A nanocrystal core reinforced starch-based thixotropic agent, and a preparation method and application thereof

Abstract

The application provides a nanocrystal core reinforced starch-based thixotropic agent and a preparation method and application thereof, and each raw material component of the starch-based thixotropic agent is as follows in percentage by mass: nanocrystal core material (0.2-0.8%), modified carboxymethyl starch ether (15-30%), cellulose ether (20-40%), auxiliary dispersant (1.5-3%), rheological stabilizer (0.5-2%), and the balance is water. In the application, the hydrophobic group is introduced into the carboxymethyl starch ether through etherification reaction, the hydrophobic association area is increased, the emulsifying property, the surface activity and the smoothness are improved, and the dispersion of the nanocrystal core material is further promoted. The nanocrystal core reinforced starch-based thixotropic agent provided by the application can significantly improve the thixotropy when being incorporated into a cement-based material, especially the smoothness during construction, so as to facilitate the construction and promote the development of early strength, thereby solving the problem of strength damage caused by a large amount of thixotropic agent, and having a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of thixotropic agent technology, and in particular to a nanocrystalline nucleus-enhanced starch-based thixotropic agent, its preparation method, and its application. Background Technology

[0002] Thixotropic agents can form a network structure in cement-based systems. When the system is subjected to shear force, the network structure is destroyed, restoring fluidity. When the shear force stops, the network structure reforms, increasing viscosity. Besides good shape retention, thixotropic agents also provide mortar with excellent water retention and cohesive properties. They can also be used in reduced-dosage applications in ordinary ready-mixed concrete to increase workability and water retention, solving segregation and bleeding problems caused by excessive water-reducing agents, thus improving the workability of concrete.

[0003] Inorganic thixotropic agents are widely used, including clay minerals (such as bentonite), sulfates (such as calcium sulfate and aluminum sulfate), and alkali metal carbonates (sodium carbonate, potassium carbonate, and lithium carbonate). However, inorganic thixotropic agents require large dosages and have poorer thixotropic effects than organic thixotropic agents, making it difficult to meet increasingly complex construction requirements. In contrast, organic thixotropic agents (including starch-based and redispersible latex powders) require smaller dosages, have better lubricity and adhesion, but also have disadvantages such as poor weather resistance and reduced strength.

[0004] Patent CN107602013A discloses a bentonite-based cementitious composite material, which achieves good thixotropic effects through calcium-based bentonite and a thickener. Although this cementitious composite material can solve the problem of segregation and bleeding while enhancing thixotropy, the addition of calcium-based bentonite, accounting for 60%-120% of the cement weight, results in a very high dosage. Patent CN104370488B discloses a thixotropic agent for cementitious systems and its preparation method. It develops a novel thixotropic agent for cementitious systems to address the problem of high dosage and mediocre thixotropic performance of inorganic thixotropic agents. Its main components include fatty acid glycerides, sodium fatty acid salts, small molecule polyethers, and the balance being water. However, it still has drawbacks such as poor weather resistance and reduced strength. Patent CN202111038682.1 discloses adding octenyl succinate starch ester to cementitious mortar, ensuring that the building mortar has lightweight, sound-absorbing, and aesthetically pleasing properties while maintaining high strength. However, while simple physical mixing can improve the workability of plastering mortar, it cannot fundamentally and significantly enhance the tensile bond strength, water retention, and freeze-thaw stability of dry-mixed plastering mortar. Therefore, there is an urgent need to develop an organic thixotropic agent that can enhance anti-sagging properties without compromising mortar strength. Summary of the Invention

[0005] The purpose of this invention is to provide a nanocrystalline nucleus-reinforced starch-based thixotropic agent, its preparation method, and its application, in order to solve the technical problems of poor anti-sagging properties and easy damage to mortar strength in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides a nanocrystalline nucleus-enhanced starch-based thixotropic agent, which includes nanocrystalline nucleus material, modified carboxymethyl starch ether, cellulose ether, dispersant and / or rheology stabilizer;

[0007] The nanocrystalline nucleus material is selected from one or more of the following: nano-hydrated calcium silicate, nano-silica, carbon nanotubes, and nano-calcium carbonate.

[0008] Nanocrystalline nuclei materials can improve early strength through the nucleation effect, solving problems such as strength loss caused by the incorporation of organic thixotropic agents, and can play a synergistic and complementary role with modified carboxymethyl starch ether.

[0009] The modified carboxymethyl starch ether is an alkyloxy-carboxymethyl starch ether, which is obtained by introducing a hydrophobic alkyloxy group through an etherification reaction on the basis of carboxymethyl starch ether, resulting in a modified starch ether with hydrophilic-hydrophobic balance.

[0010] Furthermore, the particle size of the nanocrystalline nucleus material is 20-40 nm to ensure its high dispersibility and nucleation effect during the mixing process are not affected.

[0011] Furthermore, the cellulose ether is selected from one or more mixtures of hydroxyethyl methylcellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methylcellulose. Cellulose ethers contribute to increased thickening properties and enhance the thixotropic properties of starch ethers.

[0012] Furthermore, the dispersant is selected from any one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, octyl alcohol polyoxyethylene ether, polyacrylamide, or coagulant anhydride. This enhances the dispersibility and stability of the mixed solution, particularly the dispersion of nanocrystalline nuclei.

[0013] Furthermore, the rheology stabilizer is selected from any one of gum arabic, gum guar, or gum guar.

[0014] This invention also provides a method for preparing the above-mentioned nanocrystalline nucleus-reinforced starch-based thixotropic agent, which mainly includes the following steps:

[0015] Step 1: Add 0.5-2% of the rheology stabilizer to continuously stirred deionized water to obtain a first mixed solution;

[0016] Step 2: Add 15-30% of the modified carboxymethyl starch ether and 20-40% of the cellulose ether to the first mixed solution, ensuring that they are uniformly dispersed and fully dissolved in the solution to obtain the second mixed solution;

[0017] Step 3: Add 1.5-3% of the dispersant to the second mixed solution to improve the dispersibility and stability of each component, and obtain the third mixed solution;

[0018] The reaction temperature for all the above steps should be 30-60℃ and the stirring speed should be maintained at 400-800 r / min to ensure that the components are mixed more thoroughly.

[0019] Step four: Add 0.2-0.8% of the nanocrystalline nucleus material to the third mixed solution, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 minutes, and then perform ultrasonic dispersion to ensure thorough mixing, thereby obtaining a nanocrystalline nucleus-enhanced starch-based thixotropic agent;

[0020] All components are listed by weight.

[0021] Furthermore, the preparation steps of the modified carboxymethyl starch ether are as follows:

[0022] Step a: Take 1 part of commercially available carboxymethyl starch ether and mix it with 10-15 parts of water and stir continuously at a rate of 400-800 r / min. The mixing temperature is 40-80℃ to obtain a carboxymethyl starch ether solution.

[0023] Step b: Weigh 0.03-0.1 parts of N,N-dimethylbenzylamine catalyst (BDMA) and add it to the carboxymethyl starch ether solution. The mixing temperature is 40-80℃, and the mixture is stirred at a rate of 400-800 r / min for 10 min. Then, add 1-2 parts of alkyl glycidyl ether and react for 30-60 min to obtain the modified carboxymethyl starch ether solution.

[0024] Step c: The modified carboxymethyl starch ether solution is poured into methanol, ethanol or isopropanol to precipitate the catalyst and some byproducts. Then, the solution is filtered, dried and ground to obtain the modified carboxymethyl starch ether powder.

[0025] All the above components are added by weight.

[0026] Preferably, the alkyl glycidyl ether in step b is selected from either n-butyl glycidyl ether or benzyl glycidyl ether.

[0027] Modified carboxymethyl starch ether, a hydrophobically associated water-soluble polymer obtained through a hydrophilic-lipophilic balance, can improve thickening properties, shear resistance, emulsion stability, and dispersibility. On the one hand, it enhances the smoothness and anti-sagging properties of thixotropic agents; on the other hand, it can promote the dispersion of nanocrystalline nuclei materials.

[0028] Electron microscopy analysis of the prepared modified carboxymethyl starch ether revealed that the modified product exhibited the following characteristics: Figure 1 As shown.

[0029] The present invention also provides an application of the above-mentioned nanocrystalline nucleus-reinforced starch-based thixotropic agent in mortar.

[0030] Furthermore, the application includes the following steps:

[0031] The first step is to dilute the nanocrystalline nucleus-enhanced starch-based thixotropic agent to a concentration of 10% as an additive;

[0032] The second step is to add the admixture to the mortar according to the mass ratio of the admixture to the cementitious material being (0.01-0.2):1.

[0033] Nanocrystalline nucleus-reinforced starch-based thixotropic agents can effectively improve the thixotropic properties of mortars and gypsums by adding only a small amount, while ensuring that their mechanical properties such as compressive strength and flexural strength are not damaged.

[0034] By adopting the above technical solution, the present invention has the following beneficial effects:

[0035] The nanocrystalline nucleus-reinforced starch-based thixotropic agent provided by this invention achieves a certain hydrophilic-lipophilic balance by introducing a very small amount of alkoxy hydrophobic groups into the main component, carboxymethyl starch ether, thereby obtaining a hydrophobically associated water-soluble polymer. In aqueous solution, it can form a reversible three-dimensional network structure through physical chain entanglement, hydrophobic association (intermolecular association, intramolecular association), and hydrogen bonding, giving carboxymethyl starch excellent thickening ability. Furthermore, due to the intramolecular or intermolecular association of the hydrophobic groups and electrostatic interactions, its aqueous solution exhibits certain rheological properties and can possess good shear resistance. The modified starch ether, as the main raw material, is mixed with nanocrystalline nucleus materials, cellulose, and dispersing agents to obtain a nanocrystalline nucleus-reinforced starch-based thixotropic agent, which maintains superior thixotropic properties while also solving the problem of strength loss caused by the addition of thixotropic agents. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 Electron micrograph of modified carboxymethyl starch ether;

[0038] Figure 2 This is a flowchart illustrating the preparation process of the nanocrystalline nucleus-enhanced starch-based thixotropic agent of the present invention.

[0039] Figure 3 This is a flowchart illustrating the preparation process of modified carboxymethyl starch ether.

[0040] Figure 4 Line graph showing the effect of different thixotropic agents on the thixotropic index of mortar;

[0041] Figure 5 Line graph showing the effect of different thixotropic agents on the compressive strength of mortar; Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The present invention will be further explained below with reference to specific embodiments.

[0044] Examples 1-6 show that six types of nanocrystalline nucleus-reinforced starch-based thixotropic agents were prepared using different raw material ratios.

[0045] Example 1, the specific steps are as follows:

[0046] (1) Add 10g of commercially available carboxymethyl starch ether and 100ml of deionized water to a 200ml three-necked flask. Place the flask in an 80℃ water bath for heating while mechanically stirring at a rate of 500r / min.

[0047] (2) When the solution is stirred until it becomes a colorless and transparent viscous solution, add 0.5g of N,N-dimethylbenzylamine catalyst (BDMA). After the addition is complete, stir for 10min, then add 5g of n-butyl glycidyl ether, and continue to react for 60min. The solution is milky white.

[0048] (3) After the reaction is complete, the solution is poured into ethanol to precipitate the catalyst and some by-products. Then, the solution is filtered, dried at 60°C, and finally ground to obtain the product powder.

[0049] (4) Add 4 parts of the above modified carboxymethyl starch ether, 0.5 parts of guar gum, 3 parts of hydroxyethyl cellulose and 2 parts of sodium dodecylbenzene sulfonate according to the mass ratio and stir until uniformly mixed to obtain starch-based thixotropic agent.

[0050] (5) Finally, add 2 parts of nano-hydrated calcium silicate, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 minutes, then perform ultrasonic dispersion to ensure thorough mixing, and finally obtain nano-crystal core-enhanced starch-based thixotropic agent.

[0051] Example 2, the specific steps are as follows:

[0052] (1) Add 5g of commercially available carboxymethyl starch ether and 50ml of deionized water to a 200ml three-necked flask. Place the flask in an 80℃ water bath for heating while mechanically stirring at a rate of 500r / min.

[0053] (2) When the solution is stirred until it becomes a colorless and transparent viscous solution, add 0.3g of N,N-dimethylbenzylamine catalyst (BDMA). After the addition is complete, stir for 10min, then add 2.5g of n-butyl glycidyl ether, and continue to react for 60min. The solution is milky white.

[0054] (3) After the reaction is complete, the solution is poured into ethanol to precipitate the catalyst and some by-products. Then, the solution is filtered, dried at 60°C, and finally ground to obtain the product powder.

[0055] (4) Add 4 parts of the above modified carboxymethyl starch ether, 1 part of guar gum, 4 parts of hydroxyethyl cellulose and 3 parts of sodium dodecylbenzene sulfonate in proportion and stir until uniformly mixed to obtain starch-based thixotropic agent.

[0056] (5) Finally, add 4 parts of nano-hydrated calcium silicate, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 min, then perform ultrasonic dispersion to ensure thorough mixing, and finally obtain nano-crystal core-enhanced starch-based thixotropic agent.

[0057] Example 3, the specific steps are as follows:

[0058] (1) Add 10g of commercially available carboxymethyl starch ether and 100ml of deionized water to a 200ml three-necked flask. Place the flask in an 80℃ water bath for heating while mechanically stirring at a rate of 500r / min.

[0059] (2) When the solution is stirred until it becomes a colorless and transparent viscous solution, add 0.5g of N,N-dimethylbenzylamine catalyst (BDMA). After the addition is complete, stir for 10min, then add 5g of n-butyl glycidyl ether, and continue to react for 60min. The solution is milky white.

[0060] (3) After the reaction is complete, the solution is poured into ethanol to precipitate the catalyst and some by-products. Then, the solution is filtered, dried at 60°C, and finally ground to obtain the product powder.

[0061] (4) Add 2 parts of the above modified carboxymethyl starch ether, 2 parts of guar gum, 3 parts of hydroxyethyl cellulose and 2 parts of sodium dodecylbenzene sulfonate in proportion and stir until uniformly mixed to obtain starch-based thixotropic agent.

[0062] (5) Finally, add 1 part of nano-hydrated calcium silicate, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 min, then perform ultrasonic dispersion to ensure thorough mixing, and finally obtain nano-crystal core-enhanced starch-based thixotropic agent.

[0063] Example 4, the specific steps are as follows:

[0064] (1) Add 5g of commercially available carboxymethyl starch ether and 50ml of deionized water to a 200ml three-necked flask. Place the flask in an 80℃ water bath for heating while mechanically stirring at a rate of 500r / min.

[0065] (2) When the solution is stirred until it becomes a colorless and transparent viscous solution, add 0.3g of N,N-dimethylbenzylamine catalyst (BDMA). After the addition is complete, stir for 10min, then add 3g of n-butyl glycidyl ether, and continue to react for 60min. The solution is milky white.

[0066] (3) After the reaction is complete, the solution is poured into ethanol to precipitate the catalyst and some by-products. Then, the solution is filtered, dried at 60°C, and finally ground to obtain the product powder.

[0067] (4) Add 4 parts of the above modified carboxymethyl starch ether, 0.5 parts of guar gum, 3 parts of hydroxyethyl cellulose and 2 parts of sodium dodecylbenzene sulfonate in proportion and stir until uniformly mixed to obtain starch-based thixotropic agent.

[0068] (5) Finally, add 2 parts of nano-hydrated calcium silicate, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 minutes, then perform ultrasonic dispersion to ensure thorough mixing, and finally obtain nano-crystal core-enhanced starch-based thixotropic agent.

[0069] Example 5, the specific steps are as follows:

[0070] (1) Add 8g of commercially available carboxymethyl starch ether and 120ml of deionized water to a 200ml three-necked flask. Place the flask in an 80℃ water bath for heating while mechanically stirring at a rate of 500r / min.

[0071] (2) When the solution is stirred until it becomes a colorless and transparent viscous solution, add 1g of N,N-dimethylbenzylamine catalyst (BDMA). After the addition is complete, stir for 10min, then add 8g of n-butyl glycidyl ether, and continue the reaction for 60min. The solution is milky white.

[0072] (3) After the reaction is complete, the solution is poured into ethanol to precipitate the catalyst and some by-products. Then, the solution is filtered, dried at 60°C, and finally ground to obtain the product powder.

[0073] (4) Add 3 parts of the above modified carboxymethyl starch ether, 1.5 parts of guar gum, 2.5 parts of hydroxyethyl cellulose and 1.5 parts of sodium dodecylbenzene sulfonate in proportion and stir until uniformly mixed to obtain starch-based thixotropic agent.

[0074] (5) Finally, add 4 parts of nano-hydrated calcium silicate, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 min, then perform ultrasonic dispersion to ensure thorough mixing, and finally obtain nano-crystal core-enhanced starch-based thixotropic agent.

[0075] Example 6, the specific steps are as follows:

[0076] (1) Add 20g of commercially available carboxymethyl starch ether and 150ml of deionized water to a 200ml three-necked flask. Place the flask in an 80℃ water bath for heating while mechanically stirring at a rate of 500r / min.

[0077] (2) When the solution is stirred until it becomes a colorless and transparent viscous solution, add 1.5g of N,N-dimethylbenzylamine catalyst (BDMA). After the addition is complete, stir for 20min, then add 7.5g of n-butyl glycidyl ether, and continue to react for 60min. The solution is milky white.

[0078] (3) After the reaction is complete, the solution is poured into ethanol to precipitate the catalyst and some by-products. Then, the solution is filtered, dried at 60°C, and finally ground to obtain the product powder.

[0079] (4) Add 3 parts of the above modified carboxymethyl starch ether, 1.5 parts of guar gum, 2.5 parts of hydroxyethyl cellulose and 2 parts of sodium dodecylbenzene sulfonate in proportion and stir until uniformly mixed to obtain starch-based thixotropic agent.

[0080] (5) Finally, add 4 parts of nano-hydrated calcium silicate, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 min, then perform ultrasonic dispersion to ensure thorough mixing, and finally obtain nano-crystal core-enhanced starch-based thixotropic agent.

[0081] Example 7: This example studies the thixotropic properties of mortar using the nanocrystalline nucleus-reinforced starch-based thixotropic agent prepared according to the present invention.

[0082] The experimental mortar was prepared using the following method: Lafarge P·O52.5 silicate cement (56%), ordinary silica fume (7.2%), quartz sand (28.8%), thixotropic lubricant (0.2%), and polycarboxylate superplasticizer (1.0%).

[0083] Rheological tests on the mortar were conducted using an RS-SST soft solids tester manufactured by Brookfield Instruments, USA. The mortar was mixed thoroughly in a mixer and immediately transferred to the rheometer for testing. Tests were performed at 20°C using a CC25 rotor, with a maximum shear rate of 100 s⁻¹. -1 .

[0084] Thixotropic index was measured using a Brookfield DV-Ⅱ+Pro viscometer.

[0085] Experimental subjects:

[0086] Six groups of nanocrystalline nucleus-reinforced starch-based thixotropic agents were prepared in Examples 1-6;

[0087] Comparative Example 1 is a thixotropic agent prepared by compounding commercially available hydroxypropyl starch ether with other raw materials of the present invention;

[0088] Comparative Example 2 uses modified carboxymethyl starch ether directly as a thixotropic agent;

[0089] Comparative Example 3 is a starch-based thixotropic agent prepared without the addition of nanocrystalline nuclei;

[0090] The control example is mortar without any thixotropic agent;

[0091] The results of measuring the thixotropic index of the mortar for the above 10 groups of experimental samples are shown in Table 1:

[0092] Table 1. Effects of adding different thixotropic agents on the thixotropic index of mortar.

[0093]

[0094] From Table 1 and Figure 4It is evident that the starch-based thixotropic agent prepared according to the method provided by this invention can significantly improve the thixotropic properties of mortar; the incorporation of nanocrystal nuclei has no significant effect on the thixotropic properties of mortar. Furthermore, in the comparative examples, it can be found that the modified carboxymethyl starch ether exhibits enhanced thixotropic properties compared to commercially available hydroxypropyl starch ether.

[0095] Example 8: This example studies the improvement effect of the nanocrystalline nucleus-reinforced starch-based thixotropic agent prepared in this invention on the compressive strength of mortar.

[0096] The experimental mortar was prepared using the following method: Lafarge P·O 52.5 silicate cement (56%), ordinary silica fume (7.2%), quartz sand (28.8%), thixotropic lubricant (0.2%), and polycarboxylate superplasticizer (1.0%).

[0097] The compressive strength of mortar was tested in accordance with the "Standard for Test Methods of Basic Performance of Building Mortar" JGJ / T70-2009.

[0098] Experimental subjects:

[0099] Six groups of nanocrystalline nucleus-reinforced starch-based thixotropic agents were prepared in Examples 1-6;

[0100] Comparative Example 1 is a thixotropic agent prepared by compounding commercially available hydroxypropyl starch ether with other raw materials of the present invention;

[0101] Comparative Example 2 uses modified carboxymethyl starch ether directly as a thixotropic agent;

[0102] Comparative Example 3 is a starch-based thixotropic agent prepared without the addition of nanocrystalline nuclei;

[0103] The control example is mortar without any thixotropic agent.

[0104] The results of measuring the compressive strength of the mortar for the above 10 groups of experimental samples are shown in Table 2:

[0105] Table 2. Effects of adding different thixotropic agents on the compressive strength of mortar.

[0106] sample 1d (MPa) 3d (MPa) 7 days (MPa) 28 days (MPa) Example 1 15.3 26.3 40.3 45.3 Example 2 16.5 27.8 46.7 45.8 Example 3 15.9 26.9 45.9 46.8 Example 4 16.2 28.3 43.2 46.3 Example 5 17.2 29.4 48.3 44.6 Example 6 14.9 27.2 44.3 46.2 Comparative Example 1 14.2 25.9 39.2 43.3 Comparative Example 2 6.2 17.8 33.4 36.6 Comparative Example 3 5.8 14.7 35.6 36.4 control group 4.9 14.2 32.3 35.4

[0107] From Table 2 and Figure 5 As can be seen from the above, the starch-based thixotropic agent prepared according to the method provided by the present invention can significantly improve the early strength and overall strength of cement mortar when applied to cement mortar.

[0108] In summary, the nanocrystalline nucleus-reinforced starch-based thixotropic agent provided by this invention achieves a certain hydrophilic-lipophilic balance by introducing a very small amount of alkoxy hydrophobic groups into the main component, carboxymethyl starch ether, thereby obtaining a hydrophobically associated water-soluble polymer. In aqueous solution, it can form a reversible three-dimensional network structure through physical chain entanglement, hydrophobic association (intermolecular association, intramolecular association), and hydrogen bonding, giving carboxymethyl starch excellent thickening ability. Furthermore, due to the intramolecular or intermolecular association of the hydrophobic groups and electrostatic interactions, its aqueous solution exhibits certain rheological properties and can possess good shear resistance. The modified starch ether, as the main raw material, is mixed with nanocrystalline nucleus materials, cellulose, and dispersing agents to obtain a nanocrystalline nucleus-reinforced starch-based thixotropic agent, which maintains superior thixotropic properties while also solving the problem of strength loss caused by the addition of thixotropic agents.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nanocrystalline nucleus-reinforced starch-based thixotropic agent, characterized in that, The starch-based thixotropic agent includes nanocrystalline nuclei, modified carboxymethyl starch ether, cellulose ether, dispersant, and rheology stabilizer; The nanocrystalline nucleus material is selected from one or more of the following: nano-hydrated calcium silicate, nano-silica, carbon nanotubes, and nano-calcium carbonate. The modified carboxymethyl starch ether is an alkyloxy-carboxymethyl starch ether; The preparation method of the starch-based thixotropic agent mainly includes the following steps: Step 1: Add 0.5-2% of the rheology stabilizer to continuously stirred deionized water to obtain a first mixed solution; Step two, add 15-30% of the modified carboxymethyl starch ether and 20-40% of the cellulose ether to the first mixed solution to obtain the second mixed solution; Step 3: Add 1.5-3% of the dispersant to the second mixed solution to obtain the third mixed solution; The reaction temperature for all the above steps should be 30-60℃ and the stirring rate should be maintained at 400-800 r / min; Step four: Add 0.2-0.8% of the nanocrystalline nucleus material to the third mixed solution, first perform high-speed shear mixing at 8000-12000 rpm for 4-8 min, and then perform ultrasonic dispersion to obtain nanocrystalline nucleus-enhanced starch-based thixotropic agent; All components are listed as percentages by mass.

2. The starch-based thixotropic agent according to claim 1, characterized in that, The particle size of the nanocrystalline nucleus material is 20-40 nm.

3. The starch-based thixotropic agent according to claim 1, characterized in that, The cellulose ether is selected from one or more mixtures of hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose.

4. The starch-based thixotropic agent according to claim 1, characterized in that, The dispersant is selected from any one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, octyl alcohol polyoxyethylene ether, and polyacrylamide.

5. The starch-based thixotropic agent according to claim 1, characterized in that, The rheology stabilizer is selected from any one of gum arabic, gum coumar, or gum guar.

6. The starch-based thixotropic agent according to claim 1, characterized in that, The preparation steps of the modified carboxymethyl starch ether in the preparation method are as follows: Step a: Take 1 part of commercially available carboxymethyl starch ether and mix it with 10-15 parts of water and stir continuously at 400-800 r / min. The mixing temperature is 40-80℃ to obtain a carboxymethyl starch ether solution. Step b: Weigh 0.03-0.1 parts of N,N-dimethylbenzylamine catalyst and add it to the carboxymethyl starch ether solution. The mixing temperature is 40-80℃, and the mixture is stirred at 400-800 r / min for 10 min. Then, add 1-2 parts of alkyl glycidyl ether and react for 30-60 min to obtain the modified carboxymethyl starch ether solution. Step c: The modified carboxymethyl starch ether solution is poured into the extraction liquid to help the catalyst and some reaction byproducts precipitate out, and then filtered, dried and ground to obtain modified carboxymethyl starch ether powder; All the above components are added by mass.

7. The starch-based thixotropic agent according to claim 6, characterized in that, The alkyl glycidyl ether mentioned in step b is selected from either n-butyl glycidyl ether or benzyl glycidyl ether; The extract in step c is selected from any one of methanol, ethanol, and isopropanol.

8. The application of a starch-based thixotropic agent according to any one of claims 1-7 in mortar.

9. The application in mortar according to claim 8, characterized in that, The steps are as follows: The first step is to dilute the nanocrystalline nucleus-enhanced starch-based thixotropic agent to a concentration of 10% as an additive; The second step is to add the admixture to the mortar according to the mass ratio of the admixture to the cementitious material of (0.01-0.2):1.

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