Anti-aging sand water retention film material and preparation method thereof

Abstract

The invention relates to the technical field of preparation of layered composite films, and discloses an anti-aging sand water retention film material and a preparation method thereof. According to the anti-aging sand water retention film material, a protective layer, a base material layer and a saline-alkaline resistant layer are sequentially arranged from top to bottom, and the protective layer comprises linear low-density polyethylene, high-density polyethylene, an ethylene-vinyl acetate copolymer, metallocene polyethylene, carbon fibers and polyethylene grafted maleic anhydride. The base material layer comprises high-density polyethylene, an organic-inorganic hybrid composite material, a thermoplastic polyamide elastomer and polyethylene grafted glycidyl methacrylate, and the saline-alkaline resistant layer comprises aerogel filler and high-density polyethylene. The anti-aging sand water retention membrane material has good mechanical strength, puncture resistance, toughness, hydrophilic water retention and saline-alkaline aging resistance, is easy to recover and reduces white pollution.

Description

Technical Field

[0001] The invention relates to the technical field of layered composite membrane preparation, in particular to an aging-resistant sand water-retaining membrane material and a preparation method thereof. Background Art

[0002] In the prior art, in order to better develop and utilize sandy land, expand cultivated land, and improve water conservation, the principle of soilless cultivation is used to lay plastic lining films at a certain depth from the surface, which can effectively prevent the loss of water and fertilizer in sandy soil. However, the tensile strength and toughness of ordinary plastic lining films need to be improved. In highly saline and alkaline sandy land, they are easily aged into residual film fragments, which will cause crop roots to rot and seedlings to die. Moreover, they are not easy to be removed for recycling, causing white pollution. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an aging-resistant sand water-retaining film material, which comprises a protective layer, a substrate layer, and a salt-alkali resistant layer arranged in sequence from top to bottom. The protective layer comprises 45-60 parts of linear low-density polyethylene, 40-55 parts of high-density polyethylene, 15-18 parts of ethylene-vinyl acetate copolymer, 16-20 parts of metallocene polyethylene, 5-15 parts of carbon fiber, and 3-8 parts of polyethylene grafted maleic anhydride; the substrate layer comprises 100-120 parts of high-density polyethylene, 5-15 parts of organic-inorganic hybrid composite materials, 2-6 parts of thermoplastic polyamide elastomers, and 3-8 parts of polyethylene grafted glycidyl methacrylate; and the salt-alkali resistant layer comprises 0.1-0.5 parts of aerogel filler and 100-120 parts of high-density polyethylene.

[0004] Preferably, the thickness ratio of the protective layer, the substrate layer and the salt-alkali resistant layer is (0.1-0.5):(1-2):(0.1-0.5).

[0005] Preferably, the method for preparing the organic-inorganic hybrid composite material in the substrate layer comprises the following steps: Step B1, at room temperature, add ethylthioacetamide to ultrapure water and stir for 20-40 minutes, add tungsten hexachloride and continue stirring to react for 50-70 minutes, then add multi-walled carbon nanotubes, ultrasonically disperse for 100-150 minutes, react in a closed environment at 190-210° C. for 20-28 hours, filter, wash, and dry after the reaction to obtain tungsten disulfide / multi-walled carbon nanotube composite nanoparticles; wherein the mass ratio of ethylthioacetamide, ultrapure water, tungsten hexachloride, and multi-walled carbon nanotubes is (3.2-6.4):(10-30):(4.5-10):(2.1-3.9); In the above process, tungsten disulfide nanosheets are grown on the surface of multi-walled carbon nanotubes by an in-situ growth method.

[0006] Step B2, 3-mercaptopropyltrimethoxysilane, water, and ethanol are mixed and stirred for 20-40 minutes, and then tungsten disulfide / multi-walled carbon nanotube composite nanoparticles are added, and the pH of the mixed system is adjusted to 5-5.6 by acetic acid, and ultrasonic treatment is performed for 100-150 minutes, and then stirred at 50-70° C. for 5.5-7.5 hours, filtered, washed, and dried to obtain modified composite nanoparticles; wherein the amount ratio of 3-mercaptopropyltrimethoxysilane, water, ethanol, and tungsten disulfide / multi-walled carbon nanotube composite nanoparticles is (3.2-6.4) mL: (10-30) mL: (4.5-10) mL: (2.1-3.9) g; In the above process, silanol formed by hydrolysis of 3-mercaptopropyltrimethoxysilane reacts with hydroxyl groups on the surface of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles to introduce mercapto groups on the surface of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles.

[0007] Step B3, adding the modified composite nanoparticles to ethanol, ultrasonically dispersing for 20-40 minutes, heating to 50-80°C, adding 1,5-hexadiene and azobisisobutyronitrile, stirring and reacting at a speed of 200-400 r / min for 2-5 hours, centrifuging, washing, and drying to obtain an organic-inorganic hybrid composite material; wherein the mass ratio of the modified composite nanoparticles, ethanol, 1,5-hexadiene, and azobisisobutyronitrile is (2-3):(30-50):(3.5-5.5):(0.02-0.05); In the above process, the thiol groups on the surface of the modified composite nanoparticles react with 1,5-hexadiene through a thiol-ene click reaction to introduce olefin chains on the modified composite nanoparticles.

[0008] Preferably, the method for preparing the aerogel filler in the salt-alkali resistant layer comprises the following steps: Step A1, acrylic acid, acrylamide, 1,1'-azo (cyanocyclohexane) and ethyl acetate are mixed, purged with nitrogen for 15-35 minutes at room temperature, and then heated to 85-95° C. under sealed conditions, and stirred at a speed of 600-800 r / min for 11-13 hours, filtered, and washed to obtain an acrylic acid-acrylamide copolymer; In the above process, 1,1'-azo(cyanocyclohexane) is used as an initiator, and acrylic acid and acrylamide are polymerized to form a copolymer; Step A2, adding potassium carbonate to a 4 wt % aqueous solution of acrylic acid-acrylamide copolymer at 2-5° C., stirring at 500-600 r / min at 24-26° C. for 12-14 h, transferring to an 8-12° C. ice bath, adding dropwise 3-8 wt % aqueous solution of citric acid at a rate of 1.5-2.5 mL / min, and finally stirring at 500-600 r / min at 24-26° C. for 12-14 h. After the reaction is completed, cyclic dialysis purification treatment is performed, and vacuum drying is performed to obtain a modified acrylic acid-acrylamide copolymer; In the above process, potassium carbonate is used as a catalyst, and the carboxyl groups in the acrylic acid-acrylamide copolymer react with the hydroxyl groups in the citric acid to undergo an esterification reaction, thereby introducing more carboxyl groups into the acrylic acid-acrylamide copolymer; Step A3, under vacuum stirring conditions, maintaining the temperature at 28-32° C., mixing xanthan gum, modified acrylic acid-acrylamide copolymer, potassium persulfate, trimethylolpropane triglycidyl ether, and water, and then reacting at 65-75° C. for 3.5-4.5 hours to obtain a hydrogel, washing the hydrogel with distilled water, and freeze-drying it at (-56)-(-52)° C. for 20-28 hours to obtain an aerogel filler; In the above process, potassium persulfate is used as an initiator and trimethylolpropane triglycidyl ether is used as a cross-linking agent to cross-link xanthan gum and modified acrylic acid-acrylamide copolymer to form a semi-interpenetrating network hydrogel, which is then freeze-dried to form a porous aerogel rich in carboxyl, hydroxyl and amide groups.

[0009] Furthermore, in the step A1, the mass ratio of acrylic acid, acrylamide, 1,1'-azo(cyanocyclohexane) and ethyl acetate is (22-28):(72-78):(0.03-0.08):(500-800).

[0010] Furthermore, in step A2, the mass ratio of acrylic acid-acrylamide copolymer, citric acid and potassium carbonate is 1:(0.04-0.1):(0.1-0.2); cyclic dialysis purification treatment method: a dialysis membrane with a molecular weight cutoff of 50KD is used for cyclic dialysis purification treatment 4-6 times, each dialysis for 12-14 hours.

[0011] Furthermore, in step A3, the mass ratio of xanthan gum, modified acrylic acid-acrylamide copolymer, potassium persulfate, trimethylolpropane triglycidyl ether and water is (1-1.5):(14-35):(0.08-0.12):(0.3-0.9):(200-300).

[0012] The present invention also provides a method for preparing an aging-resistant sand water-retaining film material, which is characterized by comprising the following steps: Step (1), by weight, mixing aerogel filler and high-density polyethylene, crushing, and extruding to obtain a salt-alkali resistant layer mixture; In parts by weight, linear low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, metallocene polyethylene, carbon fiber, and polyethylene grafted maleic anhydride are mixed and extruded to obtain a protective layer mixture; In parts by weight, high-density polyethylene, an organic-inorganic hybrid composite material, a thermoplastic polyamide elastomer, and polyethylene grafted glycidyl methacrylate are mixed and extruded to obtain a substrate layer mixture; Step (2), the protective layer mixture, the base material layer mixture, and the salt-alkali resistant layer mixture are pressurized and stabilized by a melt pump and then cast by a distributor and a casting die head to obtain an aging-resistant sand water-retaining film material; In the above process, ethylene-vinyl acetate copolymer is added to the protective layer to make the protective layer have good flexibility, and carbon fiber can improve the puncture resistance of the protective layer; the aerogel filler in the salt-alkali resistant layer has excellent water absorption and retention and salt-alkali aging resistance; the organic-inorganic hybrid composite material in the substrate layer can improve the mechanical strength and toughness.

[0013] Preferably, in the step (1), the crushing conditions are: crushing at a rotation speed of 20000-30000 r / min for 2-5 min.

[0014] Preferably, in step (1), the extrusion conditions for preparing the salt-alkali resistant layer mixture, the protective layer mixture and the substrate layer mixture are the same, the extrusion temperature is 145-165° C., and the extrusion speed is 10-20 r / min.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The aging-resistant sandy land water-retaining film material of the present invention is arranged in sequence from top to bottom with a protective layer, a substrate layer, and a salt-alkali resistant layer. The protective layer is added with ethylene-vinyl acetate copolymer to make the protective layer have good flexibility, and carbon fiber can improve the puncture resistance of the protective layer; the aerogel filler in the salt-alkali resistant layer has excellent water absorption and water retention, and salt-alkali aging resistance; the organic-inorganic hybrid composite material in the substrate layer can improve the mechanical strength and toughness of the substrate layer. Therefore, the aging-resistant sandy land water-retaining film material of the present invention has good mechanical strength, puncture resistance, toughness, hydrophilic water retention and salt-alkali aging resistance, which can not only prevent the erosion of the saline-alkali sandy soil on the film material, prevent the film material from being punctured by crop roots and sand and gravel in the soil, prevent water and fertilizer from infiltrating, and avoid groundwater from reaching the surface through capillary action and causing evaporation, but also solve the problem that ordinary sandy land cultivation lining films are easy to age to form residual film fragments, which are difficult to recycle and cause crop root rot and seedling death; in addition, the substrates of the protective layer, substrate layer, and salt-alkali resistant layer of the aging-resistant sandy land water-retaining film material of the present invention are all polyethylene, and the single material reduces the difficulty of recycling and reduces white pollution.

[0016] 2. The aerogel filler in the present invention is obtained by cross-linking xanthan gum and modified acrylic acid-acrylamide copolymer to form a semi-interpenetrating network hydrogel, which is then freeze-dried. The aerogel not only has a porous structure, but also contains abundant hydrophilic groups such as carboxyl, hydroxyl and amide groups inside, so as to achieve a good water absorption and water retention effect. The aerogel filler obtained by compounding acrylic acid, acrylamide and xanthan gum, which are salt- and alkali-resistant in themselves, has excellent salt- and alkali resistance. In addition, the acrylic acid-acrylamide copolymer is modified with citric acid to increase the carboxyl content in the aerogel system, thereby improving the water absorption and water retention and salt- and alkali aging resistance of the aerogel.

[0017] 3. The organic-inorganic hybrid composite material of the present invention in situ grows tungsten disulfide nanosheets on the surface of multi-walled carbon nanotubes. The tungsten disulfide nanosheet structure solves the problem that multi-walled nanotubes increase the mechanical strength of the substrate layer while reducing the toughness. Tungsten disulfide and multi-walled carbon nanotubes synergistically effectively improve the mechanical strength and toughness of the substrate layer. In addition, the tungsten disulfide nanosheets and the polymer matrix have a strong interface interaction, which improves the dispersibility and compatibility of the tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in the substrate layer. Furthermore, thiol groups are introduced on the surface of the tungsten disulfide / multi-walled carbon nanotube composite nanoparticles by 3-mercaptopropyltrimethoxysilane, and then olefin chains are introduced by reaction with 1,5-hexadiene, thereby improving the dispersion uniformity and adhesion of the inorganic composite material tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in the high-density polyethylene in the substrate layer, and further improving the mechanical properties of the substrate layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a comparison chart of the dart drop impact strength test of the aging-resistant sand water-retaining film materials of Examples 3-5 of the present invention and Comparative Examples 3-6; Figure 2 It is a comparison chart of tensile strength test of anti-aging sand water-retaining film materials of Examples 3-5 of the present invention and Comparative Examples 3-6; Figure 3 It is a comparison chart of the tensile strength retention rate test of the aging-resistant sand water-retaining film material of Examples 3-5 of the present invention and Comparative Examples 3-6; Figure 4 This is a schematic structural diagram of the aging-resistant sand water-retaining film material of the present invention; Among them, 1-protective layer, 2-base material layer, 3-salt-alkali resistant layer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] Example 1 This embodiment discloses a method for preparing an aerogel filler, comprising the following steps: Step A1, acrylic acid, acrylamide, 1,1'-azo (cyanocyclohexane), and ethyl acetate are mixed in a mass ratio of 25:75:0.05:650, purged with nitrogen at room temperature for 25 minutes, and then heated to 90°C under sealed conditions, and stirred at a speed of 700 r / min for 12 hours. The precipitate obtained by the reaction is separated by filtration, and the product is washed with ethyl acetate 4 times, and dried at 60°C for 13 hours to obtain an acrylic acid-acrylamide copolymer; Step A2, adding potassium carbonate to a 4 wt % aqueous solution of acrylic acid-acrylamide copolymer at 4°C, stirring at 550 r / min at 25°C for 13 h, transferring to a 10°C ice bath, adding a 6 wt % aqueous solution of citric acid dropwise at a rate of 2 mL / min, and finally stirring at 550 r / min at 25°C for 13 h. After the reaction is completed, performing a cyclic dialysis purification treatment 5 times using a dialysis membrane with a molecular weight cutoff of 50 KD, each dialysis for 13 h, and vacuum drying the obtained purified solution at 45°C until constant weight to obtain a modified acrylic acid-acrylamide copolymer; Wherein, the mass ratio of acrylic acid-acrylamide copolymer, citric acid, and potassium carbonate is 1:0.07:0.15; Step A3, under vacuum stirring conditions, maintaining the temperature at 30°C, mixing xanthan gum, modified acrylic acid-acrylamide copolymer, potassium persulfate, trimethylolpropane triglycidyl ether, and water in a mass ratio of 1.2:24.5:0.1:0.6:250, and then reacting at 70°C for 4 hours to obtain a hydrogel, and after washing the hydrogel with distilled water, freeze-drying it at -54°C for 24 hours to obtain an aerogel filler.

[0021] Example 2 This embodiment discloses a method for preparing an organic-inorganic hybrid composite material, comprising the following steps: Step B1, at room temperature, add 4.8g of ethylthioacetamide to 20mL of ultrapure water and stir for 30min, add 7.2g of tungsten hexachloride and continue stirring and reacting for 60min, then add 3g of multi-walled carbon nanotubes, ultrasonically disperse for 120min, react in a closed environment at 200°C for 24h, filter after the reaction, wash the obtained solid product with acetic acid and ultrapure water, and vacuum dry at 90°C for 25h to obtain tungsten disulfide / multi-walled carbon nanotube composite nanoparticles; Step B2, 4.5 mL of 3-mercaptopropyltrimethoxysilane, 12.5 mL of water, and 50 mL of ethanol were mixed and stirred for 30 min, and then 3 g of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles were added, and the pH of the mixed system was adjusted to 5.5 by acetic acid. After ultrasonic treatment for 120 min, the mixture was stirred at 60 ° C for 6.5 h. After the reaction was completed, it was filtered, and the obtained solid product was washed with ethanol and water, and then vacuum dried at 55 ° C for 15 h to obtain modified composite nanoparticles; Step B3, add 2.5g of modified composite nanoparticles to 40g of ethanol, ultrasonically disperse for 30min, heat to 65°C, add 4.5g of 1,5-hexadiene and 0.03g of azobisisobutyronitrile, stir and react at a speed of 300r / min for 3.5h. After the reaction is completed, centrifuge 4 times at 5500r / min, wash the centrifuged product with ethanol 4 times, and vacuum dry at 75°C for 12h to obtain an organic-inorganic hybrid composite material.

[0022] Example 3 This embodiment discloses a method for preparing an aging-resistant sand water-retaining film material, comprising the following steps: Step (1), by weight, 0.1 parts of the aerogel filler prepared in Example 1 and 100 parts of high-density polyethylene are mixed, crushed at a speed of 20000 r / min for 5 minutes, and then extruded at a speed of 10 r / min at 145° C. to obtain a salt-alkali resistant layer mixture; In parts by weight, 45 parts of linear low-density polyethylene, 40 parts of high-density polyethylene, 15 parts of ethylene-vinyl acetate copolymer, 16 parts of metallocene polyethylene, 5 parts of carbon fiber, and 3 parts of polyethylene grafted maleic anhydride were mixed, and then extruded at 145° C. at a rotation speed of 10 r / min to obtain a protective layer mixture; In parts by weight, 100 parts of high-density polyethylene, 5 parts of the organic-inorganic hybrid composite material prepared in Example 2, 2 parts of a thermoplastic polyamide elastomer, and 3 parts of polyethylene-grafted glycidyl methacrylate were mixed, and then extruded at 145° C. at a speed of 10 r / min to obtain a substrate layer mixture; Step (2), pressurizing and stabilizing the protective layer mixture, the substrate layer mixture, and the salt-alkali resistant layer mixture through a melt pump, and then casting through a distributor and a casting die head to obtain an aging-resistant sand water-retaining film material, wherein the thickness of the protective layer is 0.3 mm, the thickness of the substrate layer is 1.5 mm, and the thickness of the salt-alkali resistant layer is 0.3 mm.

[0023] Example 4 This embodiment discloses a method for preparing an aging-resistant sand water-retaining film material, comprising the following steps: Step (1), by weight, 0.5 parts of the aerogel filler prepared in Example 1 and 120 parts of high-density polyethylene are mixed, crushed at a speed of 30000 r / min for 2 min, and then extruded at a speed of 20 r / min at 165° C. to obtain a salt-alkali resistant layer mixture; In parts by weight, 60 parts of linear low-density polyethylene, 55 parts of high-density polyethylene, 18 parts of ethylene-vinyl acetate copolymer, 20 parts of metallocene polyethylene, 15 parts of carbon fiber, and 8 parts of polyethylene grafted maleic anhydride were mixed, and then extruded at 165° C. at a speed of 20 r / min to obtain a protective layer mixture; In parts by weight, 120 parts of high-density polyethylene, 15 parts of the organic-inorganic hybrid composite material prepared in Example 2, 6 parts of thermoplastic polyamide elastomer, and 8 parts of polyethylene grafted glycidyl methacrylate were mixed, and then extruded at 165° C. at a speed of 20 r / min to obtain a substrate layer mixture; Step (2), pressurizing and stabilizing the protective layer mixture, the substrate layer mixture, and the salt-alkali resistant layer mixture through a melt pump, and then casting through a distributor and a casting die head to obtain an aging-resistant sand water-retaining film material, wherein the thickness of the protective layer is 0.3 mm, the thickness of the substrate layer is 1.5 mm, and the thickness of the salt-alkali resistant layer is 0.3 mm.

[0024] Example 5 This embodiment discloses a method for preparing an aging-resistant sand water-retaining film material, comprising the following steps: Step (1), by weight, 0.3 parts of the aerogel filler prepared in Example 1 and 110 parts of high-density polyethylene are mixed, crushed at a speed of 25000 r / min for 3 minutes, and then extruded at a speed of 15 r / min at 155° C. to obtain a salt-alkali resistant layer mixture; In parts by weight, 52 parts of linear low-density polyethylene, 46 parts of high-density polyethylene, 17 parts of ethylene-vinyl acetate copolymer, 18 parts of metallocene polyethylene, 10 parts of carbon fiber, and 5.5 parts of polyethylene grafted maleic anhydride were mixed, and then extruded at 155° C. and a rotation speed of 15 r / min to obtain a protective layer mixture; In parts by weight, 110 parts of high-density polyethylene, 10 parts of the organic-inorganic hybrid composite material prepared in Example 2, 4 parts of a thermoplastic polyamide elastomer, and 5.5 parts of polyethylene-grafted glycidyl methacrylate were mixed, and then extruded at 155° C. at a speed of 15 r / min to obtain a substrate layer mixture; Step (2), pressurizing and stabilizing the protective layer mixture, the substrate layer mixture, and the salt-alkali resistant layer mixture through a melt pump, and then casting through a distributor and a casting die head to obtain an aging-resistant sand water-retaining film material, wherein the thickness of the protective layer is 0.3 mm, the thickness of the substrate layer is 1.5 mm, and the thickness of the salt-alkali resistant layer is 0.3 mm.

[0025] Comparative Example 1 Compared with Example 2, in the process of preparing the modified composite nanoparticles in Comparative Example 1, a mixture of tungsten disulfide and multi-walled carbon nanotubes was used instead of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles, and other conditions remained unchanged.

[0026] Comparative Example 2 Compared with Example 2, in the process of preparing the modified composite nanoparticles in Comparative Example 2, multi-walled carbon nanotubes are used instead of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles, and other conditions remain unchanged.

[0027] Comparative Example 3 Compared with Example 5, Comparative Example 3 adopts the organic-inorganic hybrid composite material prepared in Comparative Example 1, and other conditions remain unchanged.

[0028] Comparative Example 4 Compared with Example 5, Comparative Example 4 uses the organic-inorganic hybrid composite material prepared in Comparative Example 2, and other conditions remain unchanged.

[0029] Comparative Example 5 Compared with Example 5, the modified composite nanoparticles are used in the substrate layer mixture of Comparative Example 5 instead of the organic-inorganic hybrid composite material, and other conditions remain unchanged.

[0030] Comparative Example 6 Compared with Example 5, the aging-resistant sand water-retaining film material of Comparative Example 6 does not contain a salt-alkali resistant layer, and a protective layer is used instead of the salt-alkali resistant layer, while other conditions remain unchanged.

[0031] In the above embodiments and comparative examples, xanthan gum, CAS No.: 11138-66-2, active ingredient content 99%, from Maoming Xiongda Chemical Co., Ltd.; 50KD dialysis membrane, item No. 132542, from Zhejiang Lianshuo Biotechnology Co., Ltd.; multi-walled carbon nanotubes, inner diameter: 5-10nm, outer diameter: 10-20nm, length: 10-30um, from Shanghai Yien Chemical Technology Co., Ltd.; high-density polyethylene, brand HHM5502LW, melt flow rate 0.34g / 10min, from Shenzhen Zhengrui Plastic Co., Ltd.; linear low-density polyethylene, brand Borealis (Borouge), brand FK1828, melt flow rate 1.5g / 10min, from Shenzhen Zhengrui Plastic Co., Ltd.; metallocene polyethylene, brand Dow, Brand 5538G, melt flow rate 1.3g / 10min, from Shanghai Oushuo Plastic Co., Ltd.; ethylene-vinyl acetate copolymer, brand DowDuPont, specific gravity 0.940g / cm³, melt flow rate 2.2g / 10min, from Dongguan Zhenxuan Plastic Raw Materials Co., Ltd.; polyethylene grafted maleic anhydride, brand Arkema, brand 18341, melt flow rate 1.5g / 10min, from Dongguan Changping Longcheng New Materials Business Department; thermoplastic polyamide elastomer, brand French Arkema, item number HH7140CNPJ4R, from Dongguan Zhengtao Plastic Co., Ltd.; polyethylene grafted glycidyl methacrylate, brand Shenghao Plastic, item number 1125AC, melting temperature 65℃, from Dongguan Zhangmutou Hengtai Plastic Raw Materials Business Department.

[0032] Experimental example The performance tests were conducted on the aging-resistant sand water-retaining film materials prepared in Examples 3-5 and Comparative Examples 3-6.

[0033] Test 1: Drop impact performance: Use the "GB / T9639-1988 Plastic film and sheet impact resistance test method free falling dart method" standard test to obtain the corresponding drop impact strength.

[0034] Test 2: Tensile performance test: Use the standard "GB13022-1991 Plastic Film Tensile Performance Test Method" to test and obtain the corresponding tensile strength.

[0035] Test 3: Aging resistance test: Samples of each group of aging-resistant sand water-retaining film materials were buried in saline-alkali sandy soil at a depth of 50 cm (the alkalinity of saline-alkali sandy soil was 43.5%), and taken out after 30 days. According to the method of Test 2, the tensile strength retention rate of each group of samples was tested.

[0036] The test results are shown in Table 1: Table 1

[0037] It can be seen from the test results in Table 1 that the aging-resistant sand water-retaining film materials prepared in Examples 3-5 of the present invention have excellent mechanical strength, toughness and salt-alkali aging resistance. From the comparison between Comparative Examples 3-4 and Example 5, it can be seen that the organic-inorganic hybrid composite material in the substrate layer can improve the mechanical strength and toughness of the membrane material. Tungsten disulfide is in situ grown on the surface of multi-walled carbon nanotubes, which improves the dispersibility and compatibility of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in the substrate layer by changing the interface interaction with the substrate, thereby improving the performance of the membrane material; from the comparison between Comparative Example 5 and Example 5, it can be seen that by introducing olefin chains into the organic-inorganic hybrid composite material of 1,5-hexadiene, the dispersion uniformity and adhesion of the inorganic composite material tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in the high-density polyethylene in the substrate layer are improved, thereby exerting a better modification effect; from the comparison between Comparative Example 6 and Example 5, it can be seen that replacing the salt-alkali resistant layer with a protective layer improves the mechanical properties of the membrane material, but causes a significant decrease in the salt-alkali aging resistance of the membrane material.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An aging-resistant sand water-retaining film material, characterized in that: The protective layer, the substrate layer and the salt-alkali resistant layer are arranged in sequence from top to bottom. In terms of weight, the protective layer comprises 45-60 parts of linear low-density polyethylene, 40-55 parts of high-density polyethylene, 15-18 parts of ethylene-vinyl acetate copolymer, 16-20 parts of metallocene polyethylene, 5-15 parts of carbon fiber, and 3-8 parts of polyethylene grafted maleic anhydride; the substrate layer comprises 100-120 parts of high-density polyethylene, 5-15 parts of organic-inorganic hybrid composite material, 2-6 parts of thermoplastic polyamide elastomer, and 3-8 parts of polyethylene grafted glycidyl methacrylate; and the salt-alkali resistant layer comprises 0.1-0.5 parts of aerogel filler and 100-120 parts of high-density polyethylene.

2. The aging-resistant sand water-retaining film material according to claim 1, characterized in that: The thickness ratio of the protective layer, the base material layer and the salt-alkali resistant layer is (0.1-0.5):(1-2):(0.1-0.5).

3. The aging-resistant sand water-retaining film material according to claim 1, characterized in that: The method for preparing the organic-inorganic hybrid composite material in the substrate layer comprises the following steps: Step B1, at room temperature, add ethylthioacetamide to ultrapure water and stir for 20-40 minutes, add tungsten hexachloride and continue stirring to react for 50-70 minutes, then add multi-walled carbon nanotubes, ultrasonically disperse for 100-150 minutes, react in a closed environment at 190-210° C. for 20-28 hours, filter, wash, and dry after the reaction to obtain tungsten disulfide / multi-walled carbon nanotube composite nanoparticles; wherein the mass ratio of ethylthioacetamide, ultrapure water, tungsten hexachloride, and multi-walled carbon nanotubes is (3.2-6.4):(10-30):(4.5-10):(2.1-3.9); Step B2, 3-mercaptopropyltrimethoxysilane, water, and ethanol are mixed and stirred for 20-40 minutes, and then tungsten disulfide / multi-walled carbon nanotube composite nanoparticles are added, and the pH of the mixed system is adjusted to 5-5.6 by acetic acid, and ultrasonic treatment is performed for 100-150 minutes, and then stirred at 50-70° C. for 5.5-7.5 hours, filtered, washed, and dried to obtain modified composite nanoparticles; wherein the amount ratio of 3-mercaptopropyltrimethoxysilane, water, ethanol, and tungsten disulfide / multi-walled carbon nanotube composite nanoparticles is (3.2-6.4) mL: (10-30) mL: (4.5-10) mL: (2.1-3.9) g; Step B3, adding the modified composite nanoparticles to ethanol, ultrasonically dispersing for 20-40 minutes, heating to 50-80°C, adding 1,5-hexadiene and azobisisobutyronitrile, stirring and reacting at a speed of 200-400 r / min for 2-5 hours, centrifuging, washing, and drying to obtain an organic-inorganic hybrid composite material; wherein the mass ratio of the modified composite nanoparticles, ethanol, 1,5-hexadiene, and azobisisobutyronitrile is (2-3):(30-50):(3.5-5.5):(0.02-0.05).

4. The aging-resistant sand water-retaining film material according to claim 1, characterized in that: The method for preparing the aerogel filler in the salt-alkali resistant layer comprises the following steps: Step A1, acrylic acid, acrylamide, 1,1'-azo (cyanocyclohexane) and ethyl acetate are mixed, purged with nitrogen for 15-35 minutes at room temperature, and then heated to 85-95° C. under sealed conditions, and stirred at a speed of 600-800 r / min for 11-13 hours, filtered, and washed to obtain an acrylic acid-acrylamide copolymer; Step A2, adding potassium carbonate to a 4 wt % aqueous solution of acrylic acid-acrylamide copolymer at 2-5° C., stirring at 500-600 r / min at 24-26° C. for 12-14 h, transferring to an 8-12° C. ice bath, adding dropwise 3-8 wt % aqueous solution of citric acid at a rate of 1.5-2.5 mL / min, and finally stirring at 500-600 r / min at 24-26° C. for 12-14 h. After the reaction is completed, cyclic dialysis purification treatment is performed, and vacuum drying is performed to obtain a modified acrylic acid-acrylamide copolymer; Step A3, under vacuum stirring conditions, maintaining the temperature at 28-32°C, mixing xanthan gum, modified acrylic acid-acrylamide copolymer, potassium persulfate, trimethylolpropane triglycidyl ether and water, and then reacting at 65-75°C for 3.5-4.5 hours to obtain a hydrogel. After the hydrogel is washed with distilled water, it is freeze-dried at (-56)-(-52)°C for 20-28 hours to obtain an aerogel filler.

5. The aging-resistant sand water-retaining film material according to claim 4, characterized in that: In step A1 of the method for preparing the aerogel filler in the salt-alkali resistant layer, the mass ratio of acrylic acid, acrylamide, 1,1'-azo(cyanocyclohexane) and ethyl acetate is (22-28):(72-78):(0.03-0.08):(500-800).

6. The aging-resistant sand water-retaining film material according to claim 4, characterized in that: In step A2 of the method for preparing the aerogel filler in the salt-alkali resistant layer, the mass ratio of acrylic acid-acrylamide copolymer, citric acid and potassium carbonate is 1:(0.04-0.1):(0.1-0.2); the cyclic dialysis purification treatment method: a dialysis membrane with a molecular weight cutoff of 50KD is used for 4-6 times of cyclic dialysis purification treatment, and each dialysis is for 12-14 hours.

7. The aging-resistant sand water-retaining film material according to claim 4, characterized in that: In step A3 of the method for preparing aerogel filler in the salt-alkali resistant layer, the mass ratio of xanthan gum, modified acrylic acid-acrylamide copolymer, potassium persulfate, trimethylolpropane triglycidyl ether, and water is (1-1.5):(14-35):(0.08-0.12):(0.3-0.9):(200-300).

8. A method for preparing the aging-resistant sand water-retaining film material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step (1), by weight, mixing aerogel filler and high-density polyethylene, crushing, and extruding to obtain a salt-alkali resistant layer mixture; In parts by weight, linear low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, metallocene polyethylene, carbon fiber, and polyethylene grafted maleic anhydride are mixed and extruded to obtain a protective layer mixture; In parts by weight, high-density polyethylene, an organic-inorganic hybrid composite material, a thermoplastic polyamide elastomer, and polyethylene grafted glycidyl methacrylate are mixed and extruded to obtain a substrate layer mixture; Step (2), the protective layer mixture, the base material layer mixture, and the salt-alkali resistant layer mixture are pressurized and stabilized by a melt pump and then cast by a distributor and a casting die head to obtain an aging-resistant sand water-retaining film material.

9. The method for preparing the aging-resistant sand water-retaining film material according to claim 8, characterized in that: In the step (1), the crushing conditions are: crushing at a rotation speed of 20000-30000 r / min for 2-5 min.

10. The method for preparing the aging-resistant sand water-retaining film material according to claim 8, characterized in that: The extrusion conditions for preparing the salt-alkali resistant layer mixture, the protective layer mixture and the substrate layer mixture in step (1) are the same, the extrusion temperature is 145-165° C., and the extrusion speed is 10-20 r / min.

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