Self-supplementing slow-release hydrogel and preparation method thereof

Abstract

The invention discloses self-supplementing slow-release hydrogel and a preparation method thereof, and belongs to the technical field of underwater drag reduction. The preparation method comprises the following steps: mixing granulated sugar particles, anti-drag high polymer solid particles and a granulated sugar concentrated solution, pressing into a blocky structure by using a forming machine, and drying to obtain the polymer cube sugar; coating the lateral circumferential surface of the polymer cube sugar with an organic silicon precursor without immersing the top surface of the polymer cube sugar, and curing after vacuum degassing treatment to obtain an organic silicon layer; swelling the organic silicon layer to obtain an organic silicon substrate with improved surface performance; and placing the hydrogel pre-polymerization liquid containing the drag-reducing high polymer on an organic silicon substrate, so that the top surface of the polymer cube sugar is completely covered by the hydrogel pre-polymerization liquid, and curing to obtain the self-supplementing slow-release hydrogel. The durability and environmental protection property of the drag reducer are improved, and the preparation method is low in cost and can be popularized and applied.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater drag reduction, and in particular relates to a self-supplementing sustained-release hydrogel and a preparation method thereof. Background Art

[0002] Since Toms discovered the drag reduction effect, polymer drag reduction has always attracted the attention of scholars. Over the past few decades, a large number of studies have shown that polymer solutions of a certain concentration have excellent drag reduction capabilities. However, polymer drag reduction currently requires external force to be injected in order to work in the outflow, so many scholars add polymers to the drag reduction coating in order to use the released polymers for drag reduction. However, the polymers added in advance often cause the polymer carrying amount in the coating to be seriously insufficient due to the configuration of the solution, and the polymer release time is short; at the same time, after long-term use, the surface coating is easily lost due to water scouring, friction or biological attachment, resulting in a decrease in the drag reduction effect.

[0003] The currently disclosed use of polymer solutions to prepare hydrogel surfaces that can slowly release polymers has a 10% speed-up effect. However, it has no effect on the duration. The concentration of the polymer solution used in this technology is 1%. Theoretically, if there is no polymer supplementation, after a period of time, the polymer is completely released and the drag reduction effect fails. The polymer coating release technology disclosed in the prior art, but due to the solubility of polyvinyl pyrrolidone, its duration in water is less than half an hour, and there are serious deficiencies in sustained release. The preparation method of high-strength anti-fouling and drag-reducing hydrogel soft coating disclosed in the prior art, after forming a flexible first network hydrogel on the surface of the substrate, introduces a rigid zwitterionic polymer chain, which is placed in water until swelling equilibrium is reached. The chemical bonding method on this basis will obtain a lower concentration by swelling in the hydrogel, and the drag reduction durability in the external flow field is insufficient.

[0004] Therefore, the related drag reduction technologies that have been disclosed have only improved the speed-increasing effect, and there has not been a significant improvement in the duration of drag reducer release. Further improvements are needed in terms of durability, environmental protection, cost and other issues. Summary of the invention

[0005] Technical issues to be solved: In order to avoid the shortcomings of the prior art, the present invention provides a self-replenishing sustained-release hydrogel and a preparation method thereof. The hydrogel is formed by coupling an organic silicon layer and a hydrogel layer. A polymer sugar cube is arranged in the organic silicon layer as a storage unit for a drag-reducing polymer. The drag-reducing polymer in the polymer sugar cube is released by inducing water in the hydrogel, thereby achieving self-replenishment of the drag-reducing polymer, improving the durability and environmental protection of the drag reducer, and the preparation method has low cost and can be widely used.

[0006] A technical solution of the present invention is: a method for preparing a self-replenishing sustained-release hydrogel, the specific steps are as follows: The granulated sugar particles, the drag-reducing polymer solid particles and the granulated sugar concentrated solution are mixed, pressed into a block structure using a molding machine, and dried to obtain a polymer sugar cube; The organosilicon precursor is coated on the lateral peripheral surface of the polymer sugar cube without immersing the top surface thereof, and is cured after vacuum degassing to obtain an organosilicon layer; Swelling the organic silicon layer to obtain an organic silicon substrate with improved surface properties; A hydrogel prepolymer containing a drag-reducing polymer is placed on an organic silicon substrate so that the top surface of the polymer sugar cube is completely covered by the hydrogel prepolymer, and a self-replenishing sustained-release hydrogel is obtained after curing.

[0007] A further technical solution of the present invention is that the particle size of the granulated sugar particles is 0.5 to 2 mm, and the mass ratio of the granulated sugar particles to the drag-reducing polymer solid particles is 1 to 5:1.

[0008] A further technical solution of the present invention is: the concentration of the concentrated sugar solution is 50-65%, and the mass ratio of the concentrated sugar solution to the sugar granules is 1:100-10.

[0009] A further technical solution of the present invention is: the preparation method of the organosilicon precursor is: polydimethylsiloxane, a curing agent, and a diluent are mixed and stirred sufficiently to obtain the organosilicon precursor; The mass ratio of the polydimethylsiloxane to the curing agent is 5 to 8:1; The diluent is an alkane with a carbon atomic weight between 4 and 10; The mass ratio of the diluent to polydimethylsiloxane is 1:1-5.

[0010] A further technical solution of the present invention is: the specific operation of the vacuum degassing is to place the organosilicon precursor containing polymer sugar cubes in a vacuum box, and set the process parameters as: maintaining a pressure of -0.1 MPa for 20 to 30 minutes.

[0011] A further technical solution of the present invention is: the preparation method of the hydrogel prepolymer solution is: acrylic acid, acrylamide, ‌N,N'-methylenebisacrylamide, potassium persulfate, and polymer solution are mixed, and the hydrogel prepolymer solution is obtained after sufficient stirring; The mass ratio of acrylic acid to acrylamide is 9:1-21; The mass fraction of the N,N'-methylenebisacrylamide in the hydrogel prepolymer solute is 2% to 5%; The mass fraction of potassium persulfate in the hydrogel prepolymer solution solute is 1-2‰; The mass ratio of the polymer solution to the hydrogel prepolymer solution solute is 4 to 5:1; The polymer in the polymer solution is a drag-reducing polymer with a concentration of 100 to 500 ppm.

[0012] A further technical solution of the present invention is that the drag-reducing polymer is one or a mixture of polyethylene oxide, polyacrylamide, biopolysaccharide or a product obtained by drying bionic drag-reducing mucus.

[0013] A further technical solution of the present invention is: the method for swelling the organic silicon layer is to immerse the organic silicon layer in a methanol solution of benzophenone for swelling, take it out after 12 to 24 hours and blow dry it with nitrogen to obtain the organic silicon substrate.

[0014] A technical solution of the present invention is: a self-replenishing sustained-release hydrogel prepared by the preparation method of the self-replenishing sustained-release hydrogel.

[0015] A technical solution of the present invention is: a drag-reducing surface, comprising the self-replenishing sustained-release hydrogel, wherein the organic silicon substrate is grafted or bonded to the surface to be drag-reduced to form the drag-reducing surface.

[0016] Beneficial Effects The beneficial effects of the present invention are as follows: the self-replenishing sustained-release hydrogel and the preparation method thereof proposed in the present invention have significant advantages in terms of drag reduction performance, environmental protection, cost control and long-term stability. The specific advantages are analyzed as follows: 1. Self-replenishing mechanism to achieve long-term drag reduction: Drag-reducing polymer storage unit: The present invention combines drag-reducing polymer solid particles with sugar particles to form polymer sugar cubes as a storage carrier for the drag-reducing polymer. The sugar particles release the drag-reducing polymer after dissolving in water, forming a continuous replenishment mechanism, which solves the problem of insufficient carrying capacity of the drag-reducing polymer in traditional coatings due to premature dissolution.

[0017] Pore ​​control of the organosilicon layer: The organosilicon layer is usually dense and impermeable to water, but the pores of the mesh are artificially enlarged by the sugar template method (for example, the sugar particles in the embodiment have a particle size of 0.5 to 2 mm), so that water can penetrate into the sugar cube layer and trigger the slow release of the drag-reducing polymer. This design significantly improves the release efficiency of the drag-reducing agent.

[0018] 2. Significantly extend the duration of drag reduction: Figure 3 The comparative data show that the drag reduction effect of the ordinary sustained-release hydrogel fails after 12 hours (the surface tension no longer changes), while the drag reduction effect of the self-replenishing sustained-release hydrogel of the present invention can last for more than 40 hours (the surface tension continues to decrease).

[0019] The mass ratio of acrylic acid to acrylamide (9:1-21) and the cross-linking agent (2%-5% of ‌N,N'-methylenebisacrylamide) in the hydrogel prepolymer solution of the present invention are optimized to form a stable three-dimensional network structure, control the slow release of the drag-reducing polymer, and avoid exhaustion in a short time.

[0020] 3. Environmental protection and efficient use of materials: The present invention uses hydrogels and silicone materials with good biocompatibility to reduce pollution to the water environment. Traditional technologies require frequent replenishment of polymer solutions, while the present invention increases the time for ordinary sustained-release hydrogels to release drag-reducing polymers through sugar cube storage and self-replenishment mechanisms, thereby achieving efficient use of resources.

[0021] 4. Low-cost preparation and simplified process: The present invention uses common materials such as granulated sugar, polydimethylsiloxane (PDMS), acrylic acid, etc., which significantly reduces the production cost (for example, the mass ratio of granulated sugar particles to drag-reducing polymer solid particles in the embodiment is 1-5:1). At the same time, the preparation process is simple, such as vacuum degassing (-0.1MPa, 20-30min), room temperature curing (12 hours) and other steps are easy to industrialize and do not require complex equipment.

[0022] 5. Enhance mechanical properties and interface bonding: After the organic silicon layer of the present invention is swollen with benzophenone methanol solution (12 to 24 hours), the surface is dried with nitrogen to form active sites, which are chemically bonded with the hydrogel prepolymer solution by light initiation (such as ultraviolet light curing) to enhance the interface bonding strength and obtain an organic silicon-hydrogel coupling structure to prevent the coating from falling off. At the same time, the rigidity of the organic silicon layer (for example, the diluent in the embodiment is C4-C 10 The combination of alkanes (to adjust the hardness) and the flexibility of the hydrogel enhances the coating's wear resistance and resistance to water erosion.

[0023] 6. Wide applicability and multifunctional expansion: The self-replenishing sustained-release hydrogel prepared by the present invention is suitable for surfaces that require long-term drag reduction, such as ships, underwater pipelines, and marine equipment (such as the matrix grafted or bonded to the surface to be drag reduced in the embodiments); and the formula of the drag-reducing polymer can be adjusted to various drag reducers such as polyethylene oxide, polyacrylamide, and biopolysaccharides (such as xanthan gum) according to demand.

[0024] 7. Experimental verification and parameter optimization: The drag-reducing polymer concentration (100-500ppm) in the polymer solution of the present invention is matched with the release rate to avoid waste due to excessively high initial concentration or failure due to insufficient concentration in the later stage; the silicone layer is swollen in a benzophenone methanol solution for 12 to 24 hours to ensure full penetration of active molecules and optimize the subsequent photo-initiated grafting efficiency. Figure 3 As shown, the drag reduction effect lasts for more than 40 hours, far exceeding the existing technology (less than half an hour). BRIEF DESCRIPTION OF THE DRAWINGS Figure 1is a schematic structural diagram of a self-replenishing sustained-release hydrogel in Example 1 of the present invention; Figure 2 1 is a physical picture of a self-replenishing sustained-release hydrogel in Example 1 of the present invention; (a) is the self-replenishing sustained-release hydrogel of the present invention, and (b) is the existing sustained-release hydrogel; Figure 3 This is a comparison chart of surface tension change data of a self-replenishing sustained-release hydrogel in Example 4 of the present invention and a common sustained-release hydrogel in water.

[0025] Explanation of the accompanying figures: 1-the sparse oblique cross grid is a schematic diagram of the three-dimensional grid of the hydrogel; 2-the curved curve is a schematic diagram of the morphology of the polymer in the drag-reducing polymer solution; 3-the schematic diagram of the three-dimensional grid of the silicone where there is no polymer sugar cube; 4-the dense oblique cross grid is a schematic diagram of the three-dimensional grid of the silicone where there is polymer sugar cube; 5-the solid diamond is a schematic diagram of the solid polymer particles in the polymer sugar cube. DETAILED DESCRIPTION The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] Based on the problem that the currently disclosed related drag reduction technologies only improve the speed-increasing effect, but have not significantly improved the release duration of the drag reducer, the present invention provides a method for preparing a self-replenishing sustained-release hydrogel, and the specific steps are as follows: Step 1: mix sugar particles, drag-reducing polymer solid particles, and sugar concentrated solution, use a molding machine to press into a block structure, and obtain polymer sugar cubes after drying; The particle size of the granulated sugar particles is 0.5 to 2 mm; The mass ratio of the granulated sugar particles to the drag-reducing polymer solid particles is 1 to 5:1; The concentration of the concentrated sugar solution is 50% to 65%; The mass ratio of the concentrated sugar solution to the sugar granules is 1:100-10; The drag-reducing polymer is one or a mixture of polyethylene oxide, polyacrylamide, biopolysaccharide or a product obtained by drying biomimetic drag-reducing mucus.

[0028] Step 2: coating the organosilicon precursor on the lateral surface of the polymer sugar cube without immersing the top surface thereof, and curing after vacuum degassing to obtain an organosilicon layer; The preparation method of the organosilicon precursor is: polydimethylsiloxane, a curing agent, and a diluent are mixed and stirred sufficiently to obtain the organosilicon precursor; The mass ratio of the polydimethylsiloxane to the curing agent is 5 to 8:1; The diluent is an alkane with a carbon atomic weight between 4 and 10; The mass ratio of the diluent to polydimethylsiloxane is 1:1-5.

[0029] The specific operation of the vacuum degassing is to place the organosilicon precursor containing polymer sugar cubes in a vacuum box, and set the process parameters as follows: maintaining the pressure at -0.1 MPa for 20 to 30 minutes.

[0030] Step 3: Swelling the organic silicon layer to obtain an organic silicon substrate with improved surface properties; The method for swelling the organic silicon layer is to immerse the organic silicon layer in a methanol solution of benzophenone to swell, and then take it out after 12 to 24 hours and blow it dry with nitrogen to obtain the organic silicon substrate.

[0031] Step 4: Place a hydrogel prepolymer containing a drag-reducing polymer on a silicone substrate so that the top surface of the polymer sugar cube is completely covered by the hydrogel prepolymer, and obtain a self-replenishing sustained-release hydrogel after curing.

[0032] The preparation method of the hydrogel prepolymer solution is as follows: acrylic acid, acrylamide, N,N'-methylenebisacrylamide, potassium persulfate and polymer solution are mixed and stirred sufficiently to obtain the hydrogel prepolymer solution; The mass ratio of acrylic acid to acrylamide is 9:1-21; The mass fraction of the N,N'-methylenebisacrylamide in the hydrogel prepolymer solute is 2% to 5%; The mass fraction of potassium persulfate in the hydrogel prepolymer solution solute is 1-2‰; The mass ratio of the polymer solution to the hydrogel prepolymer solution solute is 4 to 5:1; The polymer in the polymer solution is a drag-reducing polymer with a concentration of 100 to 500 ppm.

[0033] The drag-reducing polymer is one or a mixture of polyethylene oxide, polyacrylamide, biopolysaccharide or a product obtained by drying biomimetic drag-reducing mucus.

[0034] The invention provides a self-supplementing sustained-release hydrogel, which is prepared by the preparation method of the self-supplementing sustained-release hydrogel.

[0035] The present invention provides a drag reduction surface, comprising the self-replenishing slow-release hydrogel, wherein the silicone substrate is grafted or bonded to the surface to be drag-reduced to form a drag reduction surface, for example, applied to surfaces requiring long-term drag reduction such as ships, underwater pipelines, and marine equipment.

[0036] The above technical solution is further described below with reference to examples and drawings: Embodiment 1: Reference Figure 1 and Figure 2 As shown, a self-replenishing sustained-release hydrogel in this embodiment includes an organosilicon layer and a hydrogel layer. The hydrogel layer contains a drag-reducing polymer, and the organosilicon layer is made of a polymer sugar cube containing solid particles of the drag-reducing polymer as a template. The polymer sugar cube directly contacts the water in the hydrogel and dissolves to release the drag-reducing polymer, thereby replenishing the drag-reducing polymer in the hydrogel.

[0037] The organic silicon layer and the hydrogel layer are linked by benzophenone through photoinitiation. The introduction of benzophenone can change the surface energy of the organic silicon substrate, thereby improving its wettability, adhesion or biocompatibility; when combined with the hydrogel layer, the introduction of benzophenone can enhance the interface interaction and improve the bonding strength.

[0038] Embodiment 2: The specific steps of a method for preparing a self-replenishing sustained-release hydrogel are as follows: Preparation of polymer sugar cubes: Mix sugar particles, drag-reducing polymer solid particles and sugar concentrated solution, use a molding machine to press and shape, and obtain polymer sugar cubes after drying; The particle size of the granulated sugar is 0.5 mm; The drag-reducing polymer solid particles are polyethylene oxide; The concentration of the concentrated sugar solution is 50%; The mass ratio of the granulated sugar particles to the drag-reducing polymer solid particles is 1:1; The mass ratio of the concentrated sugar solution to the sugar granules is 1:100.

[0039] Preparation of silicone layer: Put polydimethylsiloxane, curing agent and diluent in a beaker and stir them thoroughly to obtain an organosilicon precursor; put a polymer sugar cube in the organosilicon precursor until the side surface of the polymer sugar cube is just immersed but the top surface of the polymer sugar cube is not immersed; then put it in a vacuum box and keep it at a pressure of -0.1MPa for 20 to 30 minutes before taking it out; finally, put the beaker in an oven for curing to obtain an organosilicon layer; The ratio of polydimethylsiloxane to curing agent is 5:1; The diluent is n-butane; The mass ratio of the diluent to polydimethylsiloxane is 1:1.

[0040] Preparation of hydrogel prepolymer solution: Acrylic acid, acrylamide, N,N'-methylenebisacrylamide, potassium persulfate and polymer solution are placed in a beaker and stirred thoroughly to obtain a hydrogel prepolymer solution; The mass ratio of acrylic acid to acrylamide is 9:1; The mass fraction of the N,N'-methylenebisacrylamide in the hydrogel prepolymer solute is 2%; The mass fraction of potassium persulfate in the hydrogel prepolymer solution solute is 1‰; The polymer in the polymer solution is polyethylene oxide; The concentration of the polymer solution is 100 ppm; The mass ratio of the polymer solution to the hydrogel prepolymer solution solute is 4:1.

[0041] Preparation of self-replenishing sustained-release hydrogel: The silicone substrate was immersed in a methanol solution of benzophenone to swell, and then taken out and dried with nitrogen after 12 hours. The hydrogel prepolymer solution was placed on the silicone substrate and cured at room temperature for 12 hours to obtain a self-replenishing sustained-release hydrogel.

[0042] Embodiment 3: The specific steps of a method for preparing a self-replenishing sustained-release hydrogel are as follows: Preparation of polymer sugar cubes: Mix sugar particles, drag-reducing polymer solid particles and sugar concentrated solution, use a molding machine to press and shape, and obtain polymer sugar cubes after drying; The particle size of the granulated sugar particles is 1.25 mm; The polymer is polyacrylamide; The concentration of the concentrated sugar solution is 60%; The mass ratio of the granulated sugar particles to the drag-reducing polymer solid particles is 3:2; The mass ratio of the concentrated sugar solution to the sugar granules is 1:50.

[0043] Preparation of silicone layer: Put polydimethylsiloxane, curing agent and diluent in a beaker and stir them thoroughly to obtain an organosilicon precursor; put a polymer sugar cube in the organosilicon precursor until the side surface of the polymer sugar cube is just immersed but the top surface of the polymer sugar cube is not immersed; then put it in a vacuum box and keep it at a pressure of -0.1MPa for 20 to 30 minutes before taking it out. Finally, put the beaker in an oven for curing to obtain an organosilicon layer; The ratio of polydimethylsiloxane to curing agent is 6.5:1; The diluent is n-heptane; The mass ratio of the diluent to polydimethylsiloxane is 1:3; Preparation of hydrogel prepolymer solution: Acrylic acid, acrylamide, N,N'-methylenebisacrylamide, potassium persulfate and polymer solution are placed in a beaker and stirred thoroughly to obtain a hydrogel prepolymer solution; The mass ratio of acrylic acid to acrylamide is 9:11; The mass fraction of the N,N'-methylenebisacrylamide in the hydrogel prepolymer solution solute is 3.5%; The mass fraction of potassium persulfate in the hydrogel prepolymer solution solute is 1.5‰; The polymer in the polymer solution is polyacrylamide; The concentration of the polymer solution is 300 ppm; The mass ratio of the polymer solution to the hydrogel prepolymer solution solute is 4.5:1.

[0044] Preparation of self-replenishing sustained-release hydrogel: The silicone substrate was immersed in a methanol solution of benzophenone to swell, and then taken out and dried with nitrogen after 18 hours. The hydrogel prepolymer solution was placed on the silicone substrate and cured at room temperature for 12 hours to obtain a self-replenishing sustained-release hydrogel.

[0045] Embodiment 4: The specific steps of a method for preparing a self-replenishing sustained-release hydrogel are as follows: Preparation of polymer sugar cubes: Mix sugar particles, drag-reducing polymer solid particles and sugar concentrated solution, use a molding machine to press and shape, and obtain polymer sugar cubes after drying; The particle size of the granulated sugar is 2 mm; The polymer is xanthan gum; The concentration of the concentrated sugar solution is 65%; The mass ratio of the granulated sugar particles to the drag-reducing polymer solid particles is 5:1; The mass ratio of the concentrated sugar solution to the sugar granules is 1:10.

[0046] Preparation of silicone layer: Put polydimethylsiloxane, curing agent and diluent in a beaker and stir them thoroughly to obtain an organosilicon precursor; put a polymer sugar cube in the organosilicon precursor until the lateral surface of the polymer sugar cube is just immersed but the top surface of the polymer sugar cube is not immersed; then put it in a vacuum box at a pressure of -0.1MPa for 20 to 30 minutes and then take it out, and finally put the beaker in an oven for curing to obtain an organosilicon layer; The ratio of polydimethylsiloxane to curing agent is 8:1; The diluent is n-decane; The mass ratio of the diluent to polydimethylsiloxane is 1:5; Preparation of hydrogel prepolymer solution: Acrylic acid, acrylamide, N,N'-methylenebisacrylamide, potassium persulfate and polymer solution are placed in a beaker and stirred thoroughly to obtain a hydrogel prepolymer solution; The mass ratio of acrylic acid to acrylamide is 9:21; The mass fraction of the N,N'-methylenebisacrylamide in the hydrogel prepolymer solute is 5%; The mass fraction of potassium persulfate in the hydrogel prepolymer solution solute is 2‰; The polymer in the polymer solution is xanthan gum; The polymer solution concentration is 500 ppm; The mass ratio of the polymer solution to the hydrogel prepolymer solution solute is 5:1.

[0047] Preparation of self-replenishing sustained-release hydrogel: The silicone substrate was immersed in a methanol solution of benzophenone to swell, and then taken out and dried with nitrogen after 24 hours. The hydrogel prepolymer solution was placed on the silicone substrate and cured at room temperature for 12 hours to obtain a self-replenishing sustained-release hydrogel.

[0048] Reference Figure 3 As shown, the curves of the self-replenishing sustained-release hydrogel of the present invention and the existing sustained-release hydrogel are basically overlapped before 12 hours; after 12 hours, the sustained-release hydrogel stops causing the solution tension to change due to the end of sustained-release; the self-replenishing sustained-release hydrogel continues to replenish and release due to the dissolution of the polymer sugar cube penetrating the hydrogel and the continued sustained-release, and the surface tension of the solution continues to decrease until 40 hours.

[0049] Embodiment 5: A drag-reducing surface is formed by grafting or bonding the organic silicon substrate of the self-replenishing slow-release hydrogel to the bottom surface of a ship.

[0050] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for preparing a self-replenishing sustained-release hydrogel, characterized in that The specific steps are as follows: The granulated sugar particles, the drag-reducing polymer solid particles and the granulated sugar concentrated solution are mixed, pressed into a block structure using a molding machine, and dried to obtain a polymer sugar cube; The organosilicon precursor is coated on the lateral peripheral surface of the polymer sugar cube without immersing the top surface thereof, and is cured after vacuum degassing to obtain an organosilicon layer; Swelling the organic silicon layer to obtain an organic silicon substrate with improved surface properties; A hydrogel prepolymer containing a drag-reducing polymer is placed on an organic silicon substrate so that the top surface of the polymer sugar cube is completely covered by the hydrogel prepolymer, and a self-replenishing sustained-release hydrogel is obtained after curing.

2. The method for preparing a self-replenishing sustained-release hydrogel according to claim 1, characterized in that: The particle size of the granulated sugar particles is 0.5 to 2 mm, and the mass ratio of the granulated sugar particles to the drag-reducing polymer solid particles is 1 to 5:

1.

3. A method for preparing a self-replenishing sustained-release hydrogel according to claim 2, characterized in that: The concentration of the concentrated sugar solution is 50-65%, and the mass ratio of the concentrated sugar solution to the sugar granules is 1:100-10.

4. The method for preparing a self-replenishing sustained-release hydrogel according to claim 3, characterized in that: The preparation method of the organosilicon precursor is: polydimethylsiloxane, a curing agent, and a diluent are mixed and stirred sufficiently to obtain the organosilicon precursor; The mass ratio of the polydimethylsiloxane to the curing agent is 5 to 8:1; The diluent is an alkane with a carbon atomic weight between 4 and 10; The mass ratio of the diluent to polydimethylsiloxane is 1:1-5.

5. The method for preparing a self-replenishing sustained-release hydrogel according to claim 4, characterized in that: The specific operation of the vacuum degassing is to place the organosilicon precursor containing polymer sugar cubes in a vacuum box, and set the process parameters as follows: maintaining the pressure at -0.1 MPa for 20 to 30 minutes.

6. The method for preparing a self-replenishing sustained-release hydrogel according to claim 4, characterized in that: The preparation method of the hydrogel prepolymer solution is as follows: acrylic acid, acrylamide, ‌N,N'-methylenebisacrylamide, potassium persulfate and polymer solution are mixed and stirred sufficiently to obtain the hydrogel prepolymer solution; The mass ratio of acrylic acid to acrylamide is 9:1-21; The mass fraction of the N,N'-methylenebisacrylamide in the hydrogel prepolymer solute is 2% to 5%; The mass fraction of potassium persulfate in the hydrogel prepolymer solution solute is 1-2‰; The mass ratio of the polymer solution to the hydrogel prepolymer solution solute is 4 to 5:1; The polymer in the polymer solution is a drag-reducing polymer with a concentration of 100 to 500 ppm.

7. A method for preparing a self-replenishing sustained-release hydrogel according to claim 6, characterized in that: The drag-reducing polymer is one or a mixture of polyethylene oxide, polyacrylamide, biopolysaccharide or a product obtained by drying biomimetic drag-reducing mucus.

8. The method for preparing a self-replenishing sustained-release hydrogel according to claim 1, characterized in that: The method for swelling the organic silicon layer is to immerse the organic silicon layer in a methanol solution of benzophenone to swell, and then take it out after 12 to 24 hours and blow it dry with nitrogen to obtain the organic silicon substrate.

9. A method for preparing a self-replenishing sustained-release hydrogel according to any one of claims 1 to 8 to prepare a self-replenishing sustained-release hydrogel.

10. A drag reducing surface, characterized in that: It comprises a self-replenishing sustained-release hydrogel as described in claim 9, wherein the organic silicon substrate of the self-replenishing sustained-release hydrogel is grafted or bonded to the surface to be drag-reduced to form a drag-reducing surface.

Images