Preparation method of multifunctional graphene composite polyethylene pipe

Abstract

The invention relates to the technical field of graphene composite high polymer materials, in particular to a preparation method of a multifunctional graphene composite polyethylene pipe, which comprises the following steps: respectively obtaining a modified polyethylene mixture and a graphene dispersion liquid, proportionally injecting into a mixing device, and melting and blending to obtain a graphene composite polyethylene melt; a core pipe is formed through a first pipeline extruder, after heating, pure polyethylene is coated with a second pipeline extruder to form a coating layer, and cooling is conducted to obtain the target composite pipe. Intercepting a test pipe section from the target composite pipe, obtaining inner and outer contour dimensions and interface bonding strength information, and calculating a first out-of-round characteristic value, a second out-of-round characteristic value and an interface bonding strength characteristic value; preliminarily judging whether a standard is met or not according to the first out-of-round characteristic value, and if yes, checking according to an interface bonding strength characteristic value; and if not, judging the reason according to the second out-of-round characteristic value. The problem that a graphene composite polyethylene pipe in the prior art is insufficient in flexibility is solved.

Description

Technical Field

[0001] This invention relates to the field of graphene composite polymer materials technology, and in particular to a method for preparing a multifunctional graphene composite polyethylene pipe. Background Technology

[0002] Polyethylene pipes are widely used in water supply and drainage, gas transmission, and other fields due to their excellent corrosion resistance, flexibility, and ease of construction. However, ordinary polyethylene pipes have inherent deficiencies in mechanical strength, heat resistance, and impermeability, which limits their application in high-pressure and harsh environments.

[0003] To enhance the overall performance of polyethylene pipes, graphene, a nanomaterial with ultra-high strength, excellent thermal conductivity, and a large specific surface area, can serve as an ideal reinforcing filler. By introducing graphene into the polyethylene matrix, graphene composite polyethylene materials are formed, significantly improving the pipe's strength, rigidity, barrier properties, and thermal stability.

[0004] However, while the introduction of graphene brings enhancement effects, it also introduces new technical challenges in existing technologies. Among these, the significant decrease in pipe flexibility is a core issue that urgently needs to be addressed. This is mainly due to two factors: First, graphene nanosheets tend to aggregate within the polyethylene matrix, forming stress concentration points that can easily lead to brittle fracture during pipe bending. Second, the addition of large amounts of graphene restricts the movement and slippage of polyethylene molecular chains, causing the material to harden, become brittle, and lose flexibility. This loss of flexibility severely impacts the efficiency of pipe coiling, transportation, and on-site laying, especially in trenchless construction and other applications requiring good pipe bending performance, where its disadvantages are particularly pronounced. Summary of the Invention

[0005] Therefore, the present invention provides a method for preparing multifunctional graphene composite polyethylene pipes to overcome the problem of insufficient flexibility in existing graphene composite polyethylene pipes.

[0006] To achieve the above objectives, the present invention provides a method for preparing a multifunctional graphene composite polyethylene pipe, comprising: Step S1: Prepare a modified polyethylene mixture and a graphene dispersion, and inject the modified polyethylene mixture and the graphene dispersion into a mixing device for melt blending to obtain a graphene composite polyethylene melt. Step S2: The graphene composite polyethylene melt is placed into the first pipe extruder to complete the core tube forming of the graphene composite polyethylene melt. Step S3: After heating the core tube to a preset temperature, it is fed into a second pipe extruder. Pure polyethylene is used to coat the graphene core tube with an outer layer, and then it is cooled and formed to obtain the target composite pipe. Step S4: Cut several test pipe segments from the target composite pipe and obtain the inner contour dimension information, outer contour dimension information and interface bonding strength information of each test pipe segment; Step S5: Based on the inner contour size information and the outer contour size information, obtain the first out-of-round feature value and the second out-of-round feature value respectively, and preliminarily determine whether the preparation of the target composite tube meets the preset standard based on the first out-of-round feature value; Step S6a: In response to the preliminary determination that the preparation of the target composite tube meets the preset standard, the preparation of the target composite tube is verified according to the interface bonding strength characteristic value to check whether it meets the preset standard. Step S6b: In response to the preliminary determination that the preparation of the target composite tube does not meet the preset standard, the reason why the preparation of the target composite tube does not meet the preset standard is determined according to the second out-of-round characteristic value, and the preset temperature of the core tube heating, the extrusion pressure of the second pipe extruder and the cooling rate of the coating layer are adjusted for the next batch of prepared core tubes.

[0007] Further, the first out-of-roundness characteristic value is the ratio of the average out-of-roundness of the inner contour of each test pipe segment to the inner out-of-roundness threshold; the inner contour out-of-roundness is the difference between the maximum diameter and the minimum diameter of the inner contour. The second out-of-roundness characteristic value is the ratio of the average out-of-roundness of the outer contour of each test pipe segment to the out-of-roundness threshold; the out-of-roundness of the outer contour is the difference between the maximum diameter and the minimum diameter of the outer contour. The characteristic value of the interface bonding strength is the ratio between the average bonding force between the core tube and the coating layer of each test tube segment and the preset bonding force.

[0008] Furthermore, in response to the first out-of-roundness characteristic value being less than the first preset out-of-roundness threshold, it is preliminarily determined that the preparation of the target composite tube meets the preset standard, and the preparation of the target composite tube is verified according to the interface bonding strength characteristic value.

[0009] Furthermore, in response to the first out-of-round characteristic value being greater than or equal to the first preset out-of-round threshold, it is preliminarily determined that the preparation of the target composite tube does not meet the preset standard, and the reason why the preparation of the target composite tube does not meet the preset standard is determined according to the second out-of-round characteristic value.

[0010] Furthermore, the fabrication of the target composite tube is verified based on the interface strength characteristic value to determine whether it meets the preset standard. If the interfacial bonding strength characteristic value is less than the preset interfacial bonding strength threshold, the preparation of the target composite tube is verified to be non-compliant with the preset standard, and the preset heating temperature of the next batch of core tubes is increased according to the difference between the preset interfacial bonding strength threshold and the interfacial bonding strength characteristic value. If the characteristic value of the interfacial bonding strength is greater than or equal to the preset interfacial bonding strength threshold, then the preparation of the target composite tube is verified to meet the preset standard.

[0011] Furthermore, the increase in the preset temperature of the next batch of core tube heating is positively correlated with the difference between the preset interface bonding strength threshold and the interface bonding strength characteristic value.

[0012] Furthermore, the reason why the preparation of the target composite tube does not meet the preset standard is determined based on the second out-of-roundness characteristic value. If the second out-of-round characteristic value is less than the second preset out-of-round threshold, it is determined that the reason why the preparation of the target composite pipe does not meet the preset standard is that the extrusion pressure of the second pipe extruder is too high, and the extrusion pressure of the second pipe extruder in the next batch is reduced according to the difference between the second preset out-of-round threshold and the second out-of-round characteristic value. If the second out-of-round characteristic value is greater than or equal to the second preset out-of-round threshold, it is determined that the reason why the preparation of the target composite tube does not meet the preset standard is that the cooling rate of the coating layer is too fast, and the cooling rate of the coating layer in the next batch is reduced according to the difference between the second out-of-round characteristic value and the second preset out-of-round threshold.

[0013] Furthermore, the reduction in the extrusion pressure of the second pipe extruder in the next batch is positively correlated with the difference between the second preset out-of-round threshold and the second out-of-round characteristic value.

[0014] Furthermore, the decrease in the cooling rate of the coating layer in the next batch is positively correlated with the difference between the second out-of-round characteristic value and the second preset out-of-round threshold.

[0015] Furthermore, the ratio of the modified polyethylene mixture to the graphene dispersion injected into the mixing device is 100:20.

[0016] Compared with existing technologies, the advantages of this invention are as follows: By defining a first out-of-roundness characteristic value and a second out-of-roundness characteristic value, and setting corresponding preset out-of-roundness thresholds, this invention can accurately assess the degree of out-of-roundness of the inner layer and the whole of the pipe. This quantitative assessment method helps to detect pipe shape deviations in a timely manner, ensuring that the produced pipes have a regular circular outline, improving the geometric accuracy of the pipes, and meeting the stringent requirements for pipe shape in different application scenarios.

[0017] Furthermore, an interfacial bonding strength characteristic value is introduced and compared with a preset interfacial bonding strength threshold for verification. This process can effectively monitor the bonding quality between the core tube and the coating layer, ensuring a tight bond between the two materials and avoiding problems such as delamination and leakage during pipe use caused by poor interfacial bonding, thereby significantly improving the reliability and service life of the pipe.

[0018] Furthermore, the multifunctional graphene-polymerized polyethylene pipe prepared by this method combines the excellent properties of graphene with the good processing performance of polyethylene. The addition of graphene can enhance the mechanical properties, thermal stability, and electrical conductivity of the pipe, giving it broader application prospects and better performance in fields such as fluid transportation and power transmission.

[0019] Furthermore, during the manufacturing process, based on the detection results of out-of-roundness characteristic values ​​and interfacial bonding strength characteristic values, it is possible to determine in real time whether the pipe manufacturing meets the preset standards and quickly pinpoint the reasons for non-compliance. For different reasons, process parameters can be adjusted promptly, such as increasing the preset heating temperature of the core tube, decreasing the extrusion pressure of the second pipe extruder, or reducing the cooling rate of the coating layer. This real-time feedback and adjustment mechanism helps reduce scrap rates, improve production efficiency, and lower production costs.

[0020] Furthermore, the positive correlation between the adjustment range of each process parameter and the difference in the corresponding characteristic value was clarified, such as the increase in the preset temperature of the core tube heating, the decrease in the extrusion pressure of the second pipe extruder, and the decrease in the cooling rate of the coating layer. This precise control method makes the adjustment of process parameters more scientific and reasonable, and can quickly and effectively control the pipe preparation process to the optimal state, ensuring the stability and consistency of product quality.

[0021] Furthermore, this method provides a complete and standardized preparation process and quality control system. From raw material acquisition, mixing and melting, pipe forming to quality inspection and process adjustment, each step has clear operating procedures and quality standards. This facilitates the large-scale industrial production of pipes, improves the controllability and repeatability of the production process, and ensures the uniformity of quality across different batches of products.

[0022] Furthermore, by cutting test sections of the target composite pipe and obtaining data on internal and external dimensions, as well as interfacial bonding strength, a comprehensive quality assessment of the pipe material can be conducted. This multi-dimensional testing method can promptly identify various potential quality problems in the pipe material, providing all-round assurance for product quality.

[0023] Furthermore, based on the detection results of different characteristic values, the reasons why pipe manufacturing does not meet preset standards can be quickly and accurately determined, and targeted solutions can be taken. For example, when the first out-of-round characteristic value does not meet the requirements, it can be preliminarily determined that there is a problem with the overall shape of the pipe; further, based on the second out-of-round characteristic value, it can be determined whether the problem is caused by extrusion pressure or cooling rate, and the process parameters can be adjusted accordingly. This ability to quickly locate and solve problems helps to shorten the production cycle and improve production efficiency.

[0024] Furthermore, because this method can monitor and adjust the production process in real time, it reduces waste and improves raw material utilization, thereby lowering production costs. At the same time, precise control of process parameters avoids over-processing and energy waste, further saving production costs.

[0025] Furthermore, the prepared multifunctional graphene composite polyethylene pipe has excellent performance and reliable quality, which can meet the demand for pipes in the high-end market and enhance the added value of the product. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a method for preparing a multifunctional graphene composite polyethylene pipe according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating the process of determining whether the preparation of the target composite tube conforms to a preset standard based on the first out-of-roundness characteristic value in an embodiment of the present invention. Figure 3 This invention provides a flowchart for verifying whether the preparation of the target composite tube conforms to a preset standard based on the interface bonding strength characteristic value. Figure 4 This is a flowchart illustrating the reason why the preparation of the target composite tube does not meet the preset standard based on the second out-of-roundness characteristic value, according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0028] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0029] Please see Figure 1-4 The following are flowcharts illustrating the preparation method of a multifunctional graphene composite polyethylene pipe according to an embodiment of the present invention: a flowchart illustrating the preliminary determination of whether the preparation of the target composite pipe conforms to a preset standard based on a first out-of-roundness characteristic value; a flowchart illustrating the verification of whether the preparation of the target composite pipe conforms to a preset standard based on an interface bonding strength characteristic value; and a flowchart illustrating the determination of the reasons why the preparation of the target composite pipe does not conform to the preset standard based on a second out-of-roundness characteristic value.

[0030] This invention provides a method for preparing a multifunctional graphene composite polyethylene pipe, comprising: Step S1: Prepare a modified polyethylene mixture and a graphene dispersion, and inject the modified polyethylene mixture and the graphene dispersion into a mixing device for melt blending to obtain a graphene composite polyethylene melt. Step S2: The graphene composite polyethylene melt is placed into the first pipe extruder to complete the core tube forming of the graphene composite polyethylene melt. Step S3: After heating the core tube to a preset temperature, it is fed into a second pipe extruder. Pure polyethylene is used to coat the graphene core tube with an outer layer, and then it is cooled and formed to obtain the target composite pipe. Step S4: Cut several test pipe segments from the target composite pipe and obtain the inner contour dimension information, outer contour dimension information and interface bonding strength information of each test pipe segment; Step S5: Based on the inner contour size information and the outer contour size information, obtain the first out-of-round feature value and the second out-of-round feature value respectively, and preliminarily determine whether the preparation of the target composite tube meets the preset standard based on the first out-of-round feature value; Step S6a: In response to the preliminary determination that the preparation of the target composite tube meets the preset standard, the preparation of the target composite tube is verified according to the interface bonding strength characteristic value to check whether it meets the preset standard. Step S6b: In response to the preliminary determination that the preparation of the target composite tube does not meet the preset standard, the reason why the preparation of the target composite tube does not meet the preset standard is determined according to the second out-of-round characteristic value, and the preset temperature of the core tube heating, the extrusion pressure of the second pipe extruder and the cooling rate of the coating layer are adjusted for the next batch of prepared core tubes.

[0031] Specifically, the preset temperature is set to 220-260℃, and 232℃ is selected in this embodiment. This temperature range ensures the structural stability of the graphene core tube during the coating process and promotes good fusion between the pure polyethylene material and the core tube surface. The cooling rate for cooling and molding is set to be controlled at 5℃ / min-8℃ / min, and 6℃ / min is selected in this embodiment. Gradual cooling is achieved through a segmented cooling process to avoid stress concentration inside the coating layer due to rapid cooling. The core tube dimensions are set to an outer diameter of 15-25mm and a wall thickness of 2-3mm. In this embodiment, an outer diameter of 20mm and a wall thickness of 2.5mm are selected to ensure that the core tube has sufficient supporting strength and flexibility. The target composite pipe is set to have a size of 25-40mm, with a coating thickness of 5-10mm. In this embodiment, the target composite pipe is selected to have a size of 35mm and a coating thickness of 7.5mm, so that the composite pipe can meet the installation size requirements of different projects while maintaining excellent comprehensive mechanical properties. The outer diameter of the target composite pipe is designed according to the application scenario requirements.

[0032] Specifically, a high-precision laser profilometer is used to acquire the inner contour dimensions of each test pipe segment, a coordinate measuring machine (CMM) is used to acquire the outer contour dimensions, and an electronic universal testing machine is used to acquire the interface bonding strength information. The laser profilometer, through a non-contact scanning method, can acquire contour data of the inner and outer surfaces of the test pipe segments in real time with an accuracy of 0.001 mm, accurately reflecting the roundness error and dimensional deviation of the pipe segments. The CMM is used to accurately verify the dimensions of key locations on the pipe segments, ensuring the repeatability and stability of the measurement results. The electronic universal testing machine is equipped with a 50 kN precision pressure sensor and performs tensile tests on the interface peel test specimens of the pipe segments using a loading rate of 10 mm / min. The interface bonding strength is calculated by recording the maximum peel force, and the test data is automatically uploaded to a data analysis system for processing. The specific information acquisition equipment is not limited, as long as it can output corresponding test results based on the test data of the test pipe segments.

[0033] Specifically, the first out-of-roundness characteristic value is the ratio of the average out-of-roundness of the inner contour of each test pipe segment to the out-of-roundness threshold; the out-of-roundness of the inner contour is the difference between the maximum diameter and the minimum diameter of the inner contour. The second out-of-roundness characteristic value is the ratio of the average out-of-roundness of the outer contour of each test pipe segment to the out-of-roundness threshold; the out-of-roundness of the outer contour is the difference between the maximum diameter and the minimum diameter of the outer contour. The characteristic value of the interface bonding strength is the ratio between the average bonding force between the core tube and the coating layer of each test tube segment and the preset bonding force.

[0034] Specifically, the inner out-of-roundness threshold is set to 0.5 mm. This threshold is determined based on the requirements for the stability of internal fluid transport during long-term use of the pipe, ensuring that inner contour deformation does not affect the medium flow rate and pressure distribution. The outer out-of-roundness threshold is set to 0.8 mm, mainly considering that the external structure of the pipe needs to adapt to the mechanical protection requirements of different laying environments, avoiding a decrease in impact resistance due to excessive deformation of the outer contour. The preset bonding force is set to 120 N. This value refers to the standard specifications for the bonding strength between the core tube and the coating layer of composite pipes in the industry, and also incorporates the characteristic test results of graphene composite polyethylene materials, to ensure that the core tube and the coating layer will not separate under tensile, bending, or other external forces. By quantitatively comparing the first out-of-roundness characteristic value, the second out-of-roundness characteristic value, and the interface bonding strength characteristic value with the corresponding thresholds, a rapid assessment of the comprehensive performance of the pipe can be achieved.

[0035] Specifically, in response to the first out-of-roundness characteristic value being less than the first preset out-of-roundness threshold, it is initially determined that the preparation of the target composite tube meets the preset standard, and the preparation of the target composite tube is verified according to the interface bonding strength characteristic value.

[0036] Specifically, in response to the first out-of-round characteristic value being greater than or equal to the first preset out-of-round threshold, it is initially determined that the preparation of the target composite tube does not meet the preset standard, and the reason why the preparation of the target composite tube does not meet the preset standard is determined based on the second out-of-round characteristic value.

[0037] Specifically, the first preset out-of-roundness threshold is set to 0.8. This threshold is set based on the required machining accuracy of the pipe's inner contour. The machining accuracy of the pipe's inner contour directly affects the overall quality and performance of the pipe. If the out-of-roundness is too large, it may cause problems during the use of the pipe. In practical applications, the pipe needs to be precisely connected with other components. An unreasonable out-of-roundness threshold setting will cause problems during the installation and connection process, affecting the assembly efficiency and quality of the entire project or product.

[0038] Specifically, the fabrication of the target composite tube is verified based on the interface combined with the strength characteristic value to determine whether it meets the preset standard. If the interfacial bonding strength characteristic value is less than the preset interfacial bonding strength threshold, the preparation of the target composite tube is verified to be non-compliant with the preset standard, and the preset heating temperature of the next batch of core tubes is increased according to the difference between the preset interfacial bonding strength threshold and the interfacial bonding strength characteristic value. If the characteristic value of the interfacial bonding strength is greater than or equal to the preset interfacial bonding strength threshold, then the preparation of the target composite tube is verified to meet the preset standard.

[0039] Specifically, the interfacial bonding strength characteristic value is set to 0.9. When the interfacial bonding strength characteristic value is greater than or equal to 0.9, the interfacial bonding strength of the target composite tube is determined to meet the preset standard; when the interfacial bonding strength characteristic value is less than 0.9, the interfacial bonding strength of the target composite tube is determined to not meet the preset standard. After adjusting the process parameters, a small-batch trial production needs to be carried out again, and the interfacial bonding strength of the newly prepared test tube section needs to be tested until the interfacial bonding strength characteristic value reaches the preset standard, so as to ensure that the core tube and the coating layer can work together to bear the force during the use of the target composite tube and avoid delamination.

[0040] Specifically, the increase in the preset temperature of the next batch of core tubes is positively correlated with the difference between the preset interfacial bonding strength threshold and the interfacial bonding strength characteristic value. It is understood that this positive correlation can be linear or nonlinear, and is not specifically limited. The slope of the linear positive correlation is also not specifically limited and can be set according to the actual preparation conditions, as long as the larger the difference between the preset interfacial bonding strength threshold and the interfacial bonding strength characteristic value, the larger the increase in the preset temperature of the next batch of core tubes. For example, if the increase in the preset temperature of the next batch of core tubes is set to ΔM, and the difference between the preset interfacial bonding strength threshold and the interfacial bonding strength characteristic value is set to Δμ, then ΔM = γ × (Δμ + μ0), where γ is the temperature rise adjustment coefficient, set to 1.06, and μ0 is a constant.

[0041] Specifically, the reason why the preparation of the target composite tube does not meet the preset standard is determined based on the second out-of-roundness characteristic value. If the second out-of-round characteristic value is less than the second preset out-of-round threshold, it is determined that the reason why the preparation of the target composite pipe does not meet the preset standard is that the extrusion pressure of the second pipe extruder is too high, and the extrusion pressure of the second pipe extruder in the next batch is reduced according to the difference between the second preset out-of-round threshold and the second out-of-round characteristic value. If the second out-of-round characteristic value is greater than or equal to the second preset out-of-round threshold, it is determined that the reason why the preparation of the target composite tube does not meet the preset standard is that the cooling rate of the coating layer is too fast, and the cooling rate of the coating layer in the next batch is reduced according to the difference between the second out-of-round characteristic value and the second preset out-of-round threshold.

[0042] Specifically, the second preset out-of-round threshold is set to 0.85. When the second out-of-round characteristic value is less than 0.85, it indicates that the out-of-roundness of the target composite pipe is lower than the expected lower limit. At this time, the extrusion pressure of the second batch of pipe extruders needs to be reduced. The reduction range is proportional to the difference between 0.85 and the current second out-of-round characteristic value to reduce the problem of excessive shrinkage of the pipe outer contour caused by excessive extrusion pressure. When the second out-of-round characteristic value is greater than or equal to 0.85, it indicates that the out-of-roundness of the pipe outer contour exceeds the acceptable range. This is usually due to the excessive cooling rate of the coating layer during the cooling process, which causes uneven stress distribution inside the material and thus leads to pipe deformation. At this time, the cooling rate of the next batch of coating layer should be reduced accordingly according to the difference between the second out-of-round characteristic value and 0.85. By slowing down the cooling rate, the coating layer material has more time to release stress, thereby ensuring that the dimensional accuracy of the target composite pipe meets the preset standard.

[0043] Specifically, the reduction in the extrusion pressure of the second pipe extruder in the next batch is directly related to the difference between the second preset out-of-roundness threshold and the second out-of-roundness characteristic value. It is understood that the adjustment of the reduction in the extrusion pressure of the second pipe extruder in the next batch can be adjusted in the same way as the adjustment of the increase in the preset temperature of the core tube heating, which will not be elaborated here.

[0044] Specifically, the reduction in the cooling rate of the coating layer in the next batch is directly related to the difference between the second out-of-roundness characteristic value and the second preset out-of-roundness threshold. It is understood that the adjustment of the reduction in the extrusion pressure of the second pipe extruder in the next batch can be adjusted in the same way as the adjustment of the increase in the preset temperature of the core tube heating, which will not be elaborated here.

[0045] Specifically, the ratio of the modified polyethylene mixture to the graphene dispersion injected into the mixing device is 100:20. This ratio has been verified through multiple experiments and can ensure the uniform dispersion of graphene particles in the matrix while maintaining the original mechanical properties of the modified polyethylene matrix, thereby effectively improving the thermal conductivity and corrosion resistance of the composite pipe. In actual production, the feeding rate of the two materials needs to be controlled by a high-precision metering pump to ensure that the ratio deviation is controlled within ±1%, so as to avoid fluctuations in pipe performance due to imbalance in the ratio.

[0046] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a multifunctional graphene composite polyethylene pipe, characterized in that, It includes: Step S1: Prepare a modified polyethylene mixture and a graphene dispersion, and inject the modified polyethylene mixture and the graphene dispersion into a mixing device for melt blending to obtain a graphene composite polyethylene melt. Step S2: The graphene composite polyethylene melt is placed into the first pipe extruder to complete the core tube forming of the graphene composite polyethylene melt. Step S3: After heating the core tube to a preset temperature, it is fed into a second pipe extruder. Pure polyethylene is used to coat the graphene core tube with an outer layer, and then it is cooled and formed to obtain the target composite pipe. Step S4: Cut several test pipe segments from the target composite pipe and obtain the inner contour dimension information, outer contour dimension information and interface bonding strength information of each test pipe segment; Step S5: Based on the inner contour size information and the outer contour size information, obtain the first out-of-round feature value and the second out-of-round feature value respectively, and preliminarily determine whether the preparation of the target composite tube meets the preset standard based on the first out-of-round feature value; Step S6a: In response to the preliminary determination that the preparation of the target composite tube meets the preset standard, the preparation of the target composite tube is verified according to the interface bonding strength characteristic value to check whether it meets the preset standard. Step S6b: In response to the preliminary determination that the preparation of the target composite tube does not meet the preset standard, the reason why the preparation of the target composite tube does not meet the preset standard is determined according to the second out-of-round characteristic value, and the preset temperature of the core tube heating, the extrusion pressure of the second pipe extruder and the cooling rate of the coating layer are adjusted for the next batch of prepared core tubes.

2. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 1, characterized in that, The first out-of-roundness characteristic value is the ratio of the average out-of-roundness of the inner contour of each test pipe segment to the out-of-roundness threshold; the out-of-roundness of the inner contour is the difference between the maximum diameter and the minimum diameter of the inner contour. The second out-of-roundness characteristic value is the ratio of the average out-of-roundness of the outer contour of each test pipe segment to the out-of-roundness threshold; the out-of-roundness of the outer contour is the difference between the maximum diameter and the minimum diameter of the outer contour. The characteristic value of the interface bonding strength is the ratio between the average bonding force between the core tube and the coating layer of each test tube segment and the preset bonding force.

3. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 2, characterized in that, When the first out-of-roundness characteristic value is less than the first preset out-of-roundness threshold, it is initially determined that the preparation of the target composite tube meets the preset standard, and the preparation of the target composite tube is verified according to the interface bonding strength characteristic value.

4. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 3, characterized in that, When the first out-of-round characteristic value is greater than or equal to the first preset out-of-round threshold, it is initially determined that the preparation of the target composite tube does not meet the preset standard, and the reason why the preparation of the target composite tube does not meet the preset standard is determined according to the second out-of-round characteristic value.

5. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 4, characterized in that, The fabrication of the target composite tube is verified based on the interface and strength characteristic value to determine whether it meets the preset standard. If the interfacial bonding strength characteristic value is less than the preset interfacial bonding strength threshold, the preparation of the target composite tube is verified to be non-compliant with the preset standard, and the preset heating temperature of the next batch of core tubes is increased according to the difference between the preset interfacial bonding strength threshold and the interfacial bonding strength characteristic value. If the characteristic value of the interfacial bonding strength is greater than or equal to the preset interfacial bonding strength threshold, then the preparation of the target composite tube is verified to meet the preset standard.

6. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 5, characterized in that, The increase in the preset temperature of the core tube heating in the next batch is positively correlated with the difference between the preset interface bonding strength threshold and the interface bonding strength characteristic value.

7. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 6, characterized in that, The reason why the preparation of the target composite tube does not meet the preset standard is determined based on the second out-of-round characteristic value. If the second out-of-round characteristic value is less than the second preset out-of-round threshold, it is determined that the reason why the preparation of the target composite pipe does not meet the preset standard is that the extrusion pressure of the second pipe extruder is too high, and the extrusion pressure of the second pipe extruder in the next batch is reduced according to the difference between the second preset out-of-round threshold and the second out-of-round characteristic value. If the second out-of-round characteristic value is greater than or equal to the second preset out-of-round threshold, it is determined that the reason why the preparation of the target composite tube does not meet the preset standard is that the cooling rate of the coating layer is too fast, and the cooling rate of the coating layer in the next batch is reduced according to the difference between the second out-of-round characteristic value and the second preset out-of-round threshold.

8. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 7, characterized in that, The reduction in the extrusion pressure of the second pipe extruder in the next batch is positively correlated with the difference between the second preset out-of-round threshold and the second out-of-round characteristic value.

9. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 8, characterized in that, The decrease in the cooling rate of the coating layer in the next batch is positively correlated with the difference between the second out-of-round characteristic value and the second preset out-of-round threshold.

10. The method for preparing the multifunctional graphene composite polyethylene pipe according to claim 9, characterized in that, The ratio of the modified polyethylene mixture to the graphene dispersion injected into the mixing device is 100:20.

Images