Durable HDPE (High-Density Polyethylene) composite material for S-shaped filter brick and preparation method thereof

Abstract

The invention discloses a durable HDPE composite material for an S-shaped filter brick and a preparation method of the durable HDPE composite material, and relates to the technical field of HDPE composites.High-density polyethylene is used for preparing the HDPE composite material, then polyethylene grafted maleic anhydride is added for modification, and the strength of the HDPE composite material is enhanced. And a modified titanium dioxide-microsphere compound is also added, so that the strength of the HDPE composite material is enhanced, and meanwhile, the HDPE composite material is endowed with aging resistance and antibacterial property. The invention provides a preparation method of polystyrene-silicon dioxide microspheres with a large specific surface area, then the polystyrene-silicon dioxide microspheres are modified by using silver nitrate, and nano-silver is loaded on the composite microspheres, so that the antibacterial property of the microspheres is improved. The invention also discloses an antifouling coating which is sprayed on the surface of the HDPE composite material, so that the problem that the durability is reduced due to attachment of algae organisms after the filter brick is used for a long time can be relieved.

Description

Technical Field

[0001] The invention relates to the technical field of HDPE composite materials, in particular to a durable HDPE composite material for S-type filter bricks and a preparation method thereof. Background Art

[0002] Filter bricks contain countless micropores. When fluid passes through these pores, suspended matter, colloids, and macromolecular organic matter in the fluid are trapped on the surface of the filter brick. S-type filter bricks offer excellent filtration performance and are generally injection-molded from a single high-density polyethylene (HDPE). Although HDPE itself exhibits excellent acid, alkali, and low-temperature resistance, it can exhibit surface pulverization, embrittlement, and cracking with long-term use, making it less durable.

[0003] In order to solve the above problems and improve the durability of filter bricks, the present application provides a durable HDPE composite material for S-type filter bricks and a preparation method thereof. Summary of the Invention

[0004] The object of the present invention is to provide a durable HDPE composite material for S-type filter bricks and a preparation method thereof, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a durable HDPE composite material for S-type filter bricks comprises the following steps:

[0007] Step 1: Take high-density polyethylene, polyethylene grafted maleic anhydride, liquid paraffin, modified titanium dioxide-microsphere composite, antioxidant, and light stabilizer, stir for 3-5 minutes, extrude granulate, and injection mold to obtain HDPE composite material;

[0008] Step 2: Take polymethacrylate sulfobetaine and deionized water, stir for 1-2 hours to obtain a polymethacrylate sulfobetaine solution; stir 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, polymethacrylate sulfobetaine solution, Tris buffer, and thioglycolic acid to obtain a mixed solution; add N-hydroxysuccinimide, dopamine hydrochloride, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and Tris buffer, stir evenly, add the mixed solution, and stir for 30-40 minutes to obtain an antifouling coating;

[0009] Step 3: Take the HDPE composite material, spray the antifouling coating on the surface of the HDPE composite material, and UV-curing for 30-40 minutes to obtain a durable HDPE composite material for S-type filter bricks.

[0010] More optimally, the HDPE composite material comprises the following components, by weight: 100-115 parts of high-density polyethylene, 4-6 parts of polyethylene grafted maleic anhydride, 5-7 parts of liquid paraffin, 10-15 parts of modified titanium dioxide-microsphere composite, 0.6-0.7 parts of light stabilizer, and 0.2-0.4 parts of antioxidant.

[0011] More optimally, the light stabilizer is 2,4-dihydroxybenzophenone.

[0012] More optimally, the antioxidant is any one of tris(2,4-di-tert-butylphenyl)phosphite and bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite.

[0013] More optimally, the preparation method of the modified titanium dioxide-microsphere composite comprises the following steps:

[0014] S1: Titanium dioxide, Tween 20, and ethyl acetate are ultrasonically dispersed to obtain a titanium dioxide dispersion; composite microspheres loaded with nanosilver, Tween 20, perchloric acid, and ethyl acetate are stirred evenly, heated to 75-80°C, and the titanium dioxide dispersion is added. The mixture is reacted for 3-4 hours, filtered, washed, and dried to obtain a titanium dioxide-microsphere composite.

[0015] S2: Take azobisisobutyronitrile and xylene, stir evenly to obtain an azobisisobutyronitrile solution; take maleic anhydride, titanium dioxide-microsphere composite, vinyltrimethoxysilane, and xylene, stir evenly, heat to 80-82°C, add azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2-3 hours, add acetone dropwise, react for 30-40 minutes, filter, wash, and dry to obtain a modified titanium dioxide-microsphere composite.

[0016] More optimally, the preparation method of the nanosilver-loaded composite microspheres is as follows: take n-butylamine and anhydrous ethanol, stir evenly to obtain an n-butylamine solution; take polystyrene-silica microspheres and anhydrous ethanol, mix evenly, add silver nitrate, stir for 3-4 hours, add n-butylamine solution, heat to 50-55°C, react for 2-3 hours, centrifuge, wash, and dry to obtain nanosilver-loaded composite microspheres.

[0017] More optimally, the preparation method of the polystyrene-silica microspheres is as follows: take tetraethyl orthosilicate and ethanol, stir evenly to obtain a tetraethyl orthosilicate solution; take deionized water and ethanol, stir evenly, add polystyrene microspheres, ultrasonically disperse, add ammonia water, heat to 48-52°C, inject the tetraethyl orthosilicate solution, react for 5-6 hours, centrifuge, wash, and dry to obtain polystyrene-silica microspheres.

[0018] More optimally, the preparation method of the polystyrene-silica microspheres is: potassium persulfate and deionized water are mixed evenly to obtain a potassium persulfate solution; styrene, acrylic acid, potassium chloride, and deionized water are mixed evenly, heated to 75-78° C. under nitrogen protection, reacted for 15-20 minutes, and then the potassium persulfate solution is added, stirred evenly, kept warm for 10-12 hours, centrifuged, washed, and dried to obtain polystyrene microspheres.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention uses high-density polyethylene (HDPE) to prepare a composite material. This material is then modified by adding polyethylene grafted with maleic anhydride to enhance the strength of the HDPE composite material. A modified titanium dioxide-microsphere composite is also added to enhance the strength of the HDPE composite material while also imparting aging resistance and antibacterial properties.

[0021] 2. The present invention provides a method for preparing polystyrene-silica microspheres with a large specific surface area. These microspheres are then modified with silver nitrate to load nanosilver onto the composite microspheres, enhancing their antibacterial properties. The composite microspheres are then composited with titanium dioxide to improve the strength and aging resistance of the titanium dioxide-microsphere composite. Maleic anhydride modification enhances the compatibility of the modified titanium dioxide-microsphere composite in polyethylene, thereby improving its mechanical properties.

[0022] 3. The present invention also prepares an antifouling coating that, when sprayed on the surface of an HDPE composite material, can alleviate the problem of decreased durability of filter bricks caused by algae adhesion after long-term use. The addition of polydopamine to the antifouling coating enhances its adhesion to the HDPE composite surface, while the addition of polymethacrylate sulfobetaine improves water flow through the filter brick. The addition of thioglycolic acid promotes cross-linking and increases the coating density, resulting in excellent durability of the durable HDPE composite material for S-type filter bricks. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0024] The sources and models of the substances involved in the present invention are not particularly limited, and illustratively include: high-density polyethylene: purchased from LG Chem, model: BE0400; polyethylene grafted maleic anhydride: purchased from DuPont, USA, model: E589; titanium dioxide: particle size 5-30 nm, purchased from Shanghai Huijing Sub-Nano New Materials Co., Ltd.; polystyrene microspheres: purchased from MacLean Reagent, model: L815936.

[0025] Example 1: A method for preparing a durable HDPE composite material for S-type filter bricks, comprising the following steps:

[0026] Step 1: Preparation of polystyrene-silica microspheres:

[0027] 0.4 g of potassium persulfate and 10 mL of deionized water were mixed uniformly to obtain a potassium persulfate solution; 16 mL of styrene, 4 mL of acrylic acid, 0.4 g of potassium chloride, and 320 mL of deionized water were mixed uniformly, and under nitrogen protection, the temperature was raised to 76°C. After reacting for 17 minutes, the potassium persulfate solution was added, stirred uniformly, and kept warm for 11 hours. The mixture was centrifuged, washed, and dried to obtain polystyrene microspheres;

[0028] Take 6 mL of tetraethyl orthosilicate and 14 mL of ethanol, stir evenly to obtain a tetraethyl orthosilicate solution; take 20 mL of deionized water and 180 mL of ethanol, stir evenly, add 2.5 g of polystyrene microspheres, ultrasonically disperse, add 3 mL of ammonia water, heat to 50°C, inject the tetraethyl orthosilicate solution, react for 5.5 hours, centrifuge, wash, and dry to obtain polystyrene-silica microspheres;

[0029] Step 2: Preparation of composite microspheres loaded with nanosilver:

[0030] Take 0.6 mL of n-butylamine and 5 mL of anhydrous ethanol, stir evenly to obtain an n-butylamine solution; take 0.2 g of polystyrene-silica microspheres and 100 mL of anhydrous ethanol, mix evenly, add 1 g of silver nitrate, stir for 3.5 hours, add the n-butylamine solution, heat to 52°C, react for 2.5 hours, centrifuge, wash, and dry to obtain composite microspheres loaded with nanosilver;

[0031] Step 3: Preparation of titanium dioxide-microsphere composite:

[0032] Take 2g of titanium dioxide, 0.1g of Tween20, and 50mL of ethyl acetate, and ultrasonically disperse them to obtain a titanium dioxide dispersion. Take nanosilver-loaded composite microspheres, 0.5g of Tween20, 0.2g of perchloric acid, and 200mL of ethyl acetate, stir evenly, heat to 78°C, add the titanium dioxide dispersion, react for 3.5h, filter, wash, and dry to obtain a titanium dioxide-microsphere composite.

[0033] Step 4: Preparation of modified titanium dioxide-microsphere composite:

[0034] Take 1.8 g of azobisisobutyronitrile and 10 mL of xylene, stir evenly to obtain an azobisisobutyronitrile solution; take 6 g of maleic anhydride, 10 g of titanium dioxide-microsphere composite, 3 g of vinyltrimethoxysilane, and 150 mL of xylene, stir evenly, heat to 81°C, add the azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2.5 hours, add 50 mL of acetone dropwise, react for 35 minutes, filter, wash, and dry to obtain a modified titanium dioxide-microsphere composite;

[0035] Step 5: Preparation of antifouling coating:

[0036] 10 g of polymethacrylate sulfobetaine and 50 mL of deionized water were stirred for 1.5 h to obtain a polymethacrylate sulfobetaine solution; 0.4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 20 g of polymethacrylate sulfobetaine solution, 50 g of Tris buffer, and 4 g of thioglycolic acid were stirred to obtain a mixed solution; 0.3 g of N-hydroxysuccinimide, 2 g of dopamine hydrochloride, 0.1 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 10 mL of Tris buffer were added, stirred to obtain an antifouling coating;

[0037] Step 6: Preparation of durable HDPE composite material for S-type filter bricks:

[0038] High-density polyethylene, polyethylene grafted maleic anhydride, liquid paraffin, modified titanium dioxide-microsphere composite, antioxidant, and light stabilizer were stirred for 4 minutes, extruded into granules, and injection molded to obtain a HDPE composite material;

[0039] Take a HDPE composite material, spray the antifouling coating on the surface of the HDPE composite material to a coating thickness of 0.1 mm, and UV-curing for 35 minutes to obtain a durable HDPE composite material for S-type filter bricks;

[0040] The HDPE composite material includes the following components, by weight: 112 parts of high-density polyethylene, 5 parts of polyethylene grafted maleic anhydride, 6 parts of liquid paraffin, 12 parts of modified titanium dioxide-microsphere composite, 0.65 parts of light stabilizer, and 0.3 parts of antioxidant; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, and the light stabilizer is 2,4-dihydroxybenzophenone.

[0041] Example 2: A method for preparing a durable HDPE composite material for S-type filter bricks, comprising the following steps:

[0042] Step 1: Preparation of polystyrene-silica microspheres:

[0043] 0.4 g of potassium persulfate and 10 mL of deionized water were mixed uniformly to obtain a potassium persulfate solution; 16 mL of styrene, 4 mL of acrylic acid, 0.4 g of potassium chloride, and 320 mL of deionized water were mixed uniformly, and under nitrogen protection, the temperature was raised to 75°C, and the reaction was carried out for 15 minutes. The potassium persulfate solution was then added, stirred uniformly, and kept warm for 10 hours. The mixture was centrifuged, washed, and dried to obtain polystyrene microspheres;

[0044] Take 6 mL of tetraethyl orthosilicate and 14 mL of ethanol, stir evenly to obtain a tetraethyl orthosilicate solution; take 20 mL of deionized water and 180 mL of ethanol, stir evenly, add 2.5 g of polystyrene microspheres, ultrasonically disperse, add 3 mL of ammonia water, heat to 48°C, inject the tetraethyl orthosilicate solution, react for 5 hours, centrifuge, wash, and dry to obtain polystyrene-silica microspheres;

[0045] Step 2: Preparation of composite microspheres loaded with nanosilver:

[0046] Take 0.6 mL of n-butylamine and 5 mL of anhydrous ethanol, stir evenly to obtain an n-butylamine solution; take 0.2 g of polystyrene-silica microspheres and 100 mL of anhydrous ethanol, mix evenly, add 1 g of silver nitrate, stir for 3 hours, add the n-butylamine solution, heat to 50°C, react for 2 hours, centrifuge, wash, and dry to obtain composite microspheres loaded with nanosilver;

[0047] Step 3: Preparation of titanium dioxide-microsphere composite:

[0048] Take 2g of titanium dioxide, 0.1g of Tween20, and 50mL of ethyl acetate, and ultrasonically disperse them to obtain a titanium dioxide dispersion; take composite microspheres loaded with nanosilver, 0.5g of Tween20, 0.2g of perchloric acid, and 200mL of ethyl acetate, stir evenly, heat to 75°C, add the titanium dioxide dispersion, react for 3h, filter, wash, and dry to obtain a titanium dioxide-microsphere composite;

[0049] Step 4: Preparation of modified titanium dioxide-microsphere composite:

[0050] Take 1.8 g of azobisisobutyronitrile and 10 mL of xylene, stir evenly to obtain an azobisisobutyronitrile solution; take 6 g of maleic anhydride, 10 g of titanium dioxide-microsphere composite, 3 g of vinyltrimethoxysilane, and 150 mL of xylene, stir evenly, heat to 80°C, add the azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2 h, add 50 mL of acetone dropwise, react for 30 min, filter, wash, and dry to obtain a modified titanium dioxide-microsphere composite;

[0051] Step 5: Preparation of antifouling coating:

[0052] 10 g of polymethacrylate sulfobetaine and 50 mL of deionized water were stirred for 1 h to obtain a polymethacrylate sulfobetaine solution; 0.4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 20 g of polymethacrylate sulfobetaine solution, 50 g of Tris buffer, and 4 g of thioglycolic acid were stirred to obtain a mixed solution; 0.3 g of N-hydroxysuccinimide, 2 g of dopamine hydrochloride, 0.1 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 10 mL of Tris buffer were added, stirred to obtain an antifouling coating;

[0053] Step 6: Preparation of durable HDPE composite material for S-type filter bricks:

[0054] High-density polyethylene, polyethylene grafted maleic anhydride, liquid paraffin, modified titanium dioxide-microsphere composite, antioxidant, and light stabilizer were stirred for 3 minutes, extruded into granules, and injection molded to obtain a HDPE composite material;

[0055] Take a HDPE composite material, spray the antifouling coating on the surface of the HDPE composite material to a coating thickness of 0.1 mm, and UV-curing for 30 minutes to obtain a durable HDPE composite material for S-type filter bricks;

[0056] The HDPE composite material includes the following components, by weight: 100 parts of high-density polyethylene, 4 parts of polyethylene grafted maleic anhydride, 5 parts of liquid paraffin, 10 parts of modified titanium dioxide-microsphere composite, 0.6 parts of light stabilizer, and 0.2 parts of antioxidant; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, and the light stabilizer is 2,4-dihydroxybenzophenone.

[0057] Example 3: A method for preparing a durable HDPE composite material for S-type filter bricks, comprising the following steps:

[0058] Step 1: Preparation of polystyrene-silica microspheres:

[0059] 0.4 g of potassium persulfate and 10 mL of deionized water were mixed uniformly to obtain a potassium persulfate solution; 16 mL of styrene, 4 mL of acrylic acid, 0.4 g of potassium chloride, and 320 mL of deionized water were mixed uniformly, and under nitrogen protection, the temperature was raised to 78°C, and the reaction was carried out for 20 minutes. The potassium persulfate solution was then added, stirred uniformly, and kept warm for 12 hours. The mixture was centrifuged, washed, and dried to obtain polystyrene microspheres;

[0060] Take 6 mL of tetraethyl orthosilicate and 14 mL of ethanol, stir evenly to obtain a tetraethyl orthosilicate solution; take 20 mL of deionized water and 180 mL of ethanol, stir evenly, add 2.5 g of polystyrene microspheres, ultrasonically disperse, add 3 mL of ammonia water, heat to 52°C, inject the tetraethyl orthosilicate solution, react for 6 hours, centrifuge, wash, and dry to obtain polystyrene-silica microspheres;

[0061] Step 2: Preparation of composite microspheres loaded with nanosilver:

[0062] Take 0.6 mL of n-butylamine and 5 mL of anhydrous ethanol, stir evenly to obtain an n-butylamine solution; take 0.2 g of polystyrene-silica microspheres and 100 mL of anhydrous ethanol, mix evenly, add 1 g of silver nitrate, stir for 4 hours, add the n-butylamine solution, heat to 55°C, react for 3 hours, centrifuge, wash, and dry to obtain composite microspheres loaded with nanosilver;

[0063] Step 3: Preparation of titanium dioxide-microsphere composite:

[0064] Take 2g of titanium dioxide, 0.1g of Tween20, and 50mL of ethyl acetate, and ultrasonically disperse them to obtain a titanium dioxide dispersion; take composite microspheres loaded with nanosilver, 0.5g of Tween20, 0.2g of perchloric acid, and 200mL of ethyl acetate, stir evenly, heat to 80°C, add the titanium dioxide dispersion, react for 4h, filter, wash, and dry to obtain a titanium dioxide-microsphere composite;

[0065] Step 4: Preparation of modified titanium dioxide-microsphere composite:

[0066] Take 1.8 g of azobisisobutyronitrile and 10 mL of xylene, stir evenly to obtain an azobisisobutyronitrile solution; take 6 g of maleic anhydride, 10 g of titanium dioxide-microsphere composite, 3 g of vinyltrimethoxysilane, and 150 mL of xylene, stir evenly, heat to 82°C, add the azobisisobutyronitrile solution dropwise under nitrogen protection, react for 3 hours, add 50 mL of acetone dropwise, react for 40 minutes, filter, wash, and dry to obtain a modified titanium dioxide-microsphere composite;

[0067] Step 5: Preparation of antifouling coating:

[0068] 10 g of polymethacrylate sulfobetaine and 50 mL of deionized water were stirred for 2 h to obtain a polymethacrylate sulfobetaine solution; 0.4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 20 g of polymethacrylate sulfobetaine solution, 50 g of Tris buffer, and 4 g of thioglycolic acid were stirred to obtain a mixed solution; 0.3 g of N-hydroxysuccinimide, 2 g of dopamine hydrochloride, 0.1 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 10 mL of Tris buffer were added, stirred to obtain an antifouling coating;

[0069] Step 6: Preparation of durable HDPE composite material for S-type filter bricks:

[0070] High-density polyethylene, polyethylene grafted maleic anhydride, liquid paraffin, modified titanium dioxide-microsphere composite, antioxidant, and light stabilizer were stirred for 5 minutes, extruded into granules, and injection molded to obtain a HDPE composite material;

[0071] Take a HDPE composite material, spray the antifouling coating on the surface of the HDPE composite material to a coating thickness of 0.1 mm, and UV-curing for 40 minutes to obtain a durable HDPE composite material for S-type filter bricks;

[0072] The HDPE composite material includes the following components, by weight: 115 parts of high-density polyethylene, 6 parts of polyethylene grafted maleic anhydride, 7 parts of liquid paraffin, 15 parts of modified titanium dioxide-microsphere composite, 0.7 parts of light stabilizer, and 0.4 parts of antioxidant; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, and the light stabilizer is 2,4-dihydroxybenzophenone.

[0073] Comparative Example 1: No titanium dioxide was added, and the rest was the same as in Example 1:

[0074] Step 1: Preparation of polystyrene-silica microspheres:

[0075] 0.4 g of potassium persulfate and 10 mL of deionized water were mixed uniformly to obtain a potassium persulfate solution; 16 mL of styrene, 4 mL of acrylic acid, 0.4 g of potassium chloride, and 320 mL of deionized water were mixed uniformly, and under nitrogen protection, the temperature was raised to 76°C. After reacting for 17 minutes, the potassium persulfate solution was added, stirred uniformly, and kept warm for 11 hours. The mixture was centrifuged, washed, and dried to obtain polystyrene microspheres;

[0076] Take 6 mL of tetraethyl orthosilicate and 14 mL of ethanol, stir evenly to obtain a tetraethyl orthosilicate solution; take 20 mL of deionized water and 180 mL of ethanol, stir evenly, add 2.5 g of polystyrene microspheres, ultrasonically disperse, add 3 mL of ammonia water, heat to 50°C, inject the tetraethyl orthosilicate solution, react for 5.5 hours, centrifuge, wash, and dry to obtain polystyrene-silica microspheres;

[0077] Step 2: Preparation of composite microspheres loaded with nanosilver:

[0078] Take 0.6 mL of n-butylamine and 5 mL of anhydrous ethanol, stir evenly to obtain an n-butylamine solution; take 0.2 g of polystyrene-silica microspheres and 100 mL of anhydrous ethanol, mix evenly, add 1 g of silver nitrate, stir for 3.5 hours, add the n-butylamine solution, heat to 52°C, react for 2.5 hours, centrifuge, wash, and dry to obtain composite microspheres loaded with nanosilver;

[0079] Step 3: Preparation of microsphere complex:

[0080] Take 1.8 g of azobisisobutyronitrile and 10 mL of xylene, stir evenly to obtain an azobisisobutyronitrile solution; take 6 g of maleic anhydride, 10 g of nanosilver-loaded composite microspheres, 3 g of vinyltrimethoxysilane, and 150 mL of xylene, stir evenly, heat to 81°C, add the azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2.5 hours, add 50 mL of acetone dropwise, react for 35 minutes, filter, wash, and dry to obtain a microsphere composite;

[0081] Step 4: Preparation of antifouling coating:

[0082] 10 g of polymethacrylate sulfobetaine and 50 mL of deionized water were stirred for 1.5 h to obtain a polymethacrylate sulfobetaine solution; 0.4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 20 g of polymethacrylate sulfobetaine solution, 50 g of Tris buffer, and 4 g of thioglycolic acid were stirred to obtain a mixed solution; 0.3 g of N-hydroxysuccinimide, 2 g of dopamine hydrochloride, 0.1 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 10 mL of Tris buffer were added, stirred to obtain an antifouling coating;

[0083] Step 5: Preparation of durable HDPE composite material for S-type filter bricks:

[0084] High-density polyethylene, polyethylene grafted maleic anhydride, liquid paraffin, microsphere compound, antioxidant, and light stabilizer were stirred for 4 minutes, extruded into granules, and injection molded to obtain a HDPE composite material;

[0085] Take a HDPE composite material, spray the antifouling coating on the surface of the HDPE composite material to a coating thickness of 0.1 mm, and UV-curing for 35 minutes to obtain a durable HDPE composite material for S-type filter bricks;

[0086] The HDPE composite material includes the following components, by weight: 112 parts of high-density polyethylene, 5 parts of polyethylene grafted maleic anhydride, 6 parts of liquid paraffin, 12 parts of microsphere composite, 0.65 parts of light stabilizer, and 0.3 parts of antioxidant; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, and the light stabilizer is 2,4-dihydroxybenzophenone.

[0087] Comparative Example 2: No maleic anhydride-modified microspheres were used, and the rest was the same as in Example 1:

[0088] Step 4: Preparation of modified titanium dioxide-microsphere composite:

[0089] Take 1.8 g of azobisisobutyronitrile and 10 mL of xylene, stir evenly to obtain an azobisisobutyronitrile solution; take 10 g of titanium dioxide-microsphere complex, 3 g of vinyltrimethoxysilane, and 150 mL of xylene, stir evenly, heat to 81°C, add azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2.5 hours, add 50 mL of acetone dropwise, react for 35 minutes, filter, wash, and dry to obtain a modified titanium dioxide-microsphere complex.

[0090] Comparative Example 3: No thioglycolic acid was added, and the rest was the same as in Example 1:

[0091] Step 5: Preparation of antifouling coating:

[0092] 10 g of polymethacrylate sulfobetaine and 50 mL of deionized water were stirred for 1.5 h to obtain a polymethacrylate sulfobetaine solution; 0.4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 20 g of polymethacrylate sulfobetaine solution, and 50 g of Tris buffer were stirred uniformly to obtain a mixed solution; 0.3 g of N-hydroxysuccinimide, 2 g of dopamine hydrochloride, 0.1 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 10 mL of Tris buffer were added, stirred uniformly, and the mixed solution was added and stirred for 35 min to obtain an antifouling coating.

[0093] Comparative Example 4: Polystyrene microspheres were used instead of polystyrene-silica microspheres, and the rest was the same as in Example 1:

[0094] Step 2: Preparation of composite microspheres loaded with nanosilver:

[0095] Take 0.6 mL of n-butylamine and 5 mL of anhydrous ethanol, stir evenly to obtain an n-butylamine solution; take 0.2 g of polystyrene microspheres and 100 mL of anhydrous ethanol, mix evenly, add 1 g of silver nitrate, stir for 3.5 hours, add n-butylamine solution, heat to 52°C, react for 2.5 hours, centrifuge, wash, and dry to obtain composite microspheres loaded with nanosilver;

[0096] Step 3: Preparation of titanium dioxide-microsphere composite:

[0097] Take 2g of titanium dioxide, 0.1g of Tween20, and 50mL of ethyl acetate, and ultrasonically disperse them to obtain a titanium dioxide dispersion. Take nanosilver-loaded composite microspheres, 0.5g of Tween20, 0.2g of perchloric acid, and 200mL of ethyl acetate, stir evenly, heat to 78°C, add the titanium dioxide dispersion, react for 3.5h, filter, wash, and dry to obtain a titanium dioxide-microsphere composite.

[0098] Step 4: Preparation of modified titanium dioxide-microsphere composite:

[0099] Take 1.8 g of azobisisobutyronitrile and 10 mL of xylene, stir evenly to obtain an azobisisobutyronitrile solution; take 6 g of maleic anhydride, 10 g of titanium dioxide-microsphere composite, 3 g of vinyltrimethoxysilane, and 150 mL of xylene, stir evenly, heat to 81 ° C, add azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2.5 hours, add 50 mL of acetone dropwise, react for 35 minutes, filter, wash, and dry to obtain a modified titanium dioxide-microsphere composite.

[0100] experiment:

[0101] The durable HDPE composite materials for S-type filter bricks prepared in Examples 1-3 and Comparative Examples 1-4 were used for performance testing. Referring to ISO 179-1, the durable HDPE composite materials for S-type filter bricks were made into 80 mm × 10 mm × 4 mm test pieces, and the impact strength of the test pieces was tested at a pendulum energy of 15 J. The durable HDPE composite materials for S-type filter bricks were immersed in a culture solution of the same concentration of Phaeophyceae for 14 days, and the surface condition of the materials was observed to characterize their anti-fouling performance. The data obtained are shown in Table 1 below:

[0102] Table 1

[0103] <![CDATA[Impact strength kJ / m 2 > Stain resistance Example 1 52 No surface damage, no algae attached Example 2 51 No surface damage, no algae attached Example 3 54 No surface damage, no algae attached Comparative Example 1 41 No surface damage, no algae attached Comparative Example 2 43 No surface damage, no algae attached Comparative Example 3 51 The surface is not damaged, but there is a small amount of algae attached Comparative Example 4 46 No surface damage, no algae attached

[0104] Conclusion: From the comparison of the data in the table, it can be seen that in Comparative Example 1, titanium dioxide is not added, and the strength of the durable HDPE composite material for filter bricks is reduced. In Comparative Example 2, maleic anhydride-modified microspheres are not used, and the compatibility of the modified titanium dioxide-microsphere composite in polyethylene is poor, which affects its mechanical properties, and the impact strength of the durable HDPE composite material for filter bricks is reduced. In Comparative Example 3, thioglycolic acid is not added, the cross-linking density of the coating is reduced, and the durable antifouling property is reduced. The durable HDPE composite material for S-type filter bricks is immersed in the culture solution of the same concentration of triangular brown algae for 14 days, and a small amount of algae is attached to the surface. In Comparative Example 4, polystyrene microspheres are used instead of polystyrene-silica microspheres, and the strength of the durable HDPE composite material for filter bricks is reduced. Examples 1-3 of the present invention provide a method for preparing polystyrene-silica microspheres with a large specific surface area, which are compounded with titanium dioxide to improve the strength and aging resistance of the titanium dioxide-microsphere composite. Maleic anhydride modification was used to enhance the compatibility of the modified titanium dioxide-microsphere composite in polyethylene, thereby improving its mechanical properties.

[0105] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a durable HDPE composite material for S-type filter bricks, characterized by: The following steps are involved: Step 1: Take high-density polyethylene, polyethylene grafted maleic anhydride, liquid paraffin, modified titanium dioxide-microsphere composite, antioxidant, and light stabilizer, stir for 3-5 minutes, extrude granulate, and injection mold to obtain HDPE composite material; Step 2: Take polymethacrylate sulfobetaine and deionized water, stir for 1-2 hours to obtain a polymethacrylate sulfobetaine solution; stir 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, polymethacrylate sulfobetaine solution, Tris buffer, and thioglycolic acid to obtain a mixed solution; add N-hydroxysuccinimide, dopamine hydrochloride, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and Tris buffer, stir evenly, add the mixed solution, and stir for 30-40 minutes to obtain an antifouling coating; Step 3: Take the HDPE composite material, spray the antifouling coating on the surface of the HDPE composite material, and UV-curing for 30-40 minutes to obtain a durable HDPE composite material for S-type filter bricks.

2. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 1, characterized in that: The HDPE composite material comprises the following components by weight: 100-115 parts of high-density polyethylene, 4-6 parts of polyethylene grafted maleic anhydride, 5-7 parts of liquid paraffin, 10-15 parts of modified titanium dioxide-microsphere composite, 0.6-0.7 parts of light stabilizer, and 0.2-0.4 parts of antioxidant.

3. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 1, characterized in that: The light stabilizer is 2,4-dihydroxybenzophenone.

4. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 1, characterized in that: The antioxidant is any one of tris(2,4-di-tert-butylphenyl)phosphite and bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite.

5. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 2, characterized in that: The preparation method of the modified titanium dioxide-microsphere composite is: The following steps are involved: S1: Titanium dioxide, Tween 20, and ethyl acetate are ultrasonically dispersed to obtain a titanium dioxide dispersion; composite microspheres loaded with nanosilver, Tween 20, perchloric acid, and ethyl acetate are stirred evenly, heated to 75-80°C, and the titanium dioxide dispersion is added. The mixture is reacted for 3-4 hours, filtered, washed, and dried to obtain a titanium dioxide-microsphere composite. S2: Take azobisisobutyronitrile and xylene, stir evenly to obtain an azobisisobutyronitrile solution; take maleic anhydride, titanium dioxide-microsphere composite, vinyltrimethoxysilane, and xylene, stir evenly, heat to 80-82°C, add azobisisobutyronitrile solution dropwise under nitrogen protection, react for 2-3 hours, add acetone dropwise, react for 30-40 minutes, filter, wash, and dry to obtain a modified titanium dioxide-microsphere composite.

6. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 5, characterized in that: The preparation method of the nanosilver-loaded composite microspheres comprises the following steps: taking n-butylamine and anhydrous ethanol, stirring evenly to obtain an n-butylamine solution; taking polystyrene-silica microspheres and anhydrous ethanol, mixing evenly, adding silver nitrate, stirring for 3-4 hours, adding the n-butylamine solution, heating to 50-55° C., reacting for 2-3 hours, centrifuging, washing, and drying to obtain the nanosilver-loaded composite microspheres.

7. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 6, characterized in that: The preparation method of the polystyrene-silica microspheres comprises the following steps: taking tetraethyl orthosilicate and ethanol, stirring evenly to obtain a tetraethyl orthosilicate solution; taking deionized water and ethanol, stirring evenly, adding polystyrene microspheres, ultrasonically dispersing, adding ammonia water, heating to 48-52° C., injecting the tetraethyl orthosilicate solution, reacting for 5-6 hours, centrifuging, washing, and drying to obtain the polystyrene-silica microspheres.

8. The method for preparing a durable HDPE composite material for S-type filter brick according to claim 7, characterized in that: The preparation method of the polystyrene-silica microspheres comprises: taking potassium persulfate and deionized water, mixing them evenly to obtain a potassium persulfate solution; taking styrene, acrylic acid, potassium chloride, and deionized water, mixing them evenly, heating to 75-78° C. under nitrogen protection, reacting for 15-20 minutes, adding the potassium persulfate solution, stirring evenly, keeping the temperature for 10-12 hours, centrifuging, washing, and drying to obtain polystyrene microspheres.

9. The durable HDPE composite material for S-type filter brick prepared according to the method for preparing a durable HDPE composite material for S-type filter brick according to any one of claims 1 to 8.