Composite plastic for geotextile and method for preparing the same

Abstract

The application discloses a kind of composite plastic for geotextile and preparation method thereof, belong to high polymer material technical field, its preparation method includes the following steps: PP resin, TPU elastomer, modified composite material, boron nitride nanosheet, talcum powder, compatilizer, lubricant are stirred and mixed in mixer, then melt blend is transferred into twin-screw extruder, extrusion granulation, namely obtained.Therein, the modified composite material is prepared using carbon nanotube@ZnO, fluorine-modified SiO2 / carbon quantum dots and (3-epoxypropoxypropyl) methyl diethoxysilane.The geotextile special composite plastic prepared by the application has the characteristics of high mechanical strength and excellent aging resistance, and the geotextile produced has good environmental adaptability and long service life.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer materials, and specifically relates to a composite plastic for geotextile and a preparation method thereof. BACKGROUND

[0002] Geotextile is a kind of water-permeable engineering material based on synthetic fibers, which is made by needle punching, weaving or thermal bonding process, and is widely used in isolation, filtration, drainage, reinforcement and protection fields in civil engineering. Geotextile prevents material mixing and enhances structural stability by physically isolating different particle sizes of soil or building materials such as sand particles and concrete, and at the same time realizes efficient water diversion through the pores between fibers to prevent water and soil loss and ground softening, and plays a role in highway, railway, dam, landfill and other engineering. In addition, geotextile can also be combined with geomembrane to form a composite anti-seepage structure to resist puncture and chemical corrosion and improve engineering durability. The main materials of traditional geotextile include polypropylene, polyester, polyethylene, etc. Polypropylene is often used in drainage and isolation scenes due to its low cost and strong acid and alkali corrosion resistance, but its ultraviolet resistance is weak and it is easy to age after long-term exposure; polyester has high tensile strength and is resistant to high temperature, and is suitable for reinforcing roadbed or steep slope protection, but its cost is high and its performance is prone to decline in humid environment, and its environmental adaptability is poor; polyethylene has excellent chemical resistance, but its flexibility is insufficient and its application range is narrow.

[0003] Chinese patent CN107190416A discloses a preparation method of geotextile, the steps are as follows: polypropylene, tetramethyl divinyl disiloxane and initiator are melt extruded, cooled, organic silicon modified polypropylene is obtained, and then stirred with polyethylene terephthalate fiber monofilament, filtered, mixed with adhesive, antioxidant and water, filtered, dried, and geotextile is obtained by laying the dry material on the screen curtain of the screen machine, reciprocating the screen curtain, and consolidating by the needle punching machine. The geotextile has good alkali resistance and hydrolysis resistance, and the strength is not easily lost. Chinese patent CN106381610A discloses a preparation method of high-strength weather-resistant geotextile, the steps are as follows: polyacrylonitrile-based carbon fiber is pretreated and mixed with antioxidant 1010, barium stearate light stabilizer UV-770 and the like, extruded, filtered, spun, and consolidated to obtain geotextile blank, then multi-walled carbon nanotubes are added to dimethylformamide, stirred and mixed, and then ultrasonically dispersed with sodium dodecylbenzenesulfonate, sprayed uniformly on the surface of the geotextile blank by using a syringe, and dried to obtain geotextile. The geotextile has high strength, strong anti-deformation ability, good weather resistance, and wide application prospect. However, in recent years, the comprehensive performance requirements of geotextile in the engineering field are increasing, and the existing single material is difficult to balance multiple demands. For example, although the short fiber needle-punched geotextile has good water permeability, it has weak anti-puncture ability, and although the high-density woven cloth has high strength, it lacks flexibility. In addition, extreme environments such as saline-alkali land and freeze-thaw cycle areas have higher requirements for the corrosion resistance and temperature adaptability of the material. Therefore, it is urgent to develop a composite plastic material specially used for geotextile to optimize the comprehensive performance such as mechanical properties and environmental stability through multi-component synergy. SUMMARY

[0004] In view of the deficiencies in the prior art described above, the present application provides a composite plastic for geotextile, taking PP resin and TPU elastomer as the matrix, and adding specific modified composite materials, boron nitride nanosheets, talcum powder and compatibilizers, etc., to further improve the comprehensive performance such as mechanical strength and aging resistance of the composite plastic.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A composite plastic for geotextile, comprising the following raw materials by weight:

[0007] 40-200 parts of PP resin, 5-50 parts of TPU elastomer, 1-10 parts of modified composite material, 0.5-5 parts of boron nitride nanosheet, 1-10 parts of talcum powder, 0.5-5 parts of compatibilizer, and 0.2-3 parts of lubricant.

[0008] Preferably, a composite plastic for geotextile, comprising the following raw materials by weight:

[0009] 60-100 parts of PP resin, 10-20 parts of TPU elastomer, 2-5 parts of modified composite material, 1-3 parts of boron nitride nanosheet, 2-6 parts of talcum powder, 1-2 parts of compatibilizer, 0.5-1.5 parts of lubricant.

[0010] Preferably, the preparation method of the modified composite material is:

[0011] The carbon nanotube@ZnO and fluorine-modified SiO2 / carbon quantum dots are added into anhydrous ethanol, heated and stirred, then (3-epoxypropoxypropyl) methyl diethoxysilane and glacial acetic acid are added, heated and reacted under nitrogen protection, cooled, centrifuged, and dried to obtain the modified composite material.

[0012] Preferably, the preparation method of the fluorine-modified SiO2 / carbon quantum dots is:

[0013] Citric acid, urea and water are mixed, hydrothermally reacted, cooled, dialyzed, and dried to obtain carbon quantum dots; ammonia water and an ethanol aqueous solution are mixed, then tetraethoxysilane is added, heated and stirred, then perfluorooctyl ethyl triethoxysilane and carbon quantum dots are added and continue to stir, cooled, centrifuged, and dried to obtain fluorine-modified SiO2 / carbon quantum dots.

[0014] Preferably, the preparation method of the carbon nanotube@ZnO is:

[0015] The carbon nanotubes are added into a sodium hexametaphosphate aqueous solution, ultrasonically treated, centrifuged, and dried to obtain pretreated carbon nanotubes; the pretreated carbon nanotubes and zinc nitrate are added into water, stirred, then the pH is adjusted to alkaline, heated and reacted, cooled, centrifuged, and dried to obtain carbon nanotube@ZnO.

[0016] Preferably, the weight ratio of the carbon nanotube@ZnO, fluorine-modified SiO2 / carbon quantum dots, and (3-epoxypropoxypropyl) methyl diethoxysilane is 1-2:3-5:0.5-1.5.

[0017] The modified composite prepared by the method has significantly improved mechanical strength and aging resistance of the composite plastic. First, the dispersibility of the carbon nanotubes is enhanced by ultrasonic pretreatment of sodium hexametaphosphate, and the problem of agglomeration of the carbon nanotubes is avoided. Then, ZnO nanocrystals are in-situ grown on the surface of the carbon nanotubes by a zinc nitrate and ammonia system, forming a core-shell structure. The ZnO not only provides excellent ultraviolet shielding capability, so that the aging resistance is excellent, but also forms a stress transfer channel in the matrix by its high hardness and rigidity, so that the tensile strength is improved. In addition, the heterojunction interface between the ZnO and the carbon nanotubes can promote uniform distribution of the load and reduce the crack propagation path, thereby improving the impact resistance. Second, carbon quantum dots are generated by a hydrothermal reaction. The small size and quantum confinement effect of the carbon quantum dots endow the material with good optical stability and chemical inertness. Then, the surface of SiO2 is fluorinated and modified by perfluorooctyl ethyl triethoxysilane, so as to endow the SiO2 with hydrophobicity and low surface energy characteristics, and reduce the interfacial tension with the polymer matrix. The fluorine-modified SiO2 / carbon quantum dot composite can form a uniformly dispersed nanometer network in the PP matrix, and the rigidity of the matrix is enhanced by the physical crosslinking points. At the same time, the fluorinated groups on the surface of the SiO2 / carbon quantum dot composite can form hydrogen bonds with the compatibilizer (PP-g-MAH), so as to further optimize the interfacial compatibility and reduce stress concentration. Finally, the epoxy group of (3-glycidoxypropyl) methyl diethoxysilane reacts with the hydroxyl groups on the surface of the inorganic material under the protection of nitrogen, so as to form a covalent bond bridge, enhance the interfacial bonding between the inorganic material and the matrix, improve the energy transfer efficiency, and at the same time, the long-chain alkyl groups of the (3-glycidoxypropyl) methyl diethoxysilane interlock with the molecular chains of the TPU elastomer by entanglement, which is helpful to improve the impact resistance.

[0018] Preferably, the preparation method of the modified composite is as follows:

[0019] 10-20 parts of citric acid, 20-30 parts of urea and 100-200 parts of water are added into a sealed reaction kettle, and a hydrothermal reaction is carried out at 180-230 DEG C for 4-8 h. After cooling, dialysis is carried out for 30-40 h, and freeze-drying is carried out, so as to obtain carbon quantum dots. 2-8 parts of ammonia water and 10-20 parts of an ethanol aqueous solution are mixed, and then 3-5 parts of tetraethoxysilane is added. Stirring is carried out at 50-65 DEG C and 100-150 r / min for 0.5-2 h. Then, 0.2-0.8 parts of perfluorooctyl ethyl triethoxysilane and 1-2 parts of carbon quantum dots are added, and stirring is continued for 10-20 h. After cooling, centrifugation is carried out, and vacuum drying is carried out, so as to obtain fluorine-modified SiO2 / carbon quantum dots.

[0020] Add 5-8 parts of carbon nanotubes to 70-150 parts of sodium hexametaphosphate aqueous solution, sonicate for 20-40 min, centrifuge, and vacuum dry to obtain pretreated carbon nanotubes; add 3-5 parts of pretreated carbon nanotubes and 4-6 parts of zinc nitrate to 150-250 parts of water, stir at 22-27℃ and 200-300 r / min for 30-50 min, then add ammonia water to adjust the pH to 9-10, heat to 70-85℃ and react for 4-6 h, cool, centrifuge, and vacuum dry to obtain carbon nanotubes. Carbon nanotubes@ZnO: 1-2 parts of carbon nanotubes@ZnO and 3-5 parts of fluorine-modified SiO2 / carbon quantum dots are added to 100-200 parts of anhydrous ethanol and stirred at 45-60℃ and 200-400 r / min for 15-30 min. Then, 0.5-1.5 parts of (3-epoxypropoxypropyl)methyldiethoxysilane and 0.05-0.15 parts of glacial acetic acid are added, and the mixture is reacted at 70-75℃ under nitrogen protection for 2-5 h. After cooling, centrifugation, and vacuum drying, the modified composite material is obtained.

[0021] Preferably, the dialysis uses a dialysis bag with a molecular weight cutoff of 500-2000 Da.

[0022] Preferably, the water is changed every 10-15 hours during the dialysis process.

[0023] Preferably, the concentration of the ammonia water is 22-28 wt%.

[0024] Preferably, the concentration of the ethanol aqueous solution is 40-50 wt%.

[0025] Preferably, the concentration of the sodium hexametaphosphate aqueous solution is 0.3-0.8 wt%.

[0026] Preferably, the frequency of the ultrasound is 20-40kHz and the power is 100-200W.

[0027] Preferably, the carbon nanotubes are multi-walled carbon nanotubes with a length of 0.1-5 μm and a diameter of 10-50 nm.

[0028] Preferably, the melt index of the PP resin is 1.0-5.0 g / 10 min, determined according to standard GB / T 3682.1-2018 at 190°C and 2.16 kg.

[0029] Preferably, the boron nitride nanosheets have a diameter of 0.08-0.8 μm.

[0030] Preferably, the talc powder is ultrafine talc powder with a particle size of 2-5 μm.

[0031] Preferably, the compatibilizer is one or a mixture of two or more of PP-g-MAH, POE-g-MAH, and POE-g-GMA.

[0032] Preferably, the compatibilizer is PP-g-MAH, and the grafting rate is determined to be 0.5-1.5% by acid-base titration.

[0033] Preferably, the lubricant is one or a mixture of two or more of ethylene bis-stearamide, pentaerythritol stearate, and oleamide.

[0034] Preferably, the lubricant is ethylene bis-stearamide.

[0035] Talc, as a rigid inorganic filler, can form an orientation-enhancing effect in the matrix due to its plate-like morphology. Through the interaction of van der Waals forces with PP segments, it restricts the free movement of molecular chains, thereby improving the tensile properties and dimensional stability of the material. However, excessive addition may lead to increased brittleness. The fibrous network structure of carbon nanotubes@ZnO can compensate for the brittleness of talc by bridging cracks and absorbing impact energy. In addition, the hydrophobic surface of talc has similar polarity to the hydrophobic groups of fluorine-modified SiO2 / carbon quantum dots. The two can form hydrophobic regions in the matrix, reducing water penetration and UV-induced degradation, and synergistically improving aging resistance. The layered structure of boron nitride nanosheets allows for energy dissipation through slippage, forming a surface-to-line interwoven network with carbon nanotubes@ZnO. This network uniformly disperses external stress, suppressing localized fractures caused by stress concentration and thus enhancing impact resistance. Furthermore, the high reflectivity of the boron nitride nanosheets creates a first-line reflection barrier against ultraviolet light, while the ZnO in the carbon nanotubes@ZnO absorbs ultraviolet light and dissipates heat. The fluorine-modified SiO2 / carbon quantum dots then process the remaining ultraviolet light through absorption-fluorescence conversion, significantly improving the aging resistance of the composite plastic. Through these synergistic effects, the composite plastic maintains high mechanical properties while also exhibiting excellent environmental stability.

[0036] This invention also provides a composite plastic for geotextiles and a method for preparing the same, comprising the following steps:

[0037] PP resin, TPU elastomer, modified composite material, boron nitride nanosheets, talc, compatibilizer, and lubricant are added to a mixer and stirred for 10-15 minutes. Then, the mixture is transferred to a twin-screw extruder for melt blending, extrusion granulation, and the composite plastic for geotextiles is obtained.

[0038] Preferably, the mixing speed of the mixer is 80-150 r / min.

[0039] Preferably, the temperature of the extruder is set sequentially from the barrel to the die head as follows: Zone 1 185-190℃, Zone 2 190-195℃, Zone 3 195-200℃, Zone 4 200-205℃, Zone 5 200-205℃, and Die head 195-200℃, and the screw speed is 100-200 r / min.

[0040] The beneficial effects of this invention are:

[0041] The geotextile-specific composite plastic prepared by this invention uses PP resin and TPU elastomer as matrix materials, and incorporates specific modified composite materials, boron nitride nanosheets, talc, compatibilizers, etc., for synergistic effects. The modified composite materials are prepared from carbon nanotubes@ZnO, fluorine-modified SiO2 / carbon quantum dots, and (3-epoxypropoxypropyl)methyldiethoxysilane, thereby significantly improving the comprehensive properties of the composite plastic, such as mechanical strength and aging resistance. Geotextiles made from this composite plastic exhibit good environmental adaptability and long service life. This invention also provides a method for preparing the aforementioned composite plastic for geotextiles. Detailed Implementation

[0042] The invention will be further described in detail below with reference to specific embodiments, but it should not be construed as limiting the scope of the invention to the following embodiments.

[0043] In the examples, the PP resin used was PP T30S (grade) from Sinopec Zhenhai Refining & Chemical Co., Ltd., with a melt index (190℃ / 2.16kg, GB / T 3682.1-2018) of 3.0g / 10min.

[0044] In the examples, the TPU elastomer used was TPU 290AE (grade) from Shanghai Lianjing Polymer Materials Co., Ltd., with a density (ASTM D792) of 1.12 g / cm³. 3 .

[0045] In the examples, the boron nitride nanosheets used were XFBN03-1 (grade) from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with a sheet diameter of 0.1-0.4 μm.

[0046] In the examples, the talc powder used was ultrafine talc powder from Guangdong Yongfeng Chemical Co., Ltd., with a particle size of 4±0.2μm.

[0047] In the examples, PP-g-MAH was made using CMG9801 (brand name) from Jiayirong Polymer (Shanghai) Co., Ltd., with a grafting rate (acid-base titration method) of 0.6-1.0%.

[0048] In the examples, the carbon nanotubes used are multi-walled carbon nanotubes XFM22 (grade) from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with a length of 0.5-2μm and a diameter of 20-30nm.

[0049] Example 1

[0050] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0051] The composition comprises 80 parts PP resin, 15 parts TPU elastomer, 3.5 parts modified composite material, 2 parts boron nitride nanosheets, 4 parts talc, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide.

[0052] The method for preparing the modified composite material is as follows:

[0053] By weight, 15 parts citric acid, 25 parts urea, and 150 parts water were added to a sealed reactor and hydrothermally reacted at 200°C for 6 hours. After cooling to room temperature, the mixture was dialyzed for 36 hours using a dialysis bag (molecular weight cutoff of 1000 Da), with water changed every 12 hours. The mixture was then freeze-dried to obtain carbon quantum dots. 5 parts 25 wt% ammonia water and 15 parts 45 wt% ethanol aqueous solution were mixed, and then 4 parts tetraethoxysilane were added. The mixture was stirred at 60°C and 120 r / min for 1 hour. Then, 0.5 parts perfluorooctylethyltriethoxysilane and 1.5 parts carbon quantum dots were added, and the mixture was stirred for another 15 hours. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain fluorine-modified SiO2 / carbon quantum dots.

[0054] 6.5 parts of carbon nanotubes were added to 100 parts of 0.5 wt% sodium hexametaphosphate aqueous solution and sonicated at 30 kHz and 150 W for 30 min. After centrifugation and vacuum drying, pretreated carbon nanotubes were obtained. 4 parts of pretreated carbon nanotubes and 5 parts of zinc nitrate were added to 200 parts of water and stirred at 25℃ and 250 r / min for 35 min. Then, 25 wt% ammonia was added to adjust the pH to 9.5, and the mixture was heated to 80℃ for 5 h. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain carbon nanotubes@ZnO. 1.5 parts of carbon nanotubes@ZnO and 4 parts of fluorine-modified SiO2 / carbon quantum dots were added to 150 parts of anhydrous ethanol and stirred at 50℃ and 300 r / min for 20 min. Then, 1 part of (3-epoxypropoxypropyl)methyldiethoxysilane and 0.1 part of glacial acetic acid were added, and the mixture was reacted at 72℃ under nitrogen protection for 3 h. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain the modified composite material.

[0055] The preparation method of the above-mentioned composite plastic for geotextile and its preparation method includes the following steps:

[0056] PP resin, TPU elastomer, modified composite material, boron nitride nanosheets, talc, compatibilizer, and lubricant were added to a mixer and stirred for 12 minutes at a mixing speed of 100 rpm. The mixture was then transferred to a twin-screw extruder for melt blending, extrusion, and granulation to obtain the composite plastic for geotextiles. The extruder temperatures were set sequentially from the barrel to the die head as follows: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, Zone 4 205℃, Zone 5 205℃, and Die Head 200℃, with a screw speed of 110 rpm.

[0057] Example 2

[0058] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0059] The mixture comprises 60 parts PP resin, 10 parts TPU elastomer, 2 parts modified composite material, 1 part boron nitride nanosheets, 2 parts talc, 1 part compatibilizer, and 0.5 parts lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide. The modified composite material is the same as in Example 1.

[0060] The preparation method of the composite plastic used in geotextile and its preparation method is the same as that in Example 1.

[0061] Example 3

[0062] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0063] The composition comprises 100 parts PP resin, 20 parts TPU elastomer, 5 parts modified composite material, 3 parts boron nitride nanosheets, 6 parts talc, 2 parts compatibilizer, and 1.5 parts lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide. The modified composite material is the same as in Example 1.

[0064] The preparation method of the composite plastic used in geotextile and its preparation method is the same as that in Example 1.

[0065] Example 4

[0066] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0067] The composition comprises 80 parts PP resin, 15 parts TPU elastomer, 3.5 parts modified composite material, 2 parts boron nitride nanosheets, 4 parts talc, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide.

[0068] The method for preparing the modified composite material is as follows:

[0069] By weight, 15 parts citric acid, 25 parts urea, and 150 parts water were added to a sealed reactor and hydrothermally reacted at 200°C for 6 hours. After cooling to room temperature, the mixture was dialyzed for 36 hours using a dialysis bag (molecular weight cutoff of 1000 Da), with water changed every 12 hours. The mixture was then freeze-dried to obtain carbon quantum dots. 5 parts 25 wt% ammonia water and 15 parts 45 wt% ethanol aqueous solution were mixed, and then 4 parts tetraethoxysilane were added. The mixture was stirred at 60°C and 120 r / min for 1 hour. Then, 0.5 parts perfluorooctylethyltriethoxysilane and 1.5 parts carbon quantum dots were added, and the mixture was stirred for another 15 hours. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain fluorine-modified SiO2 / carbon quantum dots.

[0070] 1.5 parts of carbon nanotubes and 4 parts of fluorine-modified SiO2 / carbon quantum dots were added to 150 parts of anhydrous ethanol and stirred at 50℃ and 300 r / min for 20 min. Then, 1 part of (3-epoxypropoxypropyl)methyldiethoxysilane and 0.1 part of glacial acetic acid were added and reacted at 72℃ under nitrogen protection for 3 h. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain the modified composite material.

[0071] The preparation method of the composite plastic used in geotextile and its preparation method is the same as that in Example 1.

[0072] Example 5

[0073] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0074] The composition comprises 80 parts PP resin, 15 parts TPU elastomer, 3.5 parts modified composite material, 2 parts boron nitride nanosheets, 4 parts talc, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide.

[0075] The method for preparing the modified composite material is as follows:

[0076] By weight, 6.5 parts of carbon nanotubes were added to 100 parts of 0.5 wt% sodium hexametaphosphate aqueous solution, and sonicated at 30 kHz and 150 W for 30 min. After centrifugation and vacuum drying, pretreated carbon nanotubes were obtained. 4 parts of pretreated carbon nanotubes and 5 parts of zinc nitrate were added to 200 parts of water, and stirred at 25℃ and 250 r / min for 35 min. Then, 25 wt% ammonia was added to adjust the pH to 9.5, and the mixture was heated to 80℃ for 5 h. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain carbon nanotubes@ZnO. 1.5 parts of carbon nanotubes@ZnO and 4 parts of commercially available nano-SiO2 were added to 150 parts of anhydrous ethanol, and stirred at 50℃ and 300 r / min for 20 min. Then, 1 part of (3-epoxypropoxypropyl)methyldiethoxysilane and 0.1 part of glacial acetic acid were added, and the mixture was reacted at 72℃ under nitrogen protection for 3 h. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain the modified composite material. Among them, the commercially available nano-SiO2 uses XFI03 (grade) from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with a particle size of 20nm.

[0077] The preparation method of the composite plastic used in geotextile and its preparation method is the same as that in Example 1.

[0078] Example 6

[0079] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0080] The composition comprises 80 parts PP resin, 15 parts TPU elastomer, 3.5 parts modified composite material, 2 parts boron nitride nanosheets, 4 parts talc, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide.

[0081] The method for preparing the modified composite material is as follows:

[0082] By weight, 15 parts citric acid, 25 parts urea, and 150 parts water were added to a sealed reactor and hydrothermally reacted at 200°C for 6 hours. After cooling to room temperature, the mixture was dialyzed for 36 hours using a dialysis bag (molecular weight cutoff of 1000 Da), with water changed every 12 hours. The mixture was then freeze-dried to obtain carbon quantum dots. 5 parts 25 wt% ammonia water and 15 parts 45 wt% ethanol aqueous solution were mixed, and then 4 parts tetraethoxysilane were added. The mixture was stirred at 60°C and 120 r / min for 1 hour. Then, 0.5 parts perfluorooctylethyltriethoxysilane and 1.5 parts carbon quantum dots were added, and the mixture was stirred for another 15 hours. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain fluorine-modified SiO2 / carbon quantum dots.

[0083] 6.5 parts of carbon nanotubes were added to 100 parts of 0.5 wt% sodium hexametaphosphate aqueous solution and sonicated at 30 kHz and 150 W for 30 min. After centrifugation and vacuum drying, pretreated carbon nanotubes were obtained. 4 parts of pretreated carbon nanotubes and 5 parts of zinc nitrate were added to 200 parts of water and stirred at 25℃ and 250 r / min for 35 min. Then, 25 wt% ammonia was added to adjust the pH to 9.5, and the mixture was heated to 80℃ for 5 h. After cooling to room temperature, the mixture was centrifuged and vacuum dried to obtain carbon nanotubes@ZnO. 1.5 parts of carbon nanotubes@ZnO were mixed evenly with 4 parts of fluorine-modified SiO2 / carbon quantum dots to obtain the modified composite material.

[0084] The preparation method of the composite plastic used in geotextile and its preparation method is the same as that in Example 1.

[0085] Example 7

[0086] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0087] The composition comprises 80 parts PP resin, 15 parts TPU elastomer, 2 parts boron nitride nanosheets, 4 parts talc, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide.

[0088] The preparation method of the above-mentioned composite plastic for geotextile and its preparation method includes the following steps:

[0089] PP resin, TPU elastomer, boron nitride nanosheets, talc, compatibilizer, and lubricant were added to a mixer and stirred for 12 minutes at a mixing speed of 100 rpm. The mixture was then transferred to a twin-screw extruder for melt blending, extrusion, and granulation to obtain the composite plastic for geotextiles. The extruder temperatures were set sequentially from the barrel to the die head as follows: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, Zone 4 205℃, Zone 5 205℃, and Die Head 200℃, with a screw speed of 110 rpm.

[0090] Example 8

[0091] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0092] The mixture comprises 80 parts PP resin, 15 parts TPU elastomer, 3.5 parts modified composite material, 4 parts talc, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide. The modified composite material is the same as in Example 1.

[0093] The preparation method of the above-mentioned composite plastic for geotextile and its preparation method includes the following steps:

[0094] PP resin, TPU elastomer, modified composite material, talc, compatibilizer, and lubricant were added to a mixer and stirred for 12 minutes at a mixing speed of 100 rpm. The mixture was then transferred to a twin-screw extruder for melt blending, extrusion, and granulation to obtain the composite plastic for geotextiles. The extruder temperatures were set sequentially from the barrel to the die head as follows: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, Zone 4 205℃, Zone 5 205℃, and Die Head 200℃, with a screw speed of 110 rpm.

[0095] Example 9

[0096] A composite plastic for geotextiles, prepared by weight from the following raw materials:

[0097] The mixture comprises 80 parts PP resin, 15 parts TPU elastomer, 3.5 parts modified composite material, 2 parts boron nitride nanosheets, 1.5 parts compatibilizer, and 1 part lubricant. The compatibilizer is PP-g-MAH. The lubricant is ethylene bis-stearamide. The modified composite material is the same as in Example 1.

[0098] The preparation method of the above-mentioned composite plastic for geotextile and its preparation method includes the following steps:

[0099] PP resin, TPU elastomer, modified composite material, boron nitride nanosheets, compatibilizer, and lubricant were added to a mixer and stirred for 12 minutes at a mixing speed of 100 r / min. The mixture was then transferred to a twin-screw extruder for melt blending, extrusion, and granulation to obtain the composite plastic for geotextiles. The extruder temperatures were set sequentially from the barrel to the die head as follows: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, Zone 4 205℃, Zone 5 205℃, and Die Head 200℃, with a screw speed of 110 r / min.

[0100] Test Example 1

[0101] The composite plastic granules for geotextiles prepared in Examples 1-9 were injection molded into samples for various performance tests. Tensile strength was measured according to GB / T 1040.2-2022, with sample dimensions of 80×10×4mm, dumbbell shape, and a tensile rate of 50mm / min. Impact strength was measured according to GB / T 1843-2008, with sample dimensions of 80×10×4mm and notch type A. Aging resistance was measured according to GB / T 16422.3-2022, using a UVA-340 light source. One cycle consisted of 8 hours of drying followed by 4 hours of condensation, for a total of 6 cycles (72 hours). After removal, the tensile strength was measured again using the same method, and the tensile strength retention rate was calculated. Tensile strength retention rate % = (initial tensile strength - tensile strength after aging) / initial tensile strength × 100%. The test results are shown in Table 1.

[0102] Table 1: Test results of various properties of composite plastics

[0103]

[0104] The test results above show that the composite plastics prepared in Examples 1-3, through the synergistic effect of adding specific modified composite materials and boron nitride nanosheets, talc, etc., significantly improved the mechanical strength and aging resistance of the composite plastics, and had the best overall performance. This is because, compared to Examples 4-7 which did not use specific modified composite materials, and Examples 8-9 which did not use boron nitride nanosheets or talc, Examples 1-3 simultaneously used modified composite materials, boron nitride nanosheets, and talc in a PP resin matrix. Talc, as a rigid inorganic filler, can form an orientation reinforcement effect in the matrix due to its sheet-like morphology. Through van der Waals forces, it interacts with PP chain segments, restricting the free movement of molecular chains, thereby improving the tensile properties and dimensional stability of the material. Moreover, the hydrophobic surface of talc has similar polarity to the hydrophobic groups of fluorine-modified SiO2 / carbon quantum dots. The two can form hydrophobic regions in the matrix, reducing water penetration and UV-induced degradation, and synergistically improving aging resistance. The carbon nanotube@ZnO fiber network structure contained in the modified composite material can compensate for the bridging defects of talc by bridging cracks and absorbing impact energy. The layered structure of boron nitride nanosheets allows for energy dissipation through slippage. Together with carbon nanotubes@ZnO, they form a surface-to-line interwoven network, uniformly dispersing external stress and suppressing localized fractures caused by stress concentration, thereby enhancing impact resistance. Furthermore, the high reflectivity of boron nitride nanosheets forms the first reflection barrier against ultraviolet light. The ZnO in the carbon nanotubes@ZnO absorbs ultraviolet light and dissipates heat, while the fluorine-modified SiO2 / carbon quantum dots treat the remaining ultraviolet light through absorption-fluorescence conversion, significantly improving the aging resistance of the composite plastic.

[0105] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A composite plastic for geotextiles, characterized in that, By weight, it includes the following ingredients: 40-200 parts PP resin, 5-50 parts TPU elastomer, 1-10 parts modified composite material, 0.5-5 parts boron nitride nanosheets, 1-10 parts talc, 0.5-5 parts compatibilizer, 0.2-3 parts lubricant; The method for preparing the modified composite material is as follows: Carbon nanotubes@ZnO and fluorine-modified SiO2 / carbon quantum dots were added to anhydrous ethanol, heated and stirred, and then (3-epoxypropoxypropyl)methyldiethoxysilane and glacial acetic acid were added. The mixture was heated and reacted under nitrogen protection, cooled, centrifuged and dried to obtain the modified composite material. The preparation method of the fluorine-modified SiO2 / carbon quantum dots is as follows: Citric acid, urea and water were mixed and subjected to hydrothermal reaction. After cooling, dialyzing and drying, carbon quantum dots were obtained. Ammonia water and ethanol aqueous solution were mixed, then tetraethoxysilane was added, heated and stirred, then perfluorooctylethyltriethoxysilane and carbon quantum dots were added and stirred again. After cooling, centrifugation and drying, fluorine-modified SiO2 / carbon quantum dots were obtained. The preparation method of the carbon nanotubes@ZnO is as follows: Carbon nanotubes were added to an aqueous solution of sodium hexametaphosphate, sonicated, centrifuged, and dried to obtain pretreated carbon nanotubes. Pretreated carbon nanotubes and zinc nitrate were added to water, stirred, and then the pH was adjusted to alkaline. The mixture was heated to react, cooled, centrifuged, and dried to obtain carbon nanotubes@ZnO. The weight ratio of the carbon nanotubes@ZnO, fluorine-modified SiO2 / carbon quantum dots, and (3-epoxypropoxypropyl)methyldiethoxysilane is 1-2:3-5:0.5-1.

5.

2. The composite plastic for geotextiles according to claim 1, characterized in that, By weight, it includes the following ingredients: 60-100 parts PP resin, 10-20 parts TPU elastomer, 2-5 parts modified composite material, 1-3 parts boron nitride nanosheets, 2-6 parts talc, 1-2 parts compatibilizer, 0.5-1.5 parts lubricant.

3. The composite plastic for geotextiles according to claim 1, characterized in that, The compatibilizer is one or a mixture of two or more of PP-g-MAH, POE-g-MAH, and POE-g-GMA.

4. The composite plastic for geotextiles according to claim 1, characterized in that, The lubricant is one or a mixture of two or more of ethylene bis-stearamide, pentaerythritol stearate, and oleamide.

5. The method for preparing composite plastics for geotextiles according to any one of claims 1-4, characterized in that, Includes the following steps: PP resin, TPU elastomer, modified composite material, boron nitride nanosheets, talc, compatibilizer, and lubricant are added to a mixer and stirred. Then, the mixture is transferred to a twin-screw extruder for melt blending, extrusion granulation, and the resulting composite plastic for geotextiles is obtained.

6. The method for preparing composite plastics for geotextiles according to claim 5, characterized in that, The temperature settings of the twin-screw extruder are as follows: Zone 1 185-190℃, Zone 2 190-195℃, Zone 3 195-200℃, Zone 4 200-205℃, Zone 5 200-205℃, and Die head 195-200℃, with a screw speed of 100-200 r / min.

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