Oil-absorbing foam and preparation method thereof

Abstract

The invention discloses oil-absorbing foam and a preparation method thereof, relates to the technical field of functional polymer materials, and discloses the oil-absorbing foam which is prepared from polyurethane acrylate, polystyrene-block isoprene-polystyrene and a photoinitiator. The oil-absorbing foam provided by the invention realizes efficient adsorption of petroleum, is simple to operate, and can be effectively applied to the fields of water purification, oil-water separation and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional polymer materials, and particularly relates to an oil-absorbing foam and a preparation method thereof. BACKGROUND

[0002] Oil spill accidents pose a serious threat to the ecological environment and human health. Conventional technologies mainly rely on physical, chemical and biological methods for emergency disposal, but all have significant limitations. In the physical method, oil containment booms can limit the spread of oil, but they have poor stability in harsh marine environments and high deployment costs, and the recovery efficiency is low. Chemical methods such as dispersants can promote oil emulsification and degradation, but may cause secondary pollution, and additional cleaning of residual materials is required. Biological degradation relies on specific bacteria, and the degradation period is as long as several weeks to several months, and the environmental conditions need to be strictly controlled. It can be seen that conventional technologies generally have problems such as complex operation. SUMMARY

[0003] The main purpose of the present application is to provide an oil-absorbing foam and a preparation method thereof. The oil-absorbing foam provided can realize efficient adsorption of oil, is simple to operate, and can be effectively applied to the fields of water purification and oil-water separation.

[0004] To achieve the above-mentioned purpose, the present application provides an oil-absorbing foam, the material of the oil-absorbing foam comprising: polyurethane acrylate, polystyrene-block-isoprene-polystyrene and a photoinitiator.

[0005] In an embodiment, the material of the oil-absorbing foam further comprises: an oil-absorbing filler, the particle size of the oil-absorbing filler being 0.1-2 mm.

[0006] In an embodiment, the density of the oil-absorbing foam is 0.01-0.8 g / cm2;

[0007] And / or, the porosity of the oil-absorbing foam is 50-90%;

[0008] And / or, the thickness of the oil-absorbing foam is 0.1-0.3 mm.

[0009] In an embodiment, the mass ratio between the polyurethane acrylate and the polystyrene-block-isoprene-polystyrene is 0.1-0.8;

[0010] And / or, the photoinitiator accounts for 0.5-5% of the total mass of the oil-absorbing foam.

[0011] In an embodiment, the polyurethane acrylate comprises aliphatic polyurethane acrylate and / or aromatic polyurethane acrylate.

[0012] In an embodiment, the photoinitiator comprises at least one of a free radical photoinitiator, a cationic photoinitiator, and a bifunctional photoinitiator.

[0013] In addition, to achieve the above object, the application further provides a method for preparing the oil-absorbing foam, which is applied to prepare the oil-absorbing foam as described above, and comprises the following steps:

[0014] The polyurethane acrylate, the polystyrene-block isoprene-polystyrene, the organic solvent, the photoinitiator and the soluble particles are mixed to obtain a mixed solution;

[0015] The mixed solution is subjected to photocuring to obtain a polymer material;

[0016] The polymer material is placed in a target solvent capable of dissolving the soluble particles to obtain the oil-absorbing foam.

[0017] In an embodiment, the particle size of the soluble particles is 0.1-2 mm.

[0018] In addition, to achieve the above object, the application further provides a method for preparing the oil-absorbing foam, which is applied to prepare the oil-absorbing foam as described above, and comprises the following steps:

[0019] The polyurethane acrylate, the polystyrene-block isoprene-polystyrene, the organic solvent and the photoinitiator are mixed to obtain a mixed solution;

[0020] The mixed solution is formed by a photocuring 3D printing technology to obtain the oil-absorbing foam.

[0021] In an embodiment, the printing temperature of the photocuring 3D printing technology is 180-230℃.

[0022] And / or, the printing speed of the photocuring 3D printing technology is 30-60 mm / s.

[0023] And / or, the filling density of the photocuring 3D printing technology is 30-50%.

[0024] The one or more technical solutions provided in the application have at least the following technical effects: an oil-absorbing foam is provided, and the material of the oil-absorbing foam comprises: polyurethane acrylate, polystyrene-block-isoprene-polystyrene, and a photoinitiator. The polyurethane acrylate in the oil-absorbing foam has poor compatibility with an alkane solvent, and is not easily affected by the solvent, so that the cross-linking reaction of the acrylic double bond in the polyurethane acrylate can be initiated by the photoinitiator to form a rigid three-dimensional network structure to serve as a stationary phase in the oil-absorbing foam, and excellent mechanical strength, stability and durability are given to the oil-absorbing foam. The polystyrene-block-isoprene-polystyrene in the oil-absorbing foam has a flexible chain segment, and can form a deformable soft phase to give the oil-absorbing foam good ductility and shape reversibility; at the same time, the polyisoprene chain segment contained in the polystyrene-block-isoprene-polystyrene has a flexible nonpolar structure, and has high similarity in chemical properties and intermolecular forces with long-chain hydrocarbon molecules in the alkane solvent. According to the principle of “like dissolves like”, the two have good compatibility, which is conducive to the penetration of solvent molecules and the induction of swelling of the polymer network, and promotes chain segment relaxation to achieve shape memory effect. Further, the material is prepared into a porous foam structure, and the inherent through-pore network of the foam structure can accelerate solvent penetration through capillary force, and the hierarchical pores (macro-pores, mesopores, micropores) realize selective adsorption, in which the macro-pores are responsible for fast transport of the solvent, the mesopores capture target solvent molecules through surface energy difference, and the micropores strengthen molecular-level adsorption. Therefore, when oil mainly composed of alkanes contacts the oil-absorbing foam, not only the pores are physically filled, but also the shape memory effect is triggered, so that the solvent molecules penetrate into the dynamic reversible phase of the material, the intermolecular forces are destroyed and the glass transition temperature is lowered, so that the material recovers from the compressed state to the expanded state, the porosity is significantly increased to expose more adsorption sites, to realize efficient adsorption of the oil, and the foam material has light weight characteristics and is easy to deploy and recover. At the same time, due to the stability of the material, no specific pH or temperature control is required, and the operation is simple. After the adsorption is completed, the reversible phase is restructured by solvent evaporation or external stimulation, the material shrinks and extrudes the pores and releases the adsorbate, to realize reversible circulation and avoid the difficulty of residual treatment. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A flowchart of a preparation method of the oil-absorbing foam involved in the embodiment of the application is provided.

[0026] Figure 2 Another flowchart of a preparation method of the oil-absorbing foam involved in the embodiment of the application is provided.

[0027] Figure 3 A test diagram of shape memory effect of the oil-absorbing foam in oil is provided.

[0028] Figure 4Fig. 1 is a graph showing the results of oil absorption ratio tests for the oil-absorbing foams of Examples 1 and 2 of the present application;

[0029] Figure 5 Fig. 2 is a graph showing the results of oil absorption ratio tests for the oil-absorbing foams of Examples 2 to 6 of the present application;

[0030] Figure 6 Fig. 3 is a graph showing the results of oil absorption performance tests for commercial oil-absorbing foams;

[0031] Figure 7 Fig. 4 is a graph showing the results of oil absorption performance tests for the oil-absorbing foams of Example 2 of the present application Figure 1 ;

[0032] Figure 8 Fig. 5 is a graph showing the results of oil absorption performance tests for the oil-absorbing foams of Example 2 of the present application Figure 2 ;

[0033] Figure 9 Fig. 6 is a graph showing the results of oil absorption performance tests for the oil-absorbing foams of Example 2 of the present application Figure 3 .

[0034] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be described clearly and completely below. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturers. The reagents or instruments not mentioned by the manufacturers are all conventional products that can be purchased in the market.

[0036] Hereinafter, the embodiments of the oil-absorbing foams and the methods for producing the same of the present application will be specifically described with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there will be cases where detailed descriptions of matters well known, repeated descriptions of substantially identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of the skilled person. Furthermore, the accompanying drawings and the following description are provided in order for the skilled person to fully understand the present application and are not intended to limit the subject matter recited in the claims.

[0037] The ranges disclosed herein are intended to be "open" ranges, i.e., the upper and lower limits of the range are not included. The ranges are also intended to include any and all sub-ranges of the range, i.e., all combinations of any two of the range limits, unless otherwise indicated. For example, a range of "1 to 10" is intended to include any number from 1 to 10, including the integers 1 and 10. Unless otherwise indicated, the use of "or" in the disclosed aspects herein is the inclusive, and not the exclusive use. Only the context, and not the number of times an item is used, can determine that it is the exclusive use. For example, the phrase "A uses B or C" means that A can use B, or A can use C, or A can use both B and C. As used herein, the term "about" means that the recited value is within 10% of the recited value, unless otherwise indicated. For example, "about 5" means that the value is within 10% of 5, i.e., the value is between 4.5 and 5.5. As used herein, the term "substantially" means that the recited characteristic, parameter, or value needs not be achieved exactly, but that deviations, if any, are insignificant in terms of the desired purpose. As used herein, the term "comprising" means that the recited component is included, but not necessarily exclusively. As used herein, the term "consisting essentially of means that the recited component is included, but that other components can also be included, provided that the other components do not materially alter the basic and novel characteristics of the claimed composition or method. As used herein, the term "consisting of means that the recited component is included, and that no other components are included.

[0038] All embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, unless otherwise specified.

[0039] All technical features and optional technical features of the present application can be combined with each other to form new technical solutions, unless otherwise specified.

[0040] All steps of the present application can be performed in sequence or randomly, preferably in sequence, unless otherwise specified. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0041] The terms "including" and "comprising" mentioned in the present application mean open-ended, and can also be closed-ended. For example, the terms "including" and "comprising" can mean that other components not listed can also be included, or only the listed components can be included.

[0042] If not specifically stated, the term "or" in this application is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any of the following satisfy the condition "A or B": A is true (or present) and B is false (or not present); A is false (or not present) and B is true (or present); or both A and B are true (or present).

[0043] In order to make the above objectives, features and advantages of the present application more obvious and comprehensible, the technical solutions of the present application will be further described below in conjunction with the accompanying drawings and embodiments. However, the present application is not limited to the listed embodiments, and should also include any known changes within the scope of the rights claimed by the present application.

[0044] The term "one embodiment" or "an embodiment" as used herein means that a particular feature, structure, or characteristic described can be included in at least one implementation of the present application. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily referring to the same embodiment, nor are they necessarily all directed to the same embodiment, or are they necessarily mutually exclusive of one another.

[0045] In order to better understand the technical solutions of the present application, the following will be described in detail in conjunction with the accompanying drawings and specific embodiments.

[0046] In conventional technology, oil spill mainly relies on physical, chemical and biological methods for emergency disposal, but all have significant limitations. In the physical method, the oil containment boom can limit the spread of oil, but it has poor stability in harsh marine environment and high deployment cost, and the recovery efficiency is low. Chemical methods such as dispersants can promote oil emulsification and degradation, but may cause secondary pollution, and additional cleaning of residues is required. Biological degradation relies on specific bacteria, and the degradation period is as long as several weeks to several months, and the environmental conditions need to be strictly controlled. It can be seen that conventional technology generally has problems such as complex operation.

[0047] The present application provides a solution, specifically, an oil-absorbing foam, the materials of which include: polyurethane acrylate, polystyrene-block isoprene-polystyrene, and a photoinitiator. The polyurethane acrylate in the oil-absorbing foam has poor compatibility with alkane solvents and is not easily affected by the solvent. Therefore, the photoinitiator can trigger a cross-linking reaction of the acrylic double bonds in the polyurethane acrylate to form a rigid three-dimensional network structure, which acts as a stationary phase in the oil-absorbing foam and gives the oil-absorbing foam excellent mechanical strength and stability. The polystyrene-block isoprene-polystyrene in the oil-absorbing foam has a long, flexible alkane chain, which enables the material to have good compatibility with alkane solvents. When the alkane solvent contacts the resin, due to the principle of like dissolves like, a deformable soft phase can be formed, giving the oil-absorbing foam good ductility and shape reversibility. Therefore, when the alkane solvent contacts the resin, the solvent molecules easily penetrate the resin and interact with the chain segments in the resin, causing swelling and promoting chain segment relaxation to achieve a shape memory effect. Furthermore, the material is prepared into a porous foam structure. The inherent through-pore network of the foam structure can accelerate solvent penetration through capillary forces, while the hierarchical pores (macroporous-mesopore-micropore) achieve selective adsorption. The macropores are responsible for rapid solvent transport, the mesopores capture target solvent molecules through surface energy differences, and the micropores enhance molecular-level adsorption. Therefore, when petroleum, mainly composed of alkanes, comes into contact with the oil-absorbing foam, it not only physically fills the pores but also triggers a shape memory effect, allowing solvent molecules to penetrate into the material's dynamic reversible phase, destroying the intermolecular forces and inducing a drop in the glass transition temperature, causing the material to recover from a compressed state to an expanded state. The porosity increases significantly, exposing more adsorption sites to achieve efficient adsorption of petroleum. The foam material is lightweight and therefore easy to deploy and recycle. At the same time, due to the stability of the material, it does not require specific pH or temperature control and is easy to operate. After adsorption is completed, the reversible phase is reconstructed through solvent evaporation or external stimulation, and the material shrinks, squeezing the pores and releasing the adsorbate, achieving a reversible cycle and avoiding the problem of residue disposal.

[0048] A first aspect of an embodiment of the present application provides an oil-absorbing foam, the materials of which include: polyurethane acrylate, polystyrene-block isoprene-polystyrene, and a photoinitiator.

[0049] Optionally, the material of the oil-absorbing foam is a solvent-responsive shape memory polymer, which is set as a porous foam structure to achieve a combination of the high specific surface area characteristics of the foam and the dynamic response capability of the shape memory material, thereby forming a unique synergistic adsorption mechanism.

[0050] Optionally, the oil absorbing foam has: a spiral path, a grid structure and / or a honeycomb structure.

[0051] Optionally, the oil absorbing foam has a uniform pore structure.

[0052] Optionally, the oil absorption foam has a pore size of 0.1-5 mm, for example, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc. The pore size can be adjusted according to the oil absorption performance required by the application. A smaller pore size helps to increase the surface area and adsorption rate of the foam, while a larger pore size can provide more oil storage space.

[0053] Optionally, the oil absorption foam can have a multi-layer structure, each layer having a different porosity or filler ratio to enhance the structural strength and oil absorption capacity of the foam.

[0054] For example, the surface layer of the oil absorption foam is designed with high porosity to enhance oil absorption, while the inner layer is designed with a tighter structure to provide better support and stability. Through this layered design, the physical properties of the foam are optimized, and the shape and oil absorption performance of the foam remain stable when in contact with oil substances for a long time.

[0055] Optionally, the polyurethane acrylate is a polymer that combines the advantages of polyurethane and acrylate. It is usually prepared by reacting polyurethane containing hydroxyl groups with acrylic acid or methacrylic acid, and has good mechanical properties, wear resistance, chemical resistance and excellent adhesion. In the embodiments of the present application, the crosslinking reaction of the acrylic double bond in the polyurethane acrylate is initiated by a photoinitiator to form a dense and rigid three-dimensional network structure, reducing the interaction between the material and the solvent, effectively serving as a stationary phase in the oil absorption foam, thereby imparting excellent mechanical strength, stability and durability to the material to facilitate oil absorption in various environments.

[0056] Optionally, polystyrene-block-isoprene-polystyrene (SIS, Styrene-Isoprene-Styrene block copolymer) is a thermoplastic elastomer composed of hard polystyrene blocks and soft polyisoprene blocks. Since SIS has flexible segments, it can form a deformable soft phase, so adding it to the oil absorption foam can impart good ductility and shape reversibility to the polymer. At the same time, polystyrene-block-isoprene-polystyrene has a flexible long alkane chain, which is similar in chemical properties to the long chain structure of alkane solvents, and according to the principle of similar compatibility, the two have good compatibility. Therefore, when the alkane solvent contacts the resin, the solvent molecules easily penetrate the resin and interact with the segments in the resin, causing swelling and promoting segment relaxation to achieve shape memory effect.

[0057] Optionally, the photoinitiator is a compound capable of generating active species (such as free radicals or cations) upon absorbing light energy, which can further initiate chemical reactions between monomers, oligomers or polymers, such as polymerization or crosslinking reactions. In the embodiments of the present application, the addition of the photoinitiator enables the oil-absorbing foam to undergo crosslinking reactions of the acrylic double bonds in the polyurethane acrylate under the action of light energy, with the aid of the photoinitiator, to form a rigid three-dimensional network structure. At the same time, the photoinitiator promotes the polymerization of the polyurethane acrylate and the polystyrene-block-isoprene-polystyrene, so as to combine the rigid network and the flexible chain segment, and construct a double-network structure with excellent mechanical properties and controllable shape memory effect.

[0058] In an implementable embodiment, the adsorbable solvents of the oil-absorbing foam include: alkanes solvents, such as petroleum, petroleum ether, cyclohexane, n-pentane, toluene, xylene, etc.

[0059] In an implementable embodiment, the material of the oil-absorbing foam further includes: oil-absorbing fillers. The addition of the oil-absorbing fillers can significantly improve the comprehensive adsorption performance of the material; wherein the fillers can directly enhance the capillary force by increasing the specific surface area and porosity, thereby improving the oil absorption capacity. The fillers can also optimize the mechanical strength and chemical stability of the foam, and enhance the hydrophobicity through surface modification, to realize selective adsorption of oil and water.

[0060] Optionally, the oil-absorbing fillers include: at least one of nano-silica, activated carbon and polystyrene particles.

[0061] Optionally, the nano-silica has a high specific surface area and surface silanol active sites, can efficiently adsorb oil molecules through hydrogen bonds and van der Waals forces, and is resistant to high temperature, suitable for high-temperature environment applications.

[0062] Optionally, the activated carbon has a developed microporous structure, has a high adsorption capacity for low-viscosity oil (such as gasoline), and has strong chemical stability, suitable for treatment in complex environments.

[0063] Optionally, the polystyrene particles have excellent hydrophobicity and low density, and thus can adsorb high-viscosity oil (such as crude oil) through swelling, and have low cost.

[0064] In an embodiment, the particle size of the oil absorption filler is 0.1-2 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, etc. If the particle size of the oil absorption filler is too small, the specific surface area thereof can be too large, and the oil absorption filler can easily agglomerate and affect the dispersibility. If the particle size is too large, the porosity and the adsorption sites decrease, and the rough surface can destroy the foam structure, resulting in poor mechanical properties. Therefore, the particle size of the oil absorption filler is determined to be 0.1-2 mm in the embodiments of the present application.

[0065] Optionally, the addition amount of the oil absorption filler is 1-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc. If the addition amount of the filler is too small, the oil absorption efficiency of the foam material can be slightly poor, the selectivity can be poor, and the adsorption capacity can be limited. If the addition amount of the filler is too large, the foam structure can be dense, the flexibility can decrease, and the foam forming process can be affected, and the foam structure can be destroyed, thereby affecting the overall oil absorption performance. Therefore, the addition amount of the oil absorption filler is determined to be 1-10% in the embodiments of the present application.

[0066] In an embodiment, the density of the oil absorption foam is 0.01-0.8 g / cm 2 , for example, 0.01 g / cm 2 , 0.02 g / cm 2 , 0.04 g / cm 2 , 0.06 g / cm 2 , 0.08 g / cm 2 , 0.1 g / cm 2 , 0.2 g / cm 2 , 0.3 g / cm 2 , 0.4 g / cm 2 , 0.5 g / cm 2 , 0.69 g / cm 2 , 0.7 g / cm 2 , 0.8 g / cm 2etc. If the density of the oil-absorbing foam is too large, it can cause the material to increase in weight, decrease in buoyancy, and sink in the ocean or water body, limiting its contact efficiency with oil pollution and increasing the cost of transportation and deployment. In addition, the porosity of high-density foam is usually low, so its adsorption capacity is significantly reduced, and the compression resilience is poor, making it difficult to recover oil by extrusion. If the density is too small, the foam can be easily broken by waves or water flow, losing its structural integrity. Moreover, too low a density can cause the pores to be too connected, and the adsorbed oil can easily flow out. Therefore, the density of the oil-absorbing foam is determined to be 0.01-0.8 g / cm3 in the embodiments of the present application. 2 .

[0067] In a feasible implementation, the porosity of the oil-absorbing foam is 50-90%, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc. If the porosity is too large, although the adsorption capacity can be improved, the mechanical properties can be severely weakened, causing the foam to collapse after adsorption due to the increase in weight of the oil. In addition, the high-porosity foam has poor shear resistance and can be easily torn in a dynamic water body. If the porosity is too small, the number of adsorption sites is directly limited, and the oil-absorbing capacity is significantly reduced. In addition, the reduction in pore size can hinder the diffusion of oil, prolonging the saturation adsorption time. Therefore, the porosity of the oil-absorbing foam is determined to be 50-90% in the embodiments of the present application.

[0068] In a feasible implementation, the thickness of the oil-absorbing foam is 0.1-0.3 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc. If the thickness is too large, it can hinder the uniformity of the solvent-triggered shape memory effect, and the internal pores cannot fully expand due to delayed solvent penetration, making it difficult to achieve the theoretical value of the actual adsorption capacity. In addition, the thick foam is difficult to completely desorb oil during recovery. If the thickness is too small, the effective adsorption volume is insufficient, and the single processing capacity is limited, requiring frequent replacement of materials and increasing the operation cost. Therefore, the thickness of the oil-absorbing foam is determined to be 0.1-0.3 mm in the embodiments of the present application.

[0069] In a feasible implementation, the polyurethane acrylate includes an aliphatic polyurethane acrylate and / or an aromatic polyurethane acrylate.

[0070] Alternatively, the polyurethane acrylate can also be a modified polyurethane acrylate, for example, a modified polyurethane acrylate with specific functional groups.

[0071] In an embodiment, the mass ratio of the polyurethane acrylate to the polystyrene-block-isoprene-polystyrene can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, etc. In the embodiment, the oil-absorbing foam is provided with a rigid network by the polyurethane acrylate to maintain the basic structure and stability of the material, and is provided with a flexible network by the polystyrene-block-isoprene-polystyrene to endow the material with flexibility and adsorption and response to alkanes. If the amount of the polyurethane acrylate is too large, the proportion of the stationary phase in the material is too high, which may inhibit the solvent responsiveness of the reversible phase and weaken the adsorption effect on oil. Conversely, if the amount of the polystyrene-block-isoprene-polystyrene is too large, the structural stability of the oil-absorbing foam may be poor. Therefore, the mass ratio of the polyurethane acrylate to the polystyrene-block-isoprene-polystyrene is determined to be 0.1-0.8 in the embodiment.

[0072] In an embodiment, the photoinitiator includes at least one of a free radical photoinitiator, a cationic photoinitiator, and a bifunctional photoinitiator.

[0073] The free radical photoinitiator is a photoinitiator capable of generating free radical active species after being irradiated by ultraviolet light or visible light, and the generated free radical active species can initiate chain radical polymerization of monomers containing unsaturated double bonds (such as acrylates). This type of photoinitiator has the characteristics of fast reaction speed and high curing efficiency.

[0074] Optionally, the free radical photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO), 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenyl ethan-1-one, and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0075] The cationic photoinitiator is a photoinitiator capable of generating active cations (such as superacids) by light excitation, and then initiating cationic polymerization of monomers such as epoxy resins and vinyl ethers. Compared with free radical polymerization, cationic polymerization has the advantages of being unaffected by oxygen, low shrinkage, stable performance after curing, etc., and is particularly suitable for thick coating or deep curing applications.

[0076] Optionally, the cationic photoinitiator includes at least one of aromatic diazonium salt, sulfonium salt, and iron arene complex.

[0077] Bifunctional photoinitiators refer to photoinitiators containing two different initiation functions in the same molecular structure, such as having both free radical initiation and cationic initiation capabilities, or introducing two initiation sites of the same type but respectively responding to light energy in one molecule. This design can achieve synergistic effect, improve photoinitiation efficiency, broaden the absorption spectrum range, or trigger multiple polymerization reaction mechanisms in the same material at the same time, thereby obtaining more excellent comprehensive performance.

[0078] Optionally, the bifunctional photoinitiator includes an oxime ester photoinitiator and / or a sulfur-containing xanthone derivative.

[0079] In a feasible embodiment, the photoinitiator accounts for 0.5-5% of the total mass of the oil-absorbing foam, for example, the photoinitiator accounts for 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. of the total mass of the solvent-sensitive resin. When the amount of photoinitiator is too small, it may lead to incomplete polymerization or significantly reduced reaction rate, which means that the number of free radicals or cations generated under light conditions is insufficient to effectively initiate the sufficient crosslinking process between components and between them, so that the polymer network structure is not dense enough, which may result in insufficient mechanical strength, poor stability and poor solvent absorption effect of the material. On the contrary, if the amount of photoinitiator is too large, it may cause local reaction to be too intense, forming a local overheating phenomenon, thereby damaging the microstructure and macroscopic performance of the material. At the same time, it may cause excessive crosslinking, and the polymer becomes too hard, losing the necessary flexibility and elasticity, also affecting the solvent absorption effect of the material. Therefore, the embodiments of the present application determine that the photoinitiator accounts for 0.5-5% of the total mass of the solvent-sensitive resin.

[0080] In the embodiment, an oil-absorbing foam is provided, and the material of the oil-absorbing foam comprises: polyurethane acrylate, polystyrene-block-isoprene-polystyrene and a photoinitiator. The polyurethane acrylate in the oil-absorbing foam has poor compatibility with alkanes solvent, and is not easily affected by the solvent, so that the cross-linking reaction of the acrylic double bond in the polyurethane acrylate can be initiated by the photoinitiator to form a rigid three-dimensional network structure to serve as a stationary phase in the oil-absorbing foam, and the oil-absorbing foam has excellent mechanical strength, stability and durability. The polystyrene-block-isoprene-polystyrene in the oil-absorbing foam has a flexible chain segment, and can form a deformable soft phase to give the oil-absorbing foam good ductility and shape reversibility; at the same time, the polyisoprene chain segment contained in the polystyrene-block-isoprene-polystyrene has a flexible non-polar structure, and has high similarity in chemical properties and intermolecular forces with long-chain hydrocarbon molecules in the alkanes solvent. According to the principle of "like dissolves like", the two have good compatibility, which is conducive to the penetration of solvent molecules and the induction of swelling of the polymer network, and promotes the relaxation of the chain segment to achieve the shape memory effect. Further, the material is prepared into a porous foam structure, and the inherent through-pore network of the foam structure can accelerate the penetration of the solvent through capillary force, and the hierarchical pores (macro-pores, mesopores and micropores) realize selective adsorption, in which the macro-pores are responsible for the rapid transport of the solvent, the mesopores capture target solvent molecules through surface energy difference, and the micropores strengthen the molecular level adsorption. Therefore, when the oil mainly composed of alkanes contacts the oil-absorbing foam, not only the pores are physically filled, but also the shape memory effect is triggered, so that the solvent molecules penetrate into the dynamic reversible phase of the material, the intermolecular forces are destroyed and the glass transition temperature is lowered, so that the material recovers from the compressed state to the expanded state, the porosity is significantly increased to expose more adsorption sites, to realize the efficient adsorption of the oil, and the foam material has the characteristics of light weight, so it is easy to deploy and recover. At the same time, due to the stability of the material, it is not necessary to control the specific pH or temperature, and the operation is simple. After the adsorption is completed, the reversible phase is reconstructed by solvent evaporation or external stimulation, the material shrinks and extrudes the pores and releases the adsorbate, to realize the reversible cycle and avoid the difficulty of residual treatment.

[0081] The second aspect of the embodiment of the present application provides an oil-absorbing foam preparation method, which refers to Figure 1 The oil-absorbing foam preparation method comprises the following steps:

[0082] Step A10, mixing the polyurethane acrylate, the polystyrene-block-isoprene-polystyrene, the organic solvent, the photoinitiator and the soluble particles to obtain a mixed solution.

[0083] In a feasible embodiment, the polyurethane acrylate, the polystyrene-block-isoprene-polystyrene and the organic solvent can be mixed first to obtain a first solution; then the photoinitiator and the soluble particles are added to the first solution to obtain a mixed solution.

[0084] Optionally, the organic solvent is a low boiling point solvent that can dissolve the polyurethane acrylate and the polystyrene-block-isoprene-polystyrene, so as to be volatilized quickly in the subsequent photocuring process and avoid being left in the polymer.

[0085] Optionally, the organic solvent comprises dichloromethane.

[0086] Optionally, the polyurethane acrylate comprises aliphatic polyurethane acrylate and / or aromatic polyurethane acrylate.

[0087] Optionally, the mass ratio between the polyurethane acrylate and the polystyrene-block-isoprene-polystyrene is 0.1-0.8.

[0088] Optionally, the photoinitiator comprises at least one of a free radical photoinitiator, a cationic photoinitiator and a bifunctional photoinitiator.

[0089] Optionally, the photoinitiator accounts for 0.5-5% of the total mass of the oil absorption foam.

[0090] Optionally, the amount of the dissolvable particles can be determined according to the porosity of the oil absorption foam.

[0091] Step A20, photocuring the mixed solution to obtain a polymer material;

[0092] In an available embodiment, the mixed solution is placed in a preset mold for photocuring to obtain the polymer material.

[0093] Optionally, the wavelength of the ultraviolet light for photocuring is 100-400 nm, and the curing time is 0.2-2 h.

[0094] Optionally, the polyurethane acrylate, the polystyrene-block-isoprene-polystyrene, the organic solvent and the photoinitiator are mixed to obtain a mixed solution; the mixed solution is placed in a mold containing dissolvable particles for photocuring to obtain a polymer material.

[0095] Step A30, placing the polymer material in a target solvent that can dissolve the dissolvable particles to obtain an oil absorption foam.

[0096] In an available embodiment, the polymer material is placed in a target solvent that can dissolve the dissolvable particles, so that the dissolvable particles in the polymer material are dissolved by the target solvent, and an oil absorption foam with a porous structure is obtained after drying.

[0097] Optionally, the dissolvable particles can be salt (sodium chloride) or sugar, and the target solvent can be water that can dissolve the above particles.

[0098] Optionally, the particle size of the dissolvable particles is 0.1-2 mm, for example, 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, etc. By controlling the particle size of the dissolvable particles, the oil absorption foam pore can be adjusted.

[0099] Optionally, the oil absorption foam can be compressed or programmed into various shapes above the transition temperature.

[0100] Optionally, the glass transition temperature of the oil absorption foam is 60-100℃.

[0101] Optionally, the oil absorption foam can undergo a shape memory recovery process during contact with oil.

[0102] Optionally, the oil absorption foam can be applied to the fields of oil-containing wastewater, offshore oil spills, etc.

[0103] In this embodiment, the oil absorption foam is prepared by introducing pores through a sacrificial template method, which is simple and can be customized according to actual needs, and is easy to mass-produce. The oil absorption foam prepared can achieve efficient adsorption of oil, and is easy to operate, and can be effectively applied to the fields of water purification and oil-water separation.

[0104] The third aspect of the embodiment of the present application provides an oil absorption foam preparation method, which is described with reference to Figure 2 The oil absorption foam preparation method comprises the following steps:

[0105] Step B10, mixing polyurethane acrylate, polystyrene-block-isoprene-polystyrene, organic solvent and photoinitiator to obtain a mixed solution;

[0106] Step B20, forming the mixed solution by light curing 3D printing technology to obtain the oil absorption foam.

[0107] In a feasible embodiment, polyurethane acrylate, polystyrene-block-isoprene-polystyrene, organic solvent and photoinitiator are mixed to obtain a mixed solution, and the mixed solution is formed by light curing 3D printing technology, for example, FDM (fused deposition modeling) or SLA (stereolithography), etc., and after drying, the oil absorption foam is obtained.

[0108] In a feasible embodiment, the printing temperature of the FDM light curing 3D printing technology is 180-230℃, for example, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, etc.

[0109] In an implementable embodiment, the printing speed of the light-curing 3D printing technology is 30-60 mm / s, for example, 30 mm / s, 40 mm / s, 50 mm / s, 60 mm / s, etc.

[0110] In an implementable embodiment, the filling density of the light-curing 3D printing technology is 30-50%, for example, 30%, 35%, 40%, 45%, 50%, etc. By controlling the filling density, the mechanical properties and oil absorption capacity of the foam can be adjusted.

[0111] In the present embodiment, by using the light-curing 3D printing technology, the structural parameters of the oil-absorbing foam can be accurately controlled, the oil-absorbing performance of the foam can be optimized, and the application of the foam in the field of environmental governance can be expanded.

[0112] In order to enable the above-mentioned details and operations of the embodiments of the present application to be clearly understood by those skilled in the art, and the significant performance of the embodiments of the present application to be embodied, the above-mentioned technical solutions are illustrated by multiple embodiments as follows.

[0113] Embodiment 1

[0114] (1) The aliphatic polyurethane acrylate and the polystyrene-block-isoprene-polystyrene are mixed in dichloromethane at a ratio of 1:2 to obtain a first solution, wherein the dichloromethane accounts for 80% of the total mass of the precursor solution;

[0115] (2) The photoinitiator TPO is added to the first solution, and the second solution is obtained by stirring at 200 rpm for 12 h under light-proof conditions, wherein the photoinitiator TPO accounts for 2% of the total mass of the solvent-sensitive resin;

[0116] (3) The second solution is poured into a pre-set mold, and the polymer material is obtained by curing under ultraviolet light of 395 nm for 1 h.

[0117] Embodiment 2

[0118] (1) The aliphatic polyurethane acrylate and the polystyrene-block-isoprene-polystyrene are mixed in dichloromethane at a ratio of 1:2 to obtain a first solution, wherein the dichloromethane accounts for 80% of the total mass of the precursor solution;

[0119] (2) The photoinitiator TPO is added to the first solution, and the second solution is obtained by stirring at 200 rpm for 12 h under light-proof conditions, wherein the photoinitiator TPO accounts for 2% of the total mass of the solvent-sensitive resin;

[0120] (3) The second solution is poured into a pre-set mold, and the polymer material is obtained by curing under ultraviolet light of 395 nm for 1 h.

[0121] (4) Put the polymer material into water to dissolve the sodium chloride particles, and dry to obtain the oil-absorbing foam.

[0122] Example 3

[0123] The preparation process and materials are the same as those of Example 2, except that the particle size of the sodium chloride particles is 100 μm.

[0124] Example 4

[0125] The preparation process and materials are the same as those of Example 2, except that the particle size of the sodium chloride particles is 300 μm.

[0126] Example 5

[0127] The preparation process and materials are the same as those of Example 2, except that the particle size of the sodium chloride particles is 700 μm.

[0128] Example 6

[0129] The preparation process and materials are the same as those of Example 2, except that the particle size of the sodium chloride particles is 900 μm.

[0130] The solvent response test of the polymer material in Example 1 is shown in Figure 3 , and the test process includes:

[0131] (1) Put the polymer material on a heating table, wherein the initial shape of the sample is as shown in Figure 3 (a), and then heat to 90℃ to fix the shape, and keep the external force;

[0132] (2) Cool the temperature to 25℃, and release the stress, wherein the temporary shape of the polymer material is as shown in Figure 3 (b);

[0133] (3) Put the polymer material in a container filled with oil, and it is observed that the polymer material gradually recovers from the temporary shape to the initial shape.

[0134] It can be seen from the above test that the oil-absorbing foam provided by the example has a high shape recovery rate in oil, and can perform shape memory response to oil.

[0135] The oil-absorbing rate test of the oil-absorbing foams in Example 1 and Example 2 is shown in Figure 4 , wherein Figure 4 the pore size structure in (b) represents Example 1, and the foam structure represents Example 2. It can be seen that the polymer material prepared in Example 1 can absorb oil, and the introduction of the pore structure (i.e. Example 2) can significantly improve the oil-absorbing performance of the material.

[0136] The oil absorption ratio test was performed on the oil absorption foam in Examples 2 to 6, and the results are shown in Table 1. Figure 5 As shown in Table 1, the size of the pore diameter significantly affects the oil absorption capacity; as the pore diameter increases, the oil absorption ratio increases, and the oil absorption effect is optimal at 500 μm.

[0137] The oil absorption performance of the oil absorption foam in Example 2 and the commercial oil absorption foam was compared, and the results are shown in Table 2. Figure 6 Figure 7 wherein, Figure 6 is the oil absorption effect of the commercial oil absorption foam, Figure 7 is the oil absorption effect of Example 2. As shown, the oil absorption foam of the present application has obvious advantages in terms of independent adsorption and oil absorption capacity.

[0138] The oil absorption foam in Example 2 was compressed and placed on the water surface with oil floating on it to test the oil absorption performance, and the results are shown in Table 3. Figure 8 As shown in Table 3, after contacting the oil, the oil absorption foam gradually absorbs oil and restores its shape over time, showing excellent oil absorption capacity, i.e., the oil absorption foam has high sensitivity to oil, enabling it to actively adsorb when it contacts oil.

[0139] The oil absorption foam in Example 2 was heated to 90°C, compressed and fixed in shape under external force, wherein the compression deformation was 0%, 20%, 40%, 60% and 80%, respectively, and then cooled to 25°C to release stress, so that the oil absorption foam remained in the deformed state. The deformed oil absorption foam was placed in a container containing oil, and the oil adsorption was observed, and the results are shown in Table 4. Figure 9 As shown in Table 4, as the compression strain of the foam increases, the saturated oil absorption ratio of the foam also gradually increases, proving that the oil absorption foam has the property of oil sensitivity, and the compression deformation can promote the oil absorption capacity of the foam.

[0140] The above are only preferred embodiments of the present application, and do not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the patent protection scope of the present application.​

Claims

1. An oil-absorbing foam, characterized in that: The materials of the oil-absorbing foam include polyurethane acrylate, polystyrene-block isoprene-polystyrene and a photoinitiator.

2. The oil-absorbing foam according to claim 1, wherein The material of the oil-absorbing foam further comprises: an oil-absorbing filler, and the particle size of the oil-absorbing filler is 0.1 to 2 mm.

3. The oil-absorbing foam according to claim 1, wherein The density of the oil-absorbing foam is 0.01 to 0.8 g / cm 2 ; and / or, the porosity of the oil-absorbing foam is 50 to 90%; And / or, the thickness of the oil-absorbing foam is 0.1 to 0.3 mm.

4. The oil-absorbing foam according to claim 1, wherein The mass ratio between the polyurethane acrylate and the polystyrene-block isoprene-polystyrene is 0.1 to 0.8; And / or, the photoinitiator accounts for 0.5-5% of the total mass of the oil-absorbing foam.

5. The oil-absorbing foam according to claim 1, wherein The polyurethane acrylate includes: aliphatic polyurethane acrylate and / or aromatic polyurethane acrylate.

6. The oil-absorbing foam according to claim 1, wherein The photoinitiator includes at least one of a free radical photoinitiator, a cationic photoinitiator and a bifunctional photoinitiator.

7. A method for preparing oil-absorbing foam, characterized in that: For preparing the oil-absorbing foam according to any one of claims 1 to 6, the method comprises the following steps: mixing polyurethane acrylate, polystyrene-block isoprene-polystyrene, an organic solvent, a photoinitiator and soluble particles to obtain a mixed solution; performing photocuring on the mixed solution to obtain a polymer material; The polymer material is placed in a target solvent that can dissolve the soluble particles to obtain an oil-absorbing foam.

8. The method for preparing oil-absorbing foam according to claim 7, wherein: The particle size of the soluble particles is 0.1 to 2 mm.

9. A method for preparing oil-absorbing foam, characterized in that: For preparing the oil-absorbing foam according to any one of claims 1 to 6, the method comprises the following steps: mixing polyurethane acrylate, polystyrene-block isoprene-polystyrene, an organic solvent and a photoinitiator to obtain a mixed solution; The mixed solution is formed by light-curing 3D printing technology to obtain oil-absorbing foam.

10. The method for preparing oil-absorbing foam according to claim 9, wherein: The printing temperature of the light-curing 3D printing technology is 180-230°C; And / or, the printing speed of the light-curing 3D printing technology is 30 to 60 mm / s; And / or, the filling density of the light-curing 3D printing technology is 30-50%.

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