High-temperature-resistant anti-shearing modified hydroxypropyl guar gum as well as preparation method and application of high-temperature-resistant anti-shearing modified hydroxypropyl guar gum

Abstract

The invention discloses high-temperature-resistant and anti-shearing modified hydroxypropyl guar gum as well as a preparation method and application thereof, and belongs to the technical field of modified guar gum. According to the high-temperature-resistant and anti-shearing modified hydroxypropyl guar gum as well as the preparation method and application thereof, isocyanate modified carbon nanotubes and quaternary ammonium salt are introduced into the formula for modification, and a synthesis process with multiple steps is adopted. The preparation method specifically comprises the steps of preparation of aminated carbon nanotubes, modification of isocyanate, modification of hydroxypropyl guar gum and introduction of quaternary ammonium salt. And the final modification step is completed through ultraviolet irradiation, so that the high-temperature resistance and the shear resistance are enhanced. In the preparation process, ultrasonic dispersion, stirring reaction and other operations are adopted, uniform reaction is ensured, and finally the modified hydroxypropyl guar gum with excellent mechanical properties and rheological properties is obtained. The modified material can still keep good anti-shearing performance in a high-temperature environment, and is suitable for industrial application needing high-temperature stability.

Description

Technical Field

[0001] The present invention relates to the technical field of modified guar gum, and more specifically, to a modified hydroxypropyl guar gum with high temperature resistance and shear resistance, a preparation method thereof, and an application thereof. Background Art

[0002] Hydroxypropyl guar gum (HPG), as a natural polymer material, is widely used in industries such as petroleum, chemical engineering, medicine, and coatings, especially as a thickener and stabilizer in oil drilling fluids. Its excellent rheological properties, low toxicity, and good biocompatibility make it of great application value in many fields. However, hydroxypropyl guar gum has poor stability in high-temperature and high-shear environments. Especially in the process of oil exploitation and drilling, it faces the problem of performance decline caused by temperature and pressure changes, which limits its wide use in some high-demand applications.

[0003] To overcome these deficiencies, in recent years, researchers have gradually developed a variety of modification technologies to improve the thermal stability, shear resistance, and mechanical properties of hydroxypropyl guar gum. For example, the introduction of carbon nanotubes (CNT) has been proven to effectively enhance the strength and conductivity of polymer-based materials. By treating carbon nanotubes with amino silane and reacting with polyisocyanate, introducing isocyanate groups can significantly improve the binding force between carbon nanotubes and the polymer matrix, enhancing its dispersibility and interfacial binding property.

[0004] However, there are still some deficiencies in the current modification technologies on the market. For example, most of the existing modification methods rely on high temperature, complex chemical reactions, and long reaction processes, which not only increase the production cost but also limit the flexibility of their practical applications. In addition, many modification technologies have limited surface structure modification of materials, resulting in the mechanical properties and durability of composite materials still not being satisfactory.

[0005] In the future, with the continuous progress of materials science and nanotechnology, it is expected that more innovative modification methods will emerge. For example, using ultraviolet light irradiation and plasma treatment technologies can not only further improve the surface activity of materials but also achieve efficient modification at lower temperatures and in a short time, reducing energy consumption and simplifying the process flow. In addition, by combining other advanced nanomaterials (such as graphene, nanocellulose, etc.) and environmentally friendly solvent systems, it is expected to further improve the comprehensive performance of hydroxypropyl guar gum and meet the increasingly stringent industrial requirements. Summary of the Invention

[0006] The purpose of the present invention is to provide a modified hydroxypropyl guar gum with high temperature resistance and shear resistance, a preparation method thereof, and an application thereof, which have excellent high temperature resistance and shear resistance.

[0007] A heat-resistant and shear-resistant modified hydroxypropyl guar gum, which is prepared from raw materials including the following components: carbon nanotubes, γ-aminopropyltriethoxysilane, diphenylmethane diisocyanate, hydroxypropyl guar gum, 3-chloro-2-hydroxypropyltrimethylammonium chloride, a solvent, and finally a reaction product obtained by ultraviolet irradiation.

[0008] A preparation method of a heat-resistant and shear-resistant modified hydroxypropyl guar gum, comprising the following steps: (1) Preparation of amino-functionalized carbon nanotubes: Add N,N-dimethylformamide solvent and carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add γ-aminopropyltriethoxysilane, ultrasonically disperse them evenly, stir and react at 20-40 °C for 100-180 minutes, wash with deionized water and dry to obtain amino-functionalized carbon nanotubes; (2) Preparation of isocyanate-modified carbon nanotubes: Add N,N-dimethylformamide solvent and amino-functionalized carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add diphenylmethane diisocyanate, ultrasonically disperse them evenly, carry out the reaction, cool to room temperature, and evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add N,N-dimethylformamide solvent and isocyanate-modified carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add hydroxypropyl guar gum, ultrasonically disperse them evenly, carry out the reaction, cool to room temperature, wash with deionized water and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4) Preparation of quaternary ammonium salt-modified hydroxypropyl guar gum: Add deionized water solvent and 3-chloro-2-hydroxypropyltrimethylammonium chloride to a reaction vessel, ultrasonically disperse them evenly, add carbon nanotube-modified hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at room temperature for 20-40 minutes, cool to room temperature, wash with deionized water and dry to obtain quaternary ammonium salt-modified hydroxypropyl guar gum; (5) Preparation of heat-resistant and shear-resistant modified hydroxypropyl guar gum: Expose the quaternary ammonium salt-modified hydroxypropyl guar gum to ultraviolet light to obtain the heat-resistant and shear-resistant modified hydroxypropyl guar gum.

[0009] Preferably, in the step (1), the mass ratio of N,N-dimethylformamide solvent, carbon nanotubes, and γ-aminopropyltriethoxysilane is 50-90:10:0.6-1.

[0010] Preferably, in the step (2), the mass ratio of N,N-dimethylformamide solvent, amino-functionalized carbon nanotubes, and diphenylmethane diisocyanate is 400-600:10:20-40.

[0011] Preferably, the reaction conditions in the step (2) are stirring and reacting at 60-80 °C for 2-4 h.

[0012] Preferably, in the step (3), the mass ratio of the N,N-dimethylformamide solvent, the isocyanate-modified carbon nanotubes, and the hydroxypropyl guar gum is 80-100:0.05-0.15:10.

[0013] Preferably, the reaction conditions in the step (3) are stirring and reacting at 60-80 °C for 4-6 h.

[0014] Preferably, in the step (4), the mass ratio of the deionized water solvent, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and the carbon nanotube-modified hydroxypropyl guar gum is 60-80:0.1-0.2:10.

[0015] Preferably, in the step (5), the ultraviolet light wavelength is 200-400 nm, and the irradiation time is 35-55 minutes.

[0016] Application of a high-temperature resistant and shear-resistant modified hydroxypropyl guar gum. The modified hydroxypropyl guar gum has excellent high-temperature resistance and shear resistance, and can be widely applied to fields such as oil drilling fluids, coatings, adhesives, oilfield scale inhibitors, and other material fields in high-temperature environments. In addition, due to its excellent properties after modification, this material also has good application prospects in fields such as agriculture, medicine, and food. Especially, its stability and versatility under extreme conditions make it have high commercial value.

[0017] Compared with the prior art, the advantages of the present invention are as follows: (1) The hydroxyl groups on the surface of the carbon nanotubes react with γ-aminopropyltriethoxysilane to form a siloxane linkage, introducing amino groups, which further react with diphenylmethane diisocyanate to form isocyanate groups. Taking these isocyanate groups as crosslinking sites, they react with the hydroxyl groups on the hydroxypropyl guar gum to form an amino-isocyanate three-dimensional crosslinked network structure, greatly improving the dispersibility of the carbon nanotubes in the hydroxypropyl guar gum, making the carbon nanotubes uniformly dispersed in the hydroxypropyl guar gum. At the same time, 3-chloro-2-hydroxypropyltrimethylammonium chloride conducts an ion exchange reaction with the surface of the hydroxypropyl guar gum through its chloride ions or chloroalkyl groups, introducing positively charged quaternary ammonium salt groups. Ultraviolet light irradiation can excite chemical bonds within the molecule to generate free radicals or excited state molecules, and these free radicals can react with the material surface to further strengthen surface crosslinking and structural stability.

[0018] (2) Improve thermal stability By introducing amino-functionalized carbon nanotubes and isocyanate groups, hydroxypropyl guar gum with a three-dimensional cross-linked network structure was formed. Meanwhile, ultraviolet light irradiation further enhanced surface cross-linking and structural stability, enhancing the thermal stability of hydroxypropyl guar gum. The performance of the modified hydroxypropyl guar gum was significantly improved under high-temperature conditions, and it could maintain stable physical and chemical properties at high temperatures of 200 °C and above, meeting the usage requirements in high-temperature fields such as oil drilling.

[0019] (3)Enhanced shear resistance Through the composite modification of carbon nanotubes and isocyanate, hydroxypropyl guar gum with a three-dimensional cross-linked network structure was formed. Meanwhile, ultraviolet light irradiation further strengthened surface cross-linking and structural stability. This structure effectively improved the shear strength of the material, enabling the modified hydroxypropyl guar gum to still maintain good adhesiveness and mechanical properties in a strong shear environment. At the same time, the introduced quaternary ammonium salt carried a positive charge, forming a charge-enhanced molecular network, further enhancing the shear resistance and extending its service life in industrial applications.

[0020] (4)Improved dispersibility and interfacial binding During the preparation process, amino-functionalized carbon nanotubes reacted with amino silane through ultrasonic dispersion, further improving the dispersibility of carbon nanotubes and enhancing the interfacial binding force between carbon nanotubes and hydroxypropyl guar gum. This modification method can effectively overcome the agglomeration problem of carbon nanotubes in traditional systems, improving the overall uniformity and mechanical properties of the material.

[0021] (5)Enhanced surface properties and functionality In the quaternary ammonium salt modification step, the introduced quaternary ammonium salt 3-chloro-2-hydroxypropyl trimethyl ammonium chloride not only improved the surface hydrophilicity of the modified hydroxypropyl guar gum but also optimized the surface chemical properties of the modified material. This modification process helps to enhance its dispersibility in aqueous systems, improve its compatibility with other materials, and expand its application scope in different fields.

[0022] (6)Simplified process and improved production efficiency This patent uses ultraviolet light irradiation as the final modification method, which can be rapidly modified at room temperature without high temperature and complex post-treatment. This process simplifies the complex steps and high energy consumption in traditional modification technologies, improves production efficiency, and reduces production costs. At the same time, ultraviolet light irradiation can enhance surface activity in a short time, effectively improving the mechanical properties and chemical stability of the material.

[0023] (7)Environmentally friendly and low energy consumption Surface modification by ultraviolet irradiation can significantly reduce energy consumption and environmental pollution compared with traditional heat treatment or chemical crosslinking methods. This innovative modification method not only conforms to the concept of green environmental protection, but also reduces the generation of chemical waste during the production process, with good environmental benefits. Brief Description of the Drawings

[0024] (1) Figure 1 This is the microscopic structure diagram of the modified hydroxypropyl guar gum of the present invention Reaction Principle

[0025] The reaction equation of the high-temperature resistant and shear-resistant modified hydroxypropyl guar gum of the present invention is as follows: (1)SiOEt3 + CNT-OH → CNT-Si-NH2 + ethanol(EtOH) (2)CNT-Si-NH2 + NCO-R-NCO → CNT-Si-NH-R-NCO + byproducts (3)CNT-Si-NH-R-NCO + HPG-OH → CNT-Si-NH-R-NCO-O-HPG + byproducts (4)CNT-Si-NH-R-NCO-O-HPG + Cl-CH2OH-N(CH3)3 + → CNT-Si-NH-R-NCO-O-HPG-N(CH3)3 + Cl - SiOEt3: γ-aminopropyltriethoxysilane, CNT: carbon nanotube, NCO-R-NCO: diphenylmethane diisocyanate, HPG: hydroxypropyl guar gum, Cl-CH2OH-N(CH3)3 + : 3-chloro-2-hydroxypropyltrimethylammonium chloride. Detailed Description of the Invention

[0026] Example 1 (1) Preparation of amino-functionalized carbon nanotubes: Add 50 g of N,N-dimethylformamide solvent and 10 g of carbon nanotubes to a reaction vessel, ultrasonically disperse evenly, add 0.6 g of γ-aminopropyltriethoxysilane, ultrasonically disperse evenly, stir and react at 20 °C for 100 minutes, wash with deionized water and dry to obtain amino-functionalized carbon nanotubes; (2)Preparation of isocyanate-modified carbon nanotubes: Add 400 g of N,N-dimethylformamide solvent and 10 g of amino-functionalized carbon nanotubes to a reaction vessel, ultrasonically disperse evenly, add 200 g of diphenylmethane diisocyanate, ultrasonically disperse evenly, stir and react at 60 °C for 2 h, cool to room temperature, and evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add 80 g of N,N-dimethylformamide solvent and 0.05 g of isocyanate-modified carbon nanotubes into a reaction vessel, ultrasonically disperse them evenly, add 10 g of hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at 60 °C for 4 h, cool to room temperature, wash with deionized water until clean and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4) Preparation of quaternary ammonium salt-modified hydroxypropyl guar gum: Add 60 g of deionized water solvent and 0.1 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride into a reaction vessel, ultrasonically disperse them evenly, add 10 g of carbon nanotube-modified hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at room temperature for 20 minutes, cool to room temperature, wash with deionized water until clean and dry to obtain quaternary ammonium salt-modified hydroxypropyl guar gum; (5) Preparation of modified hydroxypropyl guar gum: Expose the quaternary ammonium salt-modified hydroxypropyl guar gum to ultraviolet light with a wavelength of 200 nm for 35 minutes to obtain modified hydroxypropyl guar gum.

[0027] Example 2 (1) Preparation of amino-functionalized carbon nanotubes: Add 60 g of N,N-dimethylformamide solvent and 10 g of carbon nanotubes into a reaction vessel, ultrasonically disperse them evenly, add 0.7 g of γ-aminopropyltriethoxysilane, ultrasonically disperse them evenly, stir and react at 25 °C for 120 minutes, wash with deionized water until clean and dry to obtain amino-functionalized carbon nanotubes; (2) Preparation of isocyanate-modified carbon nanotubes: Add 450 g of N,N-dimethylformamide solvent and 10 g of amino-functionalized carbon nanotubes into a reaction vessel, ultrasonically disperse them evenly, add 25 g of diphenylmethane diisocyanate, ultrasonically disperse them evenly, stir and react at 65 °C for 2.5 h, cool to room temperature, and evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add 85 g of N,N-dimethylformamide solvent and 0.075 g of isocyanate-modified carbon nanotubes into a reaction vessel, ultrasonically disperse them evenly, add 10 g of hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at 65 °C for 4.5 h, cool to room temperature, wash with deionized water until clean and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4) Preparation of quaternary ammonium salt-modified hydroxypropyl guar gum: Add 65 g of deionized water solvent and 0.125 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride into a reaction vessel, ultrasonically disperse them evenly, add 10 g of carbon nanotube-modified hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at room temperature for 25 minutes, cool to room temperature, wash with deionized water until clean and dry to obtain quaternary ammonium salt-modified hydroxypropyl guar gum; (5) Preparation of modified hydroxypropyl guar gum: Place the quaternary ammonium salt modified hydroxypropyl guar gum under ultraviolet light irradiation. The wavelength of the ultraviolet light is 250 nm, and the irradiation time is 40 minutes to obtain the modified hydroxypropyl guar gum.

[0028] Example 3 (1) Preparation of amino-functionalized carbon nanotubes: Add 70 g of N,N-dimethylformamide solvent and 10 g of carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 0.8 g of γ-aminopropyltriethoxysilane, ultrasonically disperse them evenly, and stir and react at 30 °C for 140 minutes. Wash them clean with deionized water and dry to obtain amino-functionalized carbon nanotubes; (2) Preparation of isocyanate-modified carbon nanotubes: Add 4500 g of N,N-dimethylformamide solvent and 10 g of amino-functionalized carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 30 g of diphenylmethane diisocyanate, ultrasonically disperse them evenly, and stir and react at 70 °C for 3 h. Cool to room temperature and evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add 90 g of N,N-dimethylformamide solvent and 0.1 g of isocyanate-modified carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 10 g of hydroxypropyl guar gum, ultrasonically disperse them evenly, and stir and react at 70 °C for 5 h. Cool to room temperature, wash them clean with deionized water and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4) Preparation of quaternary ammonium salt-modified hydroxypropyl guar gum: Add 70 g of deionized water solvent and 0.15 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride to a reaction vessel, ultrasonically disperse them evenly, add 10 g of carbon nanotube-modified hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at room temperature for 30 minutes, cool to room temperature, wash them clean with deionized water and dry to obtain quaternary ammonium salt-modified hydroxypropyl guar gum; (5) Preparation of modified hydroxypropyl guar gum: Place the quaternary ammonium salt modified hydroxypropyl guar gum under ultraviolet light irradiation. The wavelength of the ultraviolet light is 300 nm, and the irradiation time is 45 minutes to obtain the modified hydroxypropyl guar gum.

[0029] Example 4 (1) Preparation of amino-functionalized carbon nanotubes: Add 80 g of N,N-dimethylformamide solvent and 10 g of carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 0.9 g of γ-aminopropyltriethoxysilane, ultrasonically disperse them evenly, and stir and react at 35 °C for 160 minutes. Wash them clean with deionized water and dry to obtain amino-functionalized carbon nanotubes; (2) Preparation of isocyanate-modified carbon nanotubes: Add 550 g of N,N-dimethylformamide solvent and 10 g of amino-functionalized carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 35 g of diphenylmethane diisocyanate, ultrasonically disperse them evenly, stir and react at 75 °C for 3.5 h, cool to room temperature, evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add 95 g of N,N-dimethylformamide solvent and 0.125 g of isocyanate-modified carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 10 g of hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at 75 °C for 5.5 h, cool to room temperature, wash with deionized water and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4) Preparation of quaternary ammonium salt-modified hydroxypropyl guar gum: Add 75 g of deionized water solvent and 0.175 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride to a reaction vessel, ultrasonically disperse them evenly, add 10 g of carbon nanotube-modified hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at room temperature for 35 minutes, cool to room temperature, wash with deionized water and dry to obtain quaternary ammonium salt-modified hydroxypropyl guar gum; (5) Preparation of modified hydroxypropyl guar gum: Expose the quaternary ammonium salt-modified hydroxypropyl guar gum to ultraviolet light with a wavelength of 350 nm for 50 minutes to obtain modified hydroxypropyl guar gum.

[0030] Example 5 (1) Preparation of amino-functionalized carbon nanotubes: Add 90 g of N,N-dimethylformamide solvent and 10 g of carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 1 g of γ-aminopropyltriethoxysilane, ultrasonically disperse them evenly, stir and react at 40 °C for 180 minutes, wash with deionized water and dry to obtain amino-functionalized carbon nanotubes; (2) Preparation of isocyanate-modified carbon nanotubes: Add 600 g of N,N-dimethylformamide solvent and 10 g of amino-functionalized carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 40 g of diphenylmethane diisocyanate, ultrasonically disperse them evenly, stir and react at 80 °C for 4 h, cool to room temperature, evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add 100 g of N,N-dimethylformamide solvent and 0.15 g of isocyanate-modified carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add 10 g of hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at 80 °C for 6 h, cool to room temperature, wash with deionized water and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4)Preparation of quaternary ammonium salt modified hydroxypropyl guar gum: Add 80 g of deionized water solvent and 0.2 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride into a reaction vessel, ultrasonically disperse evenly, add 10 g of carbon nanotube modified hydroxypropyl guar gum, ultrasonically disperse evenly, stir and react at room temperature for 40 minutes, cool to room temperature, wash with deionized water until clean and dry to obtain quaternary ammonium salt modified hydroxypropyl guar gum; (5)Preparation of modified hydroxypropyl guar gum: Place the quaternary ammonium salt modified hydroxypropyl guar gum under ultraviolet light irradiation with a wavelength of 400 nm for 55 minutes to obtain modified hydroxypropyl guar gum.

[0031] Performance testing

[0032] Thermal stability testing Take 10 mg of the modified hydroxypropyl guar gum products obtained in Examples 1-5 and perform thermal stability testing on them using a TA Instruments Q50 thermogravimetric analyzer. Place them in a nitrogen atmosphere with a flow rate of 50 mL / min, a preheating time of 30 minutes, and a heating rate of 10 °C / min. Heat from room temperature to 800 °C. The following table shows the test results:

[0033] Shear resistance performance testing Take 10 mg of the modified hydroxypropyl guar gum products obtained in Examples 1-5, dissolve them in deionized water solvent to prepare a 1% concentration solution, and use an Anton Paar MCR 302 / 501 shear rheometer to test their shear resistance performance at a temperature of 25 °C and a shear rate of 0.1 s -1 , and the following table shows the test results:

[0034] Mechanical property testing (tensile testing) Cast the modified hydroxypropyl guar gum obtained in Examples 1-5 into a film with a thickness of about 0.2 - 0.5 mm, and use an Instron 3369 universal material testing machine to test its tensile properties at a tensile rate of 5 mm / min. The following table shows the test results:

Claims

1. A modified hydroxypropyl guar gum with high temperature resistance and shear resistance, characterized in that, The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum is prepared from raw materials including the following components: carbon nanotubes, γ-aminopropyltriethoxysilane, diphenylmethane diisocyanate, hydroxypropyl guar gum, 3-chloro-2-hydroxypropyltrimethyl ammonium chloride, and a solvent, and finally the reaction product obtained by ultraviolet irradiation.

2. A preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance, characterized in that, It includes the following steps: (1) Preparation of amino-functionalized carbon nanotubes: Add N,N-dimethylformamide solvent and carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add γ-aminopropyltriethoxysilane, ultrasonically disperse them evenly, stir and react at 20 - 40 °C for 100 - 180 minutes, wash with deionized water until clean and dry to obtain amino-functionalized carbon nanotubes; (2) Preparation of isocyanate-modified carbon nanotubes: Add N,N-dimethylformamide solvent and amino-functionalized carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add diphenylmethane diisocyanate, ultrasonically disperse them evenly, carry out the reaction, cool to room temperature, and evaporate the solvent to obtain isocyanate-modified carbon nanotubes; (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: Add N,N-dimethylformamide solvent and isocyanate-modified carbon nanotubes to a reaction vessel, ultrasonically disperse them evenly, add hydroxypropyl guar gum, ultrasonically disperse them evenly, carry out the reaction, cool to room temperature, wash with deionized water until clean and dry to obtain carbon nanotube-modified hydroxypropyl guar gum; (4) Preparation of quaternary ammonium salt-modified hydroxypropyl guar gum: Add deionized water solvent and 3-chloro-2-hydroxypropyltrimethyl ammonium chloride to a reaction vessel, ultrasonically disperse them evenly, add carbon nanotube-modified hydroxypropyl guar gum, ultrasonically disperse them evenly, stir and react at room temperature for 20 - 40 minutes, cool to room temperature, wash with deionized water until clean and dry to obtain quaternary ammonium salt-modified hydroxypropyl guar gum; (5) Preparation of high-temperature resistant and shear-resistant modified hydroxypropyl guar gum: Place the quaternary ammonium salt-modified hydroxypropyl guar gum under ultraviolet light irradiation to obtain high-temperature resistant and shear-resistant modified hydroxypropyl guar gum.

3. The preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance according to claim 2, characterized in that: In the step (1), the mass ratio of N,N-dimethylformamide solvent, carbon nanotubes, and γ-aminopropyltriethoxysilane is 50 - 90:10:0.6 - 1.

4. The preparation method of a heat-resistant and shear-resistant modified hydroxypropyl guar gum according to claim 2, characterized in that: In the step (2), the mass ratio of N,N-dimethylformamide solvent, amino-functionalized carbon nanotubes, and diphenylmethane diisocyanate is 400 - 600:10:20 - 40.

5. The preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance according to claim 2, characterized in that: In the step (2), the reaction conditions are stirring and reacting at 60 - 80 °C for 2 - 4 h.

6. The preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance according to claim 2, characterized in that: In the step (3), the mass ratio of N,N-dimethylformamide solvent, isocyanate-modified carbon nanotubes, and hydroxypropyl guar gum is 80 - 100:0.05 - 0.15:

10.

7. The preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance according to claim 2, characterized in that: In the step (3), the reaction conditions are stirring and reacting at 60 - 80 °C for 4 - 6 h.

8. The preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance according to claim 2, characterized in that: In the step (4), the mass ratio of deionized water solvent, 3-chloro-2-hydroxypropyltrimethyl ammonium chloride, and carbon nanotube-modified hydroxypropyl guar gum is 60 - 80:0.1 - 0.2:

10.

9. The preparation method of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance according to claim 2, characterized in that: In the step (5), the ultraviolet light wavelength is 200 - 400 nm, and the irradiation time is 35 - 55 minutes.

10. Application of a modified hydroxypropyl guar gum with high temperature resistance and shear resistance, characterized in that: The modified hydroxypropyl guar gum has excellent high-temperature resistance and shear resistance, and can be widely used in the fields of oil drilling fluids, coatings, adhesives, oilfield scale inhibitors and other materials in high-temperature environments. In addition, due to its excellent properties after modification, this material also has good application prospects in the fields of agriculture, medicine, food, etc. In particular, its stability and versatility under extreme conditions make it have high commercial value.

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