A kind of polyolefin weather-resistant pipe and preparation method thereof

Abstract

The present application relates to a polyolefin weather-resistant pipe and a preparation method thereof, comprising a pipe body and a weather-resistant coating, wherein the weather-resistant coating is obtained by coating the weather-resistant coating on the surface of the pipe body, wherein the weather-resistant coating comprises acrylic resin, octadecane phase change microcapsules, epoxy resin, ammonium polyphosphate, a leveling agent, and a curing agent; and the octadecane phase change microcapsules comprise octadecane, polymethacrylate, and a reinforcing material. The present application has the effect of improving the overall weather resistance of the pipe.

Description

Technical Field

[0001] The present application relates to the field of pipes, and in particular to a polyolefin weather-resistant pipe and a preparation method thereof. Background Art

[0002] Pipes are essential materials for construction projects. Compared with traditional cast iron pipes, galvanized steel pipes, cement pipes and other pipes, plastic pipes are energy-saving and environmentally friendly, lightweight, and easy to construct and maintain. They are widely used in building water supply and drainage, urban gas, transportation and other fields.

[0003] In recent years, with the development of industries such as construction, municipal engineering, and water conservancy engineering and the continuous increase in market demand, plastic pipes have also shown a rapid development state. While the output of plastic pipes has increased, product quality has also been continuously improved.

[0004] However, as the demand for product applications continues to increase, the ability of pipes to withstand the climate in outdoor environments is also constantly increasing. Pipes are exposed to the outdoors for a long time, and are prone to cracking under ultraviolet rays, wind, rain and other environments, which affects the service life of the pipes. Summary of the invention

[0005] In order to improve the weather resistance of the pipe, the present application provides a polyolefin weather-resistant pipe and a preparation method thereof.

[0006] The present application provides a polyolefin weather-resistant pipe and a preparation method thereof using the following technical solutions: In the first aspect, the present application provides a polyolefin weather-resistant pipe, which adopts the following technical solution: A polyolefin weather-resistant pipe comprises a pipe body and a weather-resistant coating, wherein the weather-resistant coating is obtained by coating the weather-resistant coating on the surface of the pipe body, and the weather-resistant coating comprises acrylic resin, octadecane phase change microcapsules, ethyl acetate, epoxy resin, ammonium polyphosphate, a leveling agent, and a curing agent; The octadecane phase change microcapsules include octadecane, polymethacrylate and reinforcing materials.

[0007] By adopting the above technical scheme, after the weather-resistant coating is coated on the surface of the pipeline body, the weather-resistant coating forms a layer of weather-resistant coating on the pipeline body, and octadecane phase change microcapsules and ammonium polyphosphate are added to the weather-resistant coating. Ammonium polyphosphate is an organic phosphide, which has good compatibility in the weather-resistant coating, and has good weather resistance, corrosion resistance and flame retardancy. It can release phosphoric acid at high temperature to form a protective layer to prevent the pipeline from continuing to burn. At the same time, it can improve the overall thermal stability and mechanical properties of the pipeline, so that the overall weather resistance of the pipe is improved; the octadecane phase change microcapsules use octadecane as the core material and polymethyl methacrylate as the shell material, and the microcapsules are obtained by cross-linking. The prepared octadecane phase change microcapsules have good stability and can undergo phase transition according to their own characteristics and ambient temperature, thereby storing and releasing energy, further making the prepared weather-resistant coating have good weather resistance, so as to improve the overall stability and weather resistance of the pipe.

[0008] Preferably, the octadecane phase change microcapsules are prepared by the following method: The emulsifier is diluted with water, and the reinforcing material is added, ultrasonic treatment is performed, and heating in a water bath is performed to obtain a water phase; the initiator azobisisobutyronitrile and methyl methacrylate are mixed until the azobisisobutyronitrile is completely dissolved, and then the cross-linking agent pentaerythritol tetraacrylate is added, mixed, and octadecane is added to obtain an oil phase; the oil phase is added to the water phase, stirred to obtain a uniform emulsion, deoxygenated and continued to stir, heated to react, and dried to obtain octadecane phase change microcapsules.

[0009] Preferably, the emulsifier comprises polyvinyl alcohol.

[0010] Preferably, the mass ratio between octadecane and methyl methacrylate is 7:(3.3-3.5).

[0011] By adopting the above technical solution, preferably the mass ratio between octadecane and methyl methacrylate is within the above range, which can further improve the overall stability of the prepared phase change microcapsule material.

[0012] Preferably, the reinforcing material comprises modified graphene oxide, and the modified graphene oxide comprises graphene and L-glutamic acid.

[0013] The polymerized monomer methyl methacrylate forms polymethyl methacrylate during the polymerization process, and the density of the material changes, which will cause the microcapsules to sag. After the reinforcing material modified graphene oxide is added, the surface activity of the modified graphene oxide can solidify the graphene oxide into the microcapsules as a thermal conductive reinforcing material. The modified graphene oxide is adsorbed at the oil-water interface. During the polymerization of methyl methacrylate, it is accumulated at the oil-water interface together with polymethyl methacrylate, thereby improving the mechanical strength of the formed phase change microcapsules. At the same time, the modified graphene oxide increases the resistance of the polymerized polymethyl methacrylate molecules to the outward diffusion, so that more polymethyl methacrylate is accumulated on the surface of the phase change microcapsules, thereby improving the strength of the phase change microcapsules, and improving the surface roughness of the phase change microcapsules, so that the adhesion between the microcapsule particles is improved, and the dispersion of the particles is further improved. In addition, compared with other amino acids such as glycine, L-glutamic acid introduces dicarboxyl groups and amino groups, which are easier to associate with oxygen in the polymerized monomer esters, its own carboxyl groups and / or amino groups, thereby intervening in the dynamic polymerization process and reducing the molecular weight distribution PDI of the polymerization. At the same time, with the above-mentioned bonding effect between atoms, graphene oxide participates in the dynamic addition polymerization process during the polymerization process, and the solidification distribution in the microcapsule is more uniform, thereby improving the reinforcement effect.

[0014] Preferably, the modified graphene oxide is prepared by the following method: The graphene oxide is mixed with water and then ultrasonicated to obtain a graphene oxide dispersion, L-glutamic acid is mixed with a sodium hydroxide solution to obtain a glutamic acid solution, the glutamic acid solution is added to the graphene oxide dispersion, ultrasonically dispersed, and stirred until the system changes from black to dark brown, then the stirring is stopped, and the modified graphene oxide is washed and dried to obtain.

[0015] By adopting the above technical solution, after graphene oxide is modified by L-glutamic acid, L-glutamic acid is attached to the surface of graphene oxide, the spacing of graphene oxide is increased, and the phenomenon of graphene oxide agglomeration in the system is reduced. In addition, the amino group of L-glutamic acid can produce a strong interface interaction with the epoxy resin, thereby further improving the overall connection strength of the system.

[0016] Preferably, the mass ratio of the graphene oxide to L-glutamic acid is 1:(3.1-3.5).

[0017] By adopting the above technical solution, the mass ratio between graphene oxide and L-glutamic acid is preferably within the above range, which can further improve the overall dispersibility and stability of the modified graphene oxide.

[0018] Preferably, the modified graphene oxide accounts for 0.6-0.8% of the overall mass fraction of the octadecane phase change microcapsules.

[0019] By adopting the above technical solution, the mass fraction of the modified graphene oxide in the octadecane phase change microcapsules is preferably within the above range, which can further improve the overall stability of the prepared octadecane phase change microcapsules.

[0020] In a second aspect, the present application provides a method for preparing a polyolefin weather-resistant pipe, which adopts the following technical solution: In summary, the present application includes at least one of the following beneficial technical effects: In the present application, after the weather-resistant coating is coated on the pipeline body, a layer of weather-resistant coating is formed on the surface of the pipeline body. Octadecane phase change microcapsules and ammonium polyphosphate are added to the weather-resistant coating. Ammonium polyphosphate has good weather resistance and flame retardancy. After being added to the weather-resistant coating, the compatibility between the various components in the weather-resistant coating is improved. The octadecane phase change microcapsules use octadecane as the core material and polymethyl methacrylate as the shell material, and are prepared by cross-linking. They can undergo phase transition according to their own characteristics and ambient temperature to store and release energy. The external temperature transfers heat to the inside of the microcapsules. The shell material can effectively block the decomposition of octadecane from the microcapsules, so that the octadecane phase change microcapsules improve the weather resistance and stability of the weather-resistant coating. Modified graphene oxide is added to the octadecane phase change microcapsules as a reinforcing material. On the one hand, when the octadecane phase change microcapsules are polymerized, the modified graphene oxide is deposited at the oil-water pseudo interface together with polymethyl methacrylate, so that the mechanical strength of the formed octadecane phase change microcapsules is improved. At the same time, the modified graphene oxide increases the resistance of the polymerized polymethyl methacrylate molecules to the outward diffusion, so that more polymethyl methacrylate is deposited on the surface of the octadecane phase change microcapsules, thereby improving the mechanical strength of the phase change microcapsules. The modified graphene oxide can also improve the surface roughness of the phase change microcapsules, thereby improving the adhesion of the octadecane phase change microcapsules, and further improving the stability of the octadecane phase change microcapsules. After graphene oxide is modified by L-glutamic acid, the surface of graphene oxide contains rich groups, the compatibility of graphene oxide is improved, and at the same time, the spacing between graphene oxide sheets is increased, thereby improving the dispersion performance of graphene oxide. At the same time, the amino groups of the modified graphene oxide on the surface of octadecane phase change microcapsules undergo a ring-opening reaction with the epoxy groups of the epoxy resin, resulting in strong interfacial interactions and increased cross-linking density, thereby further improving the overall connection strength of the weather-resistant coating, improving the stability of the weather-resistant coating, and thus improving the overall service life of the pipe. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments: Raw materials description: All raw materials in the examples can be obtained from commercial sources. Example 1

[0022] Preparation of modified graphene oxide: Graphene oxide was mixed with 500 mL of deionized water and ultrasonicated for 30 minutes to obtain a graphene oxide dispersion. L-glutamic acid (CAS No.: 56-86-0) was added to 500 mL of 4 mg / mL sodium hydroxide solution, and stirred at a speed of 300 r / min for 20 minutes to obtain a glutamic acid solution. The glutamic acid solution was added to the graphene oxide dispersion so that the mass ratio between graphene oxide and L-glutamic acid was 1:3.1. Ultrasonic dispersion was performed for 20 minutes, and then stirred for 24 hours at 25°C under nitrogen protection. When the system changed from black to dark brown, stirring was stopped, ethanol and deionized water were used for centrifugal washing, and the product was dried in a vacuum drying oven at 50°C for 12 hours. The modified graphene oxide was obtained after grinding.

[0023] Preparation of octadecane phase change microcapsules: 0.7 g of polyvinyl alcohol (CAS No.: 9002-89-5) was mixed with 50 g of deionized water, heated to 80°C in a water bath, and stirred at a speed of 100 r / min until the polyvinyl alcohol was dissolved to obtain an emulsifier; the emulsifier was diluted with 20 g of deionized water, stirred and diluted at a speed of 120 r / min, and then modified graphene oxide was added, ultrasonically treated for 30 minutes, hydrochloric acid was added to adjust the pH of the dispersion to 5, and heated to 50°C in a water bath to obtain an aqueous phase; 0.25 g of initiator azobisisobutyronitrile (CAS No.: 78-67-1) was mixed with 6.41 g of methyl methacrylate (CAS No.: 80-62-6), shaken until the azobisisobutyronitrile was completely dissolved, and then 0.65 g of crosslinking agent was added. The mixture was stirred at 6000 r / min for 5 min to obtain a uniform emulsion, and the uniform emulsion was stirred at 500 r / min, and then deoxygenated for 10 min in a nitrogen environment, and then the stirring speed was adjusted to 800 r / min, the temperature was raised to 70°C, and the reaction was carried out for 2 h, and then the temperature was raised to 80°C, and the reaction was carried out for 3 h. After the reaction, the mixture was dried in a vacuum drying oven for 12 h to obtain octadecane phase change microcapsules; wherein the amount of graphene oxide added was 0.6wt% of the total octadecane phase change microcapsules.

[0024] Preparation of weather-resistant coatings: 75 g of acrylic resin, 6 g of octadecane phase change microcapsules, 14 g of epoxy resin, 3 g of ammonium polyphosphate (CAS No.: 14728-39-3), 18 g of ethyl acetate, 4 g of curing agent and 1 g of leveling agent were mixed, stirred at a speed of 300 r / min for 15 min, and allowed to stand for 10 min to obtain a weather-resistant coating.

[0025] Preparation of polyolefin weather-resistant pipes: The weather-resistant coating is evenly coated on the surface of the pipe body, and dried and cured at 50° C. for 24 hours, so that a layer of weather-resistant coating is formed on the surface of the pipe body to obtain a polyolefin weather-resistant pipe. Example 2

[0026] Preparation of modified graphene oxide: The graphene oxide was mixed with 500 mL of deionized water and ultrasonicated for 30 minutes to obtain a graphene oxide dispersion. L-glutamic acid was added to 500 mL of a 4 mg / mL sodium hydroxide solution and stirred at 300 r / min for 20 minutes to obtain a glutamic acid solution. The glutamic acid solution was added to the graphene oxide dispersion so that the mass ratio of graphene oxide to L-glutamic acid was 1:3.5. Ultrasonic dispersion was performed for 20 minutes, and then stirring was performed at 25° C. under nitrogen protection for 24 hours. When the system changed from black to dark brown, stirring was stopped, ethanol and deionized water were used for centrifugal washing, and the product was dried in a vacuum drying oven at 50° C. for 12 hours. The modified graphene oxide was obtained after grinding.

[0027] Preparation of octadecane phase change microcapsules: 0.9 g of polyvinyl alcohol was mixed with 50 g of deionized water, and the mixture was heated to 80° C. in a water bath, and stirred at a speed of 100 r / min until the polyvinyl alcohol was dissolved to obtain an emulsifier; 20 g of deionized water was added to the emulsifier to dilute it, and the mixture was stirred at a speed of 120 r / min to dilute it, and then modified graphene oxide was added, and ultrasonic treatment was performed for 30 min. Hydrochloric acid was added to adjust the pH of the dispersion to 5, and the mixture was heated to 50° C. in a water bath to obtain an aqueous phase; 0.35 g of an initiator azobisisobutyronitrile was mixed with 6.67 g of methyl methacrylate, and the mixture was shaken until the azobisisobutyronitrile was completely dissolved, and then 0.65 g of a cross-linking agent pentaerythritol tetrapropylene glycol was added. The ester was shaken and 13.33 g of octadecane was added and mixed at a temperature of 40°C to obtain an oil phase; the oil phase was added to the water phase and stirred at a speed of 6000 r / min for 5 min to obtain a uniform emulsion, the uniform emulsion was stirred at a speed of 500 r / min, and then deoxygenated for 10 min in a nitrogen environment, and then the stirring speed was adjusted to 800 r / min, the temperature was raised to 70°C, the reaction was carried out for 2 h, and then the temperature was raised to 80°C and the reaction was carried out for 3 h. After the reaction, the octadecane phase change microcapsules were dried in a vacuum drying oven for 12 h to obtain octadecane phase change microcapsules; wherein the amount of graphene oxide added was 0.8 wt% of the total octadecane phase change microcapsules.

[0028] Preparation of weather-resistant coatings: 85 g of acrylic resin, 8 g of octadecane phase change microcapsules, 22 g of ethyl acetate, 20 g of epoxy resin, 5 g of ammonium polyphosphate, 8 g of curing agent and 3 g of leveling agent were mixed, stirred at a speed of 300 r / min for 15 min, and allowed to stand for 10 min to obtain a weather-resistant coating.

[0029] Preparation of polyolefin weather-resistant pipes: The weather-resistant coating is evenly coated on the surface of the pipe body, and dried and cured at 50° C. for 24 hours, so that a layer of weather-resistant coating is formed on the surface of the pipe body to obtain a polyolefin weather-resistant pipe. Example 3

[0030] Preparation of modified graphene oxide: The graphene oxide was mixed with 500 mL of deionized water and ultrasonicated for 30 minutes to obtain a graphene oxide dispersion. L-glutamic acid was added to 500 mL of a 4 mg / mL sodium hydroxide solution and stirred at 300 r / min for 20 minutes to obtain a glutamic acid solution. The glutamic acid solution was added to the graphene oxide dispersion so that the mass ratio of graphene oxide to L-glutamic acid was 1:3.3. Ultrasonic dispersion was performed for 20 minutes, and then stirring was performed at 25° C. under nitrogen protection for 24 hours. When the system changed from black to dark brown, stirring was stopped, ethanol and deionized water were used for centrifugal washing, and the product was dried in a vacuum drying oven at 50° C. for 12 hours. The modified graphene oxide was obtained after grinding.

[0031] Preparation of octadecane phase change microcapsules: 0.8 g of polyvinyl alcohol was mixed with 50 g of deionized water, and the mixture was heated to 80° C. in a water bath, and stirred at a speed of 100 r / min until the polyvinyl alcohol was dissolved to obtain an emulsifier; 20 g of deionized water was added to the emulsifier to dilute it, and the mixture was stirred at a speed of 120 r / min to dilute it, and then modified graphene oxide was added, and ultrasonic treatment was performed for 30 min. Hydrochloric acid was added to adjust the pH of the dispersion to 5, and the mixture was heated to 50° C. in a water bath to obtain an aqueous phase; 0.3 g of an initiator azobisisobutyronitrile was mixed with 6.54 g of methyl methacrylate, and the mixture was shaken until the azobisisobutyronitrile was completely dissolved, and then 0.65 g of a cross-linking agent pentaerythritol tetrapropylene glycol was added. The ester was shaken and 13.46 g of octadecane was added and mixed at a temperature of 40°C to obtain an oil phase; the oil phase was added to the water phase and stirred at a speed of 6000 r / min for 5 min to obtain a uniform emulsion, the uniform emulsion was stirred at a speed of 500 r / min, and then deoxygenated for 10 min in a nitrogen environment, and then the stirring speed was adjusted to 800 r / min, the temperature was raised to 70°C, and the reaction was carried out for 2 h, and then the temperature was raised to 80°C and the reaction was carried out for 3 h. After the reaction, the octadecane phase change microcapsules were dried in a vacuum drying oven for 12 h to obtain octadecane phase change microcapsules; wherein the amount of graphene oxide added was 0.7wt% of the total octadecane phase change microcapsules.

[0032] Preparation of weather-resistant coatings: 80 g of acrylic resin, 7 g of octadecane phase change microcapsules, 20 g of ethyl acetate, 17 g of epoxy resin, 4 g of ammonium polyphosphate, 6 g of curing agent and 2 g of leveling agent were mixed, stirred at a speed of 300 r / min for 15 min, and allowed to stand for 10 min to obtain a weather-resistant coating.

[0033] Preparation of polyolefin weather-resistant pipes: The weather-resistant coating is evenly coated on the surface of the pipe body, and dried and cured at 50° C. for 24 hours, so that a layer of weather-resistant coating is formed on the surface of the pipe body to obtain a polyolefin weather-resistant pipe. Example 4

[0034] Example 4 is based on Example 3. The difference between Example 4 and Example 3 is that when preparing modified graphene oxide, the mass ratio between graphene oxide and L-glutamic acid is 1:2.8. Example 5

[0035] Example 5 is based on Example 3. The difference between Example 5 and Example 3 is that when preparing modified graphene oxide, the mass ratio between graphene oxide and L-glutamic acid is 1:3.8. Example 6

[0036] Example 6 is based on Example 3. The difference between Example 6 and Example 3 is that when preparing octadecane phase change microcapsules, 14 g of octadecane and 6 g of methyl methacrylate are added. Example 7

[0037] Example 7 is based on Example 3. The difference between Example 7 and Example 3 is that when preparing octadecane phase change microcapsules, 12.73 g of octadecane and 7.27 g of methyl methacrylate are added. Example 8

[0038] Example 8 is based on Example 3. The difference between Example 8 and Example 3 is that when preparing octadecane phase change microcapsules, polyvinyl alcohol in the emulsifier is replaced by an equal amount of sodium dodecyl sulfate. Example 9

[0039] Example 9 is based on Example 3. The difference between Example 9 and Example 3 is that when preparing octadecane phase change microcapsules, the amount of polyvinyl alcohol used is 0.5 g. Example 10

[0040] Example 10 is based on Example 3. The difference between Example 10 and Example 3 is that when preparing octadecane phase change microcapsules, the amount of polyvinyl alcohol used is 1.1 g. Embodiment 11

[0041] Example 11 is based on Example 3. The difference between Example 11 and Example 3 is that when preparing octadecane phase change microcapsules, the modified graphene oxide accounts for 0.4wt% of the octadecane phase change microcapsules. Example 12

[0042] Example 12 is based on Example 3. The difference between Example 12 and Example 3 is that when preparing octadecane phase change microcapsules, the modified graphene oxide accounts for 1wt% of the octadecane phase change microcapsules. Example 13

[0043] Example 13 is based on Example 3. The difference between Example 13 and Example 3 is that the modified graphene oxide in the reinforcing material is replaced by unmodified graphene oxide. Embodiment 14

[0044] Example 14 is based on Example 3. The difference between Example 14 and Example 3 is that L-glutamic acid is replaced by glycine in the preparation of modified graphene oxide.

[0045] Comparative Example 1 Comparative Example 1 is based on Example 3. The difference between Comparative Example 1 and Example 3 is that no modified graphene oxide is added to the octadecyl phase change microcapsules.

[0046] Performance testing The following performance tests were performed on the polyolefin weather-resistant pipe samples prepared in Examples 1-12 and Comparative Example 1: (1) Weathering performance test Based on GB / T 16422.2-2014, the weather resistance of the samples was tested by a cycle test: ① UV light exposure for 8 hours, light intensity 0.65W / m 2 , temperature 55℃; ② Spray for 4h, temperature 50℃, 800 hours; and fill in the test results in Table 1; the standard is △E≤3.

[0047] (2) Impact resistance test Based on GB / T 14152-2001 as the testing standard, test the impact resistance of the samples and fill in the test results in Table 1.

[0048] Table 1 Performance test results of Examples 1-12 and Comparative Example 1

[0049] Combined with Table 1, it can be seen that the ΔE of Examples 1-3 is 1.6 or less, indicating that the polyolefin weather-resistant pipe prepared in this application has good weather resistance; the impact resistance of Examples 1-3 is 68 kJ / m 2 The above indicates that the polyolefin weather-resistant pipe prepared in the present application has good impact resistance.

[0050] In Example 4 and Example 5, when preparing modified graphene oxide, the mass ratio of graphene oxide to L-glutamic acid is not within the range specified in the present application. When the content of L-glutamic acid is too little, it is difficult to modify a sufficient amount of graphene oxide, the compatibility of graphene oxide decreases, and the interlayer improvement phenomenon of graphene oxide is difficult to further improve, so the dispersion performance of graphene oxide decreases, affecting the overall stability of graphene oxide, and the binding performance with epoxy resin is also affected; when the content of L-glutamic acid is too much, the grafting of graphene oxide is saturated, it is difficult to further improve the dispersibility of graphene oxide, and too much L-glutamic acid affects the stability of graphene oxide, so the weather resistance and impact resistance of Example 4 and Example 5 are both reduced.

[0051] In Examples 6 and 7, when preparing octadecane phase change microcapsules, the mass ratio of octadecane to methyl methacrylate used is not within the range specified in the present application. When the content of methyl methacrylate is too little, the proportion of the shell material of the octadecane phase change microcapsules decreases, the stability of the shell material decreases, it is difficult to form a stable three-dimensional network structure, and adhesion occurs during drying, thereby affecting the stability of the octadecane phase change microcapsules; when the content of methyl methacrylate is too much, the shell material of the octadecane phase change microcapsules accounts for too large a proportion, the microcapsules become concave, and the particle size uniformity decreases, thereby reducing the dispersion performance of the octadecane phase change microcapsules in the system, affecting the stability of the weather-resistant coating, and therefore the performance of Examples 6 and 7 decreases.

[0052] In Example 8, polyvinyl alcohol in the emulsifier was replaced with sodium dodecyl sulfate. When sodium dodecyl sulfate was used as the emulsifier, the microspheres in the obtained emulsion agglomerated and piled up together. The stability of the subsequently prepared octadecyl microcapsules decreased, affecting the overall stability of the weather-resistant coating. Therefore, the performance of Example 8 decreased.

[0053] The amount of polyvinyl alcohol used in Examples 9 and 10 was adjusted. When the amount of polyvinyl alcohol used was too much or too little, it would have some influence on the dispersion performance of the emulsion. Therefore, the weather resistance and compressive strength of Examples 9 and 10 were reduced.

[0054] The amount of modified graphene oxide used in Example 11 and Example 12 is not within the scope specified in the present application. When the amount of modified graphene oxide used is too small, the effect of accumulation at the oil-water interface during the polymerization of methyl methacrylate decreases, the mechanical strength of the octadecane phase change microcapsules is difficult to further improve, and the roughness improvement effect is also reduced, which affects the stability of the octadecane phase change microcapsules. At the same time, the bonding performance with the epoxy resin is also reduced, so the stability of the weather-resistant coating is affected; when the content of modified graphene oxide is too much, agglomeration will occur in the system, which will also affect the stability of the octadecane phase change microcapsules, so the weather resistance and impact resistance of Example 11 and Example 12 are both reduced.

[0055] Example 13 uses ordinary graphene oxide. The dispersibility of unmodified graphene oxide is difficult to improve, and its stability in the system is reduced, so the performance of Example 13 is reduced.

[0056] In Example 14, L-glutamic acid was replaced by glycine. The binding performance of glycine with graphene oxide was poor, thus affecting the grafting rate, so the performance of Example 14 decreased.

[0057] In Comparative Example 1, no modified graphene oxide was added to the octadecane phase change microcapsules. During the polymerization process, the phase change microcapsules without modified graphene oxide showed depressions, and the particle size uniformity of the microcapsules decreased, affecting the overall stability of the system. At the same time, without modified graphene oxide, it was difficult to combine and interact with the epoxy resin, so the stability of the obtained weather-resistant coating was reduced. Therefore, the weather resistance and impact strength of Comparative Example 1 were both reduced.

[0058] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of ​​the present application. The technical scope of the present application is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A polyolefin weather-resistant pipe, characterized in that: It includes a pipeline body and a weather-resistant coating, wherein the weather-resistant coating is obtained by coating the weather-resistant coating on the surface of the pipeline body, and the weather-resistant coating includes acrylic resin, octadecane phase change microcapsules, epoxy resin, ethyl acetate, ammonium polyphosphate, leveling agent, and curing agent; The octadecane phase change microcapsules include octadecane, polymethacrylate and reinforcing materials.

2. The polyolefin weather-resistant pipe according to claim 1, characterized in that: The octadecane phase change microcapsules are prepared by the following method: The emulsifier is diluted with water, and the reinforcing material is added, ultrasonic treatment is performed, and heating in a water bath is performed to obtain a water phase; the initiator azobisisobutyronitrile and methyl methacrylate are mixed until the azobisisobutyronitrile is completely dissolved, and then the cross-linking agent pentaerythritol tetraacrylate is added, mixed, and octadecane is added to obtain an oil phase; the oil phase is added to the water phase, stirred to obtain a uniform emulsion, deoxygenated and continued to stir, heated to react, and dried to obtain octadecane phase change microcapsules.

3. A polyolefin weather-resistant pipe according to claim 2, characterized in that: The emulsifier includes polyvinyl alcohol.

4. The polyolefin weather-resistant pipe according to claim 2, characterized in that: The mass ratio between octadecane and methyl methacrylate is 7:(3.3-3.5).

5. The polyolefin weather-resistant pipe according to claim 1, characterized in that: The reinforcing material comprises modified graphene oxide, and the modified graphene oxide comprises graphene and L-glutamic acid.

6. A polyolefin weather-resistant pipe according to claim 5, characterized in that: The modified graphene oxide is prepared by the following method: The graphene oxide is mixed with water and then ultrasonicated to obtain a graphene oxide dispersion, L-glutamic acid is mixed with a sodium hydroxide solution to obtain a glutamic acid solution, the glutamic acid solution is added to the graphene oxide dispersion, ultrasonically dispersed, and stirred until the system changes from black to dark brown, then the stirring is stopped, and the modified graphene oxide is washed and dried to obtain.

7. The polyolefin weather-resistant pipe according to claim 5, characterized in that: The mass ratio between the graphene oxide and L-glutamic acid is 1:(3.1-3.5).

8. The polyolefin weather-resistant pipe according to claim 6, characterized in that: The modified graphene oxide accounts for 0.6-0.8% of the overall mass fraction of the octadecane phase change microcapsules.

9. A method for preparing the polyolefin weather-resistant pipe according to any one of claims 1 to 8, characterized in that: The steps include: The weather-resistant coating is evenly coated on the surface of the pipe body, dried and solidified, so that a layer of weather-resistant coating is formed on the surface of the pipe body to obtain a polyolefin weather-resistant pipe.

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