provided a super-retarding (initial setting time more than 24 h) and anti-dispersion cement paste formula, which contains cement, mineral powder, silica powder, anti-slump polycarboxylic acid water reducer, high-efficiency polycarboxylic acid water reducer, cement hydration control agent, flocculating agent and water in a specific ratio, and is suitable for pile punching process, which can effectively prevent sinking and hardening. Yang et al. prepared a polymer KSQ-Z using 2-acrylamide-2-methylpropanesulfonic acid and acrylamide as main raw materials. When the dosage is 1.2%, the anti-dispersion effect is the best, which can make the compressive strength of cement stone after water invasion increase by up to 41.1%, and the network structure can increase the stability and density of cement stone. It can be seen that the anti-dispersion cement paste mainly realizes its stability and effectiveness in flowing water environment by adding anti-dispersion agents (such as flocculants and polymers) to cement-based materials, regulating the hydration process, optimizing the particle size distribution and compounding various functional admixtures (such as water reducing agent, early strength agent and stabilizer).

[0004] However, in the current practical application, in order to ensure sufficient dispersion resistance, a large amount of thickening agent (such as cellulose ether) or flocculating agent (such as polyacrylamide) is often added, which inevitably leads to a significant increase in the viscosity of the slurry and a decrease in the flowability, thereby causing difficulties in pumping and pouring construction. In order to improve the flowability defect caused by high viscosity, a high-efficiency water-reducing agent is usually introduced. However, after the rapid release of the conventional water-reducing agent, it is easily adsorbed by the molecular chain of the thickening agent, and its dispersion effect is quickly offset, which causes the time loss of the flowability of the slurry to be intensified, and the effective construction window period to be shortened.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The technical problem to be solved by the present application is that the conventional water-reducing agent is easily adsorbed by the molecular chain of the thickening agent after rapid release, and its dispersion effect is quickly offset, which causes the time loss of the flowability of the slurry to be intensified. The purpose of the present application is to provide a preparation method and application of a polymer intercalation hybrid-based nanocomposite material and a dispersion-resistant cement slurry. The polycarboxylate superplasticizer (PCE) is embedded in the interlayer of the hydrotalcite (LDH) by using an in-situ intercalation polymerization method, and a nanocomposite additive (PCE-LDH) with a "nanocapsule" function is constructed. The additive can produce a synergistic effect with the water-soluble polymer flocculating agent, effectively regulate the rheological properties of the cement slurry, realize the balance between the flowability and the dispersion resistance, improve the adaptability of the cement slurry in the complex underwater environment, and enhance the ability to resist water flow scouring and ion erosion. The present application can be used for construction and application of various underwater projects.

[0007] The present application is realized by the following technical scheme: In a first aspect, the present application provides a preparation method of a polymer intercalation hybrid-based nanocomposite material, comprising the following steps: Disperse the hydrotalcite (LDH) powder in deionized water to form a stable LDH suspension; Drop the polycarboxylate superplasticizer (PCE) monomer into the LDH suspension, and adjust the pH to 7-8; Under the protection of nitrogen at 40-60 DEG C, add an initiator to carry out in-situ polymerization reaction for 6-8 h; The reaction product is dried and ground to obtain the PCE-LDH nanocomposite material.

[0008] Currently, in anti-dispersible cement slurries, water-reducing agents are rapidly released after addition, making them easily adsorbed by thickener molecular chains. This quickly negates the dispersing effect of the thickener, leading to a significant loss of slurry fluidity over time and a shortened effective construction window. To address this issue, this invention prepares a hydrotalcite-based slow-release water-reducing agent. Using an in-situ intercalation polymerization method, polycarboxylate water-reducing agent monomers are embedded into the hydrotalcite interlayer. Since the hydrotalcite interlayer contains anions, anionic monomers can be intercalated between the interlayers through ion exchange. Then, through in-situ polymerization, a nanocomposite additive with "nanocontainer" function is constructed, enabling the slow release of the water-reducing agent. When applied to anti-dispersible slurries, in the initial slow-release phase, the water-reducing agent "locked" in the hydrotalcite interlayer avoids viscosity competition with the flocculant, ensuring system stability. In the later slow-release phase, as hydration progresses, a large amount of polycarboxylate water-reducing agent is released controllably from the hydrotalcite interlayer, effectively offsetting the fluidity loss caused by the flocculant and improving the slurry's filling density and final mechanical strength.

[0009] This invention utilizes an in-situ polymerization process to construct a nanocomposite additive with "nanocontainer" functionality. Compared to existing methods that simply intercalate polycarboxylate superplasticizers into hydrotalcite using ultrasound, this invention first inserts smaller monomers into the interlayer space. These smaller monomers are easier to integrate into the interlayer structure. Secondly, under the action of an initiator, the small monomers of the polycarboxylate superplasticizer polymerize in situ within the hydrotalcite interlayer space to form a high-molecular-weight polymer. This polymerization creates an "entanglement" effect, making the structure between the superplasticizer and the hydrotalcite interlayer more stable and ensuring a slower release of the superplasticizer. In contrast, existing methods that intercalate polycarboxylate superplasticizers into hydrotalcite using ultrasound suffer from several drawbacks. Firstly, the larger molecular size of the high-molecular-weight polycarboxylate superplasticizer makes it more difficult to intercalate into the hydrotalcite interlayer space, resulting in low loading efficiency. Secondly, the polycarboxylate superplasticizer is simply intercalated into the interlayer space without a connection to the hydrotalcite interlayer structure, making it easy for it to be released rapidly from the hydrotalcite and failing to achieve a sustained-release effect.

[0010] In one specific embodiment, the hydrotalcite is a magnesium aluminum sulfate type hydrotalcite (Mg / Al-SO4). 2- -LDHs), calcium aluminum sulfate type hydrotalcite (Ca / Al-SO4) 2- -LDHs), magnesium aluminum nitrate type hydrotalcite (Mg / Al-NO3) - -LDHs), calcium aluminum nitrate type hydrotalcite (Ca / Al-NO3) - One of the LDHs.

[0011] In one specific embodiment, the polycarboxylate superplasticizer (PCE) monomer is composed of unsaturated carboxylic acid small monomers, macromonomers, and functional small monomers.

[0012] In one specific embodiment, the unsaturated carboxylic acid monomer is at least one of acrylic acid (AA), methacrylic acid (MAA), and maleic anhydride (MA); The macromonomer is one of allyl polyoxyethylene ether (HPEG) and isopentenyl polyoxyethylene ether (TPEG); The functional monomer is at least one of acrylamide (AM) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS).

[0013] In one specific embodiment, the polymerization reaction adopts a low-temperature redox initiation system, wherein the initiating oxidant is one of hydrogen peroxide, potassium persulfate, ammonium persulfate, or cumene hydrogen peroxide, and the initiating reducing agent is one of sodium sulfite or ferrous chloride.

[0014] In one specific embodiment, the concentration of the LDH powder in deionized water is 5.0-8.0 wt%; the concentration of the unsaturated carboxylic acid small monomers in deionized water is 8.0 wt%-12.0 wt%; the concentration of the macromolecular monomers in deionized water is 1.0 wt%-2.0 wt%; and the concentration of the functional small monomers in deionized water is 1.0 wt%-2.0 wt%.

[0015] In a second aspect, the present invention provides an anti-dispersion cement slurry, comprising cement, PCE-LDH nanocomposite material, water-soluble polymer flocculant, and mixing water.

[0016] The anti-dispersion cement slurry of this invention effectively ensures the initial anti-dispersion properties of the freshly mixed slurry through the addition of flocculant via rapid thickening. However, the introduction of flocculant can inhibit flowability and may also introduce an air-entraining effect, affecting the final strength of the concrete. Therefore, this invention introduces a hydrotalcite-based slow-release water-reducing agent, which provides precise time-series control: initially, a small amount of the "locked" water-reducing agent is released, avoiding viscosity competition with the flocculant and ensuring the stability of the anti-dispersion system; later, as hydration progresses, a large amount of PCE is gradually and controllably released from the LDH interlayer, effectively offsetting the flowability loss caused by the flocculant, thereby ensuring the filling density and final mechanical strength of the slurry. In addition, LDH not only serves as a slow-release carrier for the water-reducing agent but also possesses chloride ion curing capabilities. Therefore, it can combine with the uniform pore structure formed by the flocculant to optimize the microstructure of the hardened body, jointly enhancing the material's impermeability and resistance to ion erosion, thereby comprehensively improving the durability of the final concrete.

[0017] In one specific embodiment, the mass ratio of cement to mixing water is 2:1, the dosage of PCE-LDH nanocomposite material is 1.0%-3.0% of the mass of mixing water, and the dosage of flocculant is 0.1%-0.5% of the mass of mixing water.

[0018] In one specific embodiment, the water-soluble polymer flocculant is one of hydroxyethyl cellulose (HEC), polyacrylamide (PAM), and acetone.

[0019] Thirdly, the present invention provides the application of the PCE-LDH nanocomposite material prepared by the preparation method or the anti-dispersion cement slurry in concrete pouring in underwater or dynamic water environments.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention provides a method for preparing, applying, and anti-dispersion cement slurry of a polymer intercalation hybrid nanocomposite material. A hydrotalcite-based slow-release water-reducing agent is prepared by in-situ intercalation polymerization, embedding polycarboxylate water-reducing agent monomers into the hydrotalcite interlayer. Since the hydrotalcite interlayer contains anions, the anionic monomers can be intercalated between the interlayers through ion exchange. Then, through in-situ polymerization, a nanocomposite additive with a "nanocontainer" function is constructed, enabling the slow release of the water-reducing agent. 2. The preparation method, application, and anti-dispersion cement slurry of the polymer intercalation hybrid nanocomposite material provided in this invention apply the prepared hydrotalcite-based slow-release water-reducing agent to the anti-dispersion slurry. On the one hand, in the initial stage of slow release, the water-reducing agent "locked" between the hydrotalcite layers can avoid viscosity competition with the flocculant, ensuring the stability of the system. In the later stage of slow release, as hydration proceeds, a large amount of polycarboxylate water-reducing agent is released controllably from the hydrotalcite layers, which can effectively offset the fluidity loss caused by the flocculant and improve the filling density and final mechanical strength of the slurry. 3. The preparation method, application, and anti-dispersion cement slurry based on polymer intercalation hybridization of the present invention provides that the addition of flocculant can effectively ensure the initial anti-dispersion of fresh slurry through rapid thickening. The addition of hydrotalcite-based slow-release water-reducing agent can provide precise time-series control function and realize the slow release of water-reducing agent, which not only improves its utilization rate and reduces the negative risks caused by excessive addition, but also reduces the strength loss caused by thickening by flocculant alone, and achieves a balance between workability, anti-dispersion and strength development. 4. The preparation method, application and anti-dispersion cement slurry of polymer intercalation hybrid nanocomposite materials provided in the embodiments of the present invention, LDH not only serves as a slow-release carrier for water-reducing agents, but also has chloride ion curing ability. Therefore, it can combine with the uniform pore structure formed by flocculants to optimize the microstructure of the hardened body and jointly enhance the impermeability and resistance to ion erosion of the material, thereby comprehensively improving the durability of the final concrete. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 Cement slurry fluidity test prepared for the embodiments of the present invention: where a is Example 1, b is Example 2, c is Example 6, and d is Example 7; Figure 2 The anti-dispersion performance test of the cement slurry prepared for the embodiments of the present invention is as follows: where a is Example 1, b is Example 2, c is Example 6, and d is Example 7. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0024] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures have not been specifically described in order to avoid obscuring the invention.

[0025] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0027] Example 1 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: (1) Disperse 7.0% hydrotalcite (LDH) powder in deionized water that has been deionized to remove CO2, and then treat it with ultrasound to form a stable suspension; (2) Slowly add 12.0 wt% polycarboxylate superplasticizer (PCE) monomer reagent (itaconic acid (IA): isopentenyl alcohol polyoxyethylene ether (TPEG): 2-acrylamide-2-methylpropanesulfonic acid (AMPS) = 10:1:1) to the LDH suspension dispersion, adjust the pH of the working solution to 7-8 with NaOH so that the carboxyl groups exist in ionic form, and continue stirring to allow the monomer molecules to fully diffuse and adsorb on the surface and between layers of the LDH layer; (3) The system was heated to 40-60 °C, and potassium persulfate-sodium sulfite initiator was added dropwise under nitrogen protection. The reaction was carried out at a constant temperature for 6-8 hours. After the reaction was completed, the product was centrifuged, washed, dried and ground to prepare a nanocomposite material of polycarboxylate superplasticizer intercalated hydrotalcite (PCE-LDH); (4) Add a certain mass fraction of cement (200%), PCE-LDH nanocomposite material (1.5%), and hydroxypropyl methylcellulose (0.3%) to clean water respectively. Use a cement paste mixer to stir at low speed (120±5 r / min) for 2 minutes, then switch to high speed (285±10 r / min) for 2 minutes until a uniform and stable cement paste without obvious bubbles is obtained.

[0028] Example 2 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: (1) Disperse 8.0% hydrotalcite (LDH) powder in deionized water that has been deionized to remove CO2, and then treat it with ultrasound to form a stable suspension; (2) Slowly add 10.0 wt% polycarboxylate superplasticizer (PCE) monomer reagent (acrylic acid (AA) : isopentenyl alcohol polyoxyethylene ether (TPEG) : 2-acrylamide-2-methylpropanesulfonic acid (AMPS) = 8 : 1 : 1) to the LDH suspension dispersion, adjust the pH of the working solution to 7-8 with NaOH so that the carboxyl groups exist in ionic form, and continue stirring to allow the monomer molecules to fully diffuse and adsorb on the surface and between layers of the LDH layer; (3) The system was heated to 40-60 °C, and potassium persulfate-sodium sulfite initiator was added dropwise under nitrogen protection. The reaction was carried out at a constant temperature for 6-8 hours. After the reaction was completed, the product was centrifuged, washed, dried and ground to prepare a nanocomposite material of polycarboxylate superplasticizer intercalated hydrotalcite (PCE-LDH); (4) Add a certain mass fraction of cement (200%), PCE-LDH nanocomposite material (2.0%), and hydrophobic associative polymer (0.15%) to clean water respectively. Use a cement paste mixer to stir at low speed (120±5 r / min) for 2 min, and then switch to high speed (285±10 r / min) for 2 min until a uniform and stable cement paste without obvious bubbles is obtained.

[0029] Example 3 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: (1) Disperse 8.0% hydrotalcite (LDH) powder in deionized water that has been deionized to remove CO2, and then treat it with ultrasound to form a stable suspension; (2) Slowly add 14.5 wt% polycarboxylate superplasticizer (PCE) monomer reagent (methacrylic acid (MAA) : allyl polyoxyethylene ether (HPEG) : acrylamide (AM) = 12 : 1.5 : 1) to the LDH suspension dispersion, adjust the pH of the working solution to 7-8 with NaOH so that the carboxyl groups exist in ionic form, and continue stirring to allow the monomer molecules to fully diffuse and adsorb on the surface and between layers of the LDH layer; (3) The system was heated to 40-60 °C, and potassium persulfate-sodium sulfite initiator was added dropwise under nitrogen protection. The reaction was carried out at a constant temperature for 6-8 hours. After the reaction was completed, the product was centrifuged, washed, dried and ground to prepare a nanocomposite material of polycarboxylate superplasticizer intercalated hydrotalcite (PCE-LDH); (4) Add a certain mass fraction of cement (200%), PCE-LDH nanocomposite material (2.0%), and partially hydrolyzed polyacrylamide (0.2%) to clean water respectively. Use a cement paste mixer to stir at low speed (120±5 r / min) for 2 min, then switch to high speed (285±10 r / min) for 2 min until a uniform and stable cement paste without obvious bubbles is obtained.

[0030] Example 4 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: (1) Disperse 6.5% hydrotalcite (LDH) powder in deionized water that has been deionized to remove CO2, and then treat it with ultrasound to form a stable suspension; (2) Slowly add 12 wt% polycarboxylate superplasticizer (PCE) monomer reagent (maleic anhydride (MA) : isopentenyl alcohol polyoxyethylene ether (TPEG) : 2-acrylamide-2-methylpropanesulfonic acid (AMPS) = 10 : 1 : 1) to the LDH suspension dispersion, adjust the pH of the working solution to 7-8 with NaOH so that the carboxyl groups exist in ionic form, and continue stirring to allow the monomer molecules to fully diffuse and adsorb on the surface and between layers of the LDH layer; (3) The system was heated to 40-60 °C, and hydrogen peroxide-ferrous chloride initiator was added dropwise under nitrogen protection. The reaction was carried out at a constant temperature for 6-8 hours. After the reaction was completed, the product was centrifuged, washed, dried and ground to prepare a nanocomposite material of polycarboxylate superplasticizer intercalated hydrotalcite (PCE-LDH); (4) Add a certain mass fraction of cement (200%), PCE-LDH nanocomposite material (2.5%), and warm wheel adhesive (0.3%) to clean water respectively. Use a cement paste mixer to stir at low speed (120±5 r / min) for 2 min, then switch to high speed (285±10 r / min) for 2 min until a uniform and stable cement paste without obvious bubbles is obtained.

[0031] Example 5 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: (1) Disperse 8% LDH powder in deionized water that has been deionized to remove CO2, and then sonicate it to form a stable suspension; (2) Slowly add 11.0 wt% polycarboxylate superplasticizer (PCE) monomer reagent (acrylic acid (AA) : allyl polyoxyethylene ether (HPEG) : 2-acrylamide-2-methylpropanesulfonic acid (AMPS) = 8 : 1.5 : 1.5) to the LDH suspension dispersion, adjust the pH of the working solution to 7-8 with NaOH so that the carboxyl groups exist in ionic form, and continue stirring to allow the monomer molecules to fully diffuse and adsorb on the surface and between layers of the LDH layer; (3) The system was heated to 40-60 °C, and hydrogen peroxide-sodium sulfite initiator was added dropwise under nitrogen protection. The reaction was carried out at a constant temperature for 6-8 hours. After the reaction was completed, the product was centrifuged, washed, dried and ground to prepare a nanocomposite material of polycarboxylate superplasticizer intercalated hydrotalcite (PCE-LDH); (4) Add a certain mass fraction of cement (200%), PCE-LDH nanocomposite material (1.5%), and hydroxypropyl methylcellulose (0.3%) to clean water respectively. Use a cement paste mixer to stir at low speed (120±5 r / min) for 2 minutes, then switch to high speed (285±10 r / min) for 2 minutes until a uniform and stable cement paste without obvious bubbles is obtained.

[0032] Example 6 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: The only difference from Example 1 is that the concentration of PCE-LDH nanocomposite material in water is 2.0 wt%, and the concentration of hydroxypropyl methylcellulose is 0.5 wt%. All other steps and parameters are the same as in Example 1.

[0033] Example 7 The present invention provides a method for preparing an anti-dispersing cement slurry, comprising the following steps: The only difference from Example 2 is that the concentration of PCE-LDH nanocomposite material in water is 1.0 wt%, and the concentration of hydrophobic associative polymer is 0.1 wt%. All other steps and parameters are the same as in Example 2.

[0034] Performance testing Anti-dispersibility cement slurry needs to possess both good fluidity and excellent water resistance. Performance tests were conducted on the anti-dispersibility cement slurries prepared in Examples 1, 2, 6, and 7, as detailed below: 1. The diffusion diameter measured by the mold test method directly reflects the flow distance of the grout and is a key indicator for evaluating its filling and self-leveling capabilities, thereby determining whether it meets the grouting requirements. Place a glass plate horizontally and position a truncated cone mold at its center. Quickly fill the mold with the prepared cement grout, smooth the surface with a scraper, and then use a tamping rod to evenly tamp the grout from the edge to the center, ensuring the grout is full and without gaps. Then, quickly lift the truncated cone mold vertically and immediately start timing, allowing the grout to flow freely. After 30 seconds of flow, use a ruler to measure the maximum diameter in two mutually perpendicular directions of the flowed portion and calculate its average value, which is the flowability of the cement grout. Figure 1 The test results of the flowability of the cement slurry prepared in Examples 1, 2, 6, and 7 are presented. The flowability of the anti-dispersing cement slurry was synergistically regulated by the flocculant and the water-reducing agent. Examples 1 and 2 show that, under the thickening effect of appropriate concentrations of hydroxypropyl methylcellulose (HPMC) and hydrophobic associating polymer (HAWP), the cement slurry maintained good flowability, with flowabilities of 18.5 cm and 18.0 cm, respectively. Figure 1(a, b). However, excessive flocculant dosage significantly inhibits slurry flowability; for example, in Example 6, the slurry flowability decreased to 15.5 cm when the HPMC dosage was increased. Conversely, by reducing the HAWP concentration and increasing the PCE-LDH nanocomposite content, the slurry flowability was significantly improved, with the flowability in Example 7 reaching 20.5 cm.

[0035] 2. The anti-dispersion performance of cement slurry is a key indicator that prevents dispersion and cement particle loss during underwater or unstable water flow construction. Prepared cement slurry samples are directly poured into still water, and their morphology after free fall and settling is observed. Figure 2 The anti-dispersion performance test results of the cement slurries prepared in Examples 1, 2, 6, and 7 are presented. The water-reducing agent, by adsorbing onto the surface of cement particles, generates electrostatic repulsion and steric hindrance, promoting particle dispersion and releasing the trapped free water, thus improving slurry fluidity. Based on this, the flocculant (HPMC / HAWP) further increases the viscosity of the aqueous phase and, through bridging, networks the cement particles to form a stable three-dimensional structure to resist water erosion and particle loss. Therefore, as shown in Examples 1 and 2, the cement slurry maintains its aggregated form during free fall, without significant dilution or dispersion, exhibiting good anti-dispersion performance. However, as shown in Example 6, while an excessively high HPMC concentration can enhance anti-dispersion performance, it can excessively inhibit fluidity, and the dense network structure may be detrimental to the later development of the mechanical strength of the cement paste. Conversely, in Example 7, an excessively low HAWP concentration cannot provide sufficient anti-dispersion capability. In summary, the key to constructing a balanced anti-dispersion cement slurry system lies in balancing the dosage ratio of PCE-LDH nanocomposite materials and flocculant.

[0036] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing nanocomposite materials based on polymer intercalation hybridization, characterized in that, Includes the following steps: Hydrotalcite (LDH) powder is dispersed in deionized water to form a stable LDH suspension; Polycarboxylate superplasticizer (PCE) monomers were added dropwise to the LDH suspension, and the pH was adjusted to 7-8. In situ polymerization was carried out at 40-60 ℃ under nitrogen protection, with the addition of an initiator for 6-8 h. The reaction products were dried and ground to obtain PCE-LDH nanocomposite materials.

2. The method for preparing nanocomposite materials based on polymer intercalation hybridization according to claim 1, characterized in that, The hydrotalcite is a magnesium aluminum sulfate type hydrotalcite (Mg / Al-SO4). 2- -LDHs), calcium aluminum sulfate type hydrotalcite (Ca / Al-SO4) 2- -LDHs), magnesium aluminum nitrate type hydrotalcite (Mg / Al-NO3) - -LDHs), calcium aluminum nitrate type hydrotalcite (Ca / Al-NO3) - One of the LDHs.

3. The method for preparing nanocomposite materials based on polymer intercalation hybridization according to claim 1, characterized in that, The polycarboxylate superplasticizer (PCE) monomer is composed of unsaturated carboxylic acid small monomers, macromonomers, and functional small monomers.

4. The method for preparing nanocomposite materials based on polymer intercalation hybridization according to claim 3, characterized in that, The unsaturated carboxylic acid monomer is at least one of acrylic acid (AA), methacrylic acid (MAA), and maleic anhydride (MA); The macromonomer is one of allyl polyoxyethylene ether (HPEG) and isopentenyl polyoxyethylene ether (TPEG); The functional monomer is at least one of acrylamide (AM) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS).

5. The method for preparing nanocomposite materials based on polymer intercalation hybridization according to claim 1, characterized in that, The polymerization reaction employs a low-temperature redox initiation system. The initiating oxidant is one of hydrogen peroxide, potassium persulfate, ammonium persulfate, or cumene hydrogen peroxide, and the initiating reducing agent is one of sodium sulfite or ferrous chloride.

6. The method for preparing nanocomposite materials based on polymer intercalation hybridization according to claim 3, characterized in that, The concentration of LDH powder in deionized water is 5.0-8.0 wt%; the concentration of unsaturated carboxylic acid small monomers in deionized water is 8.0 wt%-12.0 wt%, the concentration of macromolecular monomers in deionized water is 1.0 wt%-2.0 wt%, and the concentration of functional small monomers in deionized water is 1.0 wt%-2.0 wt%.

7. A cement slurry with anti-dispersion properties, characterized in that, This includes cement, PCE-LDH nanocomposites, flocculants, and mixing water.

8. The anti-dispersion cement slurry according to claim 7, characterized in that, The mass ratio of cement to mixing water is 2:1, the dosage of PCE-LDH nanocomposite material is 1.0%-3.0% of the mass of mixing water, and the dosage of flocculant is 0.1%-0.5% of the mass of mixing water.

9. The anti-dispersion cement slurry according to claim 7, characterized in that, The flocculant is one of hydroxyethyl cellulose (HEC), polyacrylamide (PAM), or acetone.

10. The application of the PCE-LDH nanocomposite material prepared by any of the preparation methods of claims 1 to 5 or the anti-dispersion cement slurry of any of claims 6 to 9 in concrete pouring in underwater or dynamic water environments.

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