High-strength corrosion-resistant geogrid and preparation method thereof

Abstract

The invention relates to the technical field of high-performance polypropylene materials, and discloses a high-strength corrosion-resistant geogrid and a preparation method thereof.The preparation method of the high-strength corrosion-resistant geogrid comprises the following steps that an epoxy functionalized tri-eugenol compound is prepared; the preparation method comprises the following steps: sequentially reacting maleic anhydride grafted polypropylene with m-phthaloyl hydrazine, hexamethylene diisocyanate, 2, 6-benzothiazole diamine and an epoxy functionalized tri-eugenol compound, so as to obtain functionalized polypropylene; mixing the polypropylene master batch, the functional polypropylene, the composite nano material and other components to obtain a raw material mixture; processing the raw material mixture into a plate; the plate is subjected to cooling punching, stretching and other processes, and the high-strength corrosion-resistant geogrid is obtained. The geogrid not only has high strength, but also can resist erosion of acid and alkali environments and rainwater, has good corrosion resistance, in addition, has flame retardant property, and can meet the use requirements of high-risk fire places such as coal mines and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance polypropylene materials, and particularly relates to a high-strength corrosion-resistant geogrid and a preparation method thereof. BACKGROUND

[0002] As one of commonly used reinforced materials, geogrids can effectively improve the shear strength of soil, and are widely used in many fields such as building, water conservancy, highway, railway and port engineering due to their advantages such as large deformation, high tensile strength, good toughness and light weight. Polypropylene (PP) is widely made into plastic geogrids to replace traditional geotechnical materials such as metal, fiber and wood due to its excellent physical and chemical properties.

[0003] In the production of polypropylene geogrids, the punched plate needs to be continuously stretched, therefore, polypropylene materials with high strength can meet the needs of geogrid products. With the change of climate, there are more and more corrosive substances in rainwater, which can easily cause the polypropylene geogrid to crack under the long-term erosion of acidic or alkaline corrosive substances and rainwater, thereby affecting the normal functional use. In addition, PP is highly flammable and difficult to extinguish after ignition, which not only does not play a flame-retardant effect in the event of a fire, but on the contrary, becomes a combustion material, thereby limiting its application in high-risk fire places such as coal mines. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a preparation method of a high-strength corrosion-resistant geogrid, comprising the following steps: Step one, eugenol reacts with phosphorus oxychloride to obtain a tris-eugenol compound; the carbon-carbon double bond in the tris-eugenol compound is converted into an epoxy group to obtain an epoxy-functionalized tris-eugenol compound; Step two, maleic anhydride grafted polypropylene reacts with isophthaldehyde to obtain surface modified polypropylene; the surface modified polypropylene reacts with hexamethylene diisocyanate and 2,6-benzothiazole diamine to obtain grafted modified polypropylene; the grafted modified polypropylene reacts with the epoxy-functionalized tris-eugenol compound to obtain functionalized polypropylene; Step three, polypropylene masterbatch, functionalized polypropylene, thermoplastic elastomer, glass fiber, antioxidant 1010, composite nanomaterial and phthalate are weighed according to the proportion, mixed to obtain a raw material mixture; the raw material mixture is melt extruded and molded to obtain a plate; the plate is cooled, punched, stretched, shaped and harvested and wound to obtain a high-strength corrosion-resistant geogrid.

[0005] Preferably in step one, the preparation method of the epoxy-functionalized tris-eugenol compound is as follows: Dissolve eugenol and triethylamine in dichloromethane, then add phosphorus oxychloride, first stir at 0℃ for 20-40min, then stir at 23-25℃ for 20-30h, purify to obtain the tris-eugenol compound; wherein the mass ratio of eugenol, triethylamine, dichloromethane, phosphorus oxychloride is (15-30):(11.1-22.2):(350-550):(4.68-9.36); Dissolve meta-chloroperoxybenzoic acid and dibutylhydroxytoluene in dichloromethane, then add 5.45wt% tris-eugenol compound / dichloromethane solution, stir at 23-25℃ for 40-50h, purify to obtain the epoxy-functionalized tris-eugenol compound; wherein the mass ratio of meta-chloroperoxybenzoic acid, dibutylhydroxytoluene, dichloromethane, 5.45wt% tris-eugenol compound / dichloromethane solution mixture is (21.6-51.2):(0.01-0.03):(350-550):(350-550); In the above process, the phenolic hydroxyl group of eugenol reacts with the chlorine of phosphorus oxychloride to generate the tris-eugenol compound containing three benzene rings and three unsaturated double bonds as well as flame-retardant phosphorus element, and the unsaturated double bond of the tris-eugenol compound is converted into epoxy group under the action of meta-chloroperoxybenzoic acid and dibutylhydroxytoluene.

[0006] Preferably, in the step two, the preparation method of the surface-modified polypropylene is as follows: Mix isotactic polypropylene particles, maleic anhydride and o-xylene, heat to 55-65℃ and keep for 1.5-2.5h, add 0.04mol / L benzoyl peroxide / dimethylbenzene solution, heat to 116-124℃ under argon atmosphere, stir for 2.5-3.5h, purify to obtain the maleic anhydride grafted polypropylene; wherein the mass ratio of isotactic polypropylene particles, maleic anhydride, o-xylene, 0.04mol / L benzoyl peroxide / dimethylbenzene solution is (5-8):(2-4):(80-120):(8.75-10.51); Add the maleic anhydride grafted polypropylene into N,N-dimethylformamide, stir at 116-124℃ for 1.5-2.5h under argon atmosphere, then add 6wt% isophthalic dihydrazide / N,N-dimethylformamide solution, keep the temperature unchanged, continue to stir for 5-7h, purify to obtain the surface-modified polypropylene; wherein the mass ratio of maleic anhydride grafted polypropylene, N,N-dimethylformamide, 6wt% isophthalic dihydrazide / N,N-dimethylformamide solution is (5-8):(70-150):(32.3-38.7); In the above process, maleic anhydride groups are introduced on the polypropylene polymer chain under the action of benzoyl peroxide, and the maleic anhydride groups can react with the amino group at one end of isophthalic dihydrazide to graft isophthalic dihydrazide on the branched chain of polypropylene, thereby obtaining surface-modified polypropylene.

[0007] Preferably, in the second step, the preparation method of the functionalized polypropylene comprises: The surface-modified polypropylene is added into N,N-dimethylformamide, and hexamethylene diisocyanate is added, and the reaction is stirred at 80-100°C for 8-12h under a nitrogen atmosphere, and then 2,6-benzothiazole diamine is added, and the reaction is continuously stirred for 5-7h, and then purified to obtain the grafted modified polypropylene; wherein the mass ratio of the surface-modified polypropylene, N,N-dimethylformamide, hexamethylene diisocyanate, and 2,6-benzothiazole diamine is (5-8):(70-150):(1.68g-1.92):(1.65-3.3); The grafted modified polypropylene is added into N,N-dimethylformamide, and then an epoxy-functionalized tri-cresol compound is added, and the reaction is stirred at 75-85°C for 10-16h, and then purified to obtain the functionalized polypropylene; wherein the mass ratio of the grafted modified polypropylene, N,N-dimethylformamide, and epoxy-functionalized tri-cresol compound is (5-8):(120-200):(5.84-7.12); In the above process, the amino group on the surface modified polypropylene reacts with the isocyanate group at one end of hexamethylene diisocyanate to introduce an isocyanate group on the polypropylene branch, the isocyanate group reacts with the amino group in 2,6-benzothiazole diamine, and the remaining amino group reacts with the epoxy group of the epoxy-functionalized triphenylol compound to obtain the functionalized polypropylene. The functionalized polypropylene in the present application contains various functional groups on its branches through the above reaction, such as (1) the flame-retardant nitrogen element, hydrazide group and urethane group introduced by the reaction of isophthalic dihydrazide, which helps to form cross-linked hydrogen bonds in the functionalized polypropylene, improves the cross-linking density of the system, resists the corrosion of corrosive media, and thus improves the mechanical properties, flame-retardant properties and corrosion resistance of the functionalized polypropylene; (2) the flame-retardant nitrogen element, benzothiazole group and urethane group introduced by the reaction of 2,6-benzothiazole diamine, which helps to further improve the hydrogen bond cross-linking effect, and the benzothiazole group has good corrosion resistance; (3) the hydroxyl group, amide group, rigid benzene ring and flame-retardant phosphorus element introduced by the reaction of the epoxy-functionalized triphenylol compound, which improves the hydrogen bond cross-linking effect and the flame-retardant properties; in summary, the above functional groups combine the effects of flame-retardant nitrogen and phosphorus elements, benzene ring and thiazole group, and give the functionalized polypropylene good flame-retardant properties, and the functionalized polypropylene branches can form a dense cross-linked network through covalent cross-linking, hydrogen bonding and π-π stacking, and the rigid structure of the benzene ring enhances the strength of the cross-linked network, thereby giving the functionalized polypropylene excellent mechanical properties and corrosion resistance.

[0008] Preferably, in the step three, the content of each component in the raw material mixture is as follows: 100 parts of polypropylene masterbatch, 20-40 parts of functionalized polypropylene, 20-30 parts of thermoplastic elastomer, 10-15 parts of glass fiber, 1-5 parts of antioxidant 1010, 10-20 parts of composite nanomaterial, and 1-3 parts of phthalate.

[0009] Preferably, in the step three, the thermoplastic elastomer is obtained by mixing ethylene-propylene-diene rubber and styrene-butadiene rubber at a mass ratio of (5-6):(4-5); and the stretching conditions of the longitudinal and transverse stretching are as follows: the stretching ratio is 3-5, and the stretching temperature is 140-150℃.

[0010] Preferably, in the step three, the preparation method of the composite nanomaterial is as follows: Step S1, disperse the amino-modified nanosilicon carbide in 1,4-dioxane, ultrasonic, stir, then add 4-chlorophenylboric acid mixed solution, reflux at 110-120℃ for 8-12h, purify to obtain modified nanosilicon carbide; Step S2, adding graphene oxide into deionized water, ultrasonic, then adding 10mmol / L Tris-HCl, stirring uniformly, adding dopamine, adjusting pH value to 8.5, stirring at 60-70℃ for 16-24h, centrifuging, freeze-drying, obtaining polydopamine modified GO; wherein, the mass ratio of graphene oxide, deionized water, 10mmol / L Tris-HCl, dopamine is (2-3):(2-3):(50-100):(0.3-0.5); Mixing polydopamine modified GO and toluene with a mass ratio of (2-3):(200-300), ultrasonic, obtaining mixed liquid A; mixing modified nanometer silicon carbide and toluene with a mass ratio of (0.4-0.8):(80-120), ultrasonic, obtaining mixed liquid B; mixing mixed liquid A and mixed liquid B, stirring at 106-110℃ for 8-12h, after the reaction, purifying, obtaining composite nanomaterials; In the above process, nanometer silicon carbide as an inorganic material has the following advantages (1) quickly dispersing local heat during polymer combustion through high thermal conductivity network, inhibiting thermal decomposition chain reaction; (2) generating dense SiO2 / C oxidation layer on the surface in situ at high temperature, blocking oxygen diffusion and inhibiting combustible gas escape; (3) nanometer SiC can improve the mechanical strength of the polymer matrix and delay the structural collapse during the combustion process; (4) silicon carbide material also has certain acid and alkali corrosion resistance; the present application introduces phenylboric acid structure on the amino modified nanometer silicon carbide by the reaction of chlorine of 4-chlorophenylboronic acid with the amino group of the amino modified nanometer silicon carbide, obtaining modified nanometer silicon carbide, further improving the flame retardant performance of nanometer silicon carbide; Graphene oxide as a commonly used inorganic material can improve the mechanical properties and flame retardant properties of the polymer matrix, and due to its own sheet structure, it has good barrier performance and can effectively block the erosion of corrosive medium to the polymer matrix, the present application first modifies graphene oxide by dopamine, dopamine polymerizes on the surface of graphene oxide to form polydopamine, introducing catechol structure on the surface of graphene oxide, the catechol group can dehydrate and combine with the hydroxyl group in the phenylboric acid on the modified nanometer silicon carbide, thereby loading the modified nanometer silicon carbide on the graphene oxide to form a composite nanomaterial, the composite nanomaterial of the present application combines the advantages of graphene oxide and nanometer silicon carbide, and contains benzene ring, flame-retardant boron element and polydopamine structure, on the one hand, polydopamine can further improve the flame retardant performance of the composite nanomaterial, on the other hand, it can enhance the bonding strength of graphene oxide and nanometer silicon carbide through its own adhesion and chemical bond.

[0011] Further, in step S1, the 4-chlorophenylboronic acid mixture is obtained by mixing 4-chlorophenylboronic acid, triethylamine, and 1,4-dioxane in a mass ratio of 1.53:1:5.07; the mass ratio of the amino-modified nano-silicon carbide, 1,4-dioxane, and 4-chlorophenylboronic acid mixture is (2-3):(150-250):(4.65-7.75).

[0012] Further, in step S1, the amino-modified nano-silicon carbide is prepared by the following method: Nano-silicon carbide was dispersed in ethanol and stirred. Then, silane coupling agent KH-550 was added, and the mixture was stirred and reacted at 40-50℃ for 8-12 hours. After purification, amino-modified nano-silicon carbide was obtained. The mass ratio of nano-silicon carbide, ethanol, and silane coupling agent KH-550 was (2-3):(100-120):(0.3-0.8). In the above process, nano-silicon carbide is modified by silane coupling agent KH-550, and amino groups are introduced on the surface of nano-silicon carbide.

[0013] The high-strength corrosion-resistant geogrid is prepared by the aforementioned method.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention discloses a high-strength corrosion-resistant geogrid, which contains functionalized polypropylene, composite nanomaterials, glass fiber, and other components. Under the combined action of these components, the geogrid of this invention not only has high strength but also resists acid and alkali environments as well as rainwater erosion, exhibiting excellent corrosion resistance and extending its service life. In addition, the geogrid of this invention also possesses flame-retardant properties, meeting the requirements for use in high-risk fire locations such as coal mines. Therefore, the geogrid of this invention has excellent comprehensive performance and broad application prospects.

[0015] 2. The functionalized polypropylene of this invention contains multiple functional groups on its side chains. These functional groups not only combine the effects of flame-retardant nitrogen and phosphorus elements, benzene rings, and thiazole groups to endow the functionalized polypropylene with excellent flame-retardant properties, but also form a dense cross-linked network through covalent cross-linking, hydrogen bonding, and π-π stacking. The rigid structure of the benzene ring further enhances the strength of the cross-linked network, giving the functionalized polypropylene excellent mechanical properties and corrosion resistance, thereby improving the overall performance of the geogrid. Furthermore, the epoxy groups on the functionalized polypropylene can react with the amino and hydroxyl functional groups in the composite nanomaterials, improving the dispersibility of the composite nanomaterials in the polypropylene material of the geogrid matrix.

[0016] 3. The composite nanomaterial of the present invention combines the advantages of graphene oxide and nano-silicon carbide, and is uniformly dispersed in a polypropylene matrix to improve the mechanical properties, flame retardant properties and corrosion resistance of the geogrid; moreover, the composite nanomaterial of the present invention contains benzene rings, flame-retardant boron elements and polydopamine structures, which enhance the overall performance of the composite nanomaterial while strengthening the bonding strength between graphene oxide and nano-silicon carbide, thereby further improving the overall performance of the geogrid. Attached Figure Description

[0017] Figure 1 This is a comparison chart of the tensile strength reduction rate of high-strength corrosion-resistant geogrids prepared in Examples 2-4 and Comparative Examples 1-5 after acid immersion treatment and alkali immersion treatment. Figure 2 These are comparison charts showing the tensile strength tests of high-strength corrosion-resistant geogrids prepared in Examples 2-4 and Comparative Examples 1-5 of this invention. Figure 3 These are comparison charts of LOI tests for the high-strength corrosion-resistant geogrids prepared in Examples 2-4 and Comparative Examples 1-5 of this invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example 1 This embodiment discloses a method for preparing composite nanomaterials, including the following steps: Step S1: Disperse 2.5g of nano-silicon carbide in 110g of ethanol, stir, then add 0.55g of silane coupling agent KH-550, stir and react at 45℃ for 10h, centrifuge, wash the precipitate with ethanol and deionized water, and dry to obtain amino-modified nano-silicon carbide. 2.5 g of amino-modified nano-silicon carbide was dispersed in 200 g of 1,4-dioxane, sonicated for 50 min, stirred for 3.5 h, and then 6.2 g of 4-chlorophenylboronic acid mixture was added. The mixture was refluxed at 115 °C for 10 h, cooled to room temperature, centrifuged, and the resulting precipitate was washed with ethanol and deionized water and dried to obtain modified nano-silicon carbide. The 4-chlorophenylboronic acid mixture was obtained by mixing 4-chlorophenylboronic acid, triethylamine, and 1,4-dioxane in a mass ratio of 1.53:1:5.07. Step S2: Add 2.5g of graphene oxide to 350g of deionized water, sonicate for 60min, then add 75g of 10mmol / L Tris-HCl, stir evenly, add 0.4g of dopamine, adjust the pH to 8.5 with 0.1mol / L NaOH aqueous solution, stir and react at 65℃ for 20h, centrifuge, freeze dry to obtain polydopamine modified GO; 2.5g of polydopamine-modified GO was added to 250g of toluene and sonicated for 60min to obtain mixture A; 0.6g of modified nano-silicon carbide was added to 100g of toluene and sonicated for 60min to obtain mixture B; mixture A and mixture B were stirred and reacted at 108℃ for 10h. After the reaction was completed, the mixture was centrifuged and freeze-dried to obtain composite nanomaterials.

[0020] Example 2 This embodiment discloses a method for preparing a high-strength corrosion-resistant geogrid, including the following steps: Step 1: Dissolve 15g of eugenol and 11.1g of triethylamine in 350g of dichloromethane, then add 4.68g of phosphorus oxychloride. First, stir the mixture at 0℃ for 20min, then stir it at 23℃ for 30h. After the reaction is complete, concentrate the reaction mixture to half of its original volume, then dilute it with dichloromethane, then wash it with saturated sodium bicarbonate aqueous solution and deionized water, dry it with anhydrous magnesium sulfate, filter it, and evaporate the filtrate to obtain the eugenol compound. 21 g of m-chloroperoxybenzoic acid and 0.01 g of butylated hydroxytoluene were dissolved in 350 g of dichloromethane, and then 350 g of 5.45 wt% eugenol compound / dichloromethane solution was added. The mixture was stirred at 23 °C for 50 h. After the reaction was completed, the resulting product mixture was washed three times each with saturated sodium bicarbonate aqueous solution, deionized water and NaCl aqueous solution. The organic layer was dried with anhydrous magnesium sulfate and filtered. The filtrate was evaporated to obtain epoxy-functionalized eugenol compound. Step 2: Mix 5g of isotactic polypropylene particles, 2g of maleic anhydride and 80g of o-xylene, heat to 55℃ and maintain for 2.5h, add 8.75g of 0.04mol / L benzoyl peroxide / xylene solution, heat to 116℃ in an argon atmosphere, stir and react for 3.5h. After the reaction is complete, add 500g of deionized water at 35℃, filter, wash the obtained solid product with deionized water at 35℃ until the pH of the washing solution is 7, then wash with acetone, and finally vacuum dry at 50℃ for 24h to obtain maleic anhydride grafted polypropylene. 5g of maleic anhydride-grafted polypropylene was added to 70g of N,N-dimethylformamide. The mixture was stirred at 116℃ for 2.5h under an argon atmosphere. Then, 32.3g of 6wt% isophthalohydrazide / N,N-dimethylformamide solution was added dropwise over 30min. The temperature was kept constant and the reaction was continued with stirring for 7h. The mixture was filtered, and the resulting solid product was washed with acetone and dried under vacuum at 60℃ for 24h to obtain surface-modified polypropylene. 5g of surface-modified polypropylene was added to 70g of N,N-dimethylformamide, and 1.68g of hexamethylene diisocyanate was added. The mixture was stirred at 80°C for 12h under a nitrogen atmosphere. Then, 1.65g of 2,6-benzothiazolium diamine was added, and the mixture was stirred for another 7h. After the reaction was completed, the mixture was filtered, and the resulting solid product was washed with ethanol and dried under vacuum at 60°C for 24h to obtain grafted modified polypropylene. 5g of grafted modified polypropylene was added to 120g of N,N-dimethylformamide, and then 5.84g of epoxy-functionalized eugenol compound was added. The mixture was stirred at 75℃ for 16h. After the reaction was completed, the mixture was filtered, and the resulting solid product was washed with N,N-dimethylformamide and dried under vacuum at 60℃ for 24h to obtain functionalized polypropylene. Step 3: Weigh 100 parts by weight of polypropylene masterbatch, 20 parts by weight of functionalized polypropylene, 20 parts by weight of thermoplastic elastomer, 10 parts by weight of glass fiber, and 1 part by weight of antioxidant 1010. Mix at high speed for 10 minutes. Then add 10 parts by weight of composite nanomaterial and 1 part by weight of phthalate. Mix at high speed for 10 minutes to obtain a raw material mixture. Melt and extrude the raw material mixture at 180°C and form it through a three-roll calender to obtain a sheet. After cooling and punching, preheating, longitudinal stretching, and cooling and shaping, the sheet is further preheated, transversely stretched, cooled and shaped, and then cut and rolled to obtain a high-strength corrosion-resistant geogrid. The thermoplastic elastomer is obtained by mixing EPDM rubber and styrene-butadiene rubber in a mass ratio of 5:5. The stretching conditions for longitudinal and transverse stretching are: stretch ratio of 3 and stretching temperature of 140°C.

[0021] Example 3 This embodiment discloses a method for preparing a high-strength corrosion-resistant geogrid, including the following steps: Step 1: Dissolve 30g of eugenol and 22.2g of triethylamine in 550g of dichloromethane, then add 9.36g of phosphorus oxychloride. First, stir the mixture at 0℃ for 40min, then stir it at 25℃ for 20h. After the reaction is complete, concentrate the reaction mixture to half of its original volume, then dilute it with dichloromethane, then wash it with saturated sodium bicarbonate aqueous solution and deionized water, dry it with anhydrous magnesium sulfate, filter it, and evaporate the filtrate to obtain the eugenol compound. 51.2 g of m-chloroperoxybenzoic acid and 0.03 g of butylated hydroxytoluene were dissolved in 550 g of dichloromethane, and then 550 g of 5.45 wt% eugenol compound / dichloromethane solution was added. The mixture was stirred at 25 °C for 40 h. After the reaction was completed, the resulting product mixture was washed three times each with saturated sodium bicarbonate aqueous solution, deionized water and NaCl aqueous solution. The organic layer was dried with anhydrous magnesium sulfate and filtered. The filtrate was evaporated to obtain epoxy-functionalized eugenol compound. Step 2: Mix 8g of isotactic polypropylene particles, 4g of maleic anhydride and 120g of o-xylene, heat to 65℃ and maintain for 1.5h, add 10.51g of 0.04mol / L benzoyl peroxide / xylene solution, heat to 124℃ in an argon atmosphere, stir and react for 2.5h. After the reaction is complete, add 500g of deionized water at 35℃, filter, wash the obtained solid product with deionized water at 35℃ until the pH of the washing solution is 7, then wash with acetone, and finally vacuum dry at 50℃ for 24h to obtain maleic anhydride grafted polypropylene. 8g of maleic anhydride-grafted polypropylene was added to 150g of N,N-dimethylformamide. The mixture was stirred at 124℃ for 1.5h under an argon atmosphere. Then, 38.7g of 6wt% isophthalohydrazide / N,N-dimethylformamide solution was added dropwise over 60min. The temperature was kept constant and the reaction was continued with stirring for 5h. The mixture was filtered, and the resulting solid product was washed with acetone and dried under vacuum at 60℃ for 24h to obtain surface-modified polypropylene. 8g of surface-modified polypropylene was added to 150g of N,N-dimethylformamide, and 1.92g of hexamethylene diisocyanate was added. The mixture was stirred at 100℃ for 8h under a nitrogen atmosphere. Then, 3.3g of 2,6-benzothiazolium diamine was added, and the mixture was stirred for another 5h. After the reaction was completed, the mixture was filtered, and the resulting solid product was washed with ethanol and dried under vacuum at 60℃ for 24h to obtain grafted modified polypropylene. 8g of grafted modified polypropylene was added to 200g of N,N-dimethylformamide, and then 7.12g of epoxy-functionalized eugenol compound was added. The mixture was stirred at 85℃ for 10h. After the reaction was completed, the mixture was filtered, and the resulting solid product was washed with N,N-dimethylformamide and dried under vacuum at 60℃ for 24h to obtain functionalized polypropylene. Step 3: Weigh out 100 parts by weight of polypropylene masterbatch, 40 parts by weight of functionalized polypropylene, 30 parts by weight of thermoplastic elastomer, 15 parts by weight of glass fiber, and 5 parts by weight of antioxidant 1010. Mix at high speed for 20 minutes. Then add 20 parts by weight of composite nanomaterial and 3 parts by weight of phthalate. Mix at high speed for 20 minutes to obtain a raw material mixture. Melt and extrude the raw material mixture at 200°C and form it through a three-roll calender to obtain a sheet. After cooling and punching, preheating, longitudinal stretching, and cooling and shaping, the sheet is further preheated, transversely stretched, cooled and shaped, and then cut and rolled to obtain a high-strength corrosion-resistant geogrid. The thermoplastic elastomer is obtained by mixing EPDM rubber and styrene-butadiene rubber in a mass ratio of 6:4. The stretching conditions for longitudinal and transverse stretching are: stretch ratio of 5 and stretching temperature of 150°C.

[0022] Example 4 This embodiment discloses a method for preparing a high-strength corrosion-resistant geogrid, including the following steps: Step 1: Dissolve 22.5g of eugenol and 16.7g of triethylamine in 450g of dichloromethane, then add 7.02g of phosphorus oxychloride. First, stir the mixture at 0℃ for 30min, then stir it at 24℃ for 25h. After the reaction is complete, concentrate the reaction mixture to half of its original volume, then dilute it with dichloromethane, then wash it with saturated sodium bicarbonate aqueous solution and deionized water, dry it with anhydrous magnesium sulfate, filter it, and evaporate the filtrate to obtain the eugenol compound. 36.4 g of m-chloroperoxybenzoic acid and 0.02 g of butylated hydroxytoluene were dissolved in 450 g of dichloromethane, and then 450 g of 5.45 wt% eugenol compound / dichloromethane solution was added. The mixture was stirred at 24 °C for 45 h. After the reaction was completed, the resulting product mixture was washed three times each with saturated sodium bicarbonate aqueous solution, deionized water and NaCl aqueous solution. The organic layer was dried with anhydrous magnesium sulfate and filtered. The filtrate was evaporated to obtain epoxy-functionalized eugenol compound. Step 2: Mix 6.5g of isotactic polypropylene particles, 3g of maleic anhydride, and 100g of o-xylene. Heat to 60℃ and maintain for 2h. Add 9.63g of 0.04mol / L benzoyl peroxide / xylene solution. Heat to 120℃ in an argon atmosphere and stir for 3h. After the reaction is complete, add 500g of deionized water at 35℃, filter, and wash the obtained solid product with deionized water at 35℃ until the pH of the washing solution is 7. Then wash with acetone and finally vacuum dry at 50℃ for 24h to obtain maleic anhydride-grafted polypropylene. 6.5 g of maleic anhydride-grafted polypropylene was added to 110 g of N,N-dimethylformamide. The mixture was stirred at 120 °C for 2 h under an argon atmosphere. Then, 35.5 g of 6 wt% isophthalohydrazide / N,N-dimethylformamide solution was added dropwise over 45 min. The temperature was kept constant and the reaction was continued with stirring for 6 h. The mixture was filtered, and the resulting solid product was washed with acetone and dried under vacuum at 60 °C for 24 h to obtain surface-modified polypropylene. 6.5g of surface-modified polypropylene was added to 110g of N,N-dimethylformamide, and 1.8g of hexamethylene diisocyanate was added. The mixture was stirred at 90℃ for 10h under a nitrogen atmosphere. Then, 2.48g of 2,6-benzothiazolium diamine was added, and the mixture was stirred for another 5-7h. After the reaction was completed, the mixture was filtered, and the resulting solid product was washed with ethanol and dried under vacuum at 60℃ for 24h to obtain grafted modified polypropylene. 6.5g of grafted modified polypropylene was added to 160g of N,N-dimethylformamide, and then 6.48g of epoxy-functionalized eugenol compound was added. The mixture was stirred at 80℃ for 13h. After the reaction was completed, the mixture was filtered, and the resulting solid product was washed with N,N-dimethylformamide and dried under vacuum at 60℃ for 24h to obtain functionalized polypropylene. Step 3: Weigh out 100 parts by weight of polypropylene masterbatch, 30 parts by weight of functionalized polypropylene, 25 parts by weight of thermoplastic elastomer, 12.5 parts by weight of glass fiber, and 3 parts by weight of antioxidant 1010. Mix at high speed for 15 minutes. Then add 15 parts by weight of composite nanomaterial and 2 parts by weight of phthalate. Mix at high speed for 15 minutes to obtain a raw material mixture. Melt and extrude the raw material mixture at 190°C and form it through a three-roll calender to obtain a sheet. After cooling and punching, preheating, longitudinal stretching, and cooling and shaping, the sheet is further preheated, transversely stretched, cooled and shaped, and then cut and rolled to obtain a high-strength corrosion-resistant geogrid. The thermoplastic elastomer is obtained by mixing EPDM rubber and styrene-butadiene rubber in a mass ratio of 5.5:4.5. The stretching conditions for longitudinal and transverse stretching are: stretch ratio of 4 and stretching temperature of 145°C.

[0023] The composite nanomaterials in Examples 2-4 above are the composite nanomaterials prepared in Example 1.

[0024] Comparative Example 1 Compared with Example 4, in the process of preparing high-strength corrosion-resistant geogrid, Comparative Example 1 used polydopamine-modified GO prepared in Example 1 instead of the composite nanomaterial prepared in Example 1, while keeping other conditions unchanged.

[0025] Comparative Example 2 Compared with Example 4, Comparative Example 2 used modified nano-silicon carbide prepared in Example 1 instead of the composite nanomaterial prepared in Example 1 in the process of preparing high-strength corrosion-resistant geogrid, while keeping other conditions unchanged.

[0026] Comparative Example 3 Compared with Example 4, in the preparation of grafted modified polypropylene, maleic anhydride grafted polypropylene was used instead of surface modified polypropylene in Comparative Example 3, while other conditions remained unchanged.

[0027] Comparative Example 4 Compared with Example 4, Comparative Example 4 used surface-modified polypropylene instead of branch-modified polypropylene in the preparation of functionalized polypropylene, while keeping other conditions unchanged.

[0028] Comparative Example 5 Compared with Example 4, Comparative Example 5 used grafted modified polypropylene instead of functionalized polypropylene in the process of preparing high-strength corrosion-resistant geogrid, while other conditions remained unchanged.

[0029] In the above examples and comparative examples, the isotactic polypropylene granules, brand Total (France), grade 6823MZ, melting point 136℃, were sourced from Dongguan Mingyuan Plastics Co., Ltd.; the polypropylene masterbatch, grade 1102K, specific gravity 0.904 g / cm³, was sourced from Shanghai Tuliang Industrial Co., Ltd.; the glass fiber, 3 mm in length, was sourced from Zibo Bohan Composite Materials Technology Co., Ltd.; the EPDM rubber, brand Dow, model 3640, specific gravity 0.860 g / cm³, was sourced from Shanghai Tingyuan Plastics Technology Co., Ltd.; the styrene-butadiene rubber, brand Guohua Chemical, in sheet form, was sourced from Shandong Guohua Chemical Co., Ltd.; the antioxidant 1010 was sourced from Shandong Junteng Chemical Co., Ltd.; the nano-silicon carbide, with an average particle size of 30 nm, was sourced from Zhejiang Yamei Nanotechnology Co., Ltd.; and the graphene oxide (GO), with a thickness of 0.55-1.2 nm and a diameter of 0.5-3 μm, was sourced from Zhongke Leiming (Beijing) Technology Co., Ltd.

[0030] Experimental Example Performance tests were conducted on high-strength corrosion-resistant geogrid samples prepared in Examples 2-4 and Comparative Examples 1-5. Test 1: Mechanical property test: The tensile strength of each group of samples was tested using an ETM504C electronic universal testing machine; Test 2, Corrosion Resistance Test: According to standard ISO 175:2010 "Plastics - Test methods for chemical resistance", each group of samples was immersed in 2 mol / L sulfuric acid solution and 2 mol / L NaOH solution for 48 hours for acid immersion treatment and alkali immersion treatment, respectively. Following the method of Test 1, the tensile strength of each sample after acid and alkali immersion treatment was tested, and the tensile strength change rate was calculated. Tensile strength decrease rate = (tensile strength after acid immersion / alkali immersion treatment - tensile strength before acid immersion / alkali immersion treatment) / tensile strength after acid immersion / alkali immersion treatment × 100%; Test 3: Flame retardant performance test: The LOI of each group of samples was tested according to the standard GB / T 2406–2009. The sample size was 100mm×10mm×4mm.

[0031] The test results are shown in Table 1: Table 1 ; As can be seen from the test results in Table 1, the high-strength corrosion-resistant geogrids prepared in Examples 2-4 of the present invention have the advantages of high strength, flame retardancy, and resistance to acid and alkali corrosion. As can be seen from the comparison between Comparative Examples 1-2 and Example 4, the composite nanomaterial of the present invention combines the advantages of graphene oxide and nano silicon carbide, is uniformly dispersed in the polypropylene matrix, and contains benzene rings, flame-retardant boron elements and polydopamine structure. While improving the comprehensive performance of the composite nanomaterial, it also enhances the bonding strength of graphene oxide and nano silicon carbide, thereby improving the comprehensive performance of the geogrid. A comparison of Comparative Examples 3-5 and Example 4 shows that the functionalized polypropylene branches in this invention contain a variety of functional groups. Comparative Example 3 shows that the flame-retardant nitrogen element, hydrazide group, and carbamate group introduced by the reaction of isophthaloyl hydrazide help form cross-linking hydrogen bonds in the functionalized polypropylene, increasing the cross-linking density of the system, resisting the erosion of corrosive media, and improving the strength, flame retardant properties, and corrosion resistance of the functionalized polypropylene. Comparative Example 4 shows that the flame-retardant nitrogen element, benzothiazole group, and carbamate group introduced by the reaction of 2,6-benzothiazole diamine help further enhance the hydrogen bond cross-linking effect, and the benzothiazole group has excellent corrosion resistance. The performance of functionalized polypropylene is improved by enhancing its overall properties. As shown in Comparative Example 5, the hydroxyl groups, amide groups, rigid benzene rings, and flame-retardant phosphorus elements introduced by the reaction of epoxy-functionalized eugenol compounds improve the flame-retardant properties while enhancing the hydrogen bond crosslinking effect. In summary, the above-mentioned functional groups combine the effects of flame-retardant nitrogen and phosphorus elements, benzene rings, and thiazole groups to endow functionalized polypropylene with excellent flame-retardant properties. Furthermore, the functionalized polypropylene branches can form a dense crosslinking network through covalent crosslinking, hydrogen bonding, and π-π stacking, while the rigid structure of the benzene ring enhances the strength of the crosslinking network and improves the barrier effect against corrosive media, thereby giving the geogrid excellent overall performance.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-strength, corrosion-resistant geogrid, characterized in that, Includes the following steps: Step 1: Eugenol reacts with phosphorus oxychloride to obtain trieugenol compound; the carbon-carbon double bond in the trieugenol compound is converted into epoxy group to obtain epoxy-functionalized trieugenol compound. Step 2: Maleic anhydride-grafted polypropylene reacts with isophthalic hydrazide to obtain surface-modified polypropylene. Surface-modified polypropylene was reacted with hexamethylene diisocyanate and 2,6-benzothiazole diamine to obtain graft-modified polypropylene; graft-modified polypropylene was reacted with epoxy-functionalized eugenol compounds to obtain functionalized polypropylene. Step 3: Weigh out polypropylene masterbatch, functionalized polypropylene, thermoplastic elastomer, glass fiber, antioxidant 1010, composite nanomaterials, and phthalate according to the proportion, mix them to obtain raw material mixture; melt and extrude the raw material mixture to form a board; cool, punch, stretch, shape, cut and roll the board to obtain a high-strength corrosion-resistant geogrid.

2. The method for preparing high-strength corrosion-resistant geogrid according to claim 1, characterized in that, In step one, the preparation method of the epoxy-functionalized eugenol compound is as follows: Eugenol and triethylamine were dissolved in dichloromethane, and then phosphorus oxychloride was added. The mixture was stirred at 0°C for 20-40 min, and then stirred at 23-25°C for 20-30 h. After purification, trieugenol compound was obtained. The mass ratio of eugenol, triethylamine, dichloromethane, and phosphorus oxychloride was (15-30):(11.1-22.2):(350-550):(4.68-9.36). m-Cloroperoxybenzoic acid and butylated hydroxytoluene were dissolved in dichloromethane, and then a 5.45wt% trieugenol compound / dichloromethane solution was added. The mixture was stirred and reacted at 23-25℃ for 40-50 h, and purified to obtain an epoxy-functionalized trieugenol compound. The mass ratio of the mixture of m-Cloroperoxybenzoic acid, butylated hydroxytoluene, dichloromethane, and 5.45wt% trieugenol compound / dichloromethane solution was (21.6-51.2):(0.01-0.03):(350-550):(350-550).

3. The method for preparing high-strength corrosion-resistant geogrid according to claim 1, characterized in that, In step two, the preparation method of the surface-modified polypropylene is as follows: Isotactic polypropylene particles, maleic anhydride, and o-xylene were mixed, heated to 55-65℃ and maintained for 1.5-2.5 h, and a 0.04 mol / L benzoyl peroxide / xylene solution was added. The mixture was heated to 116-124℃ under an argon atmosphere and stirred for 2.5-3.5 h. After purification, maleic anhydride-grafted polypropylene was obtained. The mass ratio of the isotactic polypropylene particles, maleic anhydride, o-xylene, and 0.04 mol / L benzoyl peroxide / xylene solution was (5-8):(2-4):(80-120):(8.75-10.51). Maleic anhydride-grafted polypropylene was added to N,N-dimethylformamide and stirred at 116-124℃ for 1.5-2.5 h in an argon atmosphere. Then, a 6 wt% isophthalohydrazide / N,N-dimethylformamide solution was added, and the temperature was kept constant while stirring was continued for 5-7 h. After purification, surface-modified polypropylene was obtained. The mass ratio of maleic anhydride-grafted polypropylene, N,N-dimethylformamide, and 6 wt% isophthalohydrazide / N,N-dimethylformamide solution was (5-8):(70-150):(32.3-38.7).

4. The method for preparing high-strength corrosion-resistant geogrid according to claim 1, characterized in that, In step two, the preparation method of the functionalized polypropylene is as follows: Surface-modified polypropylene was added to N,N-dimethylformamide, followed by hexamethylene diisocyanate. The mixture was stirred and reacted at 80-100°C for 8-12 hours under a nitrogen atmosphere. Then, 2,6-benzothiazolium diamine was added, and the mixture was stirred and reacted for another 5-7 hours. After purification, graft-modified polypropylene was obtained. The mass ratio of the surface-modified polypropylene, N,N-dimethylformamide, hexamethylene diisocyanate, and 2,6-benzothiazolium diamine was (5-8):(70-150):(1.68g-1.92):(1.65-3.3). Graft-modified polypropylene was added to N,N-dimethylformamide, followed by the addition of epoxy-functionalized eugenol compound. The mixture was stirred and reacted at 75-85℃ for 10-16 hours, and then purified to obtain functionalized polypropylene. The mass ratio of the graft-modified polypropylene, N,N-dimethylformamide, and epoxy-functionalized eugenol compound was (5-8):(120-200):(5.84-7.12).

5. The method for preparing high-strength corrosion-resistant geogrid according to claim 1, characterized in that, In step three, the content of each component in the raw material mixture by weight is as follows: 100 parts of polypropylene masterbatch, 20-40 parts of functionalized polypropylene, 20-30 parts of thermoplastic elastomer, 10-15 parts of glass fiber, 1-5 parts of antioxidant 1010, 10-20 parts of composite nanomaterials, and 1-3 parts of phthalate.

6. The method for preparing high-strength corrosion-resistant geogrid according to claim 1, characterized in that, In step three, the thermoplastic elastomer is obtained by mixing EPDM rubber and styrene-butadiene rubber in a mass ratio of (5-6):(4-5); the stretching conditions for longitudinal and transverse stretching are: a stretching ratio of 3-5 and a stretching temperature of 140-150℃.

7. The method for preparing high-strength corrosion-resistant geogrid according to claim 1, characterized in that, In step three, the preparation method of the composite nanomaterial is as follows: Step S1: Disperse amino-modified nano-silicon carbide in 1,4-dioxane, sonicate, stir, then add 4-chlorophenylboronic acid mixture, reflux at 110-120℃ for 8-12 h, purify, and obtain modified nano-silicon carbide. Step S2: Add graphene oxide to deionized water, sonicate, then add 10 mmol / L Tris-HCl, stir evenly, add dopamine, adjust the pH to 8.5, stir and react at 60-70℃ for 16-24 h, purify to obtain polydopamine modified GO; wherein, the mass ratio of graphene oxide, deionized water, 10 mmol / L Tris-HCl and dopamine is (2-3):(2-3):(50-100):(0.3-0.5); Polydopamine-modified GO was mixed with toluene at a mass ratio of (2-3):(200-300) to obtain mixture A; modified nano-silicon carbide was mixed with toluene at a mass ratio of (0.4-0.8):(80-120) to obtain mixture B; mixture A and mixture B were stirred and reacted at 106-110℃ for 8-12 h, and purified to obtain composite nanomaterials.

8. The method for preparing high-strength corrosion-resistant geogrid according to claim 7, characterized in that, In step S1, the 4-chlorophenylboronic acid mixture is obtained by mixing 4-chlorophenylboronic acid, triethylamine, and 1,4-dioxane in a mass ratio of 1.53:1:5.07; the mass ratio of the amino-modified nano-silicon carbide, 1,4-dioxane, and 4-chlorophenylboronic acid mixture is (2-3):(150-250):(4.65-7.75).

9. The method for preparing high-strength corrosion-resistant geogrid according to claim 7, characterized in that, In step S1, the amino-modified nano-silicon carbide is prepared by the following method: Nano-silicon carbide was dispersed in ethanol and stirred. Then, silane coupling agent KH-550 was added and stirred at 40-50℃ for 8-12 hours. After purification, amino-modified nano-silicon carbide was obtained. The mass ratio of nano-silicon carbide, ethanol and silane coupling agent KH-550 was (2-3):(100-120):(0.3-0.8).

10. A high-strength corrosion-resistant geogrid prepared by the preparation method of the high-strength corrosion-resistant geogrid as described in any one of claims 1-9.

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