A novel carboxylic acid-based viscosity-reducing nanopowder modifier, its preparation method and its application

Abstract

This invention discloses a novel carboxylic acid-based viscosity-reducing nanopowder modifier, its preparation method, and its application. A group of novel carboxylic acid modifiers containing PEG fragments were successfully prepared. By molecularly coupling the carboxylic acid anchoring unit with the PEGylated acrylate structure, a modifier system with three functions of "anchoring-reaction-dispersion" was constructed. This provides a novel multifunctional modifier that combines the activity of acrylate, the flexibility of polyethylene glycol, and the anchoring ability of carboxylic acid. By introducing carboxyl groups as strongly polar anchoring groups, they can undergo esterification or coordination reactions with the hydroxyl groups on the surface of nanopowders, significantly enhancing the interfacial chemical bonding force and effectively preventing the modifier from desorbing during processing. At the same time, by introducing the rigid aromatic ring structure of phthalic anhydride, the steric hindrance effect of the molecule is increased. Its rigid framework helps maintain the effective thickness of the steric hindrance layer, which can more effectively inhibit the secondary aggregation of nanoparticles and improve the long-term stability of the dispersion.

Description

Technical Field

[0001] This invention relates to the field of modified nanopowder technology, specifically a novel carboxylic acid-based viscosity-reducing nanopowder modifier, its preparation method, and its application. Background Technology

[0002] With the rapid development of new energy, electronic packaging, and high-end ceramics, inorganic nanoparticles (such as nano-zirconia and silicon dioxide) have become core basic materials driving the upgrading of the new materials industry due to their unique nanoscale effect and excellent physicochemical properties. However, the extremely high specific surface area and surface energy of nanoparticles make them prone to agglomeration. This agglomeration not only destroys the size advantage of nanoparticles and reduces their interfacial compatibility with organic matrices, but also raises a pressing problem in high-solids content applications: a sharp increase in the viscosity of the dispersion system. In highly filled systems, severe particle agglomeration can cause the slurry to be semi-solid or even paste-like, with extremely poor flowability, greatly limiting its application in advanced processing technologies such as precision coating, 3D printing, and injection molding.

[0003] Surface modification is a key technology for solving the agglomeration of nanoparticles and improving their dispersibility and rheological properties. Currently, the modifiers widely used in industry are mostly silane coupling agents (such as MPS and KH series). These modifiers mainly cover the active hydroxyl groups on the particle surface through chemical bonding. Although they can prevent agglomeration to a certain extent, their mechanism of action mainly relies on electrostatic repulsion or a thin organic layer covering, which often proves inadequate when dealing with high solids content systems: on the one hand, the short-chain structure cannot provide sufficient steric hindrance to resist secondary agglomeration caused by van der Waals forces; on the other hand, the modified powder is still prone to forming dense packing in organic media, resulting in excessively high system viscosity and poor processing performance. In addition, some traditional modifiers also suffer from complex synthesis processes, single functional groups, and difficulty in simultaneously meeting multiple requirements such as dispersibility and low viscosity.

[0004] To address the aforementioned limitations, introducing long-chain polymer segments to construct a steric hindrance stabilization mechanism is considered an effective way to overcome the bottleneck of high-solids content dispersion. Among them, polyethylene glycol (PEG) segments are considered an ideal choice for constructing an efficient steric hindrance layer on the surface of nanoparticles due to their excellent water / oil solubility tunability, good biocompatibility, and flexible molecular conformation. By chemically grafting PEG segments onto the surface of nanoparticles, not only can their long-chain structure effectively isolate particles and inhibit aggregation, but also the viscosity of high-concentration dispersion systems can be significantly reduced by changing the solvation layer thickness and interaction potential on the particle surface, achieving a rheological behavior transformation from "semi-solid" to "liquid".

[0005] Although PEG-based modifiers offer significant advantages in theoretical design, there are relatively few research reports on customized PEG modifiers specifically designed for high surface energy powders such as nano-zirconia, which combine efficient dispersion with significant viscosity reduction. Furthermore, a systematic and in-depth understanding of the structure-activity relationship between their molecular structure (e.g., chain length, introduction of rigid groups) and macroscopic rheological properties is still lacking. Therefore, designing and synthesizing a series of novel modifiers containing PEG fragments, and exploring their surface modification effects on nano-zirconia and their viscosity regulation mechanisms in dispersion systems, is of significant scientific importance and application value for the development of high-performance, easily processable nanocomposites. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a molecular design strategy of "multifunctional group synergy," aiming to molecularly couple carboxylic acid anchoring units with PEGylated acrylate structures through chemical synthesis. This design concept aims to achieve the organic unity of three functions: the carboxyl group acts as a strong anchoring group, enhancing the chemical bonding force with the nano-zirconia surface; the acrylate group acts as a reactive site, ensuring interfacial compatibility during the subsequent curing process; and the PEG segment continues to exert steric hindrance and lubrication effects, maintaining the low viscosity characteristics of the system. Through this three-in-one structural design of "anchoring-reaction-dispersion," it is expected to comprehensively compensate for the performance defects of single modifiers. By preparing a new type of multifunctional modifier that combines the activity of acrylate, the flexibility of polyethylene glycol, and the anchoring ability of carboxylic acid, the core problems of poor powder dispersibility, high slurry viscosity, and weak interfacial bonding in traditional modification systems can be solved.

[0007] To achieve the above technical effects, the following technical solution is adopted: A novel carboxylic acid-based viscosity-reducing nanopowder modifier, wherein the modifier is one of the following compounds: S-1: ; S-2: ; S-3: ; S-4: ; Furthermore, the preparation method of compound S-1 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of ethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection. Furthermore, the preparation method of compound S-2 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of diethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h, the reaction being carried out under inert gas protection; Furthermore, the preparation method of compound S-3 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of triethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection. Furthermore, the preparation method of compound S-4 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of tetraethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection. Furthermore, the following post-processing techniques are also included: After the reaction was completed, the reaction solution was cooled to room temperature under an inert atmosphere. Then, 80-120 mL of 1-2 mol / L hydrochloric acid aqueous solution was added to the reaction solution to quench the reaction. The solution was extracted with ethyl acetate 2-3 times. The organic phases were combined and washed with saturated brine. The solution was dried overnight with anhydrous magnesium sulfate, the desiccant was removed by filtration, the solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography to obtain a solid product. Furthermore, the organic solvent is selected from anhydrous tetrahydrofuran, 1,4-dioxane, and methyltetrahydrofuran, and the polymerization inhibitor is selected from 2,6-di-tert-butyl-p-cresol, hydroquinone, p-methoxyphenol, and tert-butylcatechol. Furthermore, after adding phthalic anhydride, 4-dimethylaminopyridine and polymerization inhibitor to the reaction vessel, connect the Schlenk line, evacuate the reaction system and fill it with argon gas for protection, and repeat the replacement 2 to 4 times to remove the air in the system. This invention also provides the application of the above-mentioned novel carboxylic acid-type viscosity-reducing nanopowder modifier in the modification of nano-zirconia; Furthermore, the application method includes the following steps: 20-30 mL of organic solvent and one of the modifiers S-1, S-2, S-3, and S-4 are placed in a reaction vessel, the amount of the modifier added is 20-35 wt% of the mass of nano-zirconia, and after stirring and mixing evenly at room temperature, 0.3-0.6 g of nano-zirconia powder is added; the reaction system is heated to 45-60℃ and stirred at a constant temperature for 5-7 h to achieve surface modification of nano-zirconia.

[0008] The beneficial effects of this invention are as follows: This invention addresses the challenge of traditional modifiers in simultaneously achieving dispersion stability and low viscosity processability. Based on a molecular design strategy of "synergistic multifunctional groups," a novel group of carboxylic acid modifiers containing PEG fragments was successfully prepared. By molecularly coupling the carboxylic acid anchoring unit with the PEGylated acrylate structure, a modifier system with triple functions of "anchoring-reaction-dispersion" was constructed. The embodiments of this invention prepared a novel multifunctional modifier possessing the activity of acrylate, the flexibility of polyethylene glycol, and the anchoring ability of carboxylic acid, and verified the feasibility of the "synergistic multifunctional group" design strategy. The modifier achieved an organic unity of low viscosity and high stability in nano-zirconia dispersions. The carboxyl group, as a strongly polar anchoring group, can undergo esterification or coordination reactions with the hydroxyl groups on the surface of nanoparticles, significantly enhancing the interfacial chemical bonding force and effectively preventing the modifier from desorbing during processing. Simultaneously, the introduction of the rigid aromatic ring structure of phthalic anhydride increases the steric hindrance effect of the molecule. Its rigid framework helps maintain the effective thickness of the steric hindrance layer, more effectively inhibiting the secondary aggregation of nanoparticles and improving the long-term stability of the dispersion. Through this synthetic strategy, a novel modifier with both "strong anchoring and increased steric hindrance" properties is constructed, providing a material basis for the preparation of highly stable nano-dispersions and a technical solution for the large-scale preparation and application of high-performance nano-slurries. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0010] Figure 1The synthesis process flow diagrams of the modifiers in Examples 1-4 of this invention are shown below; Figure 2 S-1 prepared for the embodiments of the present invention 1 H NMR spectrum; Figure 3 S-1 prepared for the embodiments of the present invention 13 C NMR spectrum; Figure 4 S-2 prepared for the embodiments of the present invention 1 H NMR spectrum; Figure 5 S-2 prepared for the embodiments of the present invention 13 C NMR spectrum; Figure 6 S-3 prepared for the embodiments of the present invention 1 H NMR spectrum; Figure 7 S-3 prepared for the embodiments of the present invention 13 C NMR spectrum; Figure 8 S-4 prepared for the embodiments of the present invention 1 H NMR spectrum; Figure 9 S-4 prepared for the embodiments of the present invention 13 C NMR spectrum; Figure 10 Here is a high-resolution mass spectrum of compound S-1 prepared in an embodiment of the present invention; Figure 11 Here is a high-resolution mass spectrum of compound S-2 prepared in an embodiment of the present invention; Figure 12 Here is a high-resolution mass spectrum of compound S-3 prepared in an embodiment of the present invention; Figure 13 This is a high-resolution mass spectrum of compound S-4 prepared in an embodiment of the present invention; Figure 14 This is a microscopic characterization diagram of the dispersion of nano-zirconia modified in Example 5 of the present invention, wherein... Figure 14 a represents a TEM image of MPS-modified nano-zirconia. Figure 14 b represents a TEM image of S-4 modified nano-zirconia. Figure 14 c represents the STEM image of S-4 modified nano-zirconia; Figure 15 This is a comparison diagram of nano-zirconia dispersions modified with different modifiers in Example 5 of the present invention; wherein... Figure 15 a represents the MPS-modified nano-zirconia dispersion in Example 5 of this invention. Figure 15 b is a diagram of the S-4 modified nano-zirconia dispersion in Example 5 of this invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0012] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0013] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0014] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used are conventional methods and techniques in the art.

[0015] See Figure 1 , Figure 1 The above is a flowchart of the synthesis process of modifiers S-1, S-2, S-3 and S-4 in Examples 1-4 of the present invention.

[0016] Example 1: Preparation of ethylene glycol monoacrylate: Weigh 9.3 g (0.15 mol) of ethylene glycol and 11.4 g (0.1125 mol) of triethylamine, place them in a 250 mL round-bottom flask, and dissolve them in 100 mL of anhydrous tetrahydrofuran (THF). Fix the reaction flask on a magnetic stirrer and cool it to 0 °C in an ice-water bath. Separately weigh 6.8 g (0.075 mol) of acryloyl chloride, dissolve it in 50 mL of anhydrous THF, and transfer it into a constant-pressure dropping funnel.

[0017] With magnetic stirring on, and under ice-water bath protection, slowly add acryloyl chloride solution dropwise into a round-bottom flask. After the addition is complete, maintain ice bath conditions and continue stirring overnight. After the reaction is complete, remove insoluble solids (mainly triethylamine hydrochloride) from the reaction solution by vacuum filtration, and concentrate the filtrate by rotary evaporator to remove the solvent.

[0018] The concentrated residue was redissolved in dichloromethane (CH2Cl2), and the organic phase was washed successively with 5% hydrochloric acid aqueous solution, 5% sodium bicarbonate aqueous solution, and saturated brine. The washed organic phase was dried overnight with anhydrous magnesium sulfate, the desiccant was removed by filtration, and CH2Cl2 was removed by rotary evaporation of the filtrate. Finally, the crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:15) to separate ethylene glycol monoacrylate and ethylene glycol diacrylate, with yields of 16.5% and 36%, respectively. The reaction equations are as follows:

[0019] Preparation of mono(2-acryloyloxyethyl) phthalate (S-1): In a dry single-necked flask, add 6.0 g (40.5 mmol) phthalic anhydride, 0.5 g (4.05 mmol) 4-dimethylaminopyridine (DMAP), and 20 mg 2,6-di-tert-butyl-p-cresol (BHT). Connect a Schlenk line, evacuate the system, and purge with argon gas, repeating the purging process three times to remove air from the system. Then, under argon protection, add 4.7 g (40.5 mmol) ethylene glycol monoacrylate and 50 mL anhydrous THF. Install a reflux condenser, heat to 90 °C, and stir the reaction for 7 h. After the reaction is complete, cool to room temperature under an inert atmosphere.

[0020] The post-processing procedure is as follows: 100 mL of 1 mol / L hydrochloric acid aqueous solution was added to the reaction solution to quench the reaction. The mixture was extracted three times with ethyl acetate. The combined organic phases were washed with saturated brine and dried overnight with anhydrous magnesium sulfate. The drying agent was removed by filtration, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography to obtain a white solid product, phthalic acid mono(2-acryloyloxyethyl) ester, with a yield of 36%. The reaction equation for the preparation of S-1 is as follows:

[0021] like Figure 2-3 As shown, where, Figure 2 For compound S-1 1 The 1H NMR spectrum (solvent: CDCl3) is analyzed below, along with the assignment of each characteristic peak. The multiplet at δ 7.57–7.92 ppm is attributed to aromatic protons on the benzene ring of the phthalate ester structure; the characteristic peaks at δ 5.81, 6.13, and 6.42 ppm are protons on the terminal vinyl group (–CH=CH2) of the acrylate ester; the signal in the δ 4.46–4.60 ppm region is attributed to the methylene protons (–CH2–O–CO–) attached to the ester group. The integral area ratio of the two sets of peaks is 1:1 (each corresponding to 2H), indicating the symmetry of the molecular structure and successful modification. The residual solvent peak (CDCl3) is located at δ 7.26 ppm.

[0022] The specific NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ: 7.91(d, J = 7.2 Hz, 1H),7.69 (d, J = 7.3 Hz, 1H), 7.59(t, J = 7.5 Hz, 2H), 6.42(d, J = 17.5 Hz, 1H),6.13(dd, J = 19.7, 10.6 Hz, 1H), 5.81(d, J = 10.5 Hz, 1H), 4.60–4.56(m, 2H), 4.51–4.46 (m, 2H).

[0023] Figure 3 For compound S-1 13 C10 NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The signals at δ 62.10 and 63.49 ppm are attributed to the methylene carbon atom (–CH2–O–CO–) attached to the ester group; multiple peaks in the δ 127.91–132.91 ppm region are attributed to carbon atoms on the benzene ring skeleton carbon and the acrylate double bond; the three characteristic peaks in the high chemical shift region of δ 166.09–171.84 ppm are attributed to the carboxyl carbon (–COOH) and the two ester carbons (–COO–), respectively.

[0024] The specific NMR data are as follows: 13 C NMR (101 MHz, CDCl3) δ: 171.84, 167.87, 166.09,132.91, 132.27, 131.60, 131.06, 130.03, 129.92, 128.81, 127.91, 63.49, 62.10.

[0025] Figure 10 The high-resolution mass spectrum of compound S-1 was obtained by electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) in ESI positive ion mode.+ The spectrum shows that the main characteristic peaks are distributed in the m / z 264–266 range, with the quasi-molecular ion peak [M+H] being the most prominent. + The measured value is 265.0713 m / z, indicating a relatively high abundance (intensity approximately 6.50 × 10⁻⁶). 3 The measured value is 265.0712 (molecular formula C). 13 H 13 The peak is extremely close to that of O6, with a mass deviation of only 0.1 mDa (relative error 0.4 ppm), far below the instrument accuracy threshold of 5 ppm, indicating that the detection results are highly reliable. Combined with elemental composition analysis and unsaturation calculation (DBE = 8), this peak was confirmed as the protonated ion peak [M+H] of the target compound. + This aligns with the characteristic that small molecules readily form protonated ions under ESI positive ion mode. The overall spectrum shows no obvious impurity peaks, indicating high sample purity and a complete structure.

[0026] comprehensive 1 H NMR, 13 The results of C13NMR and HRMS analyses confirmed the successful synthesis of the target product S-1. The molecular formula of this compound is C13H. 12 O6 contains phthalate segments, ethylene glycol segments, and acrylate functional groups, and its structure is consistent with the expected design.

[0027] Example 2: The length of the PEG chain segment is a key factor in regulating the steric hindrance effect and dispersion performance of the modifier. Appropriately increasing the PEG chain length not only thickens the steric hindrance layer on the particle surface, effectively inhibiting secondary agglomeration of nanoparticles, but also enhances the solvation effect between the modifier and the organic dispersion medium, thereby further reducing the system viscosity and improving storage stability. Based on this, diethylene glycol monoacrylate (DEGA) was selected as the synthetic unit molecule. By extending the PEG chain segment length, the overall performance of the modifier was optimized, and it was then subjected to an esterification reaction with phthalic anhydride.

[0028] Preparation of diethylene glycol monoacrylate: Weigh 15.9 g (0.15 mol) of diethylene glycol and 11.4 g (0.1125 mol) of triethylamine, place them in a 250 mL round-bottom flask, and dissolve them in 100 mL of anhydrous THF. Fix the reaction flask on a magnetic stirrer and cool it in an ice-water bath. Separately weigh 6.8 g (0.075 mol) of acryloyl chloride, dissolve it in 50 mL of anhydrous THF, and transfer it into a constant-pressure dropping funnel.

[0029] Turn on the magnetic stirrer and slowly add the acryloyl chloride solution dropwise into the round-bottom flask under ice-water bath protection. After the addition is complete, maintain the ice bath conditions and continue stirring overnight. After the reaction is complete, remove the insoluble solids (mainly triethylamine hydrochloride) from the reaction solution by vacuum filtration, and concentrate the filtrate by rotary evaporator to remove the solvent.

[0030] The concentrated residue was redissolved in CH2Cl2, and the organic phase was washed successively with 5% hydrochloric acid aqueous solution, 5% sodium bicarbonate aqueous solution, and saturated brine. The washed organic phase was dried overnight with anhydrous magnesium sulfate, the desiccant was removed by filtration, and CH2Cl2 was removed by rotary evaporation of the filtrate. Finally, the crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:15) to separate pale yellow diethylene glycol monoacrylate and diethylene glycol diacrylate, with yields of 17% and 38%, respectively. The reaction equations are as follows:

[0031] Preparation of mono(2-(2-(acryloyloxy)ethoxy)ethyl) phthalate (S-2): In a dry, single-necked flask, add 6.0 g (40.5 mmol) phthalic anhydride, 0.5 g (4.05 mmol) 4-dimethylaminopyridine (DMAP), and 20 mg 2,6-di-tert-butyl-p-cresol (BHT). Connect a Schlenk line, evacuate the system, and purge with argon gas, repeating the purging process three times to remove air from the system. Then, under argon protection, add 6.5 g (40.5 mmol) diethylene glycol monoacrylate and 50 mL anhydrous THF. Install a reflux condenser, heat to 90 °C, and stir the reaction for 7 h. After the reaction is complete, cool to room temperature under an inert atmosphere.

[0032] The post-processing procedure is as follows: 100 mL of 1 mol / L hydrochloric acid aqueous solution was added to the reaction solution to quench the reaction. The mixture was extracted three times with ethyl acetate. The combined organic phases were washed with saturated brine and dried overnight with anhydrous magnesium sulfate. The drying agent was removed by filtration, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography to obtain a white solid product, phthalic acid mono(2-(2-(acryloyloxy)ethoxy)ethyl ester, with a yield of 32%. The reaction equation for the preparation of S-2 is as follows:

[0033] like Figure 4-5 As shown, where, Figure 4 For compound S-2 1 1H NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The multiplet at δ 3.73–3.82 ppm is attributed to methylene protons (–CH2–O–CH2–) linked by ether bonds in the polyethylene glycol chain, and the singlet at δ 4.45 ppm is attributed to methylene protons (–CH2–O–CO–) linked to the ester group. The integral area ratio of these peaks is 2:2:4, consistent with the theoretical number of protons. The characteristic peak in the δ 5.85–6.48 ppm region represents protons on the terminal vinyl group of the acrylate (–CH=CH2). The multiplet at δ 7.56–7.84 ppm is attributed to aromatic protons on the benzene ring of the phthalate structure. Furthermore, characteristic impurity peaks of the polymerization inhibitor BHT (such as δ 1.43, 2.27, and 6.98 ppm) were observed in the spectrum, and a residual solvent peak (CDCl3) was observed at δ 7.26 ppm.

[0034] The specific NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ: 7.86 – 7.81 (m, 1H),7.76 (d, J = 5.5 Hz, 1H), 7.60 – 7.55 (m, 2H), 6.46 (d, J = 17.3 Hz, 1H), 6.17 (dd, J = 17.1, 10.8 Hz, 1H), 5.87 (d, J = 10.4 Hz, 1H), 4.45 (s, 4H), 3.82 – 3.78 (m, 2H), 3.77 – 3.73 (m, 2H).

[0035] Figure 5 For compound S-2 13 C10 NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The signal at δ 63.70–69.04 ppm is attributed to the polyethylene glycol chain and the methylene carbon atom (–CH2–O–) attached to the ester group; multiple peaks in the region of δ 128.03–132.55 ppm are attributed to carbon atoms in the benzene ring skeleton and the acrylate double bond; the three characteristic peaks in the high chemical shift region of δ 166.54–170.37 ppm are attributed to carboxyl carbon (–COOH) and ester carbon (–COO–), respectively.

[0036] The specific NMR data are as follows: 13C NMR (101 MHz, CDCl3) δ: 170.37, 168.06, 166.54,132.55, 131.76, 131.60, 131.13, 131.01, 129.57, 128.96, 128.03, 69.04, 68.78,64.76, 63.70.

[0037] The high-resolution mass spectrum of compound S-2 is shown below. Figure 11 As shown. The test was performed using electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), operating in ESI positive ion mode (ESI...). + The elemental composition search range was limited to C: 0–15, H: 0–17, and O: 0–7. Molecular formula matching and accuracy verification were performed on the masses of individual isotopes. The main characteristic peaks in the spectrum are distributed in… m / z The region is 306–311, with the quasi-molecular ion peak [M+H]. + The measured value is m / z 309.0975, relatively high abundance (intensity approximately 1.22 × 10⁻⁶). 5 The measured value is 309.0974 (molecular formula C). 15 H 17 The peak is extremely close to that of O7, with a mass deviation of only 0.1 mDa (relative error 0.3 ppm), far below the instrument accuracy threshold of 5 ppm, indicating that the detection results are highly reliable. Combined with elemental composition analysis and unsaturation calculation (DBE = 8), this peak was confirmed as the protonated ion peak [M+H] of the target compound. + This aligns with the characteristic that small molecules readily form protonated ions under ESI positive ion mode. The overall spectrum shows no obvious impurity peaks, indicating high sample purity and a complete structure.

[0038] comprehensive 1 H NMR, 13 C10 NMR and HRMS analyses confirmed the successful synthesis of the target product S-2. The molecular formula of this compound is C10. 15 H 16 O7 contains phthalate segments, diethylene glycol segments, and acrylate functional groups, and its structure is consistent with the expected design.

[0039] Example 3 Preparation of triethylene glycol monoacrylate Weigh 22.5 g (0.15 mol) of triethylene glycol and 11.4 g (0.1125 mol) of triethylamine, place them in a 250 mL round-bottom flask, and add 100 mL of anhydrous THF to dissolve them; fix the reaction flask on a magnetic stirrer and cool it in an ice-water bath; separately weigh 6.8 g (0.075 mol) of acryloyl chloride, dissolve it in 50 mL of anhydrous THF, and transfer it into a constant pressure dropping funnel.

[0040] Turn on the magnetic stirrer and slowly add the acryloyl chloride solution dropwise into the round-bottom flask under ice-water bath protection. After the addition is complete, maintain the ice bath conditions and continue stirring overnight. After the reaction is complete, remove the insoluble solids (mainly triethylamine hydrochloride) from the reaction solution by vacuum filtration, and concentrate the filtrate by rotary evaporator to remove the solvent.

[0041] The concentrated residue was redissolved in CH2Cl2, and the organic phase was washed successively with 5% hydrochloric acid aqueous solution, 5% sodium bicarbonate aqueous solution, and saturated brine. The washed organic phase was dried over anhydrous magnesium sulfate for 8 h, the desiccant was removed by filtration, and CH2Cl2 was removed by rotary evaporation of the filtrate. Finally, the crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:15) to separate pale yellow triethylene glycol monoacrylate and triethylene glycol diacrylate, with yields of 19.5% and 32%, respectively. The reaction equations are as follows:

[0042] Preparation of triethylene glycol monoacrylate phthalate (S-3): In a dry single-necked flask, add 6.0 g (40.5 mmol) phthalic anhydride, 0.5 g (4.05 mmol) 4-dimethylaminopyridine (DMAP), and 20 mg 2,6-di-tert-butyl-p-cresol (BHT); connect a Schlenk line, evacuate the system, and purge with argon gas, repeating the purging process three times to remove air from the system; then, under argon protection, add 8.3 g (40.5 mmol) triethylene glycol monoacrylate and 50 mL anhydrous tetrahydrofuran (THF). Install a reflux condenser, heat to 90 °C, and stir the reaction for 7 h; after the reaction is complete, cool to room temperature under an inert atmosphere.

[0043] The post-processing procedure is as follows: 100 mL of 1 mol / L hydrochloric acid aqueous solution was added to the reaction solution to quench the reaction. The mixture was extracted three times with ethyl acetate. The combined organic phases were washed with saturated brine and dried overnight with anhydrous magnesium sulfate. The desiccant was removed by filtration, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography to obtain a white solid product, triethylene glycol monoacrylate phthalate, with a yield of 31%. The reaction equation for the preparation of S-3 is as follows:

[0044] like Figure 6-7 As shown, where, Figure 6 For compound S-3 1 1H NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The multiplet at δ 3.72–4.44 ppm is attributed to the methylene protons (–CH2–O–) linked by the ether bond in the polyethylene glycol chain and the methylene protons linked to the ester group, with an integrated area ratio of 4:2:2:2:2, consistent with the theoretical proton number. The characteristic peak in the δ 5.82–6.42 ppm region represents the protons on the terminal vinyl group (–CH=CH2) of the acrylate. The multiplet at δ 7.54–7.81 ppm is attributed to the aromatic protons on the benzene ring of the phthalate structure. The residual solvent peak (CDCl3) is located at δ 7.26 ppm.

[0045] The specific NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ: 7.81 (d, J = 7.1 Hz, 1H), 7.65 (d, J = 7.1 Hz, 1H), 7.54 (t, J = 6.7 Hz, 2H), 6.42 (d, J = 17.3Hz, 1H), 6.13 (dd, J = 3.77 (d, J = 5.2 Hz, 2H), 3.72 (d, J = 5.1 Hz, 2H).

[0046] Figure 7 For compound S-3 13 C10 NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The three characteristic peaks in the high chemical shift region of δ 166.12–169.58 ppm are attributed to carboxyl carbon (–COOH) and ester carbon (–COO–), respectively; the six peaks in the region of δ 128.08–131.64 ppm are attributed to carbon atoms in the benzene ring skeleton and acrylate double bonds; the six peaks in the aliphatic region of δ 62.98–70.97 ppm are attributed to methylene groups linked by ether bonds in the polyethylene glycol chain and methylene carbon atoms linked to ester groups (–CH2–O–).

[0047] The specific NMR data are as follows: 13 C NMR (101 MHz, CDCl3) δ: 169.58, 167.46, 166.12,131.64, 131.36, 130.53, 129.47, 128.44, 128.08, 70.97, 69.56, 69.30, 68.80,64.62, 62.98.

[0048] The high-resolution mass spectrum of compound S-3 is shown below. Figure 12 As shown. The test was performed using electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), operating in ESI positive ion mode (ESI). + The elemental composition search range was limited to C: 0–17, H: 0–21, and O: 0–8. Molecular formula matching and accuracy verification were performed on the masses of individual isotopes. The main characteristic peaks in the spectrum are distributed in… m / z The range is 351.75–354.25, with the quasi-molecular ion peak [M+H]. + The measured value is m / z 353.1238, relatively high abundance (intensity approximately 2.06 × 10⁻⁶). 5 The measured value is 353.1236 (molecular formula C). 17 H 21 The peak is extremely close to the [O8] peak, with a mass deviation of only 0.2 mDa (relative error 0.6 ppm), far below the instrument accuracy threshold of 5 ppm, indicating highly reliable detection results. Combined with elemental composition analysis and unsaturation calculation (DBE = 8), this peak was confirmed as the protonated ion peak [M+H] of the target compound. + This aligns with the characteristic that small molecules readily form protonated ions under ESI positive ion mode. The overall spectrum shows a stable baseline with no obvious impurity peaks, indicating high sample purity and a complete structure.

[0049] comprehensive 1 H NMR, 13 C10 NMR and HRMS analyses confirmed the successful synthesis of the target product S-3. The molecular formula of this compound is C10. 17 H 20 O8 contains phthalate segments, triethylene glycol segments, and acrylate functional groups, and its structure is consistent with the expected design.

[0050] Example 4 Preparation of tetraethylene glycol monoacrylate: Accurately weigh 29.1 g (0.15 mol) of tetraethylene glycol and 11.4 g (0.1125 mol) of triethylamine, place them in a 250 mL round-bottom flask, and dissolve them in 100 mL of anhydrous THF. Fix the reaction flask on a magnetic stirrer and cool it in an ice-water bath. Separately weigh 6.8 g (0.075 mol) of acryloyl chloride, dissolve it in 50 mL of anhydrous THF, and transfer it into a constant-pressure dropping funnel.

[0051] Turn on the magnetic stirrer and slowly add the acryloyl chloride solution dropwise into the round-bottom flask under ice-water bath protection. After the addition is complete, maintain the ice bath conditions and continue stirring overnight. After the reaction is complete, remove the insoluble solids (mainly triethylamine hydrochloride) from the reaction solution by vacuum filtration, and concentrate the filtrate by rotary evaporator to remove the solvent.

[0052] The concentrated residue was redissolved in CH2Cl2, and the organic phase was washed successively with 5% hydrochloric acid aqueous solution, 5% sodium bicarbonate aqueous solution, and saturated brine. The washed organic phase was dried over anhydrous magnesium sulfate for 8 h, the desiccant was removed by filtration, and CH2Cl2 was removed by rotary evaporation of the filtrate. Finally, the crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:20) to separate pale yellow tetraethylene glycol monoacrylate and tetraethylene glycol diacrylate, with yields of 21% and 35%, respectively. The reaction equations are as follows:

[0053] Preparation of tetraethylene glycol monoacrylate (S-4) phthalate In a dry single-necked flask, add 6.0 g (40.5 mmol) phthalic anhydride, 0.5 g (4.05 mmol) 4-dimethylaminopyridine (DMAP), and 20 mg 2,6-di-tert-butyl-p-cresol (BHT). Connect a Schlenk line and perform three purging-argon cycles to remove air from the system. Then, under argon protection, add 10.0 g (40.5 mmol) tetraethylene glycol monoacrylate and 50 mL anhydrous THF. Install a reflux condenser and heat to 90 °C with stirring for 7 h. After the reaction is complete, cool to room temperature under an inert atmosphere.

[0054] The post-processing procedure is as follows: The reaction was quenched by adding 100 mL of 1 mol / L hydrochloric acid aqueous solution to the reaction solution. The mixture was extracted three times with ethyl acetate. The combined organic phases were washed with saturated brine and dried overnight with anhydrous magnesium sulfate. The drying agent was removed by filtration, and the solvent was removed by rotary evaporation of the filtrate. The crude product was purified by silica gel column chromatography to obtain tetraethylene glycol monoacrylate phthalate in 47% yield. The reaction equation for the preparation of S-4 is as follows:

[0055] like Figure 8-9 As shown, where, Figure 8 For compound S-4 1 1H NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The multiplet at δ 3.60–4.45 ppm is attributed to the methylene protons (–CH2–O–) linked by the ether bond in the polyethylene glycol chain and the methylene protons linked to the ester group; the integrated areas of each peak group are consistent with the theoretical number of protons. The characteristic peak in the δ 5.79–6.39 ppm region is the proton on the terminal vinyl group (–CH=CH2) of the acrylate. The multiplet at δ 7.53–7.80 ppm is attributed to the aromatic protons on the benzene ring of the phthalate structure. The residual solvent peak (CDCl3) is located at δ 7.26 ppm.

[0056] The specific NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ: 7.80 (d, J = 7.0 Hz, 1H), 7.67 (d, J = 7.2 Hz, 1H), 7.53 (t, J = 6.6 Hz, 2H), 6.39 (d, J = 17.3 Hz, 1H), 6.09 (dd, J = 16.3, 11.4 Hz, 1H), 5.79 (d, J = 10.4 Hz, 1H), 4.45 (d, J = 4.7 Hz, 2H), 4.31 (s, 2H), 3.89 – 3.60 (m, 12H).

[0057] Figure 9 For compound S-4 13 C10 NMR spectrum (solvent: CDCl3). The assignment analysis of each characteristic peak in the spectrum is as follows: The three characteristic peaks in the high chemical shift region of δ 166.19–169.56 ppm are attributed to carboxyl carbon (–COOH) and ester carbon (–COO–), respectively; the eight peaks in the region of δ 128.16–133.69 ppm are attributed to carbon atoms in the benzene ring skeleton and acrylate double bonds; the eight peaks in the aliphatic region of δ 63.57–71.18 ppm are attributed to methylene groups linked by ether bonds in the polyethylene glycol chain and methylene carbon atoms linked to ester groups (–CH2–O–).

[0058] The specific NMR data are as follows: 13C NMR (101 MHz, CDCl3) δ: 169.56, 167.56, 166.19,133.69, 131.58, 131.13, 130.80, 130.55, 129.44, 128.48, 128.16, 71.18, 70.54,70.27, 69.68, 69.13, 68.74, 64.72, 63.57.

[0059] The high-resolution mass spectrum of compound S-4 is shown below. Figure 13 As shown. The test was performed using electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), operating in ESI positive ion mode (ESI). + The elemental composition search range was limited to C: 0–19, H: 0–25, and O: 0–9. Molecular formula matching and accuracy verification were performed on the masses of individual isotopes. The main characteristic peaks in the spectrum are distributed in the m / z 395–399.5 range, with the quasi-molecular ion peak [M+H] being the most prominent. + The measured value is 397.1494 m / z, indicating a relatively high abundance (intensity approximately 2.97 × 10⁻⁶). 5 The measured value is 397.1499 (molecular formula C). 19 H 25 The peak is extremely close to that of O9, with a mass deviation of only -0.5 mDa (relative error -1.3 ppm), far below the instrument accuracy threshold of 5 ppm, indicating that the detection results are highly reliable. Combined with elemental composition analysis and unsaturation calculation (DBE = 8), this peak was confirmed as the protonated ion peak [M+H] of the target compound. + This aligns with the characteristic that small molecules readily form protonated ions under ESI positive ion mode. The overall spectrum shows a stable baseline with no obvious impurity peaks, indicating high sample purity and a complete structure.

[0060] comprehensive 1 H NMR, 13 C10 NMR and HRMS analyses confirmed the successful synthesis of the target product S-4. The molecular formula of this compound is C10. 19 H 24 O9 contains phthalate segments, tetraethylene glycol segments, and acrylate functional groups, and its structure is consistent with the expected design.

[0061] Example 5 Modification of nanopowders: Preparation of modified nano-zirconia: 200 g of THF and 1.2 g of S-4 modifier (equivalent to 30 wt% ZrO2) were placed in a 500 mL round-bottom flask. After stirring evenly at room temperature, the synthesized nano-ZrO2 (dry weight approximately 4.0 g) was added. The mixture was then stirred and refluxed at 50 °C for 6 h. After complete modification, a small amount of precipitate was removed by centrifugation, yielding a clear and transparent THF solution containing modified nano-ZrO2. The precipitate was collected, dried, and weighed to be 0.2 g. Therefore, the activation rate of the modification was 3.8 g / 4.0 g = 95%. The supernatant was evaporated under reduced pressure using a rotary evaporator to remove the THF solvent, concentrated to 5-10 mL, and then added dropwise to a beaker containing 100 mL of petroleum ether. Modified nano-ZrO2 was redeposited, and the solvent was removed by centrifugation. The modified nano-ZrO2 was then dried to obtain the modified nano-ZrO2.

[0062] Preparation of modified nano-ZrO2 / OPPEA dispersion: Weigh 3 g of dried modified nano-ZrO2 and place it in a 50 mL round-bottom flask. Then, measure 30 mL of THF and pour it into the round-bottom flask. After stirring or ultrasonic assistance, the solution becomes clear and transparent. At this point, the nano-ZrO2 has been redispersed in the THF and is ready for use. Next, weigh 2 g of OPPEA monomer and add it to the THF solution containing the nano-ZrO2. Continue stirring for 5 minutes. Then, remove the solvent using a rotary evaporator and an oil pump under reduced pressure to obtain a transparent composite dispersion.

[0063] Performance evaluation of the prepared S-4 modified nano-zirconia γ-Methacryloxypropyltrimethoxysilane (MPS), a classic silane coupling agent, is widely used for the surface modification of nano-zirconia. The active siloxane groups in its molecular structure can undergo condensation reactions with the hydroxyl groups on the particle surface, forming stable covalent bonds, while the double bond structure endows the surface with organic reactivity. This chemical anchoring effectively achieves hydrophobic modification of the particle surface, significantly improving the dispersibility of nano-zirconia. However, in the actual preparation of high-solids-content dispersions, traditional MPS modifiers exhibit significant limitations: due to the high rigidity of its molecular chains, the modified particle surface organic layer is thin and lacks flexibility, leading to increased internal frictional resistance in the dispersion system. With increasing solids content, the rheological behavior of the system deteriorates significantly, viscosity rises sharply, and fluidity decreases. This not only increases the difficulty of subsequent processing steps such as conveying and coating but also limits its large-scale application in the field of high-performance, easily processed nano-dispersions. Therefore, developing novel modifiers that combine excellent dispersion stability with low-viscosity rheological properties is key to overcoming the bottlenecks in the application of nano-zirconia.

[0064] To address the aforementioned issues, this embodiment introduces a novel modifier, S-4, containing flexible PEG segments, to optimize the rheological properties of the dispersion system. PEG segments possess excellent flexibility and solvation capabilities; after grafting onto the particle surface, they form a thick solvation layer. On one hand, the long-chain structure provides sufficient steric hindrance, inhibiting van der Waals aggregation between particles; on the other hand, the flexible segments effectively reduce intermolecular forces, significantly improving the system's flowability and low shear viscosity. The modification effects of MPS and S-4 on nano-zirconia will be compared, and the viscosity characteristics, flow behavior, and long-term dispersion stability of the modified dispersions will be systematically analyzed. This aims to verify the advantages of S-4 in reducing system viscosity and improving processing performance, elucidating the synergistic modification mechanism of "rigid anchoring + flexible stabilization," and providing theoretical basis and technical support for preparing high-solids-content, high-stability nano-zirconia dispersions.

[0065] (1) Microscopic characterization analysis of dispersion Figure 14 The transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) characterization results of MPS (γ-methacryloyloxypropyltrimethoxysilane) and S-4 modified zirconium oxide nanoparticles are presented. Figure 14 a and Figure 14 b shows the TEM morphology at different magnifications. Figure 14 c is a high-resolution STEM image. TEM observations show that the modified zirconia nanoparticles are uniformly distributed in the field of view, with no obvious hard agglomeration observed. The particle boundaries are clear, with only a small amount of loose soft agglomerates caused by van der Waals forces, and no dense agglomerated structures formed. Combined with 20 nm scale analysis, the primary particle size of individual particles is mainly distributed in the range of 3-5 nm. This indicates that the modifier molecules were successfully grafted onto the particle surface, effectively overcoming the high surface energy of the nanoparticles through steric hindrance, suppressing spontaneous agglomeration between particles, and resulting in a well-dispersed system.

[0066] The dispersion effect was further verified using STEM images. Due to the high atomic number of zirconium, it exhibits high Z-contrast (bright field) in STEM mode, with the bright white spots in the images clearly corresponding to individual nano-zirconia particles. High-resolution STEM images show no obvious overlap or adhesion between particles, with uniform spatial distribution and no large-sized clusters. The combined TEM and STEM characterization results confirm that both MPS and S-4 modifiers can effectively modify the surface of nano-zirconia, significantly improving its micro-dispersion in the dispersion medium, laying a structural foundation for subsequent optimization of macroscopic rheological properties.

[0067] (2) Analysis of the viscosity and rheological properties of the dispersion Compared with traditional MPS modifiers, S-4 modifiers, which introduce flexible PEG fragments, significantly improve the rheological properties of the dispersion system while maintaining excellent dispersion stability. Figure 15 The macroscopic morphology comparison of MPS and S-4 modified nano-zirconia dispersions is shown, among which... Figure 15 a represents the MPS modified system. Figure 15 b represents the S-4 modified system.

[0068] See Figure 15 a. Macroscopic observation shows that the MPS-modified dispersion exhibits an opaque, high-viscosity, gel-like state, lacking free flowability and possessing significant yield stress. It can be grasped with tweezers and maintains a self-supporting blocky morphology. This phenomenon is attributed to the high rigidity of the MPS molecular chains, the thin organic layer on the surface of the modified particles, and the significant van der Waals forces between particles, leading to a sharp increase in internal frictional resistance and the formation of a dense network structure. This results in a significant increase in viscosity and the loss of conventional liquid characteristics. (See also...) Figure 15 b. The S-4 modified dispersion exhibits a uniform and stable liquid state, with excellent free flowability and pourability within a container. This is mainly due to the introduction of flexible PEG long chains in the S-4 molecule: the flexible segments form a thick solvation layer on the particle surface, which not only provides sufficient steric hindrance but also acts as a "molecular lubricant," effectively reducing the interaction forces between particles and the friction within the system, thereby significantly reducing the viscosity of the system while maintaining dispersion stability.

[0069] Quantitative viscometer tests further validated the aforementioned macroscopic observations. Under the same test conditions, the viscosity of the MPS-modified dispersion reached approximately 30,000 cP, while the viscosity of the S-4-modified dispersion decreased to approximately 10,000 cP, a reduction of 66.7%. In summary, both the macroscopic morphology and viscosity test data confirm that the S-4 modifier successfully overcomes the defects of high viscosity and poor processability caused by traditional MPS modifiers. Through a strategy of "rigid anchoring + flexible control," S-4 significantly improves the flowability of the dispersion while ensuring good dispersion of nano-zirconia, providing a superior technical solution for the industrial preparation and application of high-solids-content nano-dispersions.

[0070] This invention addresses the challenge of traditional modifiers in simultaneously achieving dispersion stability and low-viscosity processability. Based on a molecular design strategy of "synergistic use of multifunctional groups," a novel group of carboxylic acid modifiers containing PEG fragments was successfully prepared. By molecularly coupling the carboxylic acid anchoring unit with the PEGylated acrylate structure, a modifier system with triple functions of "anchoring-reaction-dispersion" was constructed. Structural characterization and application performance verification were performed using S-4 as a representative example. The following technical effects were verified in the examples: (1) Directed synthesis of multifunctional modifiers: Using ethylene glycol monoacrylates with different degrees of polymerization as raw materials, four novel modifiers, S-1 to S-4, were successfully synthesized through esterification and ring-opening reactions with phthalic anhydride. This synthetic route, while retaining the reactivity of acrylates and the flexible segments of PEG, introduces carboxyl functional groups, realizing the molecular structure construction of "carboxylic acid anchoring + PEG dispersion + acrylate reaction", laying the material foundation for the development of high-performance modifiers; (2) Confirmation of the "trinity" structure: using nuclear magnetic resonance spectroscopy (NMR) 1 The product was comprehensively characterized by 1H NMR and mass spectrometry (MS). The spectral results confirmed that the characteristic signals of the carboxyl group, acrylate double bond, and PEG segment in the synthesized product were in high agreement with the theoretical design, and there were no obvious impurities. This verifies the successful construction of the integrated molecular structure of "anchoring (carboxyl group)-reaction (double bond)-dispersion (PEG)," ensuring the functional integrity of the modifier at the theoretical design level. (3) Synergistic optimization of dispersion performance and rheological properties: Taking S-4 as an example, the modification effect of the novel modifier on nano-zirconia was investigated. TEM characterization showed that the modified particles were uniformly dispersed and without obvious agglomeration, confirming that the strong anchoring effect of carboxyl groups and the steric hindrance effect of PEG jointly ensured the dispersion stability. Viscosity test showed that, under the same solid content, the viscosity of the S-4 modified dispersion (about 10,000 cP) was significantly lower than that of the traditional MPS system (about 30,000 cP), verifying the lubrication and viscosity reduction function of the flexible segments of PEG, and also reflecting the interfacial compatibility advantage brought by the chemisorption of carboxyl groups, effectively solving the problems of high viscosity and difficult processing of the traditional system.

[0071] In summary, this invention provides a novel multifunctional modifier that combines the activity of acrylates, the flexibility of polyethylene glycol, and the anchoring ability of carboxylic acids. It not only verifies the feasibility of the "multifunctional group synergy" design strategy, but also achieves the organic unity of low viscosity and high stability of nano-zirconia dispersions through the S-4 modifier, providing key material support and technical solutions for the large-scale preparation and application of high-performance nano-slurries.

[0072] Therefore, those skilled in the art will recognize that although embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A novel carboxylic acid-based viscosity-reducing nanopowder modifier, characterized in that, The modifier is one of the following compounds: S-1： ； S-2： ； S-3： ； S-4： 。 2. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claim 1, characterized in that, The preparation method of compound S-1 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of ethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection.

3. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claim 1, characterized in that, The preparation method of compound S-2 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of diethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection.

4. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claim 1, characterized in that, The preparation method of compound S-3 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of triethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection.

5. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claim 1, characterized in that, The preparation method of compound S-4 includes the following steps: Add 30-50 mmol of phthalic anhydride, 3-5 mmol of 4-dimethylaminopyridine, and 10-30 mg of polymerization inhibitor to a reaction vessel; add 30-50 mmol of tetraethylene glycol monoacrylate and 40-60 mL of organic solvent under inert gas protection; heat to 70-90°C and stir under reflux for 6-8 h. The reaction is carried out under inert gas protection.

6. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claims 2-5, characterized in that, It also includes the following post-processing techniques: After the reaction was completed, the reaction solution was cooled to room temperature under an inert atmosphere. Then, 80-120 mL of 1-2 mol / L hydrochloric acid aqueous solution was added to the reaction solution to quench the reaction. The solution was extracted with ethyl acetate 2-3 times. The organic phases were combined and washed with saturated brine. The solution was dried overnight with anhydrous magnesium sulfate, the desiccant was removed by filtration, the solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography to obtain a solid product.

7. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claims 2-5, characterized in that, The organic solvent is selected from anhydrous tetrahydrofuran, 1,4-dioxane, and methyltetrahydrofuran, and the polymerization inhibitor is selected from 2,6-di-tert-butyl-p-cresol, hydroquinone, p-methoxyphenol, and tert-butylcatechol.

8. The preparation method of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claims 2-5, characterized in that, After adding phthalic anhydride, 4-dimethylaminopyridine and polymerization inhibitor to the reaction vessel, connect the Schlenk line, evacuate the reaction system and fill it with argon gas for protection, and repeat the replacement 2 to 4 times to remove the air in the system.

9. The application of a novel carboxylic acid-based viscosity-reducing nanopowder modifier as described in claims 1 to 8 in the modification of nano-zirconia.

10. The application of the novel carboxylic acid-type viscosity-reducing nanopowder modifier as described in claim 9 in the modification of nano-zirconia, characterized in that, Includes the following steps: Measure 20-30 mL of organic solvent and one of the modifiers S-1, S-2, S-3, and S-4 and place it in a reaction vessel. The amount of the modifier added is 20-35 wt% of the mass of nano-zirconia. After stirring and mixing evenly at room temperature, add 0.3-0.6 g of nano-zirconia powder. Heat the reaction system to 45-60℃ and stir at a constant temperature for 5-7 h to achieve surface modification of nano-zirconia.

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