Reinforced hydrophobic emulsion with pH-complexation response mechanism and preparation process and application thereof

Abstract

The application discloses a kind of pH-complex response mechanism's reinforced hydrophobic emulsion and its preparation process and application.The hydrophobic emulsion includes: the hydrophobic agent microparticle with complex response mechanism dispersed in aqueous emulsion, and the nano calcium salt complex dissolved in the aqueous emulsion.Wherein: the hydrophobic agent microparticle with complex response mechanism includes hydrophobic substance core and the coating layer formed by the hydrophobic modification nano calcium salt solid particle coated on the core surface, and the nano calcium salt is insoluble in water or slightly soluble in water.The nano calcium salt complex is formed by the nano calcium salt and complexing agent through complexation reaction.The hydrophobic emulsion provided by the application can delay the premature release of hydrophobic substance, and play multiple synergistic effects in the process of complexation, to further improve the compactness and mechanical strength of concrete material.

Description

Technical Field

[0001] This invention relates to the field of concrete admixture technology, specifically to a pH-complexation response mechanism-enhanced hydrophobic emulsion and its preparation process and application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Currently, two main technical approaches are used to optimize the hydrophobic properties of cement-based materials: one is to introduce organic hydrophobic substances (such as silanes and siloxane polymers) into the cement system; the other is to physically coat the hydrophobic substances with inorganic nanomaterials before introducing them into the cement system. It is worth noting that the hydration reaction mechanism of cement-based materials has significant unique characteristics. It not only involves the physical adsorption between cementitious particles and the water medium, but also a series of chemical evolution processes involved in the formation of products such as ettringite and hydrated calcium silicate. Directly incorporating hydrophobic substances can interfere with the cement hydration reaction because these substances adsorb onto the surface of unhydrated cement particles, thus affecting the increase in cement strength and the formation of the final microstructure of the cement.

[0004] While physical coating methods can help delay the release of modifiers by encapsulating them in carriers, the coating materials themselves have low stability and are easily affected by environmental factors during cement hydration, leading to premature cracking or failure of the coating layer. Furthermore, the limited mechanical properties of the coating materials prevent them from effectively filling the pores and microcracks within the concrete, resulting in a significant deficiency in improving the strength of cement-based materials and failing to compensate for the decline in mechanical properties caused by the addition of hydrophobic agents. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a pH-complexation-responsive enhanced hydrophobic emulsion, its preparation process, and its application. This emulsion can delay the premature release of hydrophobic substances and exerts multiple synergistic effects during the decomplexation process, thereby improving the density and mechanical strength of concrete materials. Specifically, this invention discloses the following technical solutions.

[0006] First, this invention discloses a pH-enhanced hydrophobic emulsion with a complexing response mechanism, comprising: hydrophobic microparticles with a complexing response mechanism dispersed in an aqueous emulsion, and a nano-calcium salt complex dissolved in the aqueous emulsion. Specifically, the hydrophobic microparticles with the complexing response mechanism comprise a hydrophobic core and a coating layer formed by hydrophobically modified nano-calcium salt solid particles covering the surface of the core. The hydrophobically modified nano-calcium salt is a substance modified by a silane coupling agent that is insoluble or slightly soluble in water. The nano-calcium salt complex is formed by a complexation reaction between the nano-calcium salt and the complexing agent.

[0007] Furthermore, the hydrophobic material includes at least one of the following: trichlorotrimethylsilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, triisopropylsilane, trimethylethoxysilane, polydimethylsiloxane, polymethylhydrosiloxane, methyltrimethoxysilane, isobutyltriethoxysilane, and hexadecyltrimethoxysilane.

[0008] Furthermore, the nano-calcium salt includes at least one of calcium sulfate, calcium carbonate, calcium oxalate, and calcium fluoride.

[0009] Furthermore, the complexing agent includes at least one of the following: triethanolamine, triethylenetetramine, tetrahydroxypropylethylenediamine, ethylenediaminetetraacetic acid ammonium, diethylenetriaminepentaacetic acid ammonium, ethylene glycol diethyl ether diaminetetraacetic acid ammonium, hydroxyethyl ethylenediamine triacetic acid ammonium, etc.

[0010] Secondly, this invention discloses a preparation process for the enhanced hydrophobic emulsion with the pH-complexation response mechanism, comprising the following steps:

[0011] (1) The complexing agent is added to water and dissolved to form a complexing agent solution. Then, an excess of nano-calcium salt is added and a complexing reaction is carried out under stirring conditions. After removing the insoluble matter, a complexing product solution is obtained for later use.

[0012] (2) Take another nano-calcium salt, add it and silane coupling agent to an aqueous ethanol solution, react under heating and stirring conditions, separate the solid product, and dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use.

[0013] (3) The modified nano-calcium salt and hydrophobic substance are added to the complex product solution and then emulsified to obtain the hydrophobic emulsion.

[0014] Further, in step (1), the concentration of the complexing agent solution does not exceed 0.5 mol / L, preferably 0.2~0.5 mol / L.

[0015] Furthermore, in step (1), the complexation reaction takes 1 to 5 hours. During this process, the nano-calcium salt and the complexing agent form a complex product and then dissolve in the complex product solution.

[0016] Further, in step (2), the mass ratio of the nano-calcium salt, the silane coupling agent, and the ethanol aqueous solution is 1~3:0.7~1.2:10. Optionally, the silane coupling agent includes at least one of KH-550, KH-560, KH-570, etc. The mass fraction of the ethanol aqueous solution is 50~60%.

[0017] Further, in step (2), the heating temperature is 70~85℃, and the reaction time is 1.5~2 hours. During this process, the hydroxyl (-OH) groups on the surface of the nano-calcium salt react with the hydroxyl groups of the silane coupling agent to form chemical bonds that connect the two, so that the nano-calcium salt exists stably at the water-oil interface (i.e., the interface between the hydrophobic substance and the complex product solution), which facilitates the coating of the hydrophobic substance.

[0018] Further, in step (3), the modified nano-calcium salt accounts for 30-40% of the mass of the complex product solution. The hydrophobic substance accounts for 20-25% of the mass of the complex product solution.

[0019] Further, in step (3), the shear rate of the emulsification treatment is 12000~15000 r / min, and the treatment time is 2~5 min. During this process, the modified nano-calcium salt solid particles coat the surface of the oily particles formed by the hydrophobic substance to form a core-shell structure. Then, it forms a hydrophobic emulsion together with the complex product solution containing the complex product.

[0020] Finally, this invention discloses the application of the pH-complexation response mechanism-enhanced hydrophobic emulsion in silicate cement-based materials. Optionally, the hydrophobic emulsion content is 6-9% of the mass of the cement component in the silicate cement-based material.

[0021] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0022] The hydrophobic emulsion of this invention not only delays the premature release of hydrophobic substances but also exerts a seeding effect during the decomposition process, thereby improving the density and mechanical strength of concrete materials. This is because the process employed in this invention first uses a complexing agent to convert nano-calcium salt solid particles into soluble complexes that dissolve in water, and then uses hydrophobically modified nano-calcium salt solid particles as a coating material to coat the hydrophobic substances. When this hydrophobic emulsion is incorporated into concrete materials, the modified nano-calcium salt coating layer on the surface of the hydrophobic substances can delay the release of the hydrophobic substances, preventing them from prematurely intervening in the hydration reaction of cement, which would hinder the hydration reaction of cement components and affect the development of mechanical strength. As the hydration reaction proceeds, the pH of the concrete material gradually decreases. The complex of the nano-calcium salt dispersed in the concrete material gradually begins to de-complex, forming water-insoluble nano-calcium salts. Simultaneously, the nano-calcium salts released during the de-complexation process aggregate and grow using the solid nano-calcium salts formed after the hydrophobic coating layer is destroyed due to the decrease in environmental pH as crystal nuclei. These solid particles fill the pores and microcracks in the concrete material, thereby improving the density and mechanical strength of the concrete. Furthermore, because the de-complexation reaction proceeds slowly, it can be well matched with the hydration and hardening process of the concrete material, thus filling the microcracks caused by shrinkage during hydration and hardening, which helps to improve the mechanical properties of the concrete material. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 The image shows a sample of the enhanced hydrophobic emulsion with a pH-complexation response mechanism prepared in Example 1 below.

[0025] Figure 2 The contact angle test diagram is for the specimen prepared in Example 1 below.

[0026] Figure 3 The contact angle test diagram is for the specimen prepared in Example 2 below.

[0027] Figure 4 The contact angle test diagram is for the specimen prepared in Example 3 below.

[0028] Figure 5 The contact angle test diagram is for the specimen prepared in Example 4 below.

[0029] Figure 6 The contact angle test diagram is for the specimen prepared in Example 5 below.

[0030] Figure 7The contact angle test diagram is for the specimen prepared in Example 6 below.

[0031] Figure 8 The contact angle test diagram is for the specimen prepared in Example 7 below. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0033] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. All reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions.

[0034] Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the method of this invention. The technical solution of this invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0037] (1) The complexing agent (triethanolamine) is added to water and dissolved completely to form a complexing agent solution with a concentration of 0.5 mol / L. Then, excess nano-calcium salt (calcium sulfate) is added and stirred continuously for 3 hours to carry out the complexing reaction. After completion, the undissolved nano-calcium salt is removed by filtration to obtain the complexing product solution for later use.

[0038] (2) Take another nano-calcium salt (calcium sulfate) and add it and silane coupling agent (KH-550) to a 50% ethanol aqueous solution, with a mass ratio of 1:1:10. Then heat to 80℃ and stir for 2 hours. After completion, filter out the solid product, dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use.

[0039] (3) Add 40% by mass of the modified nano-calcium salt and 20% by mass of trichlorosilane to the complex product solution, and then perform emulsification treatment (shear rate of 15000 r / min, treatment time of 4 min). After completion, the hydrophobic emulsion is obtained, such as... Figure 1 As shown.

[0040] Performance Testing: Referring to standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)", the hydrophobic emulsion prepared in this embodiment was added to cement mortar (mass ratio of cement (PO 42.5): water: standard sand = 2:1:6, the hydrophobic emulsion accounting for 7.5% of the cement mass), stirred evenly, and then poured into a mold. After hardening and shaping, it was demolded and cured under standard conditions for 28 days to obtain the test block. The compressive strength of the test block was then tested according to the above standard. In addition, the contact angle of the test block surface was measured using an optical contact angle meter (model JC2000D3A). Figure 2 As shown. The test results for the above indicators are as follows: 28-day compressive strength = 46.36 MPa, contact angle = 125°.

[0041] Example 2

[0042] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0043] (1) The complexing agent (ethylenediaminetetraacetic acid ammonium) is added to water and dissolved completely to form a complexing agent solution with a concentration of 0.3 mol / L. Then, excess nano calcium salt (calcium carbonate) is added and stirred continuously for 2 hours to carry out the complexing reaction. After completion, the undissolved nano calcium salt is removed by filtration to obtain the complexing product solution for later use.

[0044] (2) Take another nano-calcium salt (calcium carbonate) and add it and silane coupling agent (KH-560) to a 55% ethanol aqueous solution with a mass ratio of 2:0.7:10. Then heat to 70°C and stir for 2 hours. After completion, filter out the solid product, dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use.

[0045] (3) Add 30% by mass of the modified nano-calcium salt and 20% by mass of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the complex product solution and then perform emulsification treatment (shear rate of 12000 r / min, treatment time of 5 min) to obtain the hydrophobic emulsion.

[0046] Performance testing: The 28-day compressive strength and contact angle (e.g., of cement-based specimens containing the hydrophobic emulsion of this embodiment) were tested using the same method as in Example 1 above. Figure 3 (As shown). The test results for the above indicators are as follows: 28-day compressive strength = 44.27 MPa, contact angle = 137°.

[0047] Example 3

[0048] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0049] (1) The complexing agent (triethylenetetramine) is added to water and dissolved completely to form a complexing agent solution with a concentration of 0.2 mol / L. Then, excess nano-calcium salt (calcium fluoride) is added and stirred continuously for 1 hour to carry out the complexing reaction. After completion, the undissolved nano-calcium salt is removed by filtration to obtain the complexing product solution for later use.

[0050] (2) Take another nano-calcium salt (calcium fluoride) and add it and silane coupling agent (KH-570) to a 60% ethanol aqueous solution, with a mass ratio of 3:1.2:10. Then heat to 85℃ and stir for 1.5 hours. After completion, filter out the solid product, dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use.

[0051] (3) Add 34% of the modified nano-calcium salt and 20% of isobutyltriethoxysilane to the complex product solution and then perform emulsification treatment (shear rate of 15000 r / min, treatment time of 2 min) to obtain the hydrophobic emulsion.

[0052] Performance testing: The 28-day compressive strength and contact angle (e.g., of cement-based specimens containing the hydrophobic emulsion of this embodiment) were tested using the same method as in Example 1 above. Figure 4 (As shown). The test results for the above indicators are as follows: 28-day compressive strength = 43.78 MPa, contact angle = 135°.

[0053] Example 4

[0054] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0055] (1) The complexing agent (tetrahydroxypropylethylenediamine) is added to water and dissolved completely to form a complexing agent solution with a concentration of 0.4 mol / L. Then, excess nano-calcium salt (calcium oxalate) is added and stirred continuously for 5 hours to carry out the complexing reaction. After completion, the undissolved nano-calcium salt is removed by filtration to obtain the complexing product solution for later use.

[0056] (2) Take another nano-calcium salt (calcium oxalate) and add it and silane coupling agent (KH-550) to a 50% ethanol aqueous solution with a mass ratio of 2:0.9:10. Then heat to 80℃ and stir for 2 hours. After completion, filter out the solid product, dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use.

[0057] (3) Add 32% of the modified nano-calcium salt and 20% of polydimethylsiloxane to the complex product solution and then perform emulsification treatment (shear rate of 15000 r / min, treatment time of 2 min) to obtain the hydrophobic emulsion.

[0058] Performance testing: The 28-day compressive strength and contact angle (e.g., of cement-based specimens containing the hydrophobic emulsion of this embodiment) were tested using the same method as in Example 1 above. Figure 5 (As shown). The test results for the above indicators are as follows: 28-day compressive strength = 44.89 MPa, contact angle = 131°.

[0059] Example 5

[0060] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0061] (1) Take nano-calcium salt (calcium sulfate) and add it and silane coupling agent (KH-550) to a 50% ethanol aqueous solution with a mass ratio of 1:1:10. Then heat to 80℃ and stir for 2 hours. After completion, filter out the solid product, dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use.

[0062] (2) Add 40% of the modified nano-calcium salt and 20% of chlorotrimethylsilane to water, and then perform emulsification treatment (shear rate of 15000 r / min, treatment time of 4 min) to obtain the hydrophobic emulsion.

[0063] Performance testing: The 28-day compressive strength and contact angle (e.g., of cement-based specimens containing the hydrophobic emulsion of this embodiment) were tested using the same method as in Example 1 above. Figure 6 (As shown). The test results for the above indicators are as follows: 28-day compressive strength = 35.17 MPa, contact angle = 121°.

[0064] Example 6

[0065] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0066] (1) The complexing agent (ethylenediaminetetraacetic acid ammonium) is added to water and dissolved completely to form a complexing agent solution with a concentration of 0.3 mol / L. Then, excess nano calcium salt (calcium carbonate) is added and stirred continuously for 2 hours to carry out the complexing reaction. After completion, the undissolved nano calcium salt is removed by filtration to obtain the complexing product solution for later use.

[0067] (2) Add 30% by mass of nano-calcium salt (calcium carbonate) and 20% by mass of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the complex product solution, and then perform emulsification treatment (shear rate of 12000 r / min, treatment time of 5 min) to obtain the hydrophobic emulsion.

[0068] Performance testing: The 28-day compressive strength and contact angle (e.g., of cement-based specimens containing the hydrophobic emulsion of this embodiment) were tested using the same method as in Example 1 above. Figure 7 (As shown). The test results for the above indicators are as follows: 28-day compressive strength = 38.09 MPa, contact angle = 134°.

[0069] Example 7

[0070] A process for preparing a pH-complexation-responsive enhanced hydrophobic emulsion includes the following steps:

[0071] (1) The complexing agent (triethylenetetramine) is added to water and dissolved completely to form a complexing agent solution with a concentration of 0.2 mol / L. Then, excess nano-calcium salt (calcium fluoride) is added and stirred continuously for 1 hour to carry out the complexing reaction. After completion, the undissolved nano-calcium salt is removed by filtration to obtain the complexing product solution for later use.

[0072] (2) Add 20% by mass of a hydrophobic substance (isobutyltriethoxysilane) to the complex product solution, and then perform emulsification treatment (shear rate of 15000 r / min, treatment time of 2 min) to obtain the hydrophobic emulsion.

[0073] Performance testing: The 28-day compressive strength and contact angle (e.g., of cement-based specimens containing the hydrophobic emulsion of this embodiment) were tested using the same method as in Example 1 above. Figure 8 (As shown). The test results for the above indicators are as follows: 28-day compressive strength = 30.27 MPa, contact angle = 126°.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pH-complexation-responsive enhanced hydrophobic emulsion, characterized in that, include: Hydrophobic microparticles with a complexing response mechanism dispersed in an aqueous emulsion, the microparticles comprising: a hydrophobic core and a coating layer formed by hydrophobically modified nano-calcium salt solid particles covering the surface of the core, wherein the hydrophobically modified nano-calcium salt is a substance modified by a silane coupling agent that is insoluble or slightly soluble in water. And, the nano-calcium salt complex dissolved in the aqueous emulsion, which is formed by the complexation reaction of nano-calcium salt and complexing agent.

2. The enhanced hydrophobic emulsion with pH-complexation response mechanism according to claim 1, characterized in that, The hydrophobic material includes at least one of the following: trichlorotrimethylsilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, triisopropylsilane, trimethylethoxysilane, polydimethylsiloxane, polymethylhydrosiloxane, methyltrimethoxysilane, isobutyltriethoxysilane, and hexadecyltrimethoxysilane.

3. The enhanced hydrophobic emulsion with pH-complexation response mechanism according to claim 1, characterized in that, The nano-calcium salt includes at least one of calcium sulfate, calcium carbonate, calcium oxalate, and calcium fluoride.

4. The enhanced hydrophobic emulsion with a pH-complexation response mechanism according to any one of claims 1-3, characterized in that, The complexing agent includes at least one of the following: triethanolamine, triethylenetetramine, tetrahydroxypropylethylenediamine, ethylenediaminetetraacetate, diethylenetriaminepentaacetate, ethylene glycol diethyl ether diaminetetraacetate, and hydroxyethylethylenediaminetriacetate.

5. The preparation process of the enhanced hydrophobic emulsion with pH-complexation response mechanism according to any one of claims 1-4, characterized in that, Includes the following steps: (1) The complexing agent is added to water and dissolved completely to form a complexing agent solution. Then, an excess of nano-calcium salt is added and a complexing reaction is carried out under stirring conditions. After removing the insoluble matter, a complexing product solution is obtained for later use. (2) Take another nano-calcium salt, add it and silane coupling agent to an ethanol aqueous solution, react under heating and stirring conditions, separate the solid product, and dry it to obtain hydrophobically modified nano-calcium salt solid particles for later use. (3) The modified nano-calcium salt and hydrophobic substance are added to the complex product solution and then emulsified to obtain the hydrophobic emulsion.

6. The preparation process of the enhanced hydrophobic emulsion with pH-complexation response mechanism as described in claim 5, characterized in that, In step (1), the concentration of the complexing agent solution does not exceed 0.5 mol / L.

7. The preparation process of the enhanced hydrophobic emulsion with pH-complexation response mechanism as described in claim 5, characterized in that, In step (1), the complexation reaction takes 1 to 5 hours.

8. The preparation process of the enhanced hydrophobic emulsion with pH-complexation response mechanism as described in claim 5, characterized in that, In step (2), the mass ratio of the nano-calcium salt, silane coupling agent, and ethanol aqueous solution is 1~3:0.7~1.2:10; Optionally, in step (2), the silane coupling agent includes at least one of KH-550, KH-560, and KH-570; Optionally, in step (2), the mass fraction of the ethanol aqueous solution is 50-60%; Optionally, in step (2), the heating temperature is 70~85℃ and the reaction time is 1.5~2 hours.

9. The preparation process of the enhanced hydrophobic emulsion with pH-complexation response mechanism according to any one of claims 5-8, characterized in that, In step (3), the modified nano-calcium salt accounts for 30-40% of the mass of the complexing product solution; the hydrophobic substance accounts for 20-25% of the mass of the complexing product solution. Optionally, in step (3), the shear rate of the emulsification treatment is 12000~15000 r / min, and the time is 2~5 min.

10. The application of the enhanced hydrophobic emulsion with pH-complexation response mechanism according to any one of claims 1-4, or the hydrophobic emulsion obtained by the preparation process according to any one of claims 5-8, in silicate cement-based materials; optionally, the amount of the hydrophobic emulsion is 6-9% of the mass of the cement component in the silicate cement-based material.

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