Modified glass fiber and asphalt composite protective pad for submarine pipeline and preparation method of modified glass fiber and asphalt composite protective pad

Abstract

The invention belongs to the technical field of glass fiber composite materials, and particularly relates to a modified glass fiber asphalt composite protective pad for a submarine pipeline and a preparation method. The protective pad comprises an asphalt base layer, a CNTs modified glass fiber reinforcement layer and a nano-montmorillonite modified asphalt outer surface layer, the thickness of the asphalt base layer is 20-30 mm; the thickness of the CNTs modified glass fiber reinforcement layer is 10 to 15 mm; the spraying thickness of the nano-montmorillonite modified asphalt is 2-9 mm, the CNTs modified glass fiber reinforcement layer constructs a nanoscale reinforcement phase on the fiber surface, and the MMT modified asphalt outer surface layer remarkably inhibits seawater chloride ion permeation and delays asphalt aging through layered structure physical barrier and ion exchange effects. The protective pad prepared by the invention meets the requirements of flexibility and rigidity, not only can adapt to irregular surface laying of the submarine pipeline, but also can directionally enhance the tensile strength through a fiber laying design (unidirectional / orthogonal), and is simple in preparation method and suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of glass fiber composite materials, and particularly relates to a modified glass fiber asphalt composite protective pad for a submarine pipeline and a preparation method. BACKGROUND

[0002] As a key infrastructure for marine oil and gas transportation, submarine pipelines inevitably face the threat of third-party impact, mainly including impact load caused by fishing drag, ship anchoring and exploration operation, which can reach 80-150 kN, enough to cause pipe body indentation, coating damage and even penetrating cracks, and further cause oil and gas leakage and major environmental disasters.

[0003] The existing protection system mainly adopts passive protection methods such as traditional riprap covering or cement block, but these methods have significant technical limitations. The riprap protection not only has high construction cost and long construction period, but also causes serious interference to channel dredging operation due to its loose accumulation structure; although the cement block is relatively simple to install, due to the over-strong rigidity of the material itself, the lack of necessary flexibility and elastic deformation capacity, it cannot effectively absorb and disperse impact energy when subjected to external impact, but may cause local deformation or even damage of the pipeline due to stress concentration, forming a "protection-damage" contradiction effect.

[0004] In addition, these traditional protection systems also have the problem of insufficient durability in long-term seawater corrosion environment, and are difficult to meet the strict requirements of modern submarine pipelines on protection performance. Therefore, developing new protection materials and structures with high energy absorption efficiency has become a key scientific problem to be solved to ensure the safe operation of submarine pipelines. SUMMARY

[0005] The technical problem to be solved by the application is to provide a modified glass fiber asphalt composite protective pad for a submarine pipeline and a preparation method. The protective pad prepared by the application has a multi-layer composite system (asphalt base layer + fiber reinforced layer + functional outer layer) that meets the requirements of flexibility and rigidity, can be laid on the irregular surface of the submarine pipeline, and can be designed (unidirectional / orthogonal) to enhance the tensile strength through the fiber layer, and the preparation method is simple.

[0006] The technical scheme adopted is as follows:

[0007] A preparation method of a modified glass fiber asphalt composite protective pad for a submarine pipeline, comprising the following steps:

[0008] (1) Preparation of thermoplastic elastomer modified asphalt base layer: after the base asphalt is heated, thermoplastic elastomer (SBS) is added, and the mixture is sheared by a high-speed shearing emulsifier until the thermoplastic elastomer is completely dissolved, forming a uniform colloid. A plasticizing agent is added, and the plasticizing agent is fully penetrated into the asphalt molecular chain by low-speed stirring to form a thermoplastic elastomer modified asphalt. The mixture is transferred into a development tank for low-speed stirring and maturation;

[0009] (2) Preparation of CNTs modified glass fiber reinforced layer: the glass fiber is pretreated, and the pretreated glass fiber is immersed in a CNTs-COCl DMF solution;

[0010] (3) Preparation of nano-montmorillonite (MMT) modified asphalt outer layer: the base asphalt is heated, and nano-montmorillonite is added. The mixture is mixed by high-speed shearing and ultrasonic treatment;

[0011] (4) The CNTs (carbon nanotubes) modified glass fiber is arranged in a unidirectional or orthogonal layering manner on the asphalt base layer, impregnated with the thermoplastic elastomer modified asphalt to form a reinforced layer, and the asphalt base layer and the reinforced layer are combined by hot pressing. Finally, the nano-montmorillonite modified asphalt is coated on the surface by thermal spraying to form a toughened and reinforced glass fiber asphalt composite flexible protective pad.

[0012] Preferably, in step (1), the asphalt base layer comprises base asphalt, thermoplastic elastomer and plasticizing agent, and the mass ratio of base asphalt to thermoplastic elastomer is 20:1; the plasticizing agent is dioctyl phthalate (DOPx), and the mass of the plasticizing agent is 2% of the mass of the asphalt base layer.

[0013] Preferably, in step (1), the base asphalt is heated to 160°C for preheating; after the plasticizing agent is added, it is stirred for 10-20 min to fully penetrate the asphalt molecular chain; the mixture is transferred into a development tank, the temperature of the fermentation tank is 165-180°C, and the stirring maturation time is 2-4 h.

[0014] Preferably, in step (2), the pretreatment of the glass fiber is a surface cleaning and activation step, the glass fiber is immersed in a 10% acid solution, treated at 50-60°C for 20 min, acid etched, then washed with deionized water to neutral, and dried at 100-120°C for 40-60 min; the acid is any one of hydrochloric acid, sulfuric acid and nitric acid.

[0015] Preferably, in the step (2), the preparation of the CNTs-COCl DMF (N,N-dimethylformamide) solution includes: taking 100 parts of dry carboxylated CNTs and 15-30 parts (preferably 20 parts) of SOCl2, refluxing at 70°C oil bath for 16-24 hours, and reacting the carboxylated carbon nanotubes (CNTs-COOH) with thionyl chloride (SOCl2) to obtain CNTs-COCl black powder.

[0016] The CNTs-COCl powder is added into DMF and ultrasonically treated under ice bath condition for 30 minutes, and then large particles not dispersed are removed by centrifugation for 5 minutes to obtain the CNTs-COCl DMF solution.

[0017] Preferably, the concentration of the CNTs-COCl DMF solution is 0.1-0.3 mg / ml.

[0018] Preferably, the CNTs-COCl DMF solution is immersed at 80°C for 3-4 hours, washed with ethanol for 3 times to remove the physically adsorbed CNTs, and then vacuum dried at 80°C for 1.5-2.5 hours (preferably 2 hours) to obtain the CNTs modified glass fiber.

[0019] Preferably, in the step (3), the matrix asphalt is heated to 160°C; the nano-montmorillonite needs to be modified by organic modification, washed, and vacuum dried, and then ground through a 400-mesh sieve to obtain organic nano-montmorillonite, and the mass ratio of the matrix asphalt to the organic nano-montmorillonite is 100:3; wherein, the organic modification process is: dispersing the nano-montmorillonite in an ethanol solvent, adding a silane coupling agent KH-550, adjusting the pH to be acidic (about 4.5) to promote hydrolysis, making the silane coupling agent KH-550 condense with the silicon hydroxyl groups on the surface of the nano-montmorillonite to form stable Si—O—Si bonds, and thus introducing active groups such as amino groups and epoxy groups to obtain the surface-organic functionalized nano-montmorillonite.

[0020] Preferably, in the step (4), the grafting amount of the CNTs modified glass fiber is 0.8-1.2 wt%, and the thermoplastic elastomer modified asphalt is impregnated at 160°C and under a pressure of 1.0 MPa to form a reinforcing layer.

[0021] The protective pad prepared by the method of the present application comprises a bitumen base layer, a CNTs modified glass fiber reinforcing layer, and a nano-montmorillonite modified asphalt outer layer; the thickness of the bitumen base layer is 20-30 mm; the thickness of the CNTs modified glass fiber reinforcing layer is 10-15 mm; and the spraying thickness of the nano-montmorillonite modified asphalt is 2-9 mm.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] (1) The application has excellent impact resistance: carbon nanotube (CNT) modified glass fiber reinforced layer significantly improves the interfacial bonding strength and energy absorption capacity of the fiber by building a nanoscale reinforcing phase on the fiber surface, while retaining the fiber body strength, so that the protective pad can effectively resist mechanical impact, rock impact and other external force damage during the construction or operation of the submarine pipeline.

[0024] (2) The application has long-term corrosion resistance: the nano-montmorillonite (MMT) modified asphalt outer layer significantly inhibits the penetration of seawater chloride ions (Cl-) through the layered structure physical barrier and ion exchange, delays the aging of asphalt, and prolongs the service life of the protective pad in harsh marine environment.

[0025] (3) The application has a flexible composite structure design: the multi-layer composite system (asphalt base layer + fiber reinforced layer + functional outer layer) meets the needs of flexibility and rigidity, which can adapt to the irregular surface of the submarine pipeline and can enhance the tensile strength through the design of fiber layer (unidirectional / orthogonal).

[0026] (4) Process controllability and scalability: hot pressing and thermal spraying process is used to ensure the close interface between the layers, and the preparation parameters (temperature, pressure, thickness) can be adjusted, which is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the cross-sectional structure of the modified glass fiber asphalt composite protective pad for submarine pipelines;

[0028] In the figure, 1 is the asphalt base layer; 2 is the CNTs modified glass fiber reinforced layer; and 3 is the nano-montmorillonite modified asphalt outer layer.

[0029] Figure 2 is a schematic diagram of the modified glass fiber laying method, wherein (a) is a longitudinal arrangement diagram, (b) is a transverse arrangement diagram, and (c) is an orthogonal arrangement diagram.

[0030] Figure 3 is a process flow of the preparation method of the modified glass fiber asphalt composite protective pad for submarine pipelines according to the application;

[0031] Figure 4 is the stress-strain curve of the flexible protective pad sample before and after modification. DETAILED DESCRIPTION

[0032] The drawings are only used for illustrative purposes; the application will be further described below in conjunction with the examples, but should not be understood as limiting the above-mentioned subject matter of the application only to the following examples. According to ordinary technical knowledge and conventional means in the art, various substitutions and modifications can be made without departing from the technical idea of the application, which should be included in the protection scope of the application.

[0033] The present application provides a modified glass fiber asphalt composite protective pad for submarine pipeline, as shown in the figure, comprising an asphalt base layer 1, a CNTs modified glass fiber reinforced layer 2, and a nano-montmorillonite modified asphalt outer layer 3. Figure 1

[0034] Example 1: Add gravel component.

[0035] As shown in the figure, the thickness of the asphalt base layer is 30 mm, the thickness of the CNTs modified glass fiber reinforced layer is 10 mm, and the spraying thickness of the modified nano-montmorillonite modified asphalt is 9 mm. A toughened chopped glass fiber reinforced gravel asphalt composite flexible protective pad is prepared by adding gravel in the asphalt base layer. Figure 1 2 As shown in the figure, the specific preparation process is as follows:

[0036] As shown in the figure, the specific preparation process is as follows: Figure 3

[0037] S1, preparation of asphalt base layer (1):

[0038] S11, heat the base asphalt to 160°C for preheating;

[0039] S12, slowly add 5 parts of SBS to 100 parts of preheated base asphalt to avoid clumping, and continuously shear using a high-speed shearing emulsifier until the SBS is completely dissolved to form a uniform colloid;

[0040] S13, add 2 parts of DOPx to the uniform colloid obtained in S12, and stir at low speed for 20 min to make it completely penetrate the asphalt molecular chain;

[0041] S14, transfer the mixture to a development tank at 165°C, and stir at low speed for 2-4 h for development and curing;

[0042] S15, add gravel to the cured asphalt mixture to prepare a 30 mm thick asphalt base layer.

[0043] S2, preparation of CNTs modified glass fiber reinforced layer (2):

[0044] S21, glass fiber surface cleaning and activation: immerse the glass fiber in a 10% HNO3 solution, treat at 60°C for 20 min for acid etching, then rinse to neutral with deionized water, and dry at 110°C for 60 min;

[0045] S22, preparation of CNTs dispersion liquid: take 100 parts of dry carboxylated CNTs and 20 parts of SOCl2, and reflux at 70°C for 24 h in an oil bath. After the reaction is completed, centrifuge to remove excess SOCl2, wash with anhydrous THF for 3 times, and vacuum dry at 40°C for 6 h to obtain CNTs-COCL black powder;

[0046] ​​​S23, Preparation of 0.3 mg / mL DMF solution: CNTs-COCL powder was slowly added to DMF, and ultrasonic treatment was performed for 30 min under ice bath condition, and then un-dispersed large particles were removed by centrifugation for 5 min;

[0047] S24, Preparation of modified glass fiber: the pretreated glass fiber was immersed in the 0.3 mg / mL CNTs-COCl DMF solution at 80°C for 4 h, washed with ethanol for 3 times to remove the physically adsorbed CNTs, and then vacuum dried at 80°C for 2 h to obtain the modified glass fiber.

[0048] S3, Preparation of nano-montmorillonite modified asphalt outer layer (3):

[0049] S31, MMT organic modification: after the sodium-based MMT was treated by organic modification, vacuum drying was performed at 80°C, and then grinding was performed through a 400 mesh sieve;

[0050] S32, Preparation of MMT modified asphalt: the base asphalt was heated to 160°C, 3 parts of organic MMT were added to 100 parts of the base asphalt, and then MMT modified asphalt was obtained by high-speed shearing for 10 min and ultrasonic treatment for 15 min.

[0051] S4, the carbon nanotube modified glass fiber was arranged in a unidirectional or orthogonal lamination manner, SBS modified asphalt was impregnated to form a reinforced layer under the conditions of 160°C and 1.0 MPa pressure, the base asphalt layer and the reinforced layer were combined by hot pressing, and finally MMT modified asphalt was coated on the surface by thermal spraying to a thickness of 2.0 mm, thereby completing the preparation of the toughened glass fiber reinforced macadam asphalt composite flexible protective pad.

[0052] Example 2: the fiber is replaced by a multi-component.

[0053] The thickness of the asphalt base layer is 30 mm, the thickness of the CNTs modified multi-component fiber reinforced layer is 10 mm, and the thickness of the modified nano-montmorillonite modified asphalt sprayed layer is 9 mm, thereby preparing the toughened short-cut multi-component fiber reinforced asphalt composite flexible protective pad. The specific preparation process is as follows:

[0054] S1, Preparation of asphalt base layer (1):

[0055] S11, the base asphalt was heated to 160°C for preheating;

[0056] S12, 5 parts of SBS were slowly added to 100 parts of the preheated base asphalt to avoid caking, and a high-speed shearing emulsifier was used for continuous shearing until the SBS was completely dissolved, thereby forming a uniform colloid;

[0057] S13, 2 parts of DOPx were added to the uniform colloid obtained in S12, and low-speed stirring was performed for 20 min to make the DOPx completely penetrate the asphalt molecular chain;

[0058] S14, the mixture is transferred into a development tank at 165℃, low speed stirring for 2-4h, development curing.

[0059] S2, preparation of CNTs modified multi-component fiber reinforced layer (2):

[0060] S21, selection of multi-component fiber: 2 parts of basalt fiber, 3 parts of glass fiber, 3 parts of carbon fiber, and 2 parts of ceramic fiber are selected;

[0061] S22, fiber surface cleaning and activation: the various fibers are immersed in a 10% HNO3 solution, treated at 60℃ for 20min, acid etched, then washed with deionized water to neutral, and dried at 110℃ for 60min;

[0062] S23, preparation of CNTs dispersion: 100 parts of dry carboxylated CNTs and 20 parts of SOCl2 are refluxed at 70℃ for 24h in an oil bath, after the reaction is completed, the excess SOCl2 is removed by centrifugation, washed with anhydrous THF for 3 times, and vacuum dried at 40℃ for 6h to obtain CNTs-COCL black powder;

[0063] S24, preparation of 0.3mg / mL DMF solution: CNTs-COCL powder is slowly added to DMF, ultrasonic treated for 30min under ice bath condition, and then the undispersed large particles are removed by centrifugation for 5min;

[0064] S25, preparation of modified fiber: the pretreated multi-component fiber is immersed in 0.3mg / mL CNTs-COCl DMF solution at 80℃ for 4h, washed with ethanol for 3 times to remove physically adsorbed CNTs, and then vacuum dried at 80℃ for 2h to obtain modified multi-component fiber.

[0065] S3, preparation of nano-montmorillonite modified asphalt outer layer (3)

[0066] S31, MMT organic modification: after sodium-based MMT is organically treated, it is vacuum dried at 80℃, and then ground through a 400 mesh sieve;

[0067] S32, preparation of MMT modified asphalt: the base asphalt is heated to 160℃, 3 parts of organic MMT are added to 100 parts of base asphalt, and MMT modified asphalt is obtained by high speed shearing for 10min and ultrasonic treatment for 15min.

[0068] S4, carbon nanotube modified glass fiber is arranged in unidirectional or orthogonal lamination mode, SBS modified asphalt is impregnated at 160℃ and 1.0MPa pressure to form a reinforced layer, the base asphalt layer and the reinforced layer are hot-pressed to be combined, and finally MMT modified asphalt is sprayed on the surface with a thickness of 2.0mm to complete the preparation of the toughened glass fiber reinforced macadam asphalt composite flexible protective pad.

[0069] Comparative Example 1: Using unmodified glass fiber

[0070] S1, Preparation of asphalt base layer (1):

[0071] S11, Preheat the base asphalt to 160°C;

[0072] S12, Slowly add 5 parts of SBS to 100 parts of the preheated base asphalt to avoid caking, and use a high-speed shearing emulsifier to continuously shear until the SBS is completely dissolved, forming a uniform colloid;

[0073] S13, Add 2 parts of DOPx to the uniform colloid obtained in S12, and stir at low speed for 20 min to allow it to fully penetrate the asphalt molecular chain;

[0074] S14, Transfer the mixture to a development tank at 165°C, and stir at low speed for 2-4 h for development and curing.

[0075] S2, Preparation of nano-montmorillonite modified asphalt outer layer (3):

[0076] S21, MMT organic modification: After the sodium-based MMT is organically treated and vacuum dried at 80°C, it is ground through a 400 mesh sieve;

[0077] S22, Preparation of MMT modified asphalt: Heat the base asphalt to 160°C, and add 3 parts of organic MMT to 100 parts of the base asphalt, and obtain the MMT modified asphalt by high-speed shearing for 10 min and ultrasonic treatment for 15 min.

[0078] S3, Arrange the unmodified glass fiber in a unidirectional or orthogonal layering manner, impregnate the SBS modified asphalt at 160°C and 1.0 MPa pressure to form a reinforcing layer, and then hot-press the base asphalt layer and the reinforcing layer, and finally spray the MMT modified asphalt on the surface with a thickness of 2.0 mm to obtain a toughened glass fiber reinforced asphalt composite flexible protective pad.

[0079] The toughened glass fiber reinforced asphalt composite flexible protective pads prepared in Examples 1, 2 and Comparative Example 1 were tested for mechanical properties and corrosion resistance. The tensile property test standard conforms to GB / T 3354-2014, and the testing machine is MTS-CMT5305 microcomputer controlled electronic universal testing machine; the bending property test standard conforms to GB / T 1449-2005, and the testing machine is MTS-CMT5305 microcomputer controlled electronic universal testing machine; the impact property standard conforms to GB / T 1451-2005, and the testing machine is Instron 9450 falling weight impact testing machine; the corrosion resistance test standard conforms to GB / T 10125-2021, and the testing machine is a salt spray tester. The results are shown in Table 1:

[0080] Table 1 Test results of the fiber reinforced asphalt composite flexible protective pads prepared in example 1, 2 and comparative example 1

[0081]

[0082] As can be seen from Table 1, the tensile strength, tensile modulus, bending strength and impact toughness of the protective pad prepared in the examples are all superior to those of the protective pad prepared in comparative example 1, and the salt spray corrosion resistance grade and chloride ion diffusion coefficient are also superior to those of the protective pad prepared in comparative example 1.

[0083] As shown in Figure 4 The stress-strain curves of the toughened glass fiber reinforced asphalt composite flexible protective pads prepared in example 1, 2 and comparative example 1 were obtained by compression test on a universal testing machine. In example 1, the crushed stone component was added, and the crushed stone was embedded in the asphalt matrix as a rigid particle, which could share the external load through the skeleton effect and reduce the direct stress of the asphalt matrix, thereby improving the overall compressive strength. In example 2, the glass fiber was replaced by multi-component fiber, in which the carbon fiber provided high modulus and the basalt fiber enhanced toughness, and the compressive strength was improved after compounding; in comparative example 1, the modified glass fiber was replaced by unmodified glass fiber, which was smooth and inert on the surface, relying only on physical adsorption and mechanical embedding, and the interfacial bonding strength was reduced, the fiber-asphalt interface was easy to debond under pressure, the stress could not be effectively transmitted, and the compressive strength decreased.

[0084] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the spirit and scope of the present application should also be within the protection scope of the present application.

Claims

1. A method for preparing a modified fiberglass asphalt composite protective mat for subsea pipelines, characterized in that, Includes the following steps: (1) Preparation of thermoplastic elastomer modified asphalt base course: After heating the base asphalt, thermoplastic elastomer is added and sheared by a high-speed shear emulsifier until the thermoplastic elastomer is completely dissolved to form a uniform colloid. Plasticizer is added and stirred to allow the plasticizer to fully penetrate the asphalt molecular chain and form thermoplastic elastomer modified asphalt. The mixture is then transferred to a development tank and stirred for development and maturation. (2) Preparation of CNTs modified glass fiber reinforcement layer: The glass fiber is pretreated and then immersed in a CNTs-COCl DMF solution; (3) Preparation of nano-montmorillonite modified asphalt outer layer: The base asphalt is heated, nano-montmorillonite is added, and the mixture is treated by high-speed shearing and ultrasonic treatment; (4) CNTs modified glass fibers are arranged in a unidirectional or orthogonal layup manner on the asphalt base layer, and thermoplastic elastomer modified asphalt is impregnated to form a reinforcing layer. The asphalt base layer and the reinforcing layer are composited by hot pressing, and finally nano-montmorillonite modified asphalt is coated on the surface by hot spraying to form a toughened and reinforced glass fiber asphalt composite flexible protective pad.

2. The method for preparing a modified fiberglass asphalt composite protective mat for subsea pipelines according to claim 1, characterized in that, In step (1), the asphalt base course includes base asphalt, thermoplastic elastomer and plasticizer, and the mass ratio of base asphalt to thermoplastic elastomer is 20:1; the plasticizer is dioctyl phthalate, and the mass of the plasticizer is 2% of the mass of the asphalt base course.

3. The method for preparing a modified fiberglass asphalt composite protective mat for subsea pipelines according to claim 1, characterized in that, In step (1), the base asphalt is heated to 160°C for preheating; after adding the plasticizer, it is stirred for 10-20 minutes to allow it to fully penetrate the asphalt molecular chain; the mixture is transferred into a fermentation tank, the temperature of which is 165-180°C, and the stirring and maturation time is 2-4 hours.

4. The method for preparing a modified glass fiber asphalt composite protective mat for subsea pipelines according to claim 1, characterized in that, In step (2), the glass fiber pretreatment is a surface cleaning and activation step. The glass fiber is immersed in a 10% acid solution and treated at 50-60°C for 15-30 minutes to perform acid etching. Then it is rinsed with deionized water until neutral and dried at 100-120°C for 40-60 minutes. The acid is any one of hydrochloric acid, sulfuric acid, or nitric acid.

5. The method for preparing a modified fiberglass asphalt composite protective mat for subsea pipelines according to claim 1, characterized in that, In step (2), the DMF solution preparation steps of CNTs-COCl include: taking 100 parts of dried carboxylated CNTs and 15-30 parts of SOCl2 and refluxing them in an oil bath at 70°C for 16-24 hours. After the reaction is completed, centrifuge to remove excess SOCl2, wash with anhydrous THF, and then vacuum dry to obtain CNTs-COCl black powder. CNTs-COCl powder was added to DMF and sonicated for 30 min under ice bath conditions. Then, undispersed large particles were removed by centrifugation for 5 min to obtain a CNTs-COCl DMF solution.

6. The method for preparing a modified glass fiber asphalt composite protective mat for subsea pipelines according to claim 5, characterized in that, The concentration of the CNTs-COCl DMF solution is 0.1–0.3 mg / ml.

7. The method for preparing a modified glass fiber asphalt composite protective mat for subsea pipelines according to claim 6, characterized in that, The CNTs-COCl solution was immersed in DMF solution and reacted at 80°C for 3-4 hours. The physically adsorbed CNTs were removed by washing three times with ethanol. The glass fibers were then vacuum dried at 80°C for 1.5-2.5 hours to obtain the CNTs-modified glass fibers.

8. The method for preparing a modified fiberglass asphalt composite protective mat for subsea pipelines according to claim 1, characterized in that, In step (3), the base asphalt is heated to 160°C; the nano-montmorillonite needs to be organically modified, washed, vacuum dried, and then ground through a 400-mesh sieve to obtain organic nano-montmorillonite. The mass ratio of base asphalt to organic nano-montmorillonite is 100:

3. The organic modification process is as follows: the nano-montmorillonite is dispersed in an ethanol solvent, a silane coupling agent KH-550 is added, and the pH is adjusted to acidic to promote hydrolysis, so that it reacts with the silanol groups on the surface of montmorillonite to form a stable Si-O-Si bond, thereby introducing active groups of amino and epoxy groups to obtain surface organically functionalized nano-montmorillonite.

9. The method for preparing a modified fiberglass asphalt composite protective mat for subsea pipelines according to claim 1, characterized in that, In step (4), the grafting amount of CNTs modified glass fiber is 0.8 to 1.2 wt%; the thermoplastic elastomer modified asphalt is impregnated at 160°C and 1.0 MPa pressure to form a reinforcing layer.

10. The protective mat prepared by the method for preparing a modified glass fiber asphalt composite protective mat for subsea pipelines according to any one of claims 1-9, characterized in that, It includes an asphalt base course, a CNTs-modified glass fiber reinforcement layer, and a nano-montmorillonite-modified asphalt outer layer; the thickness of the asphalt base course is 20-30 mm; the thickness of the CNTs-modified glass fiber reinforcement layer is 10-15 mm; and the thickness of the nano-montmorillonite-modified asphalt spray coating is 2-9 mm.

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