An anti-aging sand-fixing and water-retaining film material and its preparation method

Abstract

The present invention relates to the technical field of the preparation of laminated composite films, and discloses an anti-aging sand-fixing water-retaining film material and a preparation method thereof. The anti-aging sand-fixing water-retaining film material comprises a protective layer, a base material layer, and a salt-alkali resistance layer arranged in sequence from top to bottom. The protective layer includes linear low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, metallocene polyethylene, carbon fiber, and polyethylene grafted maleic anhydride. The base material layer includes high-density polyethylene, organic-inorganic hybrid composite material, thermoplastic polyamide elastomer, and polyethylene grafted glycidyl methacrylate. The salt-alkali resistance layer includes aerogel filler and high-density polyethylene. The anti-aging sand-fixing water-retaining film material of the present invention has good mechanical strength, puncture resistance, toughness, hydrophilic water retention property, and salt-alkali aging resistance, and is easy to recycle, reducing white pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of laminated composite films, and specifically relates to an anti-aging sand-fixing and water-retaining film 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 the water-saving rate, using the principle of soilless cultivation, a plastic lining film is laid at a certain depth from the ground surface, which can effectively prevent the loss of sandy soil water and fertilizer. However, the ordinary plastic lining film needs to improve its tensile strength and toughness. It is easy to age into residual film fragments in highly saline-alkali sandy land, which will cause crop root rot and dead seedlings, and it is not easy to remove and recycle, resulting in white pollution. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides an anti-aging sand-fixing and water-retaining film material, which is arranged in sequence from top to bottom with a protective layer, a base material layer, and a saline-alkali resistant layer. By weight, the protective layer includes 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 base material layer includes 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. The saline-alkali resistant layer includes 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 base material layer, and the saline-alkali resistant layer is (0.1-0.5):(1-2):(0.1-0.5).

[0005] Preferably, the preparation method of the organic-inorganic hybrid composite material in the base material layer includes the following steps:

[0006] Step B1: At room temperature, add ethylthioacetamide to ultrapure water and stir for 20-40 min, then add tungsten hexachloride and continue stirring and reacting for 50-70 min. Then add multi-walled carbon nanotubes, ultrasonically disperse for 100-150 min, and then react at 190-210 °C for 20-28 h in a closed environment. After the reaction, filter, wash, and dry to obtain tungsten disulfide / multi-walled carbon nanotube composite nanoparticles. Among them, 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);

[0007] In the above process, tungsten disulfide nanosheets are grown on the surface of multi-walled carbon nanotubes by in-situ growth method.

[0008] Step B2: Mix 3-mercaptopropyltrimethoxysilane, water, and ethanol, stir for 20 - 40 min, then add tungsten disulfide / multi-walled carbon nanotube composite nanoparticles. Adjust the pH of the mixed system to 5 - 5.6 with acetic acid, perform ultrasonic treatment for 100 - 150 min, then stir and react at 50 - 70 °C for 5.5 - 7.5 h, filter, wash, and dry to obtain modified composite nanoparticles; wherein, the dosage 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;

[0009] In the above process, the silanol formed by the hydrolysis of 3-mercaptopropyltrimethoxysilane reacts with the hydroxyl groups on the surface of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles, introducing mercapto groups on the surface of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles.

[0010] Step B3: Add the modified composite nanoparticles to ethanol, ultrasonically disperse for 20 - 40 min, heat to 50 - 80 °C, add 1,5-hexadiene and azobisisobutyronitrile, and stir and react at a rotation speed of 200 - 400 r / min for 2 - 5 h, centrifuge, wash, and dry 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);

[0011] In the above process, the mercapto groups on the surface of the modified composite nanoparticles and 1,5-hexadiene undergo a thiol-ene click reaction to introduce olefin chains onto the modified composite nanoparticles.

[0012] Preferably, the preparation method of the aerogel filler in the salt and alkali resistant layer includes the following steps:

[0013] Step A1: Mix acrylic acid, acrylamide, 1,1'-azobis(cyclohexanenitrile), and ethyl acetate, purge with nitrogen at room temperature for 15 - 35 min, then under sealed conditions, heat to 85 - 95 °C, and stir and react at a rotation speed of 600 - 800 r / min for 11 - 13 h, filter, wash, to obtain an acrylic acid-acrylamide copolymer;

[0014] In the above process, 1,1'-azobis(cyclohexanenitrile) serves as an initiator, and acrylic acid and acrylamide polymerize to form a copolymer;

[0015] Step A2: Potassium carbonate is added to the 4 wt% aqueous solution of acrylic acid-acrylamide copolymer at 2-5 °C. After stirring at 500-600 r / min for 12-14 h at 24-26 °C, it is transferred to an ice bath at 8-12 °C, and an aqueous solution of 3-8 wt% citric acid is added dropwise at a rate of 1.5-2.5 mL / min. Finally, it is stirred and reacted at 500-600 r / min for 12-14 h at 24-26 °C. After the reaction is completed, it is subjected to cyclic dialysis purification and vacuum drying to obtain a modified acrylic acid-acrylamide copolymer;

[0016] In the above process, potassium carbonate is used as a catalyst, and the carboxyl group in the acrylic acid-acrylamide copolymer reacts with the hydroxyl group in citric acid to introduce more carboxyl groups into the acrylic acid-acrylamide copolymer;

[0017] Step A3: Under vacuum stirring conditions, while maintaining the temperature at 28-32 °C, xanthan gum, modified acrylic acid-acrylamide copolymer, potassium persulfate, trimethylolpropane triglycidyl ether, and water are mixed, and then reacted at 65-75 °C for 3.5-4.5 h to obtain a hydrogel. After the hydrogel is washed with distilled water, it is freeze-dried at (-56)-(-52) °C for 20-28 h to obtain an aerogel filler;

[0018] 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 the modified acrylic acid-acrylamide copolymer to form a semi-interpenetrating network hydrogel, which is then freeze-dried to form a porous aerogel containing abundant carboxyl, hydroxyl, and amide groups inside.

[0019] Furthermore, in Step A1, the mass ratio of acrylic acid, acrylamide, 1,1'-azobis(cyclohexanenitrile), and ethyl acetate is (22-28):(72-78):(0.03-0.08):(500-800).

[0020] Furthermore, in Step A2, the mass ratio of the acrylic acid-acrylamide copolymer, citric acid, and potassium carbonate is 1:(0.04-0.1):(0.1-0.2); The method of cyclic dialysis purification: Cyclic dialysis purification is carried out 4-6 times using a dialysis membrane with a molecular weight cut-off of 50 KD, and each dialysis lasts for 12-14 h.

[0021] 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).

[0022] The present invention also provides a preparation method of an anti-aging sand-fixing water-retaining film material, which is characterized by comprising the following steps:

[0023] Step (1): Taking an aerogel filler and high-density polyethylene by weight, mixing, pulverizing, and extruding to obtain a saline-alkali resistant layer mixture;

[0024] Taking linear low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, metallocene polyethylene, carbon fiber, and polyethylene grafted maleic anhydride by weight, mixing, and extruding to obtain a protective layer mixture;

[0025] Taking high-density polyethylene, an organic-inorganic hybrid composite material, a thermoplastic polyamide elastomer, and polyethylene grafted glycidyl methacrylate by weight, mixing, and extruding to obtain a base layer mixture;

[0026] Step (2): Pressurizing and stabilizing the protective layer mixture, the base layer mixture, and the saline-alkali resistant layer mixture through a melt pump, and then casting them through a distributor and a casting die head to obtain the anti-aging sand-fixing water-retaining film material;

[0027] In the above process, adding ethylene-vinyl acetate copolymer to the protective layer makes the protective layer have good flexibility, and the carbon fiber can improve the puncture resistance of the protective layer; the aerogel filler in the saline-alkali resistant layer has excellent water absorption and retention and saline-alkali aging resistance; the organic-inorganic hybrid composite material in the base layer can improve the mechanical strength and toughness.

[0028] Preferably, in the step (1), the pulverizing conditions are: pulverizing at a rotation speed of 20,000 - 30,000 r / min for 2 - 5 min.

[0029] Preferably, in the step (1), the extrusion conditions for preparing the saline-alkali resistant layer mixture, the protective layer mixture, and the base layer mixture are the same, and the extrusion temperature is 145 - 165 °C and the extrusion rotation speed is 10 - 20 r / min.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. The anti-aging sand water-retaining film material of the present invention is arranged in sequence from top to bottom with a protective layer, a base material layer, and a salt and alkali resistance layer. 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 and alkali resistance layer has excellent water absorption, water retention, salt and alkali aging resistance performance; the organic-inorganic hybrid composite material in the base material layer can improve the mechanical strength and toughness of the base material layer. Therefore, the anti-aging sand water-retaining film material of the present invention has good mechanical strength, puncture resistance, toughness, hydrophilic water retention and salt and alkali aging resistance performance. It can not only prevent the erosion of salt-alkali sandy soil on the film material, prevent the film material from being punctured by crop roots and gravel in the soil, prevent the infiltration of water and fertilizer, avoid the evaporation caused by the capillary action of groundwater reaching the surface, but also solve the problem that the ordinary sand cultivation lining film is easy to age and form residual film fragments, which are difficult to recycle and cause crop root rot and dead seedlings; in addition, the base materials of the protective layer, the base material layer, and the salt and alkali resistance layer of the anti-aging sand water-retaining film material of the present invention are all polyethylene, and the single material reduces the difficulty of recycling and reduces white pollution.

[0032] 2. The aerogel filler in the present invention is formed by cross-linking xanthan gum and modified acrylic acid-acrylamide copolymer to form a semi-interpenetrating network hydrogel, and then freeze-drying. The aerogel not only contains a porous structure, but also contains rich hydrophilic groups such as carboxyl, hydroxyl, and amide groups, achieving a good water absorption and water retention effect. The aerogel filler obtained by compounding acrylic acid, acrylamide, and xanthan gum with salt and alkali resistance itself has excellent salt and alkali resistance. In addition, the acrylic acid-acrylamide copolymer is modified with citric acid, increasing the carboxyl content in the aerogel system and improving the water absorption, water retention and salt and alkali aging resistance of the aerogel.

[0033] 3. For the organic-inorganic hybrid composite material of the present invention, tungsten disulfide nanosheets are in-situ grown on the surface of multi-walled carbon nanotubes. The structure of tungsten disulfide nanosheets solves the problem that the multi-walled nanotubes reduce the toughness while improving the mechanical strength of the base material layer. Tungsten disulfide and multi-walled carbon nanotubes synergistically and effectively improve the mechanical strength and toughness of the base material layer. Moreover, the tungsten disulfide nanosheets have a strong interfacial interaction with the polymer matrix, improving the dispersibility and compatibility of the tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in the base material layer; further, 3-mercaptopropyltrimethoxysilane is used to introduce mercapto groups on the surface of the tungsten disulfide / multi-walled carbon nanotube composite nanoparticles, and then 1,5-hexadiene is reacted to introduce olefin chains, improving the dispersion uniformity and adhesion of the inorganic composite material tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in high-density polyethylene in the base material layer, and further improving the mechanical properties of the base material layer. Description of the Drawings

[0034] Figure 1 It is a comparison chart of the falling dart impact strength test of the anti-aging sand water-retaining film materials of Examples 3-5 and Comparative Examples 3-6 of the present invention;

[0035] Figure 2 It is a comparison chart of the tensile strength test of the anti-aging sandy land water-retaining film materials of Examples 3-5 and Comparative Examples 3-6 of the present invention;

[0036] Figure 3 It is a comparison chart of the tensile strength retention rate test of the anti-aging sandy land water-retaining film materials of Examples 3-5 and Comparative Examples 3-6 of the present invention;

[0037] Figure 4 It is a schematic structural diagram of the anti-aging sandy land water-retaining film material of the present invention;

[0038] Among them, 1 - protective layer, 2 - base material layer, 3 - salt and alkali resistance layer. Specific Embodiments

[0039] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0040] Example 1

[0041] This example discloses a preparation method of an aerogel filler, including the following steps:

[0042] Step A1: Mix acrylic acid, acrylamide, 1,1'-azobis(cyclohexanenitrile), and ethyl acetate in a mass ratio of 25:75:0.05:650, purge with nitrogen at room temperature for 25 min, then under sealed conditions, heat to 90 °C, and stir and react at a rotation speed of 700 r / min for 12 h. The precipitate obtained from the reaction is separated by filtration, and the product is washed 4 times with ethyl acetate and dried at 60 °C for 13 h to obtain an acrylic acid-acrylamide copolymer;

[0043] Step A2: Add potassium carbonate to a 4 wt% aqueous solution of acrylic acid-acrylamide copolymer at 4 °C, stir at a rotation speed of 550 r / min at 25 °C for 13 h, then transfer to a 10 °C ice bath, and dropwise add a 6 wt% aqueous solution of citric acid at a speed of 2 mL / min. Finally, stir and react at a rotation speed of 550 r / min at 25 °C for 13 h. After the reaction is completed, circular dialysis purification treatment is carried out 5 times with a dialysis membrane with a molecular weight cut-off of 50 KD, each dialysis for 13 h. The obtained purified solution is vacuum dried at 45 °C until constant weight to obtain a modified acrylic acid-acrylamide copolymer;

[0044] Among them, the mass ratio of acrylic acid-acrylamide copolymer, citric acid, and potassium carbonate is 1:0.07:0.15;

[0045] Step A3: Under vacuum stirring conditions, maintain the temperature at 30 °C, and mix 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. Then react at 70 °C for 4 h to obtain a hydrogel. After washing the hydrogel with distilled water, freeze-dry it at -54 °C for 24 h to obtain an aerogel filler.

[0046] Example 2

[0047] This example discloses a preparation method of an organic-inorganic hybrid composite material, including the following steps:

[0048] Step B1: At room temperature, add 4.8 g of ethylthioacetamide to 20 mL of ultrapure water and stir for 30 min. Add 7.2 g of tungsten hexachloride and continue stirring and reacting for 60 min. Then add 3 g of multi-walled carbon nanotubes, ultrasonically disperse for 120 min, and react at 200 °C for 24 h in a closed environment. After the reaction, filter, and wash the obtained solid product with acetic acid and ultrapure water, and vacuum dry at 90 °C for 25 h to obtain tungsten disulfide / multi-walled carbon nanotube composite nanoparticles;

[0049] Step B2: Mix 4.5 mL of 3-mercaptopropyltrimethoxysilane, 12.5 mL of water, and 50 mL of ethanol, stir for 30 min, then add 3 g of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles, adjust the pH of the mixed system to 5.5 with acetic acid, ultrasonically treat for 120 min, and stir and react at 60 °C for 6.5 h. After the reaction is completed, filter, wash the obtained solid product with ethanol and water, and vacuum dry at 55 °C for 15 h to obtain modified composite nanoparticles;

[0050] Step B3: Add 2.5 g of modified composite nanoparticles to 40 g of ethanol, ultrasonically disperse for 30 min, heat to 65 °C, add 4.5 g of 1,5-hexadiene and 0.03 g of azobisisobutyronitrile, stir and react at a rotation speed of 300 r / min for 3.5 h. After the reaction, centrifuge 4 times at 5500 r / min, wash the centrifuged product 4 times with ethanol, and vacuum dry at 75 °C for 12 h to obtain an organic-inorganic hybrid composite material.

[0051] Example 3

[0052] This example discloses a preparation method of an aging-resistant sandy soil water retention film material, including the following steps:

[0053] 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;

[0054] 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;

[0055] 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;

[0056] 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.

[0057] Example 4

[0058] This embodiment discloses a method for preparing an aging-resistant sand water-retaining film material, comprising the following steps:

[0059] 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;

[0060] 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;

[0061] 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;

[0062] 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.

[0063] Example 5

[0064] This embodiment discloses a method for preparing an aging-resistant sand water-retaining film material, comprising the following steps:

[0065] 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;

[0066] 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;

[0067] 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;

[0068] 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.

[0069] Comparative Example 1

[0070] 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.

[0071] Comparative Example 2

[0072] 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.

[0073] Comparative Example 3

[0074] Compared with Example 5, Comparative Example 3 uses the organic-inorganic hybrid composite material prepared in Comparative Example 1, and other conditions remain unchanged.

[0075] Comparative Example 4

[0076] Compared with Example 5, Comparative Example 4 uses the organic-inorganic hybrid composite material prepared in Comparative Example 2, and other conditions remain unchanged.

[0077] Comparative Example 5

[0078] Compared with Example 5, in the base layer mixture of Comparative Example 5, modified composite nanoparticles are used instead of the organic-inorganic hybrid composite material, and other conditions remain unchanged.

[0079] Comparative Example 6

[0080] Compared with Example 5, the aging-resistant sand water-retaining film material of Comparative Example 6 does not contain a salt and alkali resistance layer, and a protective layer is used instead of the salt and alkali resistance layer, and other conditions remain unchanged.

[0081] In the above examples and comparative examples, xanthan gum, CAS No.: 11138-66-2, active ingredient content 99%, from Maoming Xiongda Chemical Co., Ltd.; dialysis membrane with a molecular weight cut-off of 50KD, product number 132542, from Zhejiang Lianshuo Biotechnology Co., Ltd.; multi-walled carbon nanotubes, inner diameter: 5-10nm, outer diameter: 10-20nm, length: 10-30μm, from Shanghai Aladdin Biochemical Technology Co., Ltd.; high-density polyethylene, grade HHM5502LW, melt flow rate 0.34g / 10min, from Shenzhen Zhengrui Plastic Co., Ltd.; linear low-density polyethylene, brand Borealis (Borouge), grade FK1828, melt flow rate 1.5g / 10min, from Shenzhen Zhengrui Plastic Co., Ltd.; metallocene polyethylene, brand Dow, grade 5538G, melt flow rate 1.3g / 10min, from Shanghai Ousuo Plastics 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, grade 18341, melt flow rate 1.5g / 10min, from Dongguan Changping Longcheng New Materials Business Department; thermoplastic polyamide elastomer, brand Arkema France, product number HHM5502LW, from Dongguan Zhengtao Plastics Co., Ltd.; polyethylene grafted glycidyl methacrylate, brand Shenghao Plastics, product number 1125AC, melting temperature 65°C, from Dongguan Zhangmutou Hengtai Plastic Raw Materials Business Department.

[0082] Experimental Example

[0083] The performance tests were carried out on the anti-aging sandy soil water retention film materials prepared in Examples 3-5 and Comparative Examples 3-6.

[0084] Test 1, falling dart impact performance: Tested according to the standard of "GB / T9639-1988 Test method for impact resistance of plastic films and sheets - Free falling dart method" and the corresponding falling dart impact strength was obtained.

[0085] Test 2, tensile property test: Tested according to the standard of "GB13022-1991 Test method for tensile properties of plastic films" and the corresponding tensile strength was obtained.

[0086] Test 3, anti-aging property test: Samples of each group of anti-aging sandy soil water retention film materials were buried in the saline-alkali sandy soil at a depth of 50 cm (the alkalinity of the saline-alkali sandy soil was 43.5%). After 30 days, they were taken out. According to the method of Test 2, the tensile strength retention rate of each group of samples was detected.

[0087] The test results are shown in Table 1:

[0088] Table 1

[0089]

[0090] It can be seen from the test results in Table 1 that the anti-aging sandy soil water retention film materials prepared in Examples 3-5 of the present invention have excellent mechanical strength, toughness and anti-saline-alkali aging performance. From the comparison between Comparative Examples 3-4 and Example 5, it can be known that the organic-inorganic hybrid composite material in the substrate layer can improve the mechanical strength and toughness of the film material. The in-situ growth of tungsten disulfide on the surface of multi-walled carbon nanotubes can improve the dispersibility and compatibility of tungsten disulfide / multi-walled carbon nanotube composite nanoparticles in the substrate layer by changing the interfacial interaction with the substrate, thereby improving the performance of the film material. From the comparison between Comparative Example 5 and Example 5, it can be known that by introducing olefin chains into the organic-inorganic hybrid composite material with 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, so as to exert a better modification effect. From the comparison between Comparative Example 6 and Example 5, it can be known that replacing the anti-saline-alkali layer with a protective layer can improve the mechanical properties of the film material, but will cause a significant decrease in the anti-saline-alkali aging performance of the film material.

[0091] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present invention, and 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 order 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. The salt-alkali resistant layer comprises 0.1-0.5 parts of aerogel filler and 100-120 parts of high-density polyethylene. The method for preparing the organic-inorganic hybrid composite material 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).

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 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.

4. The aging-resistant sand water-retaining film material according to claim 3, 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).

5. The aging-resistant sand water-retaining film material according to claim 3, 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.

6. The aging-resistant sand water-retaining film material according to claim 3, 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).

7. A method for preparing the aging-resistant sand water-retaining film material according to any one of claims 1 to 6, 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.

8. The method for preparing the aging-resistant sand water-retaining film material according to claim 7, characterized in that: In the step (1), the conditions for crushing the aerogel filler and high-density polyethylene after mixing are: crushing at a rotation speed of 20000-30000 r / min for 2-5 min.

9. The method for preparing the aging-resistant sand water-retaining film material according to claim 7, 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 of the salt-alkali resistant layer mixture, the protective layer mixture and the substrate layer mixture is 145-165° C. and the extrusion speed is 10-20 r / min.

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