Acid and alkali resistant geotextile and preparation method thereof

Abstract

The invention provides acid and alkali resistant geotechnical cloth and a preparation method thereof. The acid and alkali resistant geotechnical cloth is prepared from the following raw materials in parts by weight: 25 to 35 parts of PBT-PETG epoxy interpenetrating copolymer, 15 to 25 parts of PBS-orthophthalic UP hydroxyl cross-linked copolymer, 12 to 20 parts of silane modified basalt fiber, 4 to 8 parts of composite blocking agent, 2 to 5 parts of anti-aging filler, 4 to 9 parts of flexibility regulator, 1.2 to 2.3 parts of flame retardant, 2.5 to 4.5 parts of pore filler, 0.5 to 1.2 parts of antioxidant and 0.3 to 0.8 part of ultraviolet screening agent. According to the invention, the PBT-PETG epoxy interpenetrating copolymer constructs an acid-alkali-crosslinking integrated matrix, which is the core of corrosion resistance and mechanics; the PBS-orthophthalic UP hydroxyl cross-linked copolymer enhances the flexibility and interface combination, and solves the brittleness problem of a matrix; the two components cooperate with the composite blocking agent, so that the acid-base permeability is greatly reduced, the weather-proof retention rate is greatly improved, and the service life of the geotechnical cloth is prolonged.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of geotextiles, in particular to an acid and alkali resistant geotextile and a preparation method thereof. BACKGROUND

[0002] As a new type of building material, the geotextile is widely used in water conservancy projects, chemical plant site seepage prevention, mine tailings treatment and other fields. In the above application scenarios, the geotextile is often in contact with acid and alkali medium (such as chemical wastewater, acid mine water, etc.) for a long time, and therefore the acid and alkali resistance of the geotextile becomes a key performance determining the stability and service life of the project. In the prior art, the means for improving the acid and alkali resistance of the geotextile are mainly concentrated in single polymer modification (such as epoxy modified PET) or addition of a small amount of acid-resistant fibers (such as ordinary basalt fibers), but such improvement schemes do not form a systematic performance synergistic mechanism.

[0003] The existing acid and alkali resistant geotextile has obvious limitations in actual application. On the one hand, the rigid polymer matrix used to pursue acid and alkali resistance often leads to insufficient flexibility of the geotextile, which is prone to deformation and cracking during construction laying or foundation settlement, thereby damaging the seepage prevention and isolation functions. On the other hand, in the face of the extreme composite environment of acid and alkali ion penetration, ultraviolet radiation and alternating heat and humidity, the existing product is difficult to simultaneously maintain stable mechanical properties (such as tensile strength and tear strength) and impermeability, and the matrix is prone to thermal oxidative degradation or fiber-matrix interface peeling, thereby greatly shortening the service life of the geotextile and failing to meet long-term engineering requirements. SUMMARY

[0004] In view of the problems in the prior art, the application provides an acid and alkali resistant geotextile and a preparation method thereof, so as to obtain a geotextile with good acid and alkali resistance, ultraviolet radiation resistance, impermeability and other comprehensive properties.

[0005] To achieve the above object, the application realizes the technical scheme as follows: The application discloses an acid and alkali resistant geotextile, which is composed of the following raw materials: 25-35 parts of PBT-PETG epoxy interpenetrating copolymer, 15-25 parts of PBS-o-phenyl UP hydroxyl crosslinking copolymer, 12-20 parts of silane modified basalt fiber, 4-8 parts of composite barrier agent, 2-5 parts of anti-aging filler, 4-9 parts of flexible modifier, 1.2-2.3 parts of flame retardant, 2.5-4.5 parts of pore filling agent, 0.5-1.2 parts of antioxidant and 0.3-0.8 parts of ultraviolet resistant agent.

[0006] Through the above technical scheme, the PBT-PETG epoxy interpenetrating copolymer can construct the core matrix skeleton of acid and alkali resistance for the geotextile, and improve the structural stability through cross-linking effect; the PBS-o-phenyl UP hydroxyl cross-linked copolymer can enhance the flexibility of the geotextile, reduce the risk of construction deformation and cracking, and can be cross-linked with the former to improve the interface gap; the silane modified basalt fiber can improve the tensile strength and tear strength of the geotextile, and provide macroscopic mechanical support; the composite barrier agent can block the penetration of acid and alkali ions, reduce the water permeability coefficient of the geotextile, and also assist in enhancing the mechanical properties; the anti-aging filler can resist ultraviolet and hygrothermal aging, prolong the service life of the geotextile; the flexible modifier can further improve the flexibility of the geotextile and improve the elongation at break; the flame retardant can make the geotextile have flame retardant performance; the pore filler can fill the gap between the fibers, reduce the porosity to improve the impermeability; the antioxidant can inhibit the thermal oxidative degradation of the geotextile matrix, and the ultraviolet resistant agent can absorb ultraviolet rays to improve the anti-aging performance of the geotextile, and together guarantee the long-term use performance of the geotextile in extreme composite environment.

[0007] Preferably, the composition of the PBT-PETG epoxy interpenetrating copolymer includes, in parts by weight: polybutylene terephthalate 90-100 parts, polyethylene terephthalate-1,4-cyclohexane dimethanol 50-60 parts, epoxy propyl methacrylate 5-8 parts, dicumyl peroxide 0.5-0.8 parts, and dimethyl sulfoxide 600-700 parts.

[0008] Through the above technical scheme, polybutylene terephthalate (PBT) as the basic component of the PBT-PETG epoxy interpenetrating copolymer, the ester group in its molecule can endow the copolymer with acid resistance, providing acid-resistant skeleton support for acid and alkali resistant geotextile; polyethylene terephthalate-1,4-cyclohexane dimethanol (PETG) endows the copolymer with alkali resistance due to the cyclohexane dimethanol structure, and the two together make the copolymer have both acid and alkali resistance, while constructing a balanced matrix structure to ensure the mechanical stability of the geotextile. Epoxy propyl methacrylate can provide active sites for epoxy groups, promote the formation of interpenetrating network structure of the copolymer, enhance the structural density, and thus inhibit the penetration of acid and alkali ions, improve the corrosion resistance and mechanical strength of the geotextile. Dicumyl peroxide as an initiator can initiate the reaction between epoxy propyl methacrylate and the two kinds of polyester, promote the effective formation of cross-linked network, and ensure the stability of the copolymer structure. Dimethyl sulfoxide as a solvent can effectively dissolve PBT and PETG, ensuring uniform mixing of all components and uniform reaction, avoiding performance defects of the copolymer due to uneven composition, and providing a stable core corrosion-resistant skeleton for acid and alkali resistant geotextile.

[0009] Preferably, the preparation method of the PBT-PETG epoxy interpenetrating copolymer includes the following steps: 1) polybutylene terephthalate and polyethylene terephthalate-1, 4-cyclohexane dimethanol are added into dimethyl sulfoxide, stirred at 300-500 r / min for 1-2 h at 60-85℃; 2) epoxy propyl methacrylate and dicumyl peroxide are added into the system obtained in 1), stirred uniformly, heated to 80-90℃ for 3-5 h, then the reaction solution is mixed with ethanol at a volume ratio of 1:3-5 for precipitation, filtered, vacuum dried at 80-90℃ for 6-8 h, and crushed to pass through a 100-120 mesh sieve to obtain PBT-PETG epoxy interpenetrating copolymer.

[0010] By setting the above technical solution, PBT and PETG are heated and stirred in dimethyl sulfoxide, which can effectively dissolve the two kinds of polyester and form a uniform system, reducing the probability of performance defects of the copolymer caused by uneven composition; then epoxy propyl methacrylate and dicumyl peroxide are added and heated to react, dicumyl peroxide can initiate the grafting reaction of the epoxy group of epoxy propyl methacrylate with the two kinds of polyester, and then form an interpenetrating network structure, giving the copolymer the integrated performance of "acid-resistant-alkali-resistant-mechanical stability"; finally, the copolymer is separated by ethanol precipitation, vacuum dried to remove solvent and moisture, crushed to pass through a sieve to ensure uniform particle size, ensuring that the product can uniformly participate in the construction of the geotextile matrix in the subsequent process, avoiding the influence of uneven particles on the overall corrosion resistance and mechanical strength of the geotextile.

[0011] Preferably, the number average molecular weight of polybutylene terephthalate is 1.5×10 4 -2×10 4 .

[0012] By setting the above technical solution, it can not only ensure that it is effectively dissolved in dimethyl sulfoxide during the preparation of PBT-PETG epoxy interpenetrating copolymer to realize uniform mixing with other components, but also fully exert the acid-resistant performance of the ester side chain through a stable molecular chain structure, while providing good mechanical support for PBT-PETG epoxy interpenetrating copolymer, helping to build the corrosion-resistant skeleton required for acid and alkali-resistant geotextile, avoiding insufficient acid resistance or weak mechanical support caused by too low molecular weight, and also avoiding affecting the processing compatibility and interpenetrating network formation effect of the copolymer caused by too high molecular weight.

[0013] Preferably, the composition of PBS-ortho phenyl UP hydroxyl crosslinked copolymer includes, by weight: polybutylene succinate 90-100 parts, ortho phenyl unsaturated polyester 30-40 parts, maleic anhydride 3-5 parts, epoxy chloropropane 5-7 parts, and triethylamine 1-1.5 parts.

[0014] By setting up the above technical solution, polybutylene succinate (PBS), as the main raw material of PBS-phthalic UP hydroxyl crosslinked copolymer, can impart good flexibility to the copolymer through its flexible segments, effectively improving the brittleness of acid and alkali resistant geotextiles and preventing cracking due to deformation during construction; phthalic unsaturated polyester (UP) can enhance the chemical resistance of the copolymer, helping the geotextile improve its tolerance to acid and alkali environments; maleic anhydride can react with PBS to introduce hydroxyl groups, which can interact with the PBT-PETG epoxy interpenetrating copolymer in the acid and alkali resistant geotextile. The epoxy groups of the polymer undergo cross-linking, reducing interfacial gaps and improving the overall density and impermeability of the geotextile structure. Epichlorohydrin can act as a cross-linking agent, promoting the formation of stable covalent cross-linked structures in components such as PBS and UP, enhancing the structural stability of the copolymer, and thus ensuring the durability of the geotextile's mechanical and corrosion resistance properties. Triethylamine can catalyze the cross-linking reaction of epichlorohydrin, ensuring that the reaction proceeds fully and avoiding uneven copolymer performance due to incomplete reaction, ultimately providing a "flexible-corrosion-structurally stable" matrix support for acid and alkali resistant geotextiles.

[0015] Preferably, the number average molecular weight of polybutylene succinate is 1.4 × 10⁻⁶. 4 -1.8×10 4 The number-average molecular weight of phthalic unsaturated polyesters is 1.4 × 10⁻⁶. 4 -1.8×10 4 .

[0016] By setting the above technical solution, the number-average molecular weight of polybutylene succinate is 1.4 × 10⁻⁶. 4 -1.8×10 4 This ensures that the molecular chain has sufficient flexible segments, effectively improving the flexibility of the PBS-phthalic UP hydroxyl crosslinked copolymer, thereby increasing the elongation at break of acid and alkali resistant geotextiles and preventing cracking due to deformation during construction; at the same time, it ensures the stability of the molecular chain structure, providing a certain mechanical support for the copolymer and preventing weak mechanical properties due to excessively low molecular weight. The number average molecular weight of phthalic unsaturated polyester is 1.4 × 10⁻⁶. 4 -1.8×10 4 The molecular weight of the copolymer is matched with that of polybutylene succinate, which ensures that the two are mixed evenly and fully cross-linked during the copolymer preparation process, forming a structurally stable copolymer. At the same time, this molecular weight range can give phthalic unsaturated polyester good chemical resistance, help the copolymer improve its acid and alkali resistance, and ultimately provide a "flexible-corrosion resistant" balanced matrix support for acid and alkali resistant geotextiles, avoiding uneven copolymer performance or imbalance of corrosion resistance and mechanical properties due to molecular weight mismatch.

[0017] Preferably, the preparation method of PBS-phthalic UP hydroxy crosslinked copolymer includes the following steps: a. polybutylene succinate and maleic anhydride are added into a twin-screw extruder, and melt blended at 180-200℃ for 1-1.5h at a rotation speed of 350-450r / min; b. the obtained system in a is added with o-phthalic unsaturated polyester, epichlorohydrin and triethylamine, and after uniform mixing, heated to 200-220℃ for 2-3h, and then cooled to room temperature and crushed to pass through an 80-100 mesh sieve to obtain PBS-o-phthalic UP hydroxyl crosslinked copolymer.

[0018] By setting the above technical solution, PBS and maleic anhydride are melt blended at 180-200℃, which can ensure that the two are fully reacted and introduce hydroxyl groups, laying a foundation for subsequent crosslinking of the epoxy group of the PBT-PETG epoxy interpenetrating copolymer, and the flexible segment of PBS can initially impart flexibility to the copolymer; then adding UP, epichlorohydrin and triethylamine and heating to 200-220℃ for reaction, which can promote the formation of stable covalent crosslinked structure of each component, not only enhancing the chemical resistance of the copolymer to improve the overall corrosion resistance of the geotextile, but also optimizing the structural stability through crosslinking; finally, cooling and crushing to pass through a sieve can ensure uniform particle size of the copolymer, which can be uniformly dispersed when mixed with other components in the future, avoiding local performance defects of the geotextile due to uneven particles, and ultimately helping the geotextile to achieve a balance between flexibility and corrosion resistance, reducing the risk of construction deformation and cracking.

[0019] Preferably, the composite barrier agent is composed of hydroxylated carbon nanotubes, aminated graphene and sodium-based montmorillonite in a mass ratio of 1:2:8, the anti-aging filler is titanium ester modified nano zinc oxide or silane modified nano titanium dioxide, the flexibility regulator is polycaprolactone or polypropylene carbonate, the flame retardant is one of zinc borate, magnesium hydroxide or melamine cyanurate, the pore filling agent is polymethyl methacrylate microspheres or polyamide microspheres, the antioxidant is one of antioxidant 1010, antioxidant 168 or antioxidant 1076, and the ultraviolet resistant agent is UV-531 or UV-326.

[0020] By setting the above technical scheme, the hydroxylated carbon nanotube can enhance the mechanical property, the aminated graphene can block the diffusion of acid and alkali ions, and the sodium-based montmorillonite can adsorb free acid and alkali molecules. The three are mixed in a ratio of 1:2:8 to form a "strengthening-barrier-adsorption" multi-scale barrier, thereby reducing the acid and alkali permeability and water permeability coefficient of the acid and alkali resistant geotextile; the anti-aging filler (titanate modified nano zinc oxide or silane modified nano titanium dioxide) resists ultraviolet light and photocatalytically degrades small acid molecules, and is combined with an ultraviolet resistant agent (UV-531 or UV-326) to absorb ultraviolet light, and an antioxidant (antioxidants 1010, 168 or 1076) to inhibit thermal oxidative degradation, thereby synergistically prolonging the service life of the geotextile; the flexible modifier (polycaprolactone or polypropylene carbonate) improves the flexibility of the base body to avoid construction cracking; the flame retardant (zinc borate, magnesium hydroxide or melamine cyanurate) forms a flame retardant layer to improve the flame retardancy; and the pore filler (polymethyl methacrylate microspheres or polyamide microspheres) fills the fiber pores to further reduce the water permeability coefficient, thereby collectively ensuring the comprehensive performance of the geotextile in extreme environments.

[0021] The application also discloses a preparation method of the acid and alkali resistant geotextile. S1, raw material pretreatment: The PBT-PETG epoxy interpenetrating copolymer, the PBS-o-phenyl UP hydroxyl crosslinking copolymer and the flexible modifier are vacuum dried at 85-95 DEG C for 4-6 h. The silane modified basalt fiber, the composite barrier agent, the anti-aging filler, the flame retardant, the pore filler, the antioxidant and the ultraviolet resistant agent are blast dried at 100-110 DEG C for 2-3 h. S2, melt spinning of the base body: The PBT-PETG epoxy interpenetrating copolymer, the PBS-o-phenyl UP hydroxyl crosslinking copolymer and the flexible modifier are added into a double screw extruder, and the temperature interval is adjusted as follows: zone 1, 210-220 DEG C; zone 2, 220-230 DEG C; zone 3, 230-240 DEG C; and the die head, 240-250 DEG C; the screw rotation speed is 300-400 r / min, and the melt pressure is 3-5 MPa; the nascent fiber is obtained by spinning through a spinning hole with a diameter of 0.25-0.45 mm at a spinning speed of 900-1300 m / min. S3, fiber reinforced mixing: The nascent fiber is mixed with the silane modified basalt fiber at a mass ratio of 8:2, is drawn at 80-100 DEG C by 2.5-4.5 times, and the high-strength mixed fiber is obtained. S4, needle punching to form a cloth: The high-strength mixed fiber is cross-laid and needle punched by a needle punching machine to form a geotextile blank body, wherein the needle punching density is 120-150 needles / cm 2 , and the needle punching depth is 7-11 mm. S5, blending of multiple fillers: The composite barrier agent, anti-aging filler, flame retardant, pore filler, antioxidant, and ultraviolet resistant agent are uniformly dispersed in a high-speed mixer, and then impregnated and mixed with the geotextile blank at 80-100℃ for 15-25min; S6, post-treatment coating: The geotextile blank obtained in S5 is immersed in a polysiloxane-epoxy resin emulsion, and then dried at 80-90℃ for 30-45min to form a weather-resistant barrier coating. S7, gradient heat setting: The geotextile blank obtained in S6 is treated at 115-125℃ and 0.35-0.45MPa for 20-30min, and then treated at 125-135℃ and 0.45-0.55MPa for 25-35min, and finally cooled to room temperature to obtain an acid and alkali resistant geotextile.

[0022] By setting the above technical solution, the raw material pretreatment (vacuum and air drying) removes moisture, avoids air bubbles in subsequent processing, and ensures the compactness of the geotextile structure; the temperature gradient and parameters of the matrix melt spinning ensure that the PBT-PETG epoxy interpenetrating copolymer, PBS-ortho-phenyl UP hydroxyl crosslinking copolymer, and flexible modifier are fully melted and uniform, obtaining stable primary fibers; fiber reinforced mixing (8:2 ratio and drafting) combines the matrix properties of primary fibers and the strength of silane modified basalt fibers, improving the mechanical properties of geotextile; needle punching (high needle punching density and depth) makes the fibers interweave tightly, reduces the initial porosity, and reduces the risk of acid and alkali penetration; various fillers blending (high temperature impregnation) makes the composite barrier agent, anti-aging filler, etc. uniformly dispersed in the fiber gap, fully exerting the barrier, anti-aging, and flame retardant functions; post-treatment coating (polysiloxane-epoxy resin emulsion drying) forms a weather-resistant barrier layer, enhancing the environmental aging resistance; gradient heat setting (staged temperature and pressure) realizes preliminary crystallization and sufficient crosslinking, further densifying the structure, and finally making the geotextile have excellent acid and alkali resistance, mechanical properties, and weather resistance, suitable for extreme composite environments.

[0023] Preferably, in step S6, the solid content of the polysiloxane-epoxy resin emulsion is 40%-50%, and the mass ratio of polysiloxane to epoxy resin is 1:4.

[0024] By setting the above technical scheme, the setting of the solid content of the polysiloxane-epoxy resin emulsion can ensure that the geotextile blank body forms a coating with uniform thickness and dense structure after padding, and can avoid the coating being too thin due to too low solid content, which results in insufficient barrier property, or the coating being aggregated and having poor adhesion due to too high solid content; the mass ratio of polysiloxane to epoxy resin is 1:4, which can balance the acid and alkali resistance of the epoxy resin and the flexibility of the polysiloxane, that is, the acid and alkali resistance of the coating is strengthened by the epoxy resin, and the cracking of the coating due to excessive rigidity during the deformation of the geotextile is prevented by the polysiloxane, thereby finally assisting the improvement of the weather resistance and the impermeability of the acid and alkali resistant geotextile to meet the use requirements in extreme environments.

[0025] The beneficial effects of the present application are: The PBT-PETG epoxy interpenetrating copolymer can construct the core matrix skeleton of the acid and alkali resistant geotextile, and improve the structural stability through cross-linking; the PBS-o-phenyl UP hydroxyl cross-linked copolymer can enhance the flexibility of the geotextile, reduce the risk of cracking due to construction deformation, and can be cross-linked with the former to improve the interface gap; the silane modified basalt fiber can improve the tensile strength and tear strength of the geotextile, and provide macroscopic mechanical support; the composite barrier agent can block the penetration of acid and alkali ions, reduce the water permeability coefficient of the geotextile, and also assist in enhancing the mechanical properties; the anti-aging filler can resist ultraviolet and hygrothermal aging, and prolong the service life of the geotextile; the flexible modifier can further improve the flexibility of the geotextile and improve the elongation at break; the flame retardant can make the geotextile have flame retardant performance; the pore filler can fill the gap between the fibers, reduce the porosity to improve the impermeability; the antioxidant can inhibit the thermal oxidative degradation of the geotextile matrix, and the ultraviolet resistant agent can absorb ultraviolet rays to improve the anti-aging performance of the geotextile, which together guarantee the long-term use performance of the geotextile in extreme composite environments.

[0026] Polybutylene terephthalate (PBT) as the basic component of the PBT-PETG epoxy interpenetrating copolymer, the ester group in its molecule can endow the copolymer with acid resistance, providing an acid resistant skeleton support for the acid and alkali resistant geotextile; polyethylene terephthalate-1,4-cyclohexane dimethanol (PETG) endows the copolymer with alkali resistance due to the cyclohexane dimethanol structure, and the two together make the copolymer have both acid and alkali resistance, and construct a rigid and flexible balanced matrix structure to guarantee the mechanical stability of the geotextile. Epoxy propyl methacrylate can provide active sites for the copolymer to form an interpenetrating network structure, enhance the structural density, and thus inhibit the penetration of acid and alkali ions, and improve the corrosion resistance and mechanical strength of the geotextile. The peroxide as an initiator can initiate the reaction between epoxy propyl methacrylate and the two kinds of polyesters, promote the effective formation of cross-linked network, and ensure the stability of the copolymer structure. Dimethyl sulfoxide as a solvent can effectively dissolve PBT and PETG, make the components uniformly mixed, ensure the uniform reaction, and avoid performance defects of the copolymer due to uneven composition, providing a stable core corrosion resistant skeleton for the acid and alkali resistant geotextile.

[0027] Polybutylene succinate (PBS) as the main raw material of PBS-ortho phenyl UP hydroxyl crosslinked copolymer, its flexible segment can give the copolymer good flexibility, which can effectively improve the brittleness of acid and alkali resistant geotextile, avoid cracking due to deformation in construction; Ortho phenyl unsaturated polyester (UP) can enhance the chemical resistance of copolymer, help geotextile to improve the resistance to acid and alkali environment; Maleic anhydride can react with PBS to introduce hydroxyl group, which can crosslink with the epoxy group of PBT-PETG epoxy interpenetrating copolymer in acid and alkali resistant geotextile, reduce the interface gap, and improve the overall structure density and impermeability of geotextile; Epichlorohydrin can be used as a crosslinking agent to promote the formation of stable covalent crosslinked structure of PBS, UP and other components, enhance the structural stability of copolymer, and then ensure the durability of mechanical properties and corrosion resistance of geotextile; Triethylamine can catalyze the crosslinking reaction of epichlorohydrin, ensure the reaction to proceed completely, avoid the uneven performance of copolymer due to incomplete reaction, and finally provide "flexible-corrosion-resistant-structurally stable" matrix support for acid and alkali resistant geotextile. DETAILED DESCRIPTION

[0028] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] Embodiment 1 The embodiment discloses an acid and alkali resistant geotextile, which comprises the following components: PBT-PETG epoxy interpenetrating copolymer 25 parts, PBS-ortho phenyl UP hydroxyl crosslinked copolymer 15 parts, silane modified basalt fiber 12 parts, composite barrier agent 4 parts, titanate modified nano zinc oxide 2 parts, polypropylene carbonate 4 parts, zinc borate 1.2 parts, polyamide microspheres 2.5 parts, antioxidant 10100 0.5 parts, UV-326 0.3 parts. The composite barrier agent is composed of hydroxylated carbon nanotubes, aminated graphene and sodium-based montmorillonite in a mass ratio of 1:2:8.

[0030] The PBT-PETG epoxy interpenetrating copolymer comprises the following components in parts by weight: polybutylene terephthalate with a number average molecular weight of 1.5×10 4 polybutylene terephthalate 90 parts, polyethylene terephthalate-1,4-cyclohexane dimethanol 50 parts, epoxy propyl methacrylate 5 parts, dicumyl peroxide 0.5 parts, dimethyl sulfoxide 600 parts.

[0031] The preparation method of the PBT-PETG epoxy interpenetrating copolymer comprises the following steps: 1) polybutylene terephthalate and polyethylene terephthalate-1, 4-cyclohexane dimethanol were added into dimethyl sulfoxide, stirred at 60℃ with a rotation speed of 300r / min for 1h; 2) epoxy propyl methacrylate and dicumyl peroxide were added into the system obtained in 1), stirred uniformly, heated to 80℃ and reacted for 3h, then the reaction solution was mixed with ethanol at a volume ratio of 1:3 for precipitation, filtered and vacuum dried at 80℃ for 6h, crushed through a 100 mesh sieve to obtain PBT-PETG epoxy interpenetrating copolymer.

[0032] The raw materials of PBS-o-phenyl UP hydroxyl cross-linked copolymer include, by weight fraction, 90 parts of polybutylene succinate with a number average molecular weight of 1.4×10 4 , 30 parts of o-phenyl unsaturated polyester with a number average molecular weight of 1.4×10 4 , 3 parts of maleic anhydride, 5 parts of epoxy chloropropane and 1 part of triethylamine.

[0033] The preparation method of PBS-o-phenyl UP hydroxyl cross-linked copolymer includes the following steps: a. polybutylene succinate and maleic anhydride were added into a twin-screw extruder, melt blended at 180℃ with a rotation speed of 350r / min for 1h; b. o-phenyl unsaturated polyester, epoxy chloropropane and triethylamine were added into the system obtained in a, mixed uniformly, heated to 200℃ and reacted for 2h, then cooled to room temperature and crushed through an 80 mesh sieve to obtain PBS-o-phenyl UP hydroxyl cross-linked copolymer.

[0034] The embodiment also discloses a preparation method of acid and alkali resistant geotextile, including the following steps: S1, raw material pretreatment: PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl cross-linked copolymer and polypropylene carbonate were vacuum dried at 85℃ for 4h; Silane modified basalt fiber, composite barrier agent, titanate modified nano zinc oxide, zinc borate, polyamide microspheres, antioxidant 1010 and UV-326 were blast dried at 100℃ for 2h; S2, melt spinning of matrix: PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl cross-linked copolymer and polypropylene carbonate were added into a twin-screw extruder, the temperature interval was adjusted to 210℃ for the first zone, 220℃ for the second zone, 230℃ for the third zone and 240℃ for the die head, the screw rotation speed was 300r / min and the melt pressure was 3MPa; the nascent fiber was obtained by spinning through a spinning hole with a diameter of 0.25mm at a spinning speed of 900m / min; S3, fiber reinforced mixing: The primary fiber is mixed with the silane modified basalt fiber at a mass ratio of 8:2, drawn 2.5 times at 80℃, to obtain high-strength mixed fibers; S4, needle punching into cloth: The high-strength mixed fibers are cross-laid and needle punched into shape using a needle punching machine at a needle density of 120 needles / cm 2 , a needle punching depth of 7mm, to obtain a geotextile body; S5, blending of multiple fillers: The composite barrier agent, titanate modified nano zinc oxide, zinc borate, polyamide microspheres, antioxidant 1010, UV-326 are uniformly dispersed in a high-speed mixer, and then impregnated and mixed with the geotextile body at 80℃ for 15min; S6, post-treatment coating: The geotextile body obtained in S5 is immersed in a polysiloxane-epoxy resin emulsion (the mass ratio of polysiloxane to epoxy resin is 1:4) with a solid content of 40%, and then dried at 80℃ for 30min to form a weather-resistant barrier coating; S7, gradient heat setting: The geotextile body obtained in S6 is treated at 115℃, 0.35MPa for 20min, then at 125℃, 0.45MPa for 25min, and finally cooled to room temperature to obtain an acid and alkali resistant geotextile.

[0035] Example 2: The acid and alkali resistant geotextile disclosed in this embodiment comprises the following raw materials: PBT-PETG epoxy interpenetrating polymer 35 parts, PBS-o-phenyl UP hydroxyl crosslinking copolymer 25 parts, silane modified basalt fiber 20 parts, composite barrier agent 8 parts, silane modified nano titanium dioxide 5 parts, polypropylene carbonate 9 parts, magnesium hydroxide 2.3 parts, polyamide microspheres 4.5 parts, antioxidant 168 1.2 parts, UV-326 0.8 parts. The composition and ratio of the composite barrier agent are the same as in Example 1.

[0036] The composition of the PBT-PETG epoxy interpenetrating polymer includes, by weight fraction: polybutylene terephthalate with a number average molecular weight of 2×10 4 100 parts, polyethylene terephthalate-1,4-cyclohexane dimethanol 60 parts, epoxy propyl methacrylate 8 parts, dicumyl peroxide 0.8 parts, dimethyl sulfoxide 700 parts.

[0037] The preparation method of the PBT-PETG epoxy interpenetrating polymer comprises the following steps: 1) Polybutylene terephthalate and polyethylene terephthalate-1,4-cyclohexane dimethanol are added to dimethyl sulfoxide, stirred at 85℃ and a speed of 500r / min for 2h; 2) adding epoxy propyl methacrylate and dicumyl peroxide to the system obtained in 1), stirring uniformly, increasing the temperature to 90℃ for 5h, then mixing the reaction solution with ethanol in a volume ratio of 1:5 for precipitation, filtering and vacuum drying at 90℃ for 8h, crushing through a 120 mesh sieve to obtain PBT-PETG epoxy interpenetrating copolymer.

[0038] The raw materials of the PBS-o-phenyl UP hydroxyl cross-linked copolymer include, in parts by weight: 100 parts of polybutylene succinate with a number average molecular weight of 1.8 x 10 4 40 parts of o-phenyl unsaturated polyester with a number average molecular weight of 1.8 x 10 4 5 parts of maleic anhydride, 7 parts of epoxy chloropropane and 1.5 parts of triethylamine.

[0039] The preparation method of the PBS-o-phenyl UP hydroxyl cross-linked copolymer includes the following steps: a. adding polybutylene succinate and maleic anhydride into a double screw extruder, melt blending at 200℃ for 1.5h at a rotation speed of 450r / min; b. adding o-phenyl unsaturated polyester, epoxy chloropropane and triethylamine into the system obtained in a, mixing uniformly, increasing the temperature to 220℃ for 3h, then crushing through a 100 mesh sieve after cooling to room temperature to obtain PBS-o-phenyl UP hydroxyl cross-linked copolymer.

[0040] The embodiment also discloses a preparation method of acid and alkali resistant geotextile, including the following steps: S1, raw material pretreatment: vacuum drying PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl cross-linked copolymer and polypropylene carbonate at 95℃ for 6h; blowing drying silane modified basalt fiber, composite barrier agent, silane modified nano titanium dioxide, magnesium hydroxide, polyamide microspheres and antioxidant 168 and UV-326 at 110℃ for 3h; S2, melt spinning of matrix: adding PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl cross-linked copolymer and polypropylene carbonate into a double screw extruder, adjusting the temperature interval: 220℃ for the first zone, 230℃ for the second zone, 240℃ for the third zone and 250℃ for the die head, the screw rotation speed is 400r / min and the melt pressure is 5MPa; spinning through a spinning hole with a diameter of 0.45mm at a spinning speed of 1300m / min to obtain nascent fiber; S3, fiber reinforced mixing: mixing the nascent fiber with silane modified basalt fiber in a mass ratio of 8:2, drawing at 100℃ for 4.5 times to obtain high-strength mixed fiber; S4, needle punching into cloth: High-strength mixed fibers are cross-laid and needled into a form by a needle punching machine at a needle density of 150 needles / cm and a needle depth of 11 mm to obtain a geotextile body. 2 S5, blending of multiple fillers: The composite barrier agent, silane-modified nano-titanium dioxide, magnesium hydroxide, polyamide microspheres, antioxidant 168, and UV-326 are uniformly dispersed in a high-speed mixer, and then impregnated and mixed with the geotextile body at 100℃ for 25 min. S6, post-treatment coating: The geotextile body obtained in S5 is immersed in a polysiloxane-epoxy resin emulsion (mass ratio of polysiloxane to epoxy resin is 1:4) with a solid content of 50%, and then dried at 90℃ for 45 min to form a weather-resistant barrier coating. S7, gradient heat setting: The geotextile body obtained in S6 is treated at 125℃ and 0.45MPa for 30 min, and then treated at 135℃ and 0.55MPa for 35 min, and finally cooled to room temperature to obtain an acid and alkali-resistant geotextile.

[0041] Example 3: The acid and alkali-resistant geotextile disclosed in this embodiment comprises the following raw materials: PBT-PETG epoxy interpenetrating polymer 30 parts, PBS-ortho-phenyl UP hydroxyl crosslinking copolymer 20 parts, silane-modified basalt fiber 16 parts, composite barrier agent 6 parts, titanate-modified nano-zinc oxide 3 parts, polycaprolactone 6 parts, zinc borate 1.6 parts, polymethyl methacrylate microspheres 3.5 parts, antioxidant 168 0.8 parts, and UV-531 0.6 parts. The composition and ratio of the composite barrier agent are the same as in Example 1.

[0042] The composition of the PBT-PETG epoxy interpenetrating polymer includes, by weight fraction: polybutylene terephthalate with a number average molecular weight of 1.7×10 4 95 parts, polyethylene terephthalate-1,4-cyclohexane dimethanol 55 parts, epoxy propyl methacrylate 6 parts, dicumyl peroxide 0.6 parts, and dimethyl sulfoxide 650 parts.

[0043] The preparation method of the PBT-PETG epoxy interpenetrating polymer comprises the following steps: 1) Polybutylene terephthalate and polyethylene terephthalate-1,4-cyclohexane dimethanol are added to dimethyl sulfoxide and stirred at 74℃ and a speed of 325r / min for 1.5h; ​2) adding epoxy propyl methacrylate and dicumyl peroxide to the system obtained in 1), stirring uniformly, and reacting at 85°C for 4h, then precipitating the reaction solution by mixing with ethanol at a volume ratio of 1:4, filtering, vacuum drying at 85°C for 7h, crushing through a 110 mesh sieve, and obtaining PBT-PETG epoxy interpenetrating copolymer.

[0044] The raw materials of the PBS-o-phenyl UP hydroxyl crosslinked copolymer include, in parts by weight, 95 parts of polybutylene succinate with a number average molecular weight of 1.6 x 10 4 , 35 parts of o-phenyl unsaturated polyester with a number average molecular weight of 1.6 x 10 4 , 4 parts of maleic anhydride, 6 parts of epichlorohydrin, and 1.2 parts of triethylamine.

[0045] The preparation method of the PBS-o-phenyl UP hydroxyl crosslinked copolymer includes the following steps: a. adding polybutylene succinate and maleic anhydride into a twin-screw extruder, melt blending at 400 r / min for 1.2h at 190°C; b. adding o-phenyl unsaturated polyester, epichlorohydrin and triethylamine into the system obtained in a, uniformly mixing, and reacting at 210°C for 2.5h, then, crushing through a 90 mesh sieve after cooling to room temperature, and obtaining PBS-o-phenyl UP hydroxyl crosslinked copolymer.

[0046] The embodiment also discloses a preparation method of acid and alkali resistant geotextile, including the following steps: S1, raw material pretreatment: vacuum drying PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl crosslinked copolymer and polycaprolactone at 90°C for 5h; blowing drying silane modified basalt fiber, composite barrier agent, titanate modified nano zinc oxide, zinc borate, polymethyl methacrylate microspheres, antioxidant 168 and UV-531 at 105°C for 2.5h; S2, melt spinning of matrix: adding PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl crosslinked copolymer and polycaprolactone into a twin-screw extruder, adjusting the temperature interval: 215°C in the first zone, 225°C in the second zone, 235°C in the third zone, and 245°C in the die head, and the screw rotation speed is 350 r / min, and the melt pressure is 4 MPa; spinning through a spinning hole with a diameter of 0.35 mm at a spinning speed of 1100 m / min to obtain nascent fiber; S3, fiber reinforced mixing: mixing the nascent fiber and silane modified basalt fiber at a mass ratio of 8:2, drawing at 90°C by 3.5 times to obtain high-strength mixed fiber; S4, needle punching into cloth: High-strength mixed fibers are cross-laid and needled into a form by a needle punching machine at a needle density of 135 needles / cm and a needle depth of 9 mm to obtain a geotextile body. 2 S5, blending of multiple fillers: The composite barrier agent, titanate modified nano zinc oxide, zinc borate, polymethyl methacrylate microspheres, antioxidant 168, and UV-531 are uniformly dispersed in a high-speed mixer, and then impregnated and mixed with the geotextile body at 90°C for 20 min. S6, post-treatment coating: The geotextile body obtained in S5 is immersed in a polysiloxane-epoxy resin emulsion (mass ratio of polysiloxane to epoxy resin is 1:4) with a solid content of 45%, and then dried at 85°C for 37 min to form a weather-resistant barrier coating. S7, gradient heat setting: The geotextile body obtained in S6 is treated at 120°C and 0.4 MPa for 25 min, then treated at 130°C and 0.5 MPa for 30 min, and finally cooled to room temperature to obtain an acid and alkali resistant geotextile.

[0047] Comparative Example 1: An acid and alkali resistant geotextile and its preparation method, the difference between which and Example 3 is only that PBT-PETG epoxy interpenetrating copolymer is not added, but an equal amount of polybutylene terephthalate is used instead.

[0048] Comparative Example 2: An acid and alkali resistant geotextile and its preparation method, the difference between which and Example 3 is only that PBS-o-phenyl UP hydroxyl crosslinking copolymer is not added, but an equal amount of polybutylene succinate is used instead.

[0049] Comparative Example 3: An acid and alkali resistant geotextile and its preparation method, the difference between which and Example 3 is only that composite barrier agent is not added, but an equal amount of pure graphene is used instead.

[0050] Comparative Example 4: An acid and alkali resistant geotextile and its preparation method, the difference between which and Example 3 is only that polycaprolactone is not added.

[0051] Comparative Example 5: An acid and alkali resistant geotextile and its preparation method, the difference between which and Example 3 is only that zinc borate is not added.

[0052] Comparative Example 6: An acid and alkali resistant geotextile and its preparation method, the difference between which and Example 3 is only that polymethyl methacrylate microspheres are not added.

[0053] Comparative Example 7:​ An acid and alkali resistant geotextile and a preparation method thereof, the difference between which and Example 3 is only that unmodified basalt fibers are used instead of silane modified basalt fibers.

[0054] Comparative Example 8: An acid and alkali resistant geotextile and a preparation method thereof, the difference between which and Example 3 is only that no titanate modified nano zinc oxide is added.

[0055] Comparative Example 9: An acid and alkali resistant geotextile and a preparation method thereof, the difference between which and Example 3 is only that the heat setting uses a single temperature of 125℃ (no gradient).

[0056] Comparative Example 10: An acid and alkali resistant geotextile and a preparation method thereof, the difference between which and Example 3 is only that the needling density is 80 needles / cm 2 (lower than 120-150 needles / cm 2 ).

[0057] The geotextiles obtained in Examples 1-3 and Comparative Examples 1-10 are subjected to performance testing of acid and alkali resistance, tensile strength, tear strength, water permeability coefficient, weather resistance, oxygen index, wet heat aging, and elongation at break, and the performance testing methods and standards are as follows: (I) Acid and alkali resistance: refer to GB / T 1763-2008 "Determination of Chemical Resistance of Pigments and Varnishes" (immersion time 72h), the specific steps are: prepare a sample with a size of 200mm x 50mm, immerse it in 10% sulfuric acid solution (pH=1) and 10% sodium hydroxide solution (pH=14) respectively, immerse at 23±2℃ for 72h; after taking out, rinse with distilled water for 3 times, dry and then test the tensile strength with a universal material testing machine, calculate the acid immersion tensile strength retention rate and the alkali immersion tensile strength retention rate according to the formula "retention rate = tensile strength after immersion / tensile strength before immersion x 100%".

[0058] (II) Tensile strength: refer to GB / T 15788-2020 "Geotextiles and Related Products Wide Strip Tensile Test", the specific steps are: prepare a sample with a size of 200mm x 50mm, mark 100mm, test with a universal material testing machine at a tensile speed of 50mm / min, record the maximum tensile strength.

[0059] (III) Tear strength: refer to GB / T 13763-2019 "Tear Test of Geosynthetic Materials" (trapezoidal method), the specific steps are: prepare a trapezoidal sample with a size of 150mm x 75mm, test with a universal material testing machine at a tear speed of 200mm / min, record the tear strength.

[0060] (Four) Permeability coefficient: Refer to GB / T 15789-2020 "Test method for water permeability of geosynthetics by constant head method", the specific steps are: using constant head device, setting water head height 50mm, sample area 200cm 2 , record the water permeation amount within 30min; calculate the permeability coefficient according to the formula K=QxL / (AxHxt) (wherein K is the permeability coefficient, unit m / s; Q is the water permeation amount, unit m 3 ; L is the sample thickness, unit m; A is the sample area, unit m 2 ; H is the water head height, unit m; t is the time, unit s).

[0061] (Five) Weather resistance: Refer to GB / T 16422.2-2014 "Plastics - Methods for exposure to laboratory light sources - Part 2: Xenon arc lamps" (aging 1000h), the specific steps are: put the sample into the xenon arc lamp aging box, set the irradiation intensity 0.71W / (m 2 ·nm) (340nm), temperature 63±3℃, relative humidity 50%±5%, test the tensile strength after aging 1000h, and calculate the tensile strength retention rate after weather resistance.

[0062] (Six) Oxygen index: Refer to GB / T 2406.2-2009 "Determination of the ignition behavior of plastics - Part 2: Test method in room temperature", the specific steps are: prepare the sample with the size of 80mmx10mmx3mm, use the oxygen index tester to test, and record the oxygen index value.

[0063] (Seven) Hygrothermal aging: Refer to GB / T 15788-2020 "Geotextiles and related products - Wide-width strip tensile test" (85℃, 85% relative humidity, aging 1000h), the specific steps are: put the sample into the hygrothermal aging box, set the temperature 85℃, relative humidity 85%, test the tensile strength after aging 1000h, and calculate the tensile strength retention rate after hygrothermal aging.

[0064] (Eight) Elongation at break: Refer to GB / T 15788-2020 "Geotextiles and related products - Wide-width strip tensile test", the specific steps are: prepare the sample with the size of 200mmx50mm (gauge length 100mm), use the universal material testing machine to stretch to break at the speed of 50mm / min, record the gauge length at break, and calculate the result according to the formula "elongation at break (%)=(break gauge length-initial gauge length) / initial gauge lengthx100%".

[0065] The results are shown in Table 1.

[0066] Table 1 Performance parameters of geotextiles obtained from Examples 1-3 and Comparative Examples 1-10 Group Acid dipping tensile retention rate (%) Alkali dipping tensile retention rate (%) Tensile strength (kN / m) Tear strength (N) Permeability coefficient (x 10 -11 m / s) Tensile retention rate after weather resistance (%) Humid heat aging retention rate (%) Oxygen index (%) Breaking elongation rate (%) Example 1 92 90 38 220 2.5 85 82 29 32 Example 2 95 93 42 240 1.8 89 86 31 35 Example 3 97 95 45 260 1.2 92 88 32 37 Comparative Example 1 75 78 28 180 5.8 70 65 22 18 Comparative Example 2 80 82 30 200 4.8 75 70 23 20 Comparative Example 3 88 86 36 230 6.2 82 78 30 34 Comparative Example 4 95 93 43 210 1.5 90 86 31 15 Comparative Example 5 96 94 44 250 1.3 91 87 24 36 Comparative Example 6 94 92 42 245 4.5 88 85 30 35 Comparative Example 7 85 87 34 220 3.8 78 75 25 22 Comparative Example 8 94 92 43 255 1.4 65 62 31 36 Comparative Example 9 90 88 39 218 3.0 83 80 28 32 Comparative Example 10 87 85 31 205 5.0 80 73 27 33 The performance differences and reason analysis of Comparative Examples 1-10 are as follows, taking Example 3 as the control group: Comparative Example 1 (without adding PBT-PETG epoxy interpenetrating copolymer), the acid immersion tensile retention rate decreased from 97% to 75% (a decrease of 22.7%), the alkali immersion tensile retention rate decreased from 95% to 78% (a decrease of 17.9%), the tensile strength decreased from 45 kN / m to 28 kN / m (a decrease of 37.8%), the water permeability coefficient increased from 1.2 x 10 -11 m / s to 5.8 x 10 -11 m / s (an increase of 383.3%), and the oxygen index decreased from 32% to 22% (a decrease of 31.2%). The reason is that the "PBT acid-resistant-PETG alkali-resistant" interpenetrating network and epoxy crosslinking sites of PBT-PETG epoxy interpenetrating copolymer are lacking, and a dense corrosion-resistant skeleton cannot be formed; acid and alkali ions easily penetrate through the matrix gap, and the mechanical support structure fails due to the lack of crosslinking network, and the oxygen index decreases because the copolymer loses its dispersion support for the flame retardant.

[0067] Comparative Example 2 (without adding PBS-o-phenyl UP hydroxyl crosslinking copolymer), the elongation at break decreased from 37% to 20% (a decrease of 45.9%), the tear strength decreased from 260 N to 200 N (a decrease of 23.1%), the water permeability coefficient increased from 1.2 x 10 -11 m / s to 4.8 x 10 - 11 m / s (an increase of 300%), and the acid immersion tensile retention rate decreased from 97% to 80% (a decrease of 17.5%). The reason is that the flexible segment of PBS in PBS-o-phenyl UP hydroxyl crosslinking copolymer is lost, the brittleness of the matrix increases significantly, and the matrix is prone to crack during construction deformation; the chemical resistance of o-phenyl unsaturated polyester is lost, leading to a decrease in acid resistance; at the same time, the hydroxyl group cannot be crosslinked with the matrix epoxy group, the interface gap increases, and acid and alkali easily penetrate, leading to a deterioration of the impermeability.

[0068] Comparative Example 3 (without adding composite barrier agent, using pure graphene instead), the water permeability coefficient increased from 1.2 x 10 -11 m / s to 6.2 x 10 -11 m / s (an increase of 416.7%), the tensile strength decreased from 45 kN / m to 36 kN / m (a decrease of 20%), and the acid immersion tensile retention rate decreased from 97% to 88% (a decrease of 9.3%). The reason is that pure graphene tends to agglomerate, and cannot form a multi-scale synergistic structure of "carbon nanotube one-dimensional reinforcement-graphene sheet barrier-montmorillonite adsorption"; the diffusion speed of acid and alkali ions increases, and the impermeability collapses; at the same time, the mechanical reinforcement of carbon nanotubes is lacking, and the local support of the matrix is insufficient, leading to a decrease in tensile strength.

[0069] The elongation at break of Comparative Example 4 (without adding polycaprolactone) decreased from 37% to 15% (a decrease of 59.5%), the tear strength decreased from 260 N to 210 N (a decrease of 19.2%), and the alkali leaching tensile retention rate decreased from 95% to 93% (a decrease of 2.1%). The reason is that the flexible segment of polycaprolactone cannot fill the gap between the rigid network of the matrix, and the matrix has no buffer space when deformed under stress, so the combination between fibers is easy to break, resulting in a significant decrease in toughness; but the corrosion resistance is small, because polycaprolactone does not participate in acid and alkali crosslinking and blocking, and only affects flexibility.

[0070] The oxygen index of Comparative Example 5 (without adding zinc borate) decreased from 32% to 24% (a decrease of 25%), the wet heat aging retention rate decreased from 88% to 87% (a decrease of 1.1%), and other properties did not change significantly. The reason is that the absence of zinc borate causes the formation of a glassy protective layer at high temperatures, and the resin is easy to contact with oxygen and burn, so the flame retardant performance is completely lost; but zinc borate does not participate in corrosion resistance, aging resistance and mechanical structure, so it has little effect on acid and alkali resistance, aging resistance and mechanical properties.

[0071] The water permeability coefficient of Comparative Example 6 (without adding polymethyl methacrylate microspheres) increased from 1.2 x 10 -11 m / s to 4.5 x 10 -11 m / s (an increase of 275%), the tear strength decreased from 260 N to 245 N (a decrease of 5.8%), and the oxygen index decreased from 32% to 30% (a decrease of 6.2%). The reason is that the microspheres cannot fill the fiber pores, the matrix porosity increases, and the penetration of water and acid and alkali ions is easy, so the permeability resistance decreases; at the same time, the role of the microspheres as a flame retardant skeleton is missing, and the flame retardant layer formed by zinc borate is unevenly covered, so the oxygen index decreases slightly; the mechanical properties are not affected because the fiber interweaving structure is not damaged.

[0072] The tensile strength of Comparative Example 7 (using unmodified basalt fibers instead of silane-modified basalt fibers) decreased from 45 kN / m to 34 kN / m (a decrease of 24.4%), and the water permeability coefficient increased from 1.2 x 10 -11 m / s to 3.8 x 10 -11 m / s (an increase of 216.7%). The reason is that the unmodified basalt fiber surface has no silane modification group, so it cannot react with the matrix epoxy / hydroxyl group, and there is a gap between the fiber-matrix interface; acid and alkali easily penetrate from the interface, and the permeability resistance deteriorates.

[0073] The tensile retention rate after weathering decreased from 92% to 65% (a decrease of 29.3%), the hygrothermal aging retention rate decreased from 88% to 62% (a decrease of 29.5%), and the acid immersion tensile retention rate decreased from 97% to 94% (a decrease of 3.1%). The reason is that the loss of the photocatalytic degradation of small acid molecules by nano zinc oxide and the auxiliary function of ultraviolet absorption, the resin molecular chain is easy to break under the action of ultraviolet and hygrothermal, and the anti-aging performance collapses; the auxiliary effect of nano zinc oxide on acid resistance is lost, resulting in a slight decrease in acid immersion retention rate, but the corrosion-resistant skeleton of the matrix is not damaged, so the overall effect of acid and alkali resistance is small.

[0074] In Comparative Example 9 (hot setting without gradient, single temperature 125°C), the tensile strength decreased from 45 kN / m to 39 kN / m (a decrease of 13.3%), the water permeability coefficient increased from 1.2 x 10 -11 m / s to 3.0 x 10 -11 m / s (an increase of 150%), and the tensile retention rate after weathering decreased from 92% to 83% (a decrease of 9.8%). The reason is that a single temperature cannot achieve the gradient optimization of “initial crystallization-full crosslinking”, the resin crystallization is incomplete, and the crosslinking reaction is not complete; there are small pores in the matrix, and acid and alkali easily penetrate, resulting in a decrease in impermeability; at the same time, the molecular chain arrangement is loose, and the mechanical support and anti-aging stability are weakened.

[0075] In Comparative Example 10 (needle density 80 needles / cm 2 , lower than 120-150 needles / cm 2 of the present application), the tensile strength decreased from 45 kN / m to 31 kN / m (a decrease of 31.1%), the water permeability coefficient increased from 1.2 x 10 -11 m / s to 5.0 x 10 -11 m / s (an increase of 316.7%), and the tear strength decreased from 260 N to 205 N (a decrease of 21.2%). The reason is that the low needle density leads to loose fiber interweaving, significantly increased porosity, and acid and alkali easily penetrate from the fiber gap, resulting in deterioration of impermeability; the fiber has insufficient bonding force and is prone to slipping under stress, resulting in a significant decrease in macroscopic tensile and tear strength.

[0076] In summary, the PBT-PETG epoxy interpenetrating copolymer constructs an integrated matrix of “acid resistance-alkali resistance-crosslinking”, which is the core of corrosion resistance and mechanics; the PBS-o-phenyl UP hydroxyl crosslinking copolymer enhances flexibility and interfacial bonding to solve the problem of matrix brittleness; the two are synergized with hydroxylated carbon nanotube / aminoated graphene-montmorillonite composite barrier to reduce the acid and alkali permeability by 70% and increase the weathering retention rate by 17%. Silane modified basalt fiber provides macroscopic reinforcement, titanate modified nano zinc oxide, antioxidant, and ultraviolet absorber form a triple anti-aging system, and zinc borate and polymethyl methacrylate microspheres synergistically achieve flame retardation and impermeability win-win.

[0077] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An acid and alkali resistant geotextile, characterized by, The composition raw materials include, in parts by weight, PBT-PETG epoxy interpenetrating copolymer 25-35 parts, PBS-o-phenyl UP hydroxyl crosslinking copolymer 15-25 parts, silane modified basalt fiber 12-20 parts, composite barrier agent 4-8 parts, anti-aging filler 2-5 parts, flexibility modifier 4-9 parts, flame retardant 1.2-2.3 parts, pore filler 2.5-4.5 parts, antioxidant 0.5-1.2 parts, and ultraviolet inhibitor 0.3-0.8 parts.

2. The acid and base resistant geotextile according to claim 1, wherein, The composition raw materials of the PBT-PETG epoxy interpenetrating copolymer include, in parts by weight, polybutylene terephthalate 90-100 parts, polyethylene terephthalate-1,4-cyclohexane dimethanol 50-60 parts, epoxy propyl methacrylate 5-8 parts, dicumyl peroxide 0.5-0.8 parts, and dimethyl sulfoxide 600-700 parts.

3. The acid and base resistant geotextile of claim 2, wherein, The preparation method of the PBT-PETG epoxy interpenetrating copolymer includes the following steps: 1) polybutylene terephthalate and polyethylene terephthalate-1,4-cyclohexane dimethanol are added to dimethyl sulfoxide, stirred at a speed of 300-500 r / min at 60-85℃ for 1-2 h; 2) epoxy propyl methacrylate and dicumyl peroxide are added to the system obtained in 1), stirred uniformly, heated to 80-90℃ for 3-5 h, then the reaction liquid is mixed with ethanol at a volume ratio of 1:3-5 for precipitation, filtered, vacuum dried at 80-90℃ for 6-8 h, crushed to pass through a 100-120 mesh sieve, and the PBT-PETG epoxy interpenetrating copolymer is obtained.

4. The acid and base resistant geotextile of claim 2, wherein, The number average molecular weight of the polybutylene terephthalate is 1.5 x 10 4 -2 x 10 4 .

5. The acid and base resistant geotextile of claim 1, wherein, The composition raw materials of the PBS-o-phenyl UP hydroxyl crosslinking copolymer include, in parts by weight, polybutylene succinate 90-100 parts, o-phenyl unsaturated polyester 30-40 parts, maleic anhydride 3-5 parts, epoxy chloropropane 5-7 parts, and triethylamine 1-1.5 parts.

6. The acid and base resistant geotextile of claim 5, wherein, The number average molecular weight of the polybutylene succinate is 1.4 x 10 4 -1.8 x 10 4 The number average molecular weight of the polybutylene succinate is 1.4 x 10 4 -1.8 x 10 4 .

7. The acid and base resistant geotextile of claim 5, wherein, The preparation method of the PBS-o-phenyl UP hydroxyl crosslinking copolymer includes the following steps: a. polybutylene succinate and maleic anhydride are added to a twin-screw extruder, melt blended at a speed of 350-450 r / min at 180-200℃ for 1-1.5 h; b. o-phenyl unsaturated polyester, epoxy chloropropane and triethylamine are added to the system obtained in a, mixed uniformly, heated to 200-220℃ for 2-3 h, then cooled to room temperature, crushed to pass through an 80-100 mesh sieve, and the PBS-o-phenyl UP hydroxyl crosslinking copolymer is obtained.

8. The acid and base resistant geotextile of claim 1, wherein, The composite barrier agent is a mixture of hydroxylated carbon nanotubes, aminated graphene and sodium-based montmorillonite at a mass ratio of 1:2:8, the anti-aging filler is titanium ester modified nano zinc oxide or silane modified nano titanium dioxide, the flexibility modifier is polycaprolactone or polypropylene carbonate, the flame retardant is one of zinc borate, magnesium hydroxide or melamine cyanurate, the pore filler is polymethyl methacrylate microspheres or polyamide microspheres, the antioxidant is one of antioxidant 1010, antioxidant 168 or antioxidant 1076, and the ultraviolet inhibitor is UV-531 or UV-326.

9. A method of producing the acid- and alkali-resistant geotextile according to any one of claims 1 to 8, characterized in that, The method includes the following steps: S1, raw material pretreatment: Vacuum drying PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl crosslinking copolymer, flexible modifier at 85-95℃ for 4-6h; Vacuum drying silane modified basalt fiber, composite barrier agent, anti-aging filler, flame retardant, pore filler, antioxidant, anti-ultraviolet agent at 100-110℃ for 2-3h; S2, melt spinning of the matrix: PBT-PETG epoxy interpenetrating copolymer, PBS-o-phenyl UP hydroxyl crosslinking copolymer, flexible modifier are added into the twin-screw extruder, and the temperature range is adjusted: zone 1 210-220℃, zone 2 220-230℃, zone 3 230-240℃, die 240-250℃, screw speed 300-400r / min, melt pressure 3-5MPa; spinning through the spinneret with a diameter of 0.25-0.45mm at a spinning speed of 900-1300m / min to obtain the primary fiber; S3, fiber reinforced mixing: The primary fiber is mixed with silane modified basalt fiber at a mass ratio of 8:2, drawn at 80-100℃ for 2.5-4.5 times to obtain high-strength mixed fiber; S4, needle punching into cloth: High-strength mixed fibers are cross-laid into a web and needle-punched using a needle-punching machine to a needle-punching density of 120-150 needles / cm. 2 The needle-punching depth is 7-11mm to obtain the geotextile blank; S5, blending of various fillers: The composite barrier agent, anti-aging filler, flame retardant, pore filler, antioxidant, anti-ultraviolet agent are uniformly dispersed in a high-speed mixer, and then impregnated and mixed with the geotextile blank at 80-100℃ for 15-25min; S6, post-treatment coating: The geotextile blank obtained in S5 is immersed in a polysiloxane-epoxy resin emulsion, and then dried at 80-90℃ for 30-45min to form a weather-resistant barrier coating; S7, gradient heat setting: The geotextile blank obtained in S6 is treated at 115-125℃, 0.35-0.45MPa for 20-30min, then treated at 125-135℃, 0.45-0.55MPa for 25-35min, and finally cooled to room temperature to obtain an acid and alkali resistant geotextile.

10. The method of claim 9, wherein the acid- and base-resistant geotextile is prepared by the steps of: In step S6, the solid content of the polysiloxane-epoxy resin emulsion is 40%-50%, and the mass ratio of polysiloxane to epoxy resin is 1:4.