Hydrophilic HIPE (High Impact Polyethylene) porous material as well as preparation method and application thereof

Abstract

The invention discloses a hydrophilic HIPE (High Impact Polyethylene) porous material as well as a preparation method and application thereof, the preparation method comprises the following steps: (1) preparing an HIPE emulsion by utilizing an oil phase, a water phase, an emulsifier and an initiator, and monomers used in the oil phase comprise a hydroxyl-containing monomer; (2) polymerizing and drying the HIPE emulsion to obtain an HIPE porous material; (3) modifying the HIPE porous material by using a silane coupling agent with double bonds to obtain a primary modified product; and (4) carrying out double-bond addition copolymerization reaction on the primary modified product and a hydrophilic polymeric monomer to obtain the hydrophilic HIPE porous material. Hydrophilic surface modification is replaced by body functionalization, so that the obtained HIPE porous material achieves permanent hydrophilicity and structural integrity at the same time, the hydrophilic layer is doubly fixed through high-density covalent bonds and mechanical interlocking, the performance is lasting and stable, and the problem that firmness and structural integrity cannot be considered at the same time in a traditional method is solved.

Description

Technical Field

[0001] This invention belongs to the field of porous materials technology, specifically relating to a hydrophilic HIPE porous material, its preparation method, and its application. Background Technology

[0002] High-density ethylene-polyethylene (HIPE) porous materials (PolyHIPE) are polymeric materials with a three-dimensional interconnected macroporous structure. Due to their high porosity, large specific surface area, and excellent permeability, they have shown great application potential in separation and adsorption, catalyst supports, tissue engineering scaffolds, materials science, biomedicine, and daily chemical hygiene products. However, traditional HIPE porous materials obtained by polymerizing monomers such as styrene and divinylbenzene are hydrophobic, which severely limits their application in aqueous environments.

[0003] To address this issue, existing technologies often employ methods such as plasma treatment, strong acid oxidation, or surfactant coating for hydrophilic modification. However, these methods can only solve the problem of "hydrophilicity" or "structure preservation" in one aspect, failing to address both simultaneously. Plasma treatment has a superficial effect and is prone to "hydrophobic recovery," while physical coating has weak adhesion, is prone to peeling, and has short-lived hydrophilicity. Both of these methods can ensure that the structure is not damaged, but the hydrophilicity is not durable. Strong acid oxidation, on the other hand, is subject to severe conditions and can ensure the durability of hydrophilicity, but it easily erodes and damages the delicate and fragile pore structure of HIPE porous materials.

[0004] Therefore, there is an urgent need to develop a HIPE porous material that combines structural integrity and hydrophilic durability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a hydrophilic HIPE porous material, its preparation method, and its applications.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a hydrophilic HIPE porous material, the method comprising:

[0008] (1) HIPE emulsion is prepared using an oil phase, an aqueous phase, an emulsifier and an initiator, wherein the monomers used in the oil phase include hydroxyl-containing monomers;

[0009] (2) HIPE emulsion is polymerized and dried to obtain HIPE porous material;

[0010] (3) HIPE porous materials are modified with silane coupling agents containing double bonds to obtain primary modified products;

[0011] (4) The primary modified product undergoes a double bond addition copolymerization reaction with the hydrophilic polymer monomer to obtain the hydrophilic HIPE porous material.

[0012] In the preparation method provided by this invention:

[0013] First, in the preparation of HIPE porous materials, by introducing hydroxyl-containing monomers into the copolymerization system, the final HIPE porous material is rich in active hydroxyl groups, which can provide uniform reaction sites for subsequent reactions, fundamentally solving the shortcomings of uneven sites, insufficient reaction and weak binding force in traditional surfactant modification.

[0014] Then, in the modification stage, the silanization effect of the silane coupling agent is utilized first. The silanol group after hydrolysis can form a strong Si-OC covalent bond with the hydroxyl group on the HIPE porous material, thereby forming a uniform interface layer with vinyl groups on the inner wall of the pores of the HIPE porous material, solving the problem of "weak interfacial bonding" between the traditional hydrophilic layer and the substrate.

[0015] Finally, using a uniform interface layer with vinyl groups as the starting point for polymerization, hydrophilic monomers and long-chain flexible crosslinking agents are polymerized in situ within the pores through room-temperature free radical polymerization to form a hydrophilic interpenetrating network that is covalently interlocked with the HIPE porous material, thus solving the problem of "easily detaching hydrophilic layer".

[0016] In other words, by replacing hydrophilic surface modification with "body functionalization", the HIPE porous material provided by the present invention achieves both "permanent hydrophilicity" and "structural integrity". Furthermore, the hydrophilic layer is doubly fixed by high-density covalent bonds and mechanical interlocking, resulting in durable and stable performance. This solves the problem that traditional methods cannot simultaneously ensure both robustness and structural integrity.

[0017] Preferably, in step (1), the monomers used in the oil phase include hydrophobic monomers and hydroxyl-containing monomers. The content of the hydroxyl-containing monomers is 10-15 wt%, for example, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, etc., based on the total mass of the oil phase as 100%.

[0018] Preferably, the hydroxyl-containing monomer includes any one or a combination of at least two of the following: hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, hydroxybutyl methacrylate, hydroxybutyl acrylate, dihydroxyethyl methacrylate, and dihydroxypropyl acrylate.

[0019] In this invention, the HIPE emulsion is a conventional HIPE emulsion in the art. This invention simply adds 10-15 wt% of hydroxyl-containing monomers to it to meet the requirements of this invention. Other components of the HIPE emulsion are exemplarily listed below:

[0020] The HIPE emulsion comprises an oil phase, an aqueous phase, an emulsifier, and an initiator. The oil phase includes monomers and crosslinking agents, and the monomers include hydrophobic monomers and hydroxyl-containing monomers.

[0021] In this invention, any monomer and crosslinking agent, as well as their amounts, can be used as long as they meet the requirements for preparing HIPE emulsions. This invention does not impose excessive limitations, but only provides exemplary examples:

[0022] The monomer accounts for 5-97% of the oil phase weight, for example 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 97%, etc., and includes hydrophobic monomers and hydroxyl-containing monomers. The hydrophobic monomers may contain at least one water-insoluble monofunctional alkyl acrylate and / or alkyl methacrylate, or may also include water-insoluble monomers.

[0023] The functional alkyl acrylate or alkyl methacrylate includes C4-C18 alkyl acrylates (such as butyl acrylate and octyl acrylate) and / or C2-C18 alkyl methacrylates, such as methyl methacrylate and ethyl methacrylate.

[0024] The water-insoluble monomers include styrene, vinyl chloride, vinylidene chloride, isoprene, and chloroprene, etc.

[0025] The crosslinking agent accounts for about 2-40% of the oil phase by weight, for example, 2%, 5%, 10%, 20%, 30%, 40%, etc.; this type of crosslinking monomer includes any one or a combination of at least two of acrylate, methacrylate or divinylbenzene crosslinking agents containing two or more double bonds.

[0026] Similarly, this invention does not limit the amount or specific type of initiator. Any initiator capable of initiating HIPE emulsions can be used in this invention. The initiator can be an oil-soluble initiator or a water-soluble initiator. Exemplary examples of this invention are listed below:

[0027] Preferably, the initiator is an oil-soluble initiator, and the amount of the oil-soluble initiator added is 0.05-10% of the mass of the oil phase, such as 0.05%, 1%, 2%, 5%, 10%, etc.

[0028] Preferably, the initiator is a water-soluble initiator, and the amount of the initiator can be 1-20% of the molar amount of the polymerizable monomer in the oil phase, such as 1%, 2%, 5%, 10%, 15%, 20%, etc., or 0.001-10% of the mass of the aqueous phase, such as 0.001%, 0.01%, 0.1%, 1%, 2%, 5%, 10%, etc. Commonly used initiators include, but are not limited to, persulfates, such as ammonium persulfate, sodium persulfate, potassium persulfate, suitable for thermal polymerization systems; azo compounds, such as 2,2'-azobis(N,N'-dimethyleneisobutylamidine) dihydrochloride, azo initiators, etc.; redox pairs, such as persulfate-bisulfite, persulfate-ascorbic acid, etc.

[0029] The emulsifier has an HLB value of approximately 3-6 and is added at 1-20% of the weight of the oil phase, for example, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, etc.

[0030] In this invention, the method of obtaining HIPE porous material by polymerizing and drying the HIPE emulsion is a conventional method in the art. This invention provides an exemplary example. Preferably, the polymerization temperature in step (2) is 60-65℃, such as 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, etc., and the time is 20-25 h, such as 20 h, 21 h, 22 h, 23 h, 24 h, 25 h, etc.

[0031] Preferably, the preparation method further includes purification before drying, and the purpose of the purification is to remove unreacted monomers and residual salts.

[0032] This invention introduces a hydroxyl-containing reactive monomer, such as hydroxyethyl methacrylate (HEMA), whose terminal methacrylate groups can undergo free radical copolymerization with styrene (St) and divinylbenzene (DVB), ensuring that it becomes part of the polymer network rather than a physical dopant. At the same time, the hydroxyl groups (-OH) can subsequently undergo a condensation reaction with the silanol groups (-Si-OH) of the silane coupling agent VTES. Moreover, the condensation reaction is efficient, specific, mild, and has few side reactions.

[0033] Preferably, the silane coupling agent with double bonds includes any one or a combination of at least two of vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0034] Preferably, step (3) includes: impregnating the HIPE porous material with a solution containing a silane coupling agent with double bonds to obtain a primary modified product.

[0035] Preferably, in the solution containing the silane coupling agent with double bonds, the volume percentage concentration of the silane coupling agent with double bonds is 1-5%, for example, 1%, 2%, 3%, 4%, 5%, etc.

[0036] Preferably, the solvent used in the solution is an alcohol solvent, and more preferably ethanol.

[0037] Preferably, the immersion temperature is 10-35℃, such as 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, etc., and the time is 2-4 h, such as 2 h, 2.5 h, 3 h, 3.5 h, 4 h, etc.

[0038] This invention introduces a silane coupling agent with double bonds. On one hand, the hydroxyl groups (-OH) on the silanol-based (-Si-OH) HIPE porous material after hydrolysis of the silane coupling agent undergo a condensation reaction to form a strong Si-OC covalent bond, realizing the "molecular-level" connection between the organic polymer and the inorganic silane layer. On the other hand, the vinyl group (CH2=CH-) provides chemical reaction active sites for subsequent free radical polymerization.

[0039] Preferably, step (4) includes: mixing the primary modified product with the reaction mixture and performing a double bond addition copolymerization reaction to obtain the hydrophilic HIPE porous material, wherein the reaction mixture includes a hydrophilic polymeric monomer, a crosslinking agent and an initiator.

[0040] Preferably, in the reaction mixture, the content of the hydrophilic polymeric monomer is 5-15 w / v%, for example 5 w / v%, 6 w / v%, 8 w / v%, 10 w / v%, 12 w / v%, 15 w / v%, etc., the content of the crosslinking agent is 1-3 w / v%, for example 1 w / v%, 1.5 w / v%, 2 w / v%, 2.5 w / v%, 3 w / v%, etc., and the content of the initiator is 0.1-1 w / v%, for example 0.1 w / v%, 0.2 w / v%, 0.5 w / v%, 0.6 w / v%, 0.8 w / v%, 1 w / v%, etc.

[0041] Preferably, the hydrophilic polymeric monomer includes any one or a combination of at least two of acrylamide, N-vinylpyrrolidone, and acrylic acid.

[0042] Preferably, the crosslinking agent includes any one or a combination of at least two of polyethylene glycol diacrylate (PEGMA), trimethylolpropane triacrylate, and N,N'-methylenebisacrylamide.

[0043] Preferably, the temperature of the double bond addition copolymerization reaction is 10-35℃, such as 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, etc., and the time is 10-15 h, such as 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, etc.

[0044] The preferred acrylamide of this invention, after polymerization, can produce a large number of amide groups (-CO-NH2) in the polymer product, which can form extremely strong hydrogen bonds with water molecules, and is the core source of the material's superhydrophilicity. At the same time, PEGMA is preferably used as a crosslinking agent, and its acrylate double bonds at both ends participate in the polymerization, crosslinking the linear polyacrylamide (PAM) chains into a stable three-dimensional network, preventing it from dissolving or swelling and being lost in the aqueous phase. Meanwhile, the long-chain polyethylene glycol (PEG) segments themselves are highly hydrophilic and flexible, bringing excellent elasticity to the entire hydrophilic network, avoiding network brittleness, and further improving the hydrophilic properties.

[0045] Preferably, the double bond addition copolymerization reaction is carried out under the initiation of a redox initiation system (APS / TMEDA), which can efficiently generate free radicals at room temperature to initiate the polymerization of hydrophilic monomers and crosslinking agents. The APS / TMEDA system is an ammonium persulfate / tetramethylethylenediamine system.

[0046] Preferably, step (4) specifically involves: immersing the primary modified product in the reaction mixture, performing a vacuum-release step, and repeating this process several times to ensure that the pores of the HIPE porous material are completely filled by the reaction mixture.

[0047] Secondly, the present invention provides a hydrophilic HIPE porous material obtained by the preparation method described in the first aspect.

[0048] Thirdly, the present invention provides an application of the hydrophilic HIPE porous material as described in the second aspect in water treatment (oil-containing wastewater separation, heavy metal adsorption), adsorption and separation materials, tissue engineering scaffolds, daily chemical hygiene products or biomedical dressings.

[0049] When the hydrophilic HIPE porous material described in this invention is applied to daily chemical hygiene products, it can be used in sanitary napkins, dressings, and other products. One or more layers of high internal phase emulsion porous foam material with the same or different pore sizes are used as the core of sanitary napkins, dressings, and other daily chemical hygiene products. It has the functions of absorbing and diverting moisture, menstrual blood, blood, body fluids, locking in water, preventing backflow, or slowly releasing nutrients, so that the products have excellent properties such as being thin, dry, long-lasting, and slow-release.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] To address the issue of short-lived hydrophilicity, a three-dimensional covalent interpenetrating network was constructed. Firstly, during the preparation of the HIPE porous material, reactive functional groups (-OH) were designed as reaction sites and copolymerized into the backbone network of the HIPE porous material. Then, using a silanization reaction, covalent bonding with the matrix hydroxyl groups was achieved under mild conditions (room temperature, ethanol solution). Finally, during the construction of the interpenetrating network, hydrophilic comonomers and long-chain flexible crosslinking agents were introduced to ensure the structural integrity of the polymer. Simultaneously, the resulting hydrophilic network possessed excellent elasticity and toughness, enabling it to adapt to stress changes during swelling / shrinkage, thus perfectly protecting the inherently fragile porous structure of the HIPE porous material. Attached Figure Description

[0052] Figure 1 This is a SEM image of the HIPE porous material obtained in Example 1 of the present invention;

[0053] Figure 2 This is a SEM image of the hydrophilic HIPE porous material obtained in Example 1 of the present invention. Detailed Implementation

[0054] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0055] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art, and can be purchased from commercially available products. Some raw material information is as follows:

[0056] Hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, azobisisobutyronitrile, and calcium chloride (analytical grade) were all purchased from Aladdin; styrene and divinylbenzene (80%) were purchased from Sigma-Aldrich; vinyltriethoxysilane and vinyltrimethoxysilane were purchased from Tokyo Chemical Industry Co., Ltd.; acrylamide was purchased from Sinopharm Group; polyethylene glycol diacrylate (PEGDA-700) was purchased from Sinopharm Group; and Span80 was purchased from Croda.

[0057] Polyethylene glycol: PEG-400, purchased from Aladdin, model number P103737.

[0058] Example 1

[0059] This embodiment provides a hydrophilic HIPE porous material and its preparation method, as follows:

[0060] (1) Preparation of HIPE emulsion

[0061] Oil phase: 63 wt% styrene, 22 wt% divinylbenzene, and 15 wt% hydroxyethyl methacrylate;

[0062] Aqueous phase: 0.15 M CaCl2 deionized water, comprising 82% of the total volume of the HIPE emulsion;

[0063] Emulsifier: Span 80, 7 wt% of oil phase;

[0064] Initiator: Azobisisobutyronitrile (AIBN), 1 wt% of oil phase mass;

[0065] After the oil phase is mixed evenly in proportion, the emulsifier and initiator are added and mixed until the initiator is completely dissolved. Under high-speed mechanical stirring (1200 rpm), the aqueous phase is added dropwise to the oil phase at a slow rate (about 2 mL / min) to ensure the formation of a stable water-in-oil (W / O) emulsion. After the emulsion is formed, stirring is continued for 15 min to homogenize it. The whole process is carried out under nitrogen protection.

[0066] (2) Apply HIPE emulsion

[0067] The prepared HIPE emulsion was poured into a polytetrafluoroethylene mold (4.5 cm × 20 cm × 30 cm), sealed, and polymerized in a constant temperature water bath at 65℃ for 24 h. Then, it was continuously extracted with an ethanol / water mixture (volume ratio 1:1) using a Soxhlet extractor for 48 h. Finally, it was dried in a vacuum oven at 60℃ to constant weight to obtain HIPE porous material.

[0068] (3) Vinyltriethoxysilane (VTES) was dissolved in anhydrous ethanol at a volume percentage of 1%. Then, HIPE porous material was immersed in the above solution for 2 h with slight shaking during the process. After completion, the sample was thoroughly washed 3 times with anhydrous ethanol to remove the physically adsorbed VTES. Then, it was dried at 60 °C for 2 h to obtain the primary modified product.

[0069] (4) Acrylamide (5% (w / v)), PEGMA-700 (2% (w / v)) and ammonium persulfate (10% (w / v)) were dissolved in water to obtain a reaction mixture; the primary modified product was immersed in the reaction mixture and vacuum-released (repeated twice, with vacuum maintained for 3 min each time). Then, 0.05% (v / v) tetramethylethylenediamine (TMEDA) was added as a promoter and reacted at 25°C under static conditions for 10 h. After the reaction was completed, the sample was rinsed with a large amount of deionized water to remove unreacted monomers and homopolymers. Finally, it was dried at 60°C for 6 h to obtain hydrophilic HIPE porous material.

[0070] Infrared characterization of hydrophilic HIPE porous materials shows that at 1652 cm⁻¹... -1 An absorption peak of amide I (C=O stretching vibration) appeared at 1543 cm⁻¹.-1 An absorption peak of amide II band (NH bending vibration) appeared at 1105 cm⁻¹, confirming the successful introduction of acrylamide; -1 The presence of characteristic absorption peaks for Si-OC and Si-O-Si at the surface confirms the fixation of VTES. Meanwhile, XPS analysis further shows that the percentage of oxygen atoms on the surface of the hydrophilic HIPE porous material increased from 18.3% to 26.7%, the percentage of nitrogen atoms increased from 0.4% to 5.2%, and the percentage of silicon atoms was 1.8%. These elemental changes clearly confirm the formation of the hydrophilic layer.

[0071] Example 2

[0072] This embodiment provides a hydrophilic HIPE porous material and its preparation method, as follows:

[0073] (1) Preparation of HIPE emulsion

[0074] Oil phase: 75 wt% methyl methacrylate, 10 wt% divinylbenzene, and 15 wt% hydroxyethyl acrylate;

[0075] Aqueous phase: 0.1 M CaCl2 deionized water, comprising 82% of the total volume of the HIPE emulsion;

[0076] Emulsifier: SPAN80, 7 wt% of oil phase;

[0077] Initiator: AIBN, 1 wt% of oil phase mass;

[0078] After the oil phase is mixed evenly in proportion, the emulsifier and initiator are added and mixed until the initiator is completely dissolved. Under high-speed mechanical stirring (1200 rpm), the aqueous phase is added dropwise to the oil phase at a slow rate (about 2 mL / min) to ensure the formation of a stable water-in-oil (W / O) emulsion. After the emulsion is formed, stirring is continued for 15 min to homogenize it. The whole process is carried out under nitrogen protection.

[0079] (2) Apply HIPE emulsion

[0080] The prepared HIPE emulsion was poured into a polytetrafluoroethylene mold (4.5 cm × 20 cm × 30 cm), sealed, and polymerized in a constant temperature water bath at 80℃ for 10 h. Then, it was continuously extracted with an ethanol / water mixture (volume ratio 1:1) using a Soxhlet extractor for 48 h. Finally, it was dried in a vacuum oven at 60℃ to constant weight to obtain HIPE porous material.

[0081] (3) γ-methacryloxypropyltrimethoxysilane was dissolved in anhydrous ethanol at a volume percentage of 1%. Then, HIPE porous material was immersed in the above solution for 3 h with slight shaking during the process. After completion, the sample was thoroughly washed 3 times with anhydrous ethanol to remove the physically adsorbed VTES. Then, it was dried at 60 °C for 2 h to obtain the primary modified product.

[0082] (4) N-vinylpyrrolidone (10% (w / v)), trimethylolpropane triacrylate (2% (w / v)) and ammonium persulfate (10% (w / v)) were dissolved in water to obtain a reaction mixture; the primary modified product was immersed in the reaction mixture and vacuum-released (repeated twice, with vacuum maintained for 3 min each time). Then, 0.05% (v / v) tetramethylethylenediamine (TMEDA) was added as a promoter and reacted at 10°C under static conditions for 15 h. After the reaction was completed, the sample was rinsed with a large amount of deionized water to remove unreacted monomers and homopolymers. Finally, it was dried at 60°C for 6 h to obtain hydrophilic HIPE porous material.

[0083] Example 3

[0084] This embodiment provides a hydrophilic HIPE porous material and its preparation method, as follows:

[0085] (1) Preparation of HIPE emulsion

[0086] Oil phase: 80 wt% methyl methacrylate, 5 wt% divinylbenzene, and 15 wt% hydroxyethyl acrylate;

[0087] Aqueous phase: 0.1 M CaCl2 deionized water, comprising 82% of the total volume of the HIPE emulsion;

[0088] Emulsifier: SPAN80, 7 wt% of oil phase;

[0089] Initiator: AIBN, 1 wt% of oil phase mass;

[0090] After the oil phase is mixed evenly in proportion, the emulsifier and initiator are added and mixed until the initiator is completely dissolved. Under high-speed mechanical stirring (1200 rpm), the aqueous phase is added dropwise to the oil phase at a slow rate (about 2 mL / min) to ensure the formation of a stable water-in-oil (W / O) emulsion. After the emulsion is formed, stirring is continued for 15 min to homogenize it. The whole process is carried out under nitrogen protection.

[0091] (2) Apply HIPE emulsion

[0092] The prepared HIPE emulsion was poured into a polytetrafluoroethylene mold (4.5 cm × 20 cm × 30 cm), sealed, and polymerized in a constant temperature water bath at 65℃ for 24 h. Then, it was continuously extracted with an ethanol / water mixture (volume ratio 1:1) using a Soxhlet extractor for 48 h. Finally, it was dried in a vacuum oven at 60℃ to constant weight to obtain HIPE porous material.

[0093] (3) Vinyltrimethoxysilane was dissolved in anhydrous ethanol at a volume percentage of 1%, and then HIPE porous material was immersed in the above solution for 2 h with slight shaking during the process. After completion, the sample was thoroughly washed 3 times with anhydrous ethanol to remove the physically adsorbed VTES, and then dried at 60 °C for 2 h to obtain the primary modified product.

[0094] (4) Acrylic acid (10% (w / v)), trimethylolpropane triacrylate (2% (w / v)) and ammonium persulfate (10% (w / v)) were dissolved in water to obtain a reaction mixture; the primary modified product was immersed in the reaction mixture and vacuum-released (repeated twice, with vacuum maintained for 3 min each time). Then, 0.05% (v / v) tetramethylethylenediamine (TMEDA) was added as a promoter and reacted at 35°C under static conditions for 12 h. After the reaction was completed, the sample was rinsed with a large amount of deionized water to remove unreacted monomers and homopolymers. Finally, it was dried at 60°C for 6 h to obtain hydrophilic HIPE porous material.

[0095] Examples 4-5

[0096] This embodiment provides a hydrophilic HIPE porous material and its preparation method.

[0097] The difference from Example 1 is that in this example, the content of hydroxyethyl methacrylate is 10 wt% (Example 4) and 8 wt% (Example 5), and the total mass of the oil phase is kept constant by increasing or decreasing the amount of styrene.

[0098] Examples 6-7

[0099] This embodiment provides a hydrophilic HIPE porous material and its preparation method.

[0100] The difference from Example 1 is that, in this example, the volume percentage concentration of vinyltriethoxysilane in step (3) is 5% (Example 6) and 0.5% (Example 7).

[0101] Examples 8-10

[0102] This embodiment provides a hydrophilic HIPE porous material and its preparation method.

[0103] The difference from Example 1 is that in this example, the soaking time in step (3) is 4 h (Example 8), 1 h (Example 9), and 5 h (Example 10).

[0104] Examples 11-13

[0105] The difference from Example 1 is that in this example, the concentration of acrylamide in step (4) is 15% (w / v) (Example 11), 3% (w / v) (Example 12), and 18% (w / v) (Example 13).

[0106] Examples 14-16

[0107] The difference from Example 1 is that in this example, the reaction in step (4) is 15 h (Example 14), 8 h (Example 15), and 18 h (Example 16).

[0108] Comparative Example 1

[0109] This comparative example provides a hydrophilic HIPE porous material and its preparation method.

[0110] The difference from Example 1 is that in this example, the content of hydroxyethyl methacrylate is 20 wt%, and the total mass of the oil phase is kept constant by increasing or decreasing the amount of styrene.

[0111] Comparative Example 2

[0112] This comparative example provides a hydrophilic HIPE porous material and its preparation method.

[0113] The difference from Example 1 is that in this example, the volume percentage concentration of vinyltriethoxysilane in step (3) is 8%.

[0114] Comparative Example 3

[0115] This comparative example provides a HIPE porous material and its preparation method.

[0116] The difference from Example 1 is that, in this comparative example, hydroxyethyl methacrylate is replaced with an equal mass of methyl methacrylate.

[0117] Comparative Example 4

[0118] This comparative example provides a HIPE porous material and its preparation method.

[0119] The difference from Example 1 is that step (3) is not performed in this comparative example.

[0120] Comparative Example 5

[0121] This comparative example provides a HIPE porous material and its preparation method.

[0122] The difference from Example 1 is that step (4) is not performed in this comparative example.

[0123] Comparative Example 6

[0124] This comparative example provides a HIPE porous material and its preparation method.

[0125] The difference from Example 1 is that, in this comparative example, steps (3)-(4) are replaced with:

[0126] (3) Prepare an aqueous solution of 1.0 wt% polyethylene glycol (PEG, Mn=400) and 0.5 wt% sodium dodecyl sulfate (SDS), and then immerse the HIPE porous material in the aqueous solution at 25°C and normal pressure for 2 h. Take out the material, rinse it gently with deionized water 3 times to remove excess and physically adsorbed surfactant molecules, and freeze dry for 24 hours to obtain the HIPE porous material.

[0127] Performance testing

[0128] The performance of the samples provided in the examples and comparative examples was tested using the following methods:

[0129] (1) Microstructure characterization

[0130] Figure 1 The image shows a SEM image of the HIPE porous material obtained in Example 1. As can be seen from the image, the HIPE porous material forms a well-connected porous structure with pore sizes ranging from 5 to 25 μm and obvious interconnecting windows between the pores.

[0131] Figure 2 The image shows a SEM image of the hydrophilic HIPE porous material obtained in Example 1. As can be seen from the image, the final hydrophilic HIPE porous material still maintains a well-connected porous structure. Although the average pore size decreased slightly (from 15.2 μm to 13.7 μm), this decrease in average pore size precisely demonstrates that the preparation method provided by this invention constructs a hydrophilic polymer network within the pore walls. Furthermore, BET measurements show that the specific surface area of ​​the final hydrophilic HIPE porous material obtained by this invention increased from the original 35.2 μm. 2 / g increased significantly to 58.6 m 2 / g, which is thanks to the nanoscale microstructure formed by IPN.

[0132] (2) Water contact angle: Seat drop method (JC2000D contact angle measuring instrument): 25℃, humidity 50%, water drop volume 5 μL, test 1s after drop, and take the average value of 5 sites;

[0133] (3) Equilibrium water absorption rate: After soaking in deionized water at 25℃ for 24 h, the water absorption rate = (saturated water absorption mass - initial mass) / initial mass × 100%;

[0134] (4) Specific surface area: BET nitrogen adsorption method (Micromeritics ASAP2460): sample degassed at 77K for 4 h, calculated using Brunauer-Emmett-Teller model;

[0135] (5) Hydrophilic durability: Based on the water absorption ratio of the first complete cycle, the water absorption rate retention rate of the nth cycle is calculated as follows: Water absorption rate retention rate (%) = (equilibrium water absorption rate of the nth cycle / equilibrium water absorption rate of the first cycle) × 100%;

[0136] The test results are as follows:

[0137] Table 1

[0138]

[0139] As can be seen from the examples and performance tests, the hydrophilic HIPE porous material obtained by the present invention has both excellent water absorption and structural integrity, and its water absorption is stable and durable.

[0140] As can be seen from the comparison between Examples 1 and Examples 4-16, in this invention, when the amount of hydroxyl-containing monomer added, the amount of silane coupling agent introduced, the impregnation time, the amount of hydrophilic monomer introduced, and the time of double bond addition copolymerization reaction are preferably within the range defined by this invention, the hydrophilicity and hydrophilic durability of the final hydrophilic HIPE porous material can be better.

[0141] As can be seen from the comparison between Example 1 and Comparative Examples 1-2, when the amount of hydroxyl-containing monomer and silane coupling agent introduced in this invention is within the limits of this invention, the hydrophilicity and hydrophilic durability of the final hydrophilic HIPE porous material are superior.

[0142] As can be seen from the comparison between Example 1 and Comparative Examples 3-5, the preparation method provided by the present invention is indispensable, and the effect of the present invention cannot be achieved if any step is missing.

[0143] As can be seen from the comparison between Example 1 and Comparative Example 6, the preparation method provided by the present invention has durable hydrophilicity.

[0144] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method of making a hydrophilic HIPE porous material, characterized by, The preparation method comprises: (1) preparing a HIPE emulsion by using an oil phase, an aqueous phase, an emulsifier and an initiator, wherein the monomers used in the oil phase comprise a hydroxyl-containing monomer; (2) polymerizing and drying the HIPE emulsion to obtain a HIPE porous material; (3) modifying the HIPE porous material by using a silane coupling agent with a double bond to obtain a primary modified product; (4) performing a double bond addition copolymerization reaction on the primary modified product with a hydrophilic polymer monomer to obtain the hydrophilic HIPE porous material.

2. The production method according to claim 1, characterized by, In step (1), the monomers used in the oil phase comprise a hydrophobic monomer and a hydroxyl-containing monomer, and the content of the hydroxyl-containing monomer is 10-15 wt% based on the total mass of the oil phase; And / or, the hydroxyl-containing monomer comprises any one or a combination of at least two of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, hydroxybutyl methacrylate, hydroxybutyl acrylate, dihydroxyethyl methacrylate and dihydroxypropyl acrylate.

3. The production method according to claim 1 or 2, characterized by, The temperature of the polymerization in step (2) is 60-65℃, and the time is 20-25 h.

4. The production method according to any one of claims 1 to 3, characterized by, The silane coupling agent with a double bond comprises any one or a combination of at least two of vinyltriethoxysilane, vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

5. The production method according to any one of claims 1 to 4, characterized by, Step (3) comprises: immersing the HIPE porous material in a solution containing a silane coupling agent with a double bond to obtain a primary modified product.

6. The production method according to claim 5, wherein In the solution containing the silane coupling agent with a double bond, the volume percentage concentration of the silane coupling agent with a double bond is 1-5%; And / or, the solution uses an alcohol solvent; And / or, the temperature of the immersion is 10-35℃, and the time is 2-4 h.

7. The production method according to any one of claims 1 to 6, characterized by, Step (4) comprises: mixing the primary modified product with a reaction mixture and performing a double bond addition copolymerization reaction to obtain the hydrophilic HIPE porous material, wherein the reaction mixture comprises a hydrophilic polymer monomer, a crosslinking agent and an initiator.

8. The preparation method according to claim 7, characterized in that, In the reaction mixture, the content of the hydrophilic polymer monomer is 5-15 w / v%, the content of the crosslinking agent is 1-3 w / v%, and the content of the initiator is 0.1-1 w / v%; And / or, the hydrophilic polymer monomer comprises any one or a combination of at least two of acrylamide, N-vinylpyrrolidone and acrylic acid; And / or, the crosslinking agent comprises any one or a combination of at least two of polyethylene glycol diacrylate, trimethylolpropane triacrylate and N,N'-methylenebisacrylamide; And / or, the temperature of the double bond addition copolymerization reaction is 10-35℃, and the time is 10-15 h.

9. A hydrophilic HIPE porous material obtained by the preparation method in any one of claims 1-8.

10. Use of the hydrophilic HIPE porous material in claim 9 in water treatment materials, adsorption separation materials, daily hygiene products, tissue engineering scaffolds or biomedical dressings.

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