Enhanced modified polypropylene power tube and preparation method thereof

Abstract

The invention relates to the technical field of electric power pipes, and discloses an enhanced modified polypropylene electric power pipe and a preparation method thereof, the polypropylene electric power pipe comprises the following raw materials: polypropylene resin, low-density polyethylene, a modified nanofiller, a silane coupling agent, an antioxidant, a dispersant, a plasticizer, a POE-g-MAH compatilizer and a dynamic vulcanizing agent; the preparation method comprises the following steps: adding raw materials into a container; in the stirring state, the container is heated to 155-165 DEG C and stirred for 20-30 min, then the container is heated to 175-185 DEG C and stirred for 20-30 min, then the container is heated to 195-205 DEG C and stirred for 20-30 min, molten liquid is obtained, and the stirring rotating speed is 250-350 r / min; and transferring the molten liquid into a plunger type extruder, setting the temperature of a main machine to be 170-175 DEG C, the temperature of a mold to be 175-180 DEG C and the temperature of a mold orifice to be 180-185 DEG C, carrying out extrusion molding, and cooling to obtain the polypropylene electric power tube. The tensile strength and notch impact strength of the polypropylene power tube can be improved, the modern engineering requirements are met, and the problems of engineering failure, potential safety hazards and long-term cost increase are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power pipes, and in particular relates to a reinforced modified polypropylene electric power pipe and a preparation method thereof. Background Art

[0002] Modified polypropylene trenchless power pipe is widely used as a protective conduit for power and communication cables. Its unique product characteristics are further enhanced by its trenchless jacking construction, which meets the development requirements of modern cities and is suitable for burial depths ranging from 2 to 18 meters. Trenchless construction technology is environmentally friendly, traffic-friendly, and minimally disruptive to the ground structure. It offers safe and reliable construction, short construction cycles, and low construction costs. It ensures the reliability and safety of pipeline networks, reduces pipeline failure rates, and offers significant social and economic benefits, while also significantly improving the urban environment. Therefore, it is widely used in the construction of modern urban power cable pipeline networks.

[0003] As the use of polypropylene trenchless power pipes becomes increasingly widespread, they face the risk of plastic deformation or bursting under complex stress conditions such as external mechanical loads, internal pressure fluctuations, and lateral earth pressure. These pipes can be subjected to backfill compaction or heavy vehicle pressure, leading to the risk of plastic deformation and cracking. Furthermore, impact from a drop hammer can easily cause pipe cracking, compromising cable safety. Consequently, in practical applications, the strength requirements for polypropylene trenchless power pipes are becoming increasingly stringent. Insufficient strength in polypropylene trenchless power pipes can lead to project failure, safety hazards, and increased long-term costs. Improving the tensile strength and notched impact strength of polypropylene trenchless power pipes is crucial. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a reinforced modified polypropylene power pipe and a preparation method thereof, which can improve the tensile strength and notch impact strength of the polypropylene power pipe, meet the needs of modern engineering, and avoid problems that lead to engineering failure, safety hazards and long-term cost increases.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] In the first aspect, the present invention discloses a reinforced modified polypropylene power pipe, comprising the following raw materials: polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer; the modified nanofiller is amino-functionalized nanoparticles formed by grafting aminosilane onto the surface of nano-silica; the dynamic vulcanizer is a sulfur / silane dual cross-linking system formed by blending diisopropylbenzene peroxide and vinyl silane.

[0007] Furthermore, in parts by mass, the polypropylene resin is 60-80 parts, the low-density polyethylene is 15-25 parts, the modified nanofiller is 2-4 parts, the silane coupling agent is 1-3 parts, the antioxidant is 0.5-1.0 parts, the dispersant is 0.5-1.0 parts, the plasticizer is 1-2 parts, the POE-g-MAH compatibilizer is 0.5-1.5 parts, and the dynamic vulcanizer is 0.5-1.5 parts.

[0008] Furthermore, in parts by mass, the polypropylene resin is 70 parts, the low-density polyethylene is 20 parts, the modified nanofiller is 3 parts, the silane coupling agent is 2 parts, the antioxidant is 0.75 parts, the dispersant is 0.75 parts, the plasticizer is 1.5 parts, the POE-g-MAH compatibilizer is 1 part, and the dynamic vulcanizer is 1 part.

[0009] Furthermore, the preparation method of the modified nanofiller comprises the following steps:

[0010] Bake the nano-SiO2 to remove the surface adsorbed water, weigh the dried nano-SiO2, add anhydrous ethanol, and ultrasonically disperse for 20-30 minutes to form a uniform SiO2 ethanol suspension, so that the SiO2 concentration is ≤5wt%;

[0011] Dissolve γ-aminopropyltriethoxysilane in a 70-80% mass concentration ethanol solution, add hydrochloric acid to adjust the pH to 3-4, and hydrolyze at room temperature for 20-30 minutes under stirring to generate a silanol solution. In this technical solution, hydrolysis generates silanol (≡Si-OH), which enhances the reaction activity with the hydroxyl group on the SiO2 surface.

[0012] Slowly add the hydrolyzed silanol solution into the SiO2 ethanol suspension, maintain the temperature at 40-60°C, and stir to react for 4-6 hours;

[0013] After the reaction is completed, the product is centrifuged and washed with anhydrous ethanol. The washed product is placed in a vacuum drying oven at 50-60° C. to dry to obtain a modified nanofiller.

[0014] Furthermore, the mass ratio of the γ-aminopropyltriethoxysilane to the ethanol solution is (1-2):100.

[0015] Furthermore, the dynamic vulcanizing agent includes dicumyl peroxide, vinyl silane, and sulfur, wherein the mass ratio of dicumyl peroxide, vinyl silane, and sulfur is (1-3): (1-5): (1-2). In this technical solution, the dynamic vulcanizing agent is a blend of dicumyl peroxide, vinyl silane, and sulfur.

[0016] Furthermore, the silane coupling agent is one of vinyl silane, amino silane, and methacryloxy silane; and the antioxidant is one of antioxidant 1010 and antioxidant 1076, or a combination of two of the two.

[0017] Furthermore, the dispersant is one of polyethylene wax and polypropylene wax, or a combination of two thereof; and the plasticizer is one of diisononyl adipate and trioctyl trimellitate, or a combination of two thereof.

[0018] In a second aspect, the present invention further discloses a method for preparing a reinforced modified polypropylene power pipe, comprising the following steps:

[0019] S1. Add polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer into a container;

[0020] S2. Under stirring, first heat the container to 155-165° C. and stir for 20-30 min, then heat the container to 175-185° C. and stir for 20-30 min, and then heat the container to 195-205° C. and stir for 20-30 min to obtain a molten liquid. The stirring speed is 250-350 rpm;

[0021] S3. Transfer the melt into a plunger extruder, set the main machine temperature to 170-175°C, the mold temperature to 175-180°C, and the die temperature to 180-185°C, extrude and shape, and obtain a polypropylene power pipe after cooling.

[0022] In this technical solution, polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer are stirred and plasticized at 155-165°C, dynamically vulcanized at 175-185°C, and cross-linked at 195-205°C. The modified nanofiller is evenly dispersed under high-temperature shearing and reacts with the dynamic vulcanizer to form a three-dimensional network structure. The strength of the final extruded polypropylene power pipe will be higher.

[0023] After the extruded power pipe is cooled, it is subjected to secondary vulcanization in hot air at 100-120°C for 3-5 hours. In this way, secondary vulcanization of the produced power pipe can further increase the crosslinking density and strengthen the power pipe.

[0024] In summary, this application has the following beneficial effects:

[0025] 1. The present invention stirs and plasticizes polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer at 155-165°C, stirs and plasticizes at 175-185°C for dynamic vulcanization reaction, and stirs and cross-links at 195-205°C, so that the modified nanofiller is uniformly dispersed under high-temperature shearing and reacts with the dynamic vulcanizer to form a three-dimensional network structure, producing a synergistic effect. The strength of the final extruded polypropylene power pipe will be higher. According to tests, the tensile strength of the produced power pipe is increased by more than 30%, and the notched impact strength is increased by more than 40%, meeting the needs of modern engineering.

[0026] 2. In the present invention, after the extruded power pipe is cooled, it is secondary vulcanized in hot air at 100-120°C for 3-5 hours. In this way, the produced power pipe is secondary vulcanized in hot air, which can further improve the crosslinking density of the polypropylene power pipe and increase the strength of the polypropylene power pipe.

[0027] 3. The present invention combines dynamic vulcanization with in-situ dispersion of modified nanofillers to form a synergistically enhanced structure of "dynamic cross-linking network + nano-blocking cracks", solving the problems of high brittleness and uneven dispersion of nanofillers in traditional cross-linked polypropylene power pipes. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment is a first method for preparing a modified nanofiller, comprising the following steps:

[0031] S101, baking nano-SiO2 with a particle size of 50-200 nm in a vacuum drying oven at 90°C for 6 hours to remove surface adsorbed moisture; weighing 3 kg of the dried SiO2, adding it to 100 kg of anhydrous ethanol, and ultrasonically dispersing it for 20 minutes to form a uniform suspension;

[0032] S102, dissolving 1 kg of γ-aminopropyltriethoxysilane in 100 kg of a 70% mass concentration ethanol solution, adding hydrochloric acid dropwise to adjust the pH to 3, and hydrolyzing the solution at room temperature for 20 minutes under stirring to generate a silanol solution; hydrolyzing the solution to generate silanol (≡Si-OH) to enhance its reactivity with the hydroxyl groups on the SiO2 surface;

[0033] S103, slowly adding the hydrolyzed γ-aminopropyltriethoxysilane solution dropwise to the SiO2 ethanol suspension, maintaining the temperature at 40°C, and magnetically stirring the reaction for 4 hours;

[0034] S104. After the reaction is completed, the product is centrifuged (8000 rpm, 10 minutes), washed three times with anhydrous ethanol to remove unreacted γ-aminopropyltriethoxysilane; the washed product is placed in a vacuum drying oven at 50°C and dried for 12 hours to obtain a modified nanofiller.

[0035] Example 2

[0036] This embodiment is a second method for preparing modified nanofillers, comprising the following steps:

[0037] S101, baking nano-SiO2 with a particle size of 50-200 nm in a vacuum drying oven at 95°C for 7 hours to remove surface adsorbed moisture; weighing 4 kg of the dried SiO2, adding it to 100 kg of anhydrous ethanol, and ultrasonically dispersing it for 25 minutes to form a uniform suspension;

[0038] S102, dissolving 1.5 kg of γ-aminopropyltriethoxysilane in 100 kg of a 75% mass concentration ethanol solution, adding hydrochloric acid dropwise to adjust the pH to 3.5, and hydrolyzing the solution at room temperature for 25 minutes under stirring to generate a silanol solution; hydrolyzing the solution to generate silanol (≡Si-OH) to enhance its reactivity with the hydroxyl groups on the SiO2 surface;

[0039] S103, slowly adding the hydrolyzed γ-aminopropyltriethoxysilane solution dropwise to the SiO2 ethanol suspension, maintaining the temperature at 50°C, and magnetically stirring the reaction for 5 hours;

[0040] S104. After the reaction is completed, the product is centrifuged (8000 rpm, 10 minutes), washed three times with anhydrous ethanol to remove unreacted γ-aminopropyltriethoxysilane; the washed product is placed in a vacuum drying oven at 55°C for 12 hours to obtain a modified nanofiller.

[0041] Example 3

[0042] This embodiment is a third method for preparing a modified nanofiller, comprising the following steps:

[0043] S101, baking nano-SiO2 with a particle size of 50-200 nm in a vacuum drying oven at 100°C for 8 hours to remove surface adsorbed moisture; weighing 5 kg of the dried SiO2, adding it to 100 kg of anhydrous ethanol, and ultrasonically dispersing it for 30 minutes to form a uniform suspension;

[0044] S102, dissolving 2 kg of γ-aminopropyltriethoxysilane in 100 kg of an 80% mass concentration ethanol solution, adding hydrochloric acid dropwise to adjust the pH to 4, and hydrolyzing the solution at room temperature for 30 minutes under stirring to generate a silanol solution; hydrolyzing the solution to generate silanol (≡Si-OH) to enhance its reactivity with the hydroxyl groups on the SiO2 surface;

[0045] S103, slowly adding the hydrolyzed γ-aminopropyltriethoxysilane solution dropwise to the SiO2 ethanol suspension, maintaining the temperature at 60°C, and reacting with magnetic stirring for 6 hours;

[0046] S104. After the reaction is completed, the product is centrifuged (8000 rpm, 10 minutes), washed three times with anhydrous ethanol to remove unreacted γ-aminopropyltriethoxysilane; the washed product is placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain a modified nanofiller.

[0047] Example 4

[0048] This embodiment is a preparation method for a reinforced modified polypropylene power pipe, which includes the following steps:

[0049] S1. Add 60 kg of polypropylene resin, 15 kg of low-density polyethylene, 2 kg of the modified nanofiller prepared in Example 1, 1 kg of a silane coupling agent, 0.5 kg of an antioxidant, 0.5 kg of a dispersant, 1 kg of a plasticizer, 0.5 kg of a POE-g-MAH compatibilizer, and 0.5 kg of a dynamic vulcanizer into a heating container; wherein the mass ratio of dicumyl peroxide, vinyl silane, and sulfur in the dynamic vulcanizer is 1:1:1; POE-g-MAH is produced by Shanghai Jiuju Polymer Materials Co., Ltd., and the low-density polyethylene is a linear low-density polyethylene, model DFDA-7042, produced by Qilu Petrochemical.

[0050] S2. Under stirring, first heat the container to 155°C and stir for 20 minutes, then heat the container to 175°C and stir for 20 minutes, and then heat the container to 195°C and stir for 20 minutes to obtain a molten liquid. The stirring speed is 250 rpm.

[0051] S3. Transfer the melt into a plunger extruder, set the main machine temperature to 170°C, the mold temperature to 175°C, and the die temperature to 180°C, extrude and shape, and obtain a polypropylene power pipe after cooling; after cooling the extruded power pipe, secondary vulcanize it in hot air at 100°C for 3 hours.

[0052] In this embodiment, the silane coupling agent is vinyl silane, the antioxidant is antioxidant 1010, the dispersant is polyethylene wax, and the plasticizer is diisononyl adipate.

[0053] Example 5

[0054] This embodiment is a second preparation method of a reinforced modified polypropylene power pipe, comprising the following steps:

[0055] S1. Add 70 kg of polypropylene resin, 20 kg of low-density polyethylene, 3 kg of the modified nanofiller prepared in Example 2, 2 kg of silane coupling agent, 0.75 kg of antioxidant, 0.75 kg of dispersant, 1.5 kg of plasticizer, 1.0 kg of POE-g-MAH compatibilizer, and 1.0 kg of dynamic vulcanizer into a heating container; wherein the mass ratio of dicumyl peroxide, vinyl silane, and sulfur in the dynamic vulcanizer is 4:6:3; POE-g-MAH is produced by Shanghai Jiuju Polymer Materials Co., Ltd., and the low-density polyethylene is linear low-density polyethylene, model DFDA-7042, produced by Qilu Petrochemical.

[0056] S2. Under stirring, first heat the container to 160°C and stir for 25 minutes, then heat the container to 180°C and stir for 25 minutes, and then heat the container to 200°C and stir for 25 minutes to obtain a molten liquid. The stirring speed is 300 rpm.

[0057] S3. The molten liquid is transferred to a plunger extruder, and the main machine temperature is set to 172.5°C, the mold temperature is set to 177.5°C, and the die temperature is set to 182.5°C. Extrusion molding is performed, and a polypropylene power pipe is obtained after cooling. After the extruded power pipe is cooled, secondary vulcanization is performed in hot air at 110°C for 4 hours.

[0058] In this embodiment, the silane coupling agent is aminosilane, the antioxidant is antioxidant 1076, the dispersant is polypropylene wax, and the plasticizer is trioctyl trimellitate.

[0059] Example 6

[0060] This embodiment is the preparation method 3 of the reinforced modified polypropylene power pipe, which includes the following steps:

[0061] S1. Add 80 kg of polypropylene resin, 25 kg of low-density polyethylene, 4 kg of the modified nanofiller prepared in Example 3, 3 kg of silane coupling agent, 1.0 kg of antioxidant, 1.0 kg of dispersant, 2 kg of plasticizer, 1.5 kg of POE-g-MAH compatibilizer, and 1.5 kg of dynamic vulcanizing agent into a heating container; wherein the mass ratio of dicumyl peroxide, vinyl silane, and sulfur in the dynamic vulcanizing agent is 3:5:2; POE-g-MAH is produced by Shanghai Jiuju Polymer Materials Co., Ltd., and the low-density polyethylene is linear low-density polyethylene, model DFDA-7042, produced by Qilu Petrochemical.

[0062] S2. Under stirring, first heat the container to 165°C and stir for 30 minutes, then heat the container to 185°C and stir for 30 minutes, and then heat the container to 205°C and stir for 30 minutes to obtain a molten liquid. The stirring speed is 350 rpm.

[0063] S3. The molten liquid is transferred to a plunger extruder, and the main temperature, mold temperature and die temperature are set to 175°C, 180°C and 185°C, and extruded to obtain a polypropylene power pipe after cooling. After the extruded power pipe is cooled, secondary vulcanization is performed in hot air at 120°C for 5 hours.

[0064] Among them, the silane coupling agent of this embodiment is methacryloxysilane; the antioxidant is a combination of antioxidant 1010 and antioxidant 1076 of equal mass; the dispersant is a combination of polyethylene wax and polypropylene wax of equal mass; and the plasticizer is a combination of diisononyl adipate and trioctyl trimellitate of equal mass.

[0065] Example 7

[0066] This embodiment is a fourth preparation of a reinforced modified polypropylene power pipe. The preparation method is compared with that of Example 5, with the only difference being that the nanofiller in this embodiment is ordinary nano-SiO2 with a particle size of 50-200 nm and is not modified.

[0067] Example 8

[0068] This embodiment is the fifth preparation of the reinforced modified polypropylene electric power pipe. The preparation method is compared with that of Example 5, and the only difference is that no modified nanofiller is used in the raw material of the polypropylene electric power pipe in this embodiment.

[0069] Example 9

[0070] This embodiment is the sixth preparation of the enhanced modified polypropylene power pipe. The preparation method is compared with that of Example 5, and the only difference is that no dynamic vulcanizing agent is used in the raw material of the polypropylene power pipe in this embodiment.

[0071] Example 10

[0072] This embodiment is the preparation seven of the reinforced modified polypropylene power pipe. The preparation method is compared with that of Example 5, and the only difference is that in step S2 of this embodiment, the raw materials are directly heated, melted and stirred evenly, and then the molten liquid is transferred to a plunger extruder to extrude the power pipe.

[0073] Example 11

[0074] This embodiment is the eighth preparation of the reinforced modified polypropylene power pipe. The preparation method is compared with that of Example 5, and the only difference is that the method of this embodiment does not have the step of "cooling the extruded power pipe and then secondary vulcanizing it in hot air at 110°C for 4 hours" in step S3.

[0075] The polypropylene power pipes prepared in Examples 4 to 11 and existing polypropylene power pipes were tested for tensile strength, notched impact strength, ring stiffness, and flexural modulus using the same national standards. The results are shown in the following table:

[0076] Example Tensile strength (MPa) Notched impact strength (kJ / m²) Ring stiffness (kN / m²) Flexural modulus (MPa) Example 4 55 5.9 14.2 1620 Example 5 56 6.0 14.5 1630 Example 6 56 6.0 13.9 1590 Example 7 45 4.4 10.8 1450 Example 8 44 4.2 10.8 1420 Example 9 43 4.6 10.7 1390 Example 10 48 4.7 10.9 1450 Example 11 50 4.8 11.8 1480 Existing polypropylene power pipe 40 4.0 10.0 1300

[0077] From the performance comparison between the polypropylene power pipes prepared in Examples 4 to 6 and the existing polypropylene power pipes, it can be seen that the performance indicators of the tensile strength, notched impact strength, ring stiffness and flexural modulus of the present invention are significantly better than those of the existing polypropylene power pipes, which confirms the technical effect of the present invention that "the modified nanofiller is uniformly dispersed under high-temperature shear and reacts with the dynamic vulcanizer to form a three-dimensional network structure, and the strength of the final extruded polypropylene power pipe will be higher. According to tests, the tensile strength of the produced power pipe is increased by more than 30%, and the notched impact strength is increased by more than 40%." This shows that the polypropylene power pipe of the present invention has better mechanical properties and meets increasingly higher engineering requirements.

[0078] From the comparison between Example 5 and Example 7, it can be seen that the use of ordinary nano-SiO2 with a particle size of 50-200nm cannot replace the amino-functionalized nanoparticles formed by grafting aminosilane on the surface of nano-silica in the present invention. Only by using the modified nano-filler of the present invention can it react with the dynamic vulcanizer to form a three-dimensional network structure, and the strength of the final extruded polypropylene power pipe will be higher.

[0079] From the comparison between Example 5 and Example 8, it can be seen that if the modified nanofiller is not used and only the dynamic vulcanizing agent of the present invention is used, the technical effect of the present invention cannot be achieved. From the comparison between Example 5 and Example 9, it can be seen that if the dynamic vulcanizing agent is not used and only the modified nanofiller of the present invention is used, the technical effect of the present invention cannot be achieved. This shows that in the polypropylene power pipe of the present application, the modified nanofiller and the dynamic vulcanizing agent produce a synergistic effect, forming a "dynamic cross-linking network + nano-blocking crack" synergistic reinforcement structure, which increases the strength of the polypropylene power pipe.

[0080] From the comparison between the above-mentioned Example 5 and Example 10, it can be seen that if in step S2, the raw materials are directly heated, melted and stirred evenly before the melt is transferred to a plunger extruder to extrude the power pipe, that is, without stirring and plasticizing at 155-165°C, without stirring for dynamic vulcanization reaction at 175-185°C, and without stirring for cross-linking reaction at 195-205°C, the strength of the polypropylene power pipe produced in this way will be affected.

[0081] From the comparison between the above-mentioned Example 5 and Example 11, it can be seen that if the step of "cooling the extruded power pipe and then secondary vulcanizing it in hot air at 110°C for 4 hours" is not included in step S3, the strength of the polypropylene power pipe produced in this way will be affected.

[0082] In summary, the present invention stirs and plasticizes polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer at 155-165°C, stirs and performs dynamic vulcanization reaction at 175-185°C, and stirs and performs cross-linking reaction at 195-205°C, so that the modified nanofiller is uniformly dispersed under high-temperature shear, and reacts with the dynamic vulcanizer to form a three-dimensional network structure, producing a synergistic effect. The strength of the final extruded polypropylene power pipe will be higher, and the produced power pipe will be subjected to secondary vulcanization to further improve the cross-linking density and increase the strength of the power pipe.

[0083] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or equivalents shall be encompassed by the claims of the present invention. Any techniques, shapes, and structures not described in detail herein are well known.

Claims

1. A reinforced modified polypropylene power pipe, characterized in that: The invention comprises the following raw materials: polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer; the modified nanofiller is amino-functionalized nanoparticles formed by grafting aminosilane onto the surface of nano-silica; the dynamic vulcanizer is a sulfur / silane dual cross-linking system formed by blending dicumyl peroxide and vinyl silane.

2. The reinforced modified polypropylene power pipe according to claim 1, characterized in that: In parts by mass, the polypropylene resin is 60-80 parts, the low-density polyethylene is 15-25 parts, the modified nanofiller is 2-4 parts, the silane coupling agent is 1-3 parts, the antioxidant is 0.5-1.0 parts, the dispersant is 0.5-1.0 parts, the plasticizer is 1-2 parts, the POE-g-MAH compatibilizer is 0.5-1.5 parts, and the dynamic vulcanizer is 0.5-1.5 parts.

3. The reinforced modified polypropylene power pipe according to claim 2, characterized in that: In parts by mass, the polypropylene resin is 70 parts, the low-density polyethylene is 20 parts, the modified nanofiller is 3 parts, the silane coupling agent is 2 parts, the antioxidant is 0.75 parts, the dispersant is 0.75 parts, the plasticizer is 1.5 parts, the POE-g-MAH compatibilizer is 1 part, and the dynamic vulcanizer is 1 part.

4. A reinforced modified polypropylene power pipe according to any one of claims 1 to 3, characterized in that: The preparation method of the modified nanofiller comprises the following steps: Bake the nano-SiO2 to remove the surface adsorbed water, weigh the dried nano-SiO2, add anhydrous ethanol, and ultrasonically disperse for 20-30 minutes to form a uniform SiO2 ethanol suspension, so that the SiO2 concentration is ≤5wt%; Dissolve γ-aminopropyltriethoxysilane in a 70-80% mass concentration ethanol solution, add hydrochloric acid to adjust the pH to 3-4, and hydrolyze at room temperature for 20-30 minutes under stirring to generate a silanol solution; Slowly add the hydrolyzed silanol solution into the SiO2 ethanol suspension, maintain the temperature at 40-60°C, and stir to react for 4-6 hours; After the reaction is completed, the product is centrifuged and washed with anhydrous ethanol. The washed product is placed in a vacuum drying oven at 50-60° C. to dry to obtain a modified nanofiller.

5. The reinforced modified polypropylene power pipe according to claim 4, characterized in that: The mass ratio of the γ-aminopropyltriethoxysilane to the ethanol solution is (1-2):

100.

6. The reinforced modified polypropylene power pipe according to any one of claims 1 to 3, characterized in that: The dynamic vulcanizing agent comprises dicumyl peroxide, vinyl silane and sulfur, wherein the mass ratio of the dicumyl peroxide, vinyl silane and sulfur is (1-3): (1-5): (1-2).

7. The reinforced modified polypropylene power pipe according to any one of claims 1 to 3, characterized in that: The silane coupling agent is one of vinyl silane, amino silane, and methacryloxy silane; the antioxidant is one of antioxidant 1010 and antioxidant 1076, or a combination of the two.

8. The reinforced modified polypropylene power pipe according to any one of claims 1 to 3, characterized in that: The dispersant is one of polyethylene wax and polypropylene wax or a combination of the two; the plasticizer is one of diisononyl adipate and trioctyl trimellitate or a combination of the two.

9. A method for preparing a reinforced modified polypropylene power pipe, characterized in that: The polypropylene power pipe is the polypropylene power pipe according to any one of claims 1 to 8, and the preparation method comprises the following steps: S1. Add polypropylene resin, low-density polyethylene, modified nanofiller, silane coupling agent, antioxidant, dispersant, plasticizer, POE-g-MAH compatibilizer and dynamic vulcanizer into a container; S2. Under stirring, first heat the container to 155-165° C. and stir for 20-30 min, then heat the container to 175-185° C. and stir for 20-30 min, and then heat the container to 195-205° C. and stir for 20-30 min to obtain a molten liquid. The stirring speed is 250-350 rpm; S3. Transfer the melt into a plunger extruder, set the main machine temperature to 170-175°C, the mold temperature to 175-180°C, and the die temperature to 180-185°C, extrude and shape, and obtain a polypropylene power pipe after cooling.

10. The method for preparing a reinforced modified polypropylene electric power pipe according to claim 9, characterized in that: After the extruded power pipe is cooled, it is secondary vulcanized in hot air at 100-120°C for 3-5 hours.