High-temperature-resistant and shear-resistant modified hydroxypropyl guar gum, preparation method and application thereof

Abstract

The application discloses a high-temperature-resistant and shear-resistant modified hydroxypropyl guar gum, a preparation method and application thereof, and belongs to the technical field of modified guar gum. The high-temperature-resistant and shear-resistant modified hydroxypropyl guar gum, the preparation method and application thereof have a formula which is modified by introducing isocyanate modified carbon nanotubes and quaternary ammonium salt and adopts a multi-step synthesis process. Specifically, the formula includes preparation of aminated carbon nanotubes, isocyanate modification, modification of hydroxypropyl guar gum and introduction of quaternary ammonium salt. The last modification step is completed through ultraviolet irradiation, so that the high-temperature-resistant and shear-resistant performance is enhanced. In the preparation process, ultrasonic dispersion and stirring reaction are adopted to ensure that the reaction is uniformly carried out, and finally the modified hydroxypropyl guar gum with excellent mechanical properties and rheological properties is obtained. The modified material can still maintain good shear-resistant performance in a high-temperature environment and is suitable for industrial applications requiring high-temperature stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of modified guar gum, more particularly, to a high-temperature-resistant and shear-resistant modified hydroxypropyl guar gum, a preparation method and applications thereof. BACKGROUND

[0002] Hydroxypropyl guar gum (HPG) is a natural polymer material widely used in petroleum, chemical, pharmaceutical and coating industries, especially as a thickening agent and stabilizer in oil drilling fluids. Its excellent rheological properties, low toxicity and good biocompatibility make it have important application value in many fields. However, the stability of hydroxypropyl guar gum in high temperature and high shear environment is poor, especially in the process of oil exploitation and drilling, the performance degradation problem caused by temperature and pressure changes limits its wide use in some high requirement applications.

[0003] In order to overcome these shortcomings, in recent years, researchers have gradually developed various 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 proved to effectively enhance the strength and conductivity of polymer-based materials. By treating carbon nanotubes with amino silane and reacting with polyisocyanate, isocyanate groups are introduced, which can significantly improve the bonding force between carbon nanotubes and polymer matrix, and enhance its dispersibility and interfacial bonding.

[0004] However, the current market modification technology still has some shortcomings. For example, the existing modification method mostly relies on high temperature, complex chemical reaction and long reaction process, which not only increases the production cost, but also limits the flexibility of its actual application. In addition, many modification technologies have limited modification of the surface structure of the material, resulting in unsatisfactory mechanical properties and durability of the composite material.

[0005] In the future, with the continuous progress of material science and nanotechnology, more innovative modification methods are expected to appear. For example, using ultraviolet light irradiation and plasma treatment technology, not only can further improve the surface activity of the material, but also can realize efficient modification at lower temperature and shorter time, reduce energy consumption, and simplify the process flow. In addition, combined with 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 to meet the increasingly stringent industrial demands. SUMMARY

[0006] The present application aims to provide a high-temperature-resistant and shear-resistant modified hydroxypropyl guar gum, a preparation method and applications thereof, which has excellent high-temperature-resistant and shear-resistant properties.

[0007] A high-temperature resistant and shear-resistant modified hydroxypropyl guar gum is prepared from raw materials comprising the following components: carbon nanotubes, gamma-aminopropyl triethoxysilane, diphenyl methane diisocyanate, hydroxypropyl guar gum, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride, a solvent, and finally a reaction product obtained by irradiation with ultraviolet light.

[0008] A method for preparing a high-temperature resistant and shear-resistant modified hydroxypropyl guar gum, comprising the following steps:

[0009] (1) Preparing amino-functionalized carbon nanotubes: adding N,N-dimethylformamide solvent and carbon nanotubes into a reaction vessel, uniformly ultrasonic dispersing, adding gamma-aminopropyl triethoxysilane, uniformly ultrasonic dispersing, stirring and reacting at 20-40°C for 100-180 minutes, washing with deionized water and drying to obtain amino-functionalized carbon nanotubes;

[0010] (2) Preparing isocyanate-modified carbon nanotubes: adding N,N-dimethylformamide solvent and amino-functionalized carbon nanotubes into a reaction vessel, uniformly ultrasonic dispersing, adding diphenyl methane diisocyanate, uniformly ultrasonic dispersing, reacting, cooling to room temperature, and evaporating the solvent to obtain isocyanate-modified carbon nanotubes;

[0011] (3) Preparing carbon nanotube-modified hydroxypropyl guar gum: adding N,N-dimethylformamide solvent and isocyanate-modified carbon nanotubes into a reaction vessel, uniformly ultrasonic dispersing, adding hydroxypropyl guar gum, uniformly ultrasonic dispersing, reacting, cooling to room temperature, washing with deionized water and drying to obtain carbon nanotube-modified hydroxypropyl guar gum;

[0012] (4) Preparing quaternary ammonium salt-modified modified hydroxypropyl guar gum: adding deionized water solvent and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride into a reaction vessel, uniformly ultrasonic dispersing, adding carbon nanotube-modified hydroxypropyl guar gum, uniformly ultrasonic dispersing, stirring and reacting at room temperature for 20-40 minutes, cooling to room temperature, washing with deionized water and drying to obtain quaternary ammonium salt-modified hydroxypropyl guar gum;

[0013] (5) Preparing high-temperature resistant and shear-resistant modified hydroxypropyl guar gum: irradiating the quaternary ammonium salt-modified hydroxypropyl guar gum with ultraviolet light to obtain high-temperature resistant and shear-resistant modified hydroxypropyl guar gum.

[0014] Preferably, in step (1), the mass ratio of N,N-dimethylformamide solvent, carbon nanotubes, and gamma-aminopropyl triethoxysilane is 50-90:10:0.6-1.

[0015] Preferably, in step (2), the mass ratio of N,N-dimethylformamide solvent, amino-functionalized carbon nanotubes, and diphenyl methane diisocyanate is 400-600:10:20-40.

[0016] Preferably, the reaction conditions in step (2) are stirring at 60-80℃ for 2-4h.

[0017] Preferably, the mass ratio of N,N-dimethylformamide solvent, isocyanate modified carbon nanotube and hydroxypropyl guar gum in step (3) is 80-100:0.05-0.15:10.

[0018] Preferably, the reaction conditions in step (3) are stirring at 60-80℃ for 4-6h.

[0019] Preferably, the mass ratio of deionized water solvent, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and carbon nanotube modified hydroxypropyl guar gum in step (4) is 60-80:0.1-0.2:10.

[0020] Preferably, the wavelength of ultraviolet light in step (5) is 200-400nm, and the irradiation time is 35-55 minutes.

[0021] The application of a high-temperature-resistant and shear-resistant modified hydroxypropyl guar gum, which has excellent high-temperature resistance and shear resistance, can be widely used in petroleum drilling fluid, paint, adhesive, oil field scale inhibitor and other material fields in high-temperature environment. In addition, due to its excellent performance after modification, the material also has good application prospect in the fields of agriculture, medicine and food, especially its stability and multifunctionality under extreme conditions make it have high commercial value.

[0022] Compared with the prior art, the application has the following advantages:

[0023] (1) The hydroxyl groups on the surface of the carbon nanotube react with gamma-aminopropyl triethoxysilane to form siloxane linkage, introduce amino groups, and further react with diphenyl methane diisocyanate to form isocyanate groups, introduce isocyanate groups, and react with the hydroxyl groups on the hydroxypropyl guar gum as crosslinking sites to form an amino-isocyanate three-dimensional crosslinked network structure, which greatly improves the dispersibility of the carbon nanotube in the hydroxypropyl guar gum, so that the carbon nanotube is uniformly dispersed in the hydroxypropyl guar gum, and the quaternary ammonium salt 3-chloro-2-hydroxypropyl trimethyl ammonium chloride is introduced by ion exchange reaction with the surface of the hydroxypropyl guar gum through its chloride ion or chloroalkyl group. The positively charged quaternary ammonium salt group. Ultraviolet irradiation can excite the intramolecular chemical bonds to produce free radicals or excited state molecules, and these free radicals can react with the material surface to further strengthen the surface crosslinking and structural stability.

[0024] (2) Improve thermal stability

[0025] By introducing amino-functionalized carbon nanotubes and isocyanate groups, a hydroxypropyl guar gum with a three-dimensional cross-linked network structure is formed. Simultaneously, UV irradiation further strengthens the surface cross-linking and structural stability, enhancing the thermal stability of the hydroxypropyl guar gum. The modified hydroxypropyl guar gum significantly improves its performance in high-temperature environments, maintaining stable physical and chemical properties at temperatures above 200°C, meeting the requirements for use in high-temperature fields such as oil drilling.

[0026] (3) Enhanced shear resistance

[0027] By using carbon nanotubes and isocyanate for composite modification, a hydroxypropyl guar gum with a three-dimensional cross-linked network structure is formed. Simultaneously, UV irradiation further strengthens the surface cross-linking and structural stability. This structure effectively improves the shear strength of the material, enabling the modified hydroxypropyl guar gum to maintain good adhesion and mechanical properties in a strong shear environment. The introduced quaternary ammonium salt has a positive charge, forming a charge-enhanced molecular network, further enhancing the shear resistance and prolonging the service life in industrial applications.

[0028] (4) Improved dispersibility and interfacial bonding

[0029] During preparation, amino-functionalized carbon nanotubes are dispersed by ultrasonic and react with amino silane, further improving the dispersibility of carbon nanotubes and enhancing the interfacial bonding 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.

[0030] (5) Improved surface properties and functionality

[0031] During the quaternary ammonium salt modification step, the introduced 3-chloro-2-hydroxypropyl trimethylammonium chloride not only improves the surface hydrophilicity of the modified hydroxypropyl guar gum, but also optimizes 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 range in different fields.

[0032] (6) Simplified process and improved production efficiency

[0033] This patent uses UV irradiation as the final modification method, allowing for rapid modification at room temperature without the need for high temperatures and complex post-processing. This process simplifies the complex steps and high energy consumption of traditional modification techniques, improving production efficiency and reducing production costs. At the same time, UV irradiation can complete the surface activity enhancement in a short time, effectively improving the mechanical properties and chemical stability of the material.

[0034] (7) Environmentally friendly and low energy consumption

[0035] Compared with the traditional heat treatment or chemical crosslinking method, the surface modification by ultraviolet irradiation can significantly reduce energy consumption and environmental pollution. This innovative modification method not only conforms to the green environmental protection concept, but also reduces the generation of chemical waste in the production process, and has good environmental protection benefits. BRIEF DESCRIPTION OF DRAWINGS

[0036] (1) Figure 1 Microstructure diagram of the modified hydroxypropyl guar gum of the present application

[0037] Reaction principle

[0038] The reaction equation of the modified hydroxypropyl guar gum with high temperature resistance and shear resistance of the present application is as follows:

[0039] (1) SiOEt3+CNT-OH→CNT-Si-NH2+ethanol (EtOH)

[0040] (2) CNT-Si-NH2+NCO-R-NCO→CNT-Si-NH-R-NCO+byproducts

[0041] (3) CNT-Si-NH-R-NCO+HPG-OH→CNT-Si-NH-R-NCO-O-HPG+byproducts

[0042] (4) CNT-Si-NH-R-NCO-O-HPG+Cl-CH2OH-N(CH3)3 + →CNT-Si-NH-R-NCO-O-HPG-N(CH3)3 + Cl -

[0043] SiOEt3: γ-aminopropyl triethoxysilane, CNT: carbon nanotube, NCO-R-NCO: diphenyl methane diisocyanate, HPG: hydroxypropyl guar gum, Cl-CH2OH-N(CH3)3 + : 3-chloro-2-hydroxypropyl trimethylammonium chloride. DETAILED DESCRIPTION

[0044] Example 1 (1) Preparation of aminated carbon nanotubes: 50g of N,N-dimethylformamide solvent, 10g of carbon nanotubes, ultrasonic dispersion, 0.6g of γ-aminopropyl triethoxysilane, ultrasonic dispersion, stirring at 20℃ for 100 minutes, washing with deionized water and drying to obtain aminated carbon nanotubes;

[0045] (2) Preparation of isocyanate modified carbon nanotubes: 400 g of N,N-dimethylformamide solvent, 10 g of aminated carbon nanotubes were added to the reaction vessel, ultrasonic dispersion was uniform, 200 g of diphenyl methane diisocyanate was added, ultrasonic dispersion was uniform, stirring was carried out at 60°C for 2h, cooling to room temperature, evaporation of solvent, isocyanate modified carbon nanotubes were obtained;

[0046] (3) Preparation of carbon nanotube modified hydroxypropyl guar gum: 80 g of N,N-dimethylformamide solvent, 0.05 g of isocyanate modified carbon nanotubes were added to the reaction vessel, ultrasonic dispersion was uniform, 10 g of hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, stirring was carried out at 60°C for 4h, cooling to room temperature, washing with deionized water and drying to obtain carbon nanotube modified hydroxypropyl guar gum;

[0047] (4) Preparation of quaternary ammonium salt modified modified hydroxypropyl guar gum: 60 g of deionized water solvent, 0.1 g of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride was added to the reaction vessel, ultrasonic dispersion was uniform, 10 g of carbon nanotube modified hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, stirring was carried out at room temperature for 20 minutes, cooling to room temperature, washing with deionized water and drying to obtain quaternary ammonium salt modified hydroxypropyl guar gum;

[0048] (5) Preparation of modified hydroxypropyl guar gum: the quaternary ammonium salt modified hydroxypropyl guar gum was irradiated under ultraviolet light, the wavelength of the ultraviolet light was 200 nm, and the irradiation time was 35 minutes to obtain the modified hydroxypropyl guar gum.

[0049] Example 2 (1) Preparation of aminated carbon nanotubes: 60 g of N,N-dimethylformamide solvent, 10 g of carbon nanotubes were added to the reaction vessel, ultrasonic dispersion was uniform, 0.7 g of γ-aminopropyl triethoxysilane was added, ultrasonic dispersion was uniform, stirring was carried out at 25°C for 120 minutes, washing with deionized water and drying to obtain aminated carbon nanotubes;

[0050] (2) Preparation of isocyanate modified carbon nanotubes: 450 g of N,N-dimethylformamide solvent, 10 g of aminated carbon nanotubes were added to the reaction vessel, ultrasonic dispersion was uniform, 25 g of diphenyl methane diisocyanate was added, ultrasonic dispersion was uniform, stirring was carried out at 65°C for 2.5h, cooling to room temperature, evaporation of solvent, isocyanate modified carbon nanotubes were obtained;

[0051] (3) Preparation of carbon nanotube modified hydroxypropyl guar gum: 85 g of N,N-dimethylformamide solvent, 0.075 g of isocyanate modified carbon nanotubes were added to the reaction vessel, ultrasonic dispersion was uniform, 10 g of hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, stirring was carried out at 65°C for 4.5h, cooling to room temperature, washing with deionized water and drying to obtain carbon nanotube modified hydroxypropyl guar gum;

[0052] (4) Preparation of quaternary ammonium salt modified modified hydroxypropyl guar gum: 65 g of deionized water solvent, 0.125 g of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride was added to the reaction container, ultrasonic dispersion was uniform, 10 g of carbon nanotube modified hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, room temperature stirring reaction was 25 minutes, cooling to room temperature, washed with deionized water and dried to obtain quaternary ammonium salt modified hydroxypropyl guar gum;

[0053] (5) Preparation of modified hydroxypropyl guar gum: the quaternary ammonium salt modified hydroxypropyl guar gum was irradiated under ultraviolet light, the wavelength of ultraviolet light was 250 nm, and the irradiation time was 40 minutes to obtain the modified hydroxypropyl guar gum.

[0054] (1) Preparation of aminated carbon nanotubes: 70 g of N,N-dimethylformamide solvent, 10 g of carbon nanotubes were added to the reaction container, ultrasonic dispersion was uniform, 0.8 g of γ-aminopropyl triethoxysilane was added, ultrasonic dispersion was uniform, stirring reaction was carried out at 30°C for 140 minutes, and then deionized water was used for washing and drying to obtain aminated carbon nanotubes;

[0055] (2) Preparation of isocyanate modified carbon nanotubes: 4500 g of N,N-dimethylformamide solvent, 10 g of aminated carbon nanotubes were added to the reaction container, ultrasonic dispersion was uniform, 30 g of diphenylmethane diisocyanate was added, ultrasonic dispersion was uniform, stirring reaction was carried out at 70°C for 3 h, and then the solvent was evaporated to obtain isocyanate modified carbon nanotubes;

[0056] (3) Preparation of carbon nanotube modified hydroxypropyl guar gum: 90 g of N,N-dimethylformamide solvent, 0.1 g of isocyanate modified carbon nanotubes were added to the reaction container, ultrasonic dispersion was uniform, 10 g of hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, stirring reaction was carried out at 70°C for 5 h, and then deionized water was used for washing and drying to obtain carbon nanotube modified hydroxypropyl guar gum;

[0057] (4) Preparation of quaternary ammonium salt modified modified hydroxypropyl guar gum: 70 g of deionized water solvent, 0.15 g of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride was added to the reaction container, ultrasonic dispersion was uniform, 10 g of carbon nanotube modified hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, room temperature stirring reaction was 30 minutes, cooling to room temperature, washed with deionized water and dried to obtain quaternary ammonium salt modified hydroxypropyl guar gum;

[0058] (5) Preparation of modified hydroxypropyl guar gum: the quaternary ammonium salt modified hydroxypropyl guar gum was irradiated under ultraviolet light, the wavelength of ultraviolet light was 300 nm, and the irradiation time was 45 minutes to obtain the modified hydroxypropyl guar gum.

[0059] Example 4 (1) Preparation of amino-functionalized carbon nanotubes: 80 g of N,N-dimethylformamide solvent, 10 g of carbon nanotubes were added into a reaction vessel, and ultrasonic dispersion was performed until they were uniformly dispersed. Then, 0.9 g of γ-aminopropyl triethoxysilane was added, and ultrasonic dispersion was performed until they were uniformly dispersed. The reaction was performed at 35°C for 160 minutes with stirring. After that, deionized water was added to wash the reaction product, and then the reaction product was dried to obtain amino-functionalized carbon nanotubes.

[0060] (2) Preparation of isocyanate-modified carbon nanotubes: 550 g of N,N-dimethylformamide solvent, 10 g of the amino-functionalized carbon nanotubes were added into a reaction vessel, and ultrasonic dispersion was performed until they were uniformly dispersed. Then, 35 g of diphenylmethane diisocyanate was added, and ultrasonic dispersion was performed until they were uniformly dispersed. The reaction was performed at 75°C for 3.5 hours with stirring. After that, the reaction product was cooled to room temperature, and then the solvent was evaporated to obtain isocyanate-modified carbon nanotubes.

[0061] (3) Preparation of carbon nanotube-modified hydroxypropyl guar gum: 95 g of N,N-dimethylformamide solvent, 0.125 g of the isocyanate-modified carbon nanotubes were added into a reaction vessel, and ultrasonic dispersion was performed until they were uniformly dispersed. Then, 10 g of hydroxypropyl guar gum was added, and ultrasonic dispersion was performed until they were uniformly dispersed. The reaction was performed at 75°C for 5.5 hours with stirring. After that, the reaction product was cooled to room temperature, deionized water was added to wash the reaction product, and then the reaction product was dried to obtain carbon nanotube-modified hydroxypropyl guar gum.

[0062] (4) Preparation of quaternary ammonium salt-modified carbon nanotube-modified hydroxypropyl guar gum: 75 g of deionized water solvent, 0.175 g of 3-chloro-2-hydroxypropyl trimethylammonium chloride were added into a reaction vessel, and ultrasonic dispersion was performed until they were uniformly dispersed. Then, 10 g of the carbon nanotube-modified hydroxypropyl guar gum was added, and ultrasonic dispersion was performed until they were uniformly dispersed. The reaction was performed at room temperature for 35 minutes with stirring. After that, the reaction product was cooled to room temperature, deionized water was added to wash the reaction product, and then the reaction product was dried to obtain quaternary ammonium salt-modified carbon nanotube-modified hydroxypropyl guar gum.

[0063] (5) Preparation of modified hydroxypropyl guar gum: The quaternary ammonium salt-modified carbon nanotube-modified hydroxypropyl guar gum was irradiated with ultraviolet light having a wavelength of 350 nm for 50 minutes to obtain modified hydroxypropyl guar gum.

[0064] Example 5 (1) Preparation of amino-functionalized carbon nanotubes: 90 g of N,N-dimethylformamide solvent, 10 g of carbon nanotubes were added into a reaction vessel, and ultrasonic dispersion was performed until they were uniformly dispersed. Then, 1 g of γ-aminopropyl triethoxysilane was added, and ultrasonic dispersion was performed until they were uniformly dispersed. The reaction was performed at 40°C for 180 minutes with stirring. After that, deionized water was added to wash the reaction product, and then the reaction product was dried to obtain amino-functionalized carbon nanotubes.

[0065] (2) Preparation of isocyanate-modified carbon nanotubes: 600 g of N,N-dimethylformamide solvent, 10 g of the amino-functionalized carbon nanotubes were added into a reaction vessel, and ultrasonic dispersion was performed until they were uniformly dispersed. Then, 40 g of diphenylmethane diisocyanate was added, and ultrasonic dispersion was performed until they were uniformly dispersed. The reaction was performed at 80°C for 4 hours with stirring. After that, the reaction product was cooled to room temperature, and then the solvent was evaporated to obtain isocyanate-modified carbon nanotubes.

[0066] (3) Preparation of carbon nanotube modified hydroxypropyl guar gum: 100 g of N,N-dimethylformamide solvent, 0.15 g of isocyanate modified carbon nanotube, were added to a reaction vessel, ultrasonic dispersion was uniform, 10 g of hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, stirring reaction was carried out at 80°C for 6 h, cooling to room temperature, deionized water was used for washing and drying, and carbon nanotube modified hydroxypropyl guar gum was obtained;

[0067] (4) Preparation of quaternary ammonium salt modified modified hydroxypropyl guar gum: 80 g of deionized water solvent, 0.2 g of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride, were added to a reaction vessel, ultrasonic dispersion was uniform, 10 g of carbon nanotube modified hydroxypropyl guar gum was added, ultrasonic dispersion was uniform, stirring reaction was carried out at room temperature for 40 minutes, cooling to room temperature, deionized water was used for washing and drying, and quaternary ammonium salt modified hydroxypropyl guar gum was obtained;

[0068] (5) Preparation of modified hydroxypropyl guar gum: the quaternary ammonium salt modified hydroxypropyl guar gum was irradiated under ultraviolet light, the wavelength of the ultraviolet light was 400 nm, and the irradiation time was 55 minutes, and the modified hydroxypropyl guar gum was obtained.

[0069] Performance test

[0070] Thermal stability test

[0071] 10 mg of the modified hydroxypropyl guar gum product obtained in Examples 1-5 was taken and subjected to a thermal stability test using a TA Instruments Q50 thermal gravimetric analyzer, in a nitrogen atmosphere, with a flow rate of 50 mL / min, a preheating time of 30 minutes, a heating rate of 10°C / min, and a temperature rise from room temperature to 800°C. The following table shows the test results:

[0072]

[0073] Shear resistance test

[0074] 10 mg of the modified hydroxypropyl guar gum product obtained in Examples 1-5 was dissolved in a deionized water solvent to prepare a 1% concentration solution, and its shear resistance was tested using an Anton Paar MCR 302 / 501 shear rheometer at a temperature of 25°C and a shear rate of 0.1 s -1 . The following table shows the test results:

[0075]

[0076] Mechanical property test (tensile test)

[0077] The modified hydroxypropyl guar gums obtained in Examples 1-5 were cast into thin films, about 0.2-0.5 mm thick, and tested for tensile properties using an Instron 3369 universal testing machine at a rate of 5 mm / min. The following table shows the results of the tests:

[0078]

Claims

1. A high-temperature resistant and shear-resistant modified hydroxypropyl guar gum, characterized in that, The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum is prepared from raw materials comprising the following components: carbon nanotubes, γ-aminopropyltriethoxysilane, diphenylmethane diisocyanate, hydroxypropyl guar gum, 3-chloro-2-hydroxypropyltrimethylammonium chloride, solvent, and finally the reaction product obtained by ultraviolet light irradiation. The preparation method of the high-temperature resistant and shear-resistant modified hydroxypropyl guar gum includes the following steps: (1) Preparation of aminated carbon nanotubes: N,N-dimethylformamide solvent and carbon nanotubes are added to the reaction vessel and ultrasonically dispersed evenly. γ-aminopropyltriethoxysilane is added and ultrasonically dispersed evenly. The reaction is stirred at 20-40℃ for 100-180 minutes. The mixture is washed with deionized water and dried to obtain aminated carbon nanotubes. (2) Preparation of isocyanate modified carbon nanotubes: N,N-dimethylformamide solvent and aminated carbon nanotubes were added to the reaction vessel and ultrasonically dispersed evenly. Diphenylmethane diisocyanate was added and ultrasonically dispersed evenly. The reaction was carried out, cooled to room temperature, and the solvent was evaporated to obtain isocyanate modified carbon nanotubes. (3) Preparation of carbon nanotube modified hydroxypropyl guar gum: N,N-dimethylformamide solvent and isocyanate modified carbon nanotubes were added to the reaction vessel and ultrasonically dispersed evenly. Hydroxypropyl guar gum was added and ultrasonically dispersed evenly. The reaction was carried out, cooled to room temperature, washed with deionized water and dried 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 the reaction vessel, disperse evenly by ultrasonication, add carbon nanotube modified hydroxypropyl guar gum, disperse evenly by ultrasonication, stir and react at room temperature for 20-40 minutes, cool to room temperature, wash clean with deionized water and dry to obtain quaternary ammonium salt modified hydroxypropyl guar gum; (5) Preparation of high temperature resistant and shear resistant modified hydroxypropyl guar gum: quaternary ammonium salt modified hydroxypropyl guar gum was irradiated under ultraviolet light to obtain high temperature resistant and shear resistant modified hydroxypropyl guar gum.

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

3. The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum according to claim 1, characterized in that: In step (2), the mass ratio of N,N-dimethylformamide solvent, aminated carbon nanotubes, and diphenylmethane diisocyanate is 400-600:10:20-40.

4. The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum according to claim 1, characterized in that: The reaction conditions in step (2) are 60-80℃ and stirring for 2-4 hours.

5. The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum according to claim 1, characterized in that: In 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.

6. The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum according to claim 1, characterized in that: The reaction conditions in step (3) are 60-80℃ and stirring for 4-6 hours.

7. The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum according to claim 1, characterized in that: In step (4), the mass ratio of deionized water solvent, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and carbon nanotube-modified hydroxypropyl guar gum is 60-80:0.1-0.2:

10.

8. The high-temperature resistant and shear-resistant modified hydroxypropyl guar gum according to claim 1, characterized in that: In step (5), the ultraviolet light wavelength is 200-400nm and the irradiation time is 35-55 minutes.

9. The application of a high-temperature resistant and shear-resistant modified hydroxypropyl guar gum, relating to the high-temperature resistant and shear-resistant modified hydroxypropyl guar gum as described in any one of claims 1-8, characterized in that: The modified hydroxypropyl guar gum possesses excellent high-temperature resistance and shear resistance, and can be widely used in oil drilling fluids, coatings, adhesives, and oilfield scale inhibitors.

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