UV-CIPP material for pipeline repair and stress monitoring and preparation method thereof

Abstract

The invention discloses a UV-CIPP material for pipeline repair and stress monitoring and a preparation method of the UV-CIPP material, and belongs to the technical field of intelligent materials. The preparation method comprises the following steps: respectively diluting MWCNT slurry according to a certain proportion; soaking the glass fiber in the dipping solution for a period of time, taking out and drying; coating two ends of the dried glass fiber with conductive silver adhesive, and pasting a copper electrode after curing; adding a thermal initiator into the ultraviolet curing resin; respectively preparing test pieces with different resin contents; and sequentially carrying out ultraviolet curing and thermocuring on the prepared test piece. The characteristics and advantages of the ultraviolet curing resin, the glass fiber and the resin material are combined, and the preparation problem of the ultraviolet curing composite material for repairing the intelligent pipeline, which does not influence the mechanical property of the material and can realize excellent monitoring capability, is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of smart materials, and in particular to a UV-CIPP material for pipeline repair and stress monitoring and a preparation method thereof. Background Art

[0002] The repair and monitoring of underground pipelines is a key measure to ensure urban safety, maintain normal operation, reduce economic losses, extend the service life of facilities, protect the environment, and improve the level of urban management. As a commonly used pipeline non-opening technology, UV-CIPP has been widely used due to its short construction period, convenient and fast construction, and high repair quality. However, after the pipeline is repaired, there is a lack of effective monitoring of the repair status of the pipeline and the deformation and damage after it is put into use.

[0003] Although traditional pipeline monitoring methods such as sonar, electromagnetic radar, eddy current, laser scanning, thermal imaging, etc. have good monitoring effects, acoustic technologies such as sonar have low recognition accuracy due to the complexity of the pipeline environment and signal interference. At the same time, due to on-site monitoring, real-time online high-precision monitoring cannot be achieved. Therefore, many scholars have begun to install various sensors in the pipeline and build a pipeline monitoring platform in combination with computer technology. For example, by arranging fiber optic sensors around the pipeline, the stress, deformation, corrosion, abnormal events, etc. of the pipeline can be monitored through the signal changes of the fiber optic sensors. However, due to the complex environment in the pipeline and the scouring of water flow, sensors placed on the surface are easily corroded and damaged and lose their sensing ability. Embedding them in the material will inevitably cause material defects that affect material performance. Therefore, the study of integrated pipeline repair materials with sensing capabilities has become the key to solving the problem.

[0004] At present, the pipeline repair materials used for UV-CIPP are mainly glass fiber resin composite materials. With the continuous development of nanotechnology, researchers have begun to explore the potential advantages of introducing carbon nanomaterials (such as graphene, carbon nanotubes, etc.) into composite materials. A large number of studies have shown that the introduction of carbon nanomaterials not only significantly enhances the bending strength, tensile strength, shear strength, impact resistance and corrosion resistance of composite materials, but also because carbon nanomaterials have excellent electrical conductivity, through the piezoresistive effect, real-time monitoring of material damage and destruction can be achieved. The appropriate concentration of carbon nanomaterial addition can not only ensure the mechanical properties of the material, but also achieve excellent monitoring effects. Secondly, the position of the sensing layer also has an important influence on the strain response, and the sensing performance placed in different positions is also different. In addition to monitoring the material strain, the use of electromechanical response can also realize various functions such as deformation monitoring, destruction monitoring, impact damage monitoring and fatigue damage monitoring inside and outside the material.

[0005] The Chinese patent application number CN202410703802.2 discloses a trenchless repair method for local deformation of small-diameter road pipelines. The method uses a CCTV monitoring system to accurately locate the local deformation position of the pipeline, and uses a glass fiber cloth impregnated with resin to wrap around the repair airbag to repair the pipeline. However, the patent can only repair the damaged part, and cannot use other monitoring systems to perform intelligent stress monitoring of the pipeline.

[0006] The Chinese patent application number CN201811318712.2 discloses a method for monitoring axial residual stress in small inner diameter pipelines. It uses strain gauges to be attached along the circumference of the pipeline, and a ring is cut along the circumference to measure the final value of the axial residual stress. The location of the patch and the cutting position are reasonably selected, and the residual stress of the monitoring part can be measured quickly and accurately. However, this patent can only monitor the stress of the pipeline and cannot be used to repair the pipeline.

[0007] However, it is still a huge challenge to introduce carbon nanomaterials into UV-curable resin materials. This is mainly because carbon nanomaterials are strong UV absorbers, which will weaken the intensity of UV light during the curing process, while reducing the light transmittance of the material, resulting in poor curing of the composite material, or even uncured material. A good degree of curing can be achieved by irradiating both sides, but in actual pipeline repair applications, back irradiation cannot be achieved. The introduction of MWCNTs into the UV-curable resin matrix causes a significant drop in light transmittance, and the composite material cannot be cured when the MWCNTs content exceeds 0.5wt%.

[0008] Therefore, it is necessary to provide a UV-CIPP material for pipeline repair and stress monitoring and a preparation method thereof. Summary of the invention

[0009] The purpose of the present invention is to provide a UV-CIPP material for pipeline repair and stress monitoring and a preparation method thereof, so as to solve the problem of preparing an intelligent pipeline repair UV-curable composite material that does not affect the mechanical properties of the material and can achieve excellent monitoring capabilities.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0011] A UV-CIPP material for pipeline repair and stress monitoring, comprising the following raw materials in parts by weight:

[0012] 100 parts of ultraviolet curing resin, 10-15 parts of glass fiber of woven structure, 25-30 parts of curing agent, 200 parts of carboxylation treated MWCNTs solution, and 2 parts of thermal initiator.

[0013] Furthermore, the thermal initiator is prepared by mixing a 98.5% concentration of tert-butyl perbenzoate (TBPB) solution and dibenzoyl peroxide (BPO) powder in a weight ratio of 1:2.

[0014] Furthermore, a method for preparing the UV-CIPP material for pipeline repair and stress monitoring as described above comprises the following steps:

[0015] S1, diluting the MWCNT slurry with deionized water in a certain proportion, and then stirring the slurry to form an impregnation solution;

[0016] S2, soaking the glass fiber in the impregnation solution for a period of time, and then taking it out and drying it;

[0017] S3, applying conductive silver glue on both ends of the dried glass fiber, and pasting copper electrodes after the conductive silver glue is solidified;

[0018] S4, adding the thermal initiator to the ultraviolet curing resin, mixing well and placing in a vacuum barrel;

[0019] S5, preparing specimens with different resin contents;

[0020] S6, sequentially subjecting the prepared specimen to UV curing and thermal curing, and demoulding after cooling to room temperature, thereby completing the specimen preparation.

[0021] Furthermore, the preparation method of preparing the test pieces with different resin contents in step S5 is specifically as follows:

[0022] Pour the resin into the mold, lay the glass fiber, and pour the resin again after the glass fiber is fully impregnated. Then lay the second layer of glass fiber, repeat the operation until the third layer of glass fiber is laid, and finally pour the resin on the top; then put the specimen into a vacuum barrel, place it under -100PSI pressure for 1 hour, and then take it out to complete the specimen preparation.

[0023] Furthermore, the preparation method of preparing the test pieces with different resin contents in step S5 is specifically as follows:

[0024] The vacuum resin transfer method (VARTM) was used to make the pre-cured specimens, which were then cured under ultraviolet light for 10 minutes. After the ultraviolet light curing process was completed, the specimens were placed in a 150°C oven for heat curing for 20 minutes, and then demolded after cooling to room temperature to complete the specimen preparation.

[0025] Furthermore, during specimen preparation, transparent tempered glass and fixing clamps are used to fix the pre-cured material.

[0026] Furthermore, the third layer of glass fiber is a material impregnated with MWCNTs solution.

[0027] Furthermore, the UV-curable resin is a benzyl acrylate monomer.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention combines the characteristics and advantages of multi-walled carbon nanotubes, glass fibers and resin materials, solves the problem of preparing intelligent pipeline repair UV-curing composite materials that do not affect the mechanical properties of the materials and can achieve excellent monitoring capabilities. It can be used for long-term monitoring of dynamic responses such as strain and deformation of flat and complex curved surfaces, and can also be pre-buried inside the structure, with a wide range of applications.

[0030] 2. The present invention inherits the high strength and high stability of the resin, good corrosion resistance, and is improved by multi-walled carbon nanotubes. The integrated glass fiber sensing layer has excellent conductive properties. At the same time, it can support sensing elements of different thicknesses and larger areas according to monitoring needs, and can realize surface monitoring, with good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] Figure 1 is a preparation flow chart of the present invention;

[0033] Figure 2 It is a schematic diagram of the three-dimensional structure of the UV-CIPP material in the present invention;

[0034] Figure 3 It is a schematic diagram of the main structure of the UV-CIPP material in the present invention;

[0035] Figure 4 Schematic diagram of the effect of different concentrations and different sensing layer positions on damage sensing in the present invention;

[0036] Figure 5 This is the electromechanical response diagram when the sensing layer is located at the top layer at a content of 0.2wt% MWCNTs in the present invention;

[0037] Figure 6 This is a schematic diagram of intelligent pipeline monitoring in the present invention.

[0038] Figure numerals: 1. copper electrode; 2. glass fiber layer impregnated with MWCNTs; 3. resin layer; 4. glass fiber layer not impregnated with MWCNTs. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] Reference Figure 1-Figure 3 The present invention provides a technical solution: a UV-CIPP material for pipeline repair and stress monitoring, comprising: a plurality of resin layers 3 spaced from bottom to top; a plurality of glass fiber layers arranged between two adjacent resin layers 3, the resin layer 3 being solidified and connected with the glass fiber layer; the glass fiber layer at the top is a glass fiber layer 2 impregnated with MWCNTs, and the remaining glass fiber layers are glass fiber layers 4 not impregnated with MWCNTs; and a copper electrode 1 is connected to the glass fiber layer at the top, and both ends of the copper electrode 1 extend to both sides by a predetermined distance respectively.

[0042] A preparation material of a UV-CIPP material for pipeline repair and stress monitoring includes:

[0043] 100 parts of ultraviolet curing resin, 10-15 parts of woven glass fiber, 25-30 parts of curing agent, 200 parts of carboxyl-treated MWCNTs solution, and 2 parts of thermal initiator (mixed by 98.5% tert-butyl perbenzoate (TBPB) solution and dibenzoyl peroxide (BPO) powder in a weight ratio of 1:2).

[0044] A method for preparing a UV-CIPP material for pipeline repair and stress monitoring comprises the following steps:

[0045] Step 1, dilute the MWCNT slurry with deionized water to 0.2%, 0.5%, 0.7%, and 1.0% respectively according to the proportion, stir at 1000R / min for 30min under a high-speed stirrer to form 200ml of impregnation solution, i.e., carboxylation treated MWCNTs solution.

[0046] Step 2: Soak the cut woven glass fiber for 2 hours, take it out and dry it on a tray, put it in an oven and bake it at 150°C for 15 hours, then take it out and seal it for use. The mechanical stability, toughness, impact resistance and durability of the electrical sensor of the spare glass fiber material are significantly enhanced, and it is the main sensor of the UV-CIPP material.

[0047] Step 3: To achieve a good and stable electrical signal output, apply conductive silver glue to both ends of the dried glass fiber, and after the conductive silver glue is cured, paste the copper electrode 1, and apply the conductive silver glue again for reinforcement. To achieve rapid curing of the conductive silver glue, put it in an oven at 100°C for 30 minutes, and take it out and seal it for use.

[0048] Step 4: UV curing system and thermal curing system are realized by preparing dual initiator resin. Add thermal initiator to UV curing resin material at 1.5% of the weight of UV curing resin, stir and mix well, put into vacuum barrel, and place at -100PSI pressure for 5 minutes.

[0049] Step 5: Prepare specimens with different resin contents in two ways.

[0050] The production process of the high-resin-content specimen is as follows: pour the resin into the mold, lay the glass fiber, wait for the glass fiber to be fully impregnated before pouring the resin, then lay the second layer of glass fiber, repeat the operation, lay a total of three layers of glass fiber (including the sensing layer), and finally pour the resin on the top layer. Put the mold and the material as a whole into a vacuum barrel, place it under -100PSI pressure for 1 hour, and then take it out to complete the specimen preparation. To prevent wrinkles in the resin composite material during the curing process, transparent tempered glass and fixing clamps are used to fix the pre-cured material.

[0051] The production process of the specimen with low resin content is as follows: the pre-cured specimen is made by the vacuum resin transfer method (VARTM), and then the pre-cured specimen is cured under ultraviolet light. Among them, the curing equipment is preferably FSI3000 ultraviolet light curing equipment, and the size of the cured sample is: 100mm (length) × 100mm (width) × 5mm (thickness) / 2.8mm (VARTM), the height of the curing lamp from the specimen is 200mm, the power of the ultraviolet lamp is 120mW / cm2, and the curing time is 10min. After the ultraviolet light curing process is completed, the specimen is immediately placed in a 150°C oven for thermal curing, and the thermal curing time is 20min. Finally, it is demoulded after cooling to room temperature, and the specimen preparation is completed. The preparation method of the present invention has strong operability, low cost, and good economic benefits.

[0052] In this embodiment, the UV-curable resin material preferably uses benzyl acrylate monomers. The present invention combines the characteristics and advantages of multi-walled carbon nanotubes, glass fibers and resin materials, and solves the problem of preparing intelligent pipeline repair UV-curable composite materials that do not affect the mechanical properties of the materials and can achieve excellent monitoring capabilities. It can be used for long-term monitoring of dynamic responses such as strain and deformation of planes and complex curved surfaces, and can also be pre-buried inside the structure, and has a wide range of applications.

[0053] The present invention inherits the high strength and stability of the resin, good corrosion resistance, and is improved by multi-walled carbon nanotubes, so that the integrated glass fiber sensing layer has excellent conductive properties. At the same time, it can support sensing elements of different thicknesses and larger areas according to monitoring needs, and can realize area monitoring, with good application prospects.

[0054] like Figure 4 , studied the effects of different concentrations and different sensing layer positions on damage sensing, and explained the resistance growth mechanism. Figure 5 , the influence of different positions of the sensing layer and the resin content on the bending properties of the composite material under 0.2wt% MWCNTs content was studied. The results show that the UV-CIPP material under low concentration of MWCNTs has stable mechanical properties, high sensitivity and bending strength, excellent damage sensing ability and excellent cycle repeatability, and can repair material damage such as strain, deformation, damage and long-term intelligent monitoring of plane and complex curved surfaces. In general, the high-performance intelligent UV-CIPP material studied is mainly realized through an integrated glass fiber sensing layer when applied to pipeline repair monitoring. In this study, MWCNTs were deposited on glass fibers by solution impregnation, and the sensing layer was formed after the electrodes were pasted. A UV / heat dual-curing resin system was constructed to achieve UV / heat dual curing, which solved the problem of poor curing after the introduction of MWCNTs.

[0055] Reference Figure 6 ,The pipeline wall is made of UV-CIPP material composite material, and the data collector transmits the collected information to the remote server to determine whether cracks occur in the pipeline.

[0056] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A UV-CIPP material for pipeline repair and stress monitoring, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of ultraviolet curing resin, 10-15 parts of glass fiber of woven structure, 25-30 parts of curing agent, 200 parts of carboxylation treated MWCNTs solution, and 2 parts of thermal initiator.

2. The UV-CIPP material for pipeline repair and stress monitoring according to claim 1, characterized in that: The thermal initiator is prepared by mixing a tert-butyl perbenzoate (TBPB) solution containing 98.5% concentration and dibenzoyl peroxide (BPO) powder in a weight ratio of 1:

2.

3. A method for preparing the UV-CIPP material for pipeline repair and stress monitoring according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1, diluting the MWCNT slurry with deionized water in a certain proportion, and then stirring the slurry to form an impregnation solution; S2, soaking the glass fiber in the impregnation solution for a period of time, and then taking it out and drying it; S3, applying conductive silver glue on both ends of the dried glass fiber, and pasting copper electrodes after the conductive silver glue is solidified; S4, adding the thermal initiator to the ultraviolet curing resin, mixing well and placing in a vacuum barrel; S5, preparing specimens with different resin contents; S6, sequentially subjecting the prepared specimen to UV curing and thermal curing, and demoulding after cooling to room temperature, thereby completing the specimen preparation.

4. The method for preparing the UV-CIPP material for pipeline repair and stress monitoring according to claim 3, characterized in that: The specific method for preparing test pieces with different resin contents in step S5 is as follows: Pour the resin into the mold, lay the glass fiber, and pour the resin again after the glass fiber is fully impregnated. Then lay the second layer of glass fiber, repeat the operation until the third layer of glass fiber is laid, and finally pour the resin on the top; then put the specimen into a vacuum barrel, place it under -100PSI pressure for 1 hour, and then take it out to complete the specimen preparation.

5. The method for preparing the UV-CIPP material for pipeline repair and stress monitoring according to claim 3, characterized in that: The specific method for preparing test pieces with different resin contents in step S5 is as follows: The vacuum resin transfer method (VARTM) was used to make the pre-cured specimens, which were then cured under ultraviolet light for 10 minutes. After the ultraviolet light curing process was completed, the specimens were placed in a 150°C oven for heat curing for 20 minutes, and then demolded after cooling to room temperature to complete the specimen preparation.

6. The method for preparing the UV-CIPP material for pipeline repair and stress monitoring according to claim 3, characterized in that: During specimen preparation, transparent tempered glass and fixing clamps were used to fix the pre-cured material.

7. The method for preparing the UV-CIPP material for pipeline repair and stress monitoring according to claim 4, characterized in that: The third layer of glass fiber is a material impregnated with MWCNTs solution.

8. The method for preparing the UV-CIPP material for pipeline repair and stress monitoring according to claim 3, characterized in that: The ultraviolet curable resin is a benzyl acrylate monomer.

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