A kind of super hydrophobic polyurethane foam and preparation method thereof

Abstract

The present invention provides a super-hydrophobic polyurethane foam and a preparation method thereof, and relates to the technical field of oil-water separation materials. The preparation method includes preparing polyurethane foam by reacting a polyester polyol mixed solution with isocyanate; Nano-scale silicon dioxide and nano-crystalline cellulose are mixed evenly to form a solid mixture, and the solid mixture is dispersed using an ethanol solution to dissolve and disperse to prepare a dip-coating solution; Polyurethane foam is placed in a dip-coating solution and subjected to at least one dip-coating and drying process, to prepare a super-hydrophobic polyurethane foam, and the dip-coating and drying process includes sequentially being subjected to ultrasonic treatment and drying process; Wherein, the mass ratio of polyester polyol to isocyanate in polyurethane foam is 2: 1 2: any value in 1.5, and the mass ratio of nano-scale silicon dioxide to nano-crystalline cellulose in the dip-coating solution is 5: 1 10: any value in 1. The super-hydrophobic polyurethane foam prepared by the preparation method of super-hydrophobic polyurethane foam in the present invention has excellent lipophilic and hydrophobic properties, and can be used in oil-water separation related fields.

Description

Technical Field

[0001] The invention relates to the technical field of oil-water separation materials, and in particular to a super-hydrophobic polyurethane foam and a preparation method thereof. Background Art

[0002] With the rapid development of global industrialization, a large amount of industrial water contaminated by organic matter, that is, industrial water usually contains various oils and organic solvents, has caused serious environmental and ecological pollution problems, seriously threatening the life of organisms.

[0003] In the prior art, oil-water separation methods usually include centrifugal separation, precipitation, osmosis or the use of biological materials and chemically modified materials, but the above methods have low efficiency and high cost, and cannot treat large amounts of sewage. Based on the needs of ecological and environmental protection, effective materials with fast absorption efficiency, good absorbency, large recovery volume, high selectivity, large specific surface area and low cost are widely used. Based on the spatial dimension, there are three main types of traditional oil-water separation materials: powder materials, membrane materials and three-dimensional porous materials. Among them, three-dimensional porous materials have a large specific surface area and developed pores, and are a high-capacity absorption material. As an excellent three-dimensional porous material, polyurethane foam has a large surface area and developed pores, but it does not have superhydrophobicity and cannot be used for oil-water separation. Summary of the invention

[0004] An object of the first aspect of the present invention is to provide a method for preparing a super hydrophobic polyurethane foam, so as to solve the technical problem in the prior art that the polyurethane foam has poor hydrophobic properties and cannot achieve oil-water separation.

[0005] Another object of the first aspect of the present invention is to further improve the hydrophobic properties of the superhydrophobic polyurethane foam.

[0006] The second aspect of the present invention aims to provide a super hydrophobic polyurethane foam prepared according to the above preparation method.

[0007] According to the purpose of the first aspect of the present invention, the present invention provides a method for preparing a super hydrophobic polyurethane foam, comprising:

[0008] Polyurethane foam is prepared by reacting a polyester polyol mixed solution with isocyanate;

[0009] Mixing nano-sized silicon dioxide and nano-crystalline cellulose uniformly to form a solid mixture, and dissolving and dispersing the solid mixture using an ethanol solution to prepare a dipping solution;

[0010] The polyurethane foam is placed in the dipping solution and subjected to at least one dipping and drying treatment to prepare a super-hydrophobic polyurethane foam, wherein the dipping and drying treatment includes sequentially performing an ultrasonic treatment and a drying treatment; wherein,

[0011] The mass ratio of the polyester polyol to the isocyanate in the polyurethane foam is any value in the range of 2:1-2:1.5, and the mass ratio of the nano-scale silicon dioxide to the nano-crystalline cellulose in the dipping solution is any value in the range of 5:1-10:1.

[0012] Optionally, the ultrasonic treatment time is any value between 50 min and 90 min.

[0013] Optionally, the temperature of the drying treatment is any value between 40°C and 60°C, and the time of the drying treatment is any value between 4h and 8h.

[0014] Optionally, the step of dissolving and dispersing the solid mixture using an ethanol solution to prepare a dipping solution further comprises:

[0015] The ethanol solution added to the solid mixture is sequentially subjected to magnetic stirring and ultrasonic dispersion treatments.

[0016] Optionally, before the step of placing the polyurethane foam into the dipping solution for at least one dipping and drying treatment, the method further comprises:

[0017] The polyurethane foam is pretreated.

[0018] Optionally, the polyester polyol mixed solution comprises polyester polyol, a catalyst, a foaming agent, a foam stabilizer and deionized water; wherein,

[0019] The polyester polyol is any one of polyethylene terephthalate, polyethylene adipate and polyethylene carbonate.

[0020] Optionally, the mass ratio of the catalyst to the polyester polyol in the polyester polyol mixed solution is any value in the range of 0.005-0.01.

[0021] Optionally, the mass ratio of the blowing agent to the polyester polyol in the polyester polyol mixed solution is any value between 0.06 and 0.1.

[0022] Optionally, the isocyanate is any one of diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, and isophorone diisocyanate.

[0023] According to the purpose of the second aspect of the present invention, the present invention also provides a super hydrophobic polyurethane foam prepared according to any of the preparation methods described above, wherein the super hydrophobic polyurethane foam comprises polyurethane foam, nanocrystalline cellulose and nano-scale silica.

[0024] The polyurethane foam prepared by reacting polyester polyol with isocyanate is placed in a dipping solution containing nano-silicon dioxide and nano-crystalline cellulose, and the polyurethane foam is ultrasonically treated so that the nano-crystalline cellulose and part of the nano-silicon dioxide are evenly infiltrated into the surface of the polyurethane foam, ensuring that the nano-silicon dioxide in the dipping solution is coated on the surface of the polyurethane foam through nanofiber crystallization, thereby increasing the attachment amount and attachment uniformity of the silicon dioxide on the surface of the polyurethane foam, thereby improving the hydrophobic performance of the super-hydrophobic polyurethane foam.

[0025] Furthermore, before the polyurethane foam is soaked in the dipping solution, the present invention pre-treats the polyurethane foam, including sequentially soaking the polyurethane foam in an acetone solution, soaking in an anhydrous ethanol solution, ultrasonic cleaning, and drying. That is, the acetone solution is used to dissolve the organic reagent that has not completely reacted in the polyurethane foam, and the anhydrous ethanol is used to dissolve the acetone solution. Finally, the anhydrous ethanol solution in the polyurethane foam is ultrasonically cleaned to reduce the influence of impurities on the surface of the polyurethane foam on the adhesion ability of nanocrystalline cellulose, thereby improving the combination stability of the nanocrystalline cellulose and the polyurethane foam, and further improving the hydrophobic performance of the super-hydrophobic polyurethane foam.

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0028] Figure 1 is a schematic flow chart of a method for preparing a super-hydrophobic polyurethane foam according to one embodiment of the present invention;

[0029] Figure 2 is a schematic structural diagram of the contact angle of the super-hydrophobic polyurethane foam prepared according to Example 1 of the present invention;

[0030] Figure 3 is a diagram showing the oil-water separation results of the super-hydrophobic polyurethane foam prepared according to Example 1 of the present invention;

[0031] Figure 4 is a scanning electron microscope image of the overall structure of the super-hydrophobic polyurethane foam prepared according to Example 1 of the present invention;

[0032] Figure 53 is a scanning electron microscope image of the super-hydrophobic polyurethane foam skeleton prepared according to Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0035] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0036] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] Figure 1 Detailed description of the invention The invention is a schematic flow chart of a method for preparing a superhydrophobic polyurethane foam according to an embodiment of the present invention.

[0038] like Figure 1 As shown, the present invention provides a method for preparing a super-hydrophobic polyurethane foam, comprising:

[0039] Step S100: preparing polyurethane foam by reacting a polyester polyol mixed solution with isocyanate;

[0040] Step S200: mixing nano-scale silicon dioxide and nano-crystalline cellulose uniformly to form a solid mixture, and dissolving and dispersing the solid mixture using an ethanol solution to prepare a dipping solution;

[0041] Step S300: placing the polyurethane foam in a dipping solution and performing at least one dipping and drying treatment to prepare a superhydrophobic polyurethane foam, the dipping and drying treatment comprising sequentially performing ultrasonic treatment and drying treatment, wherein the mass ratio of the polyester polyol to the isocyanate in the polyurethane foam is any value in the range of 2:1-2:1.5, and the mass ratio of nano-silicon dioxide to nano-crystalline cellulose in the dipping solution is any value in the range of 5:1-10:1.

[0042] In this embodiment, a polyester polyol mixed solution is first reacted with an isocyanate to prepare a polyurethane foam, then nano-scale silicon dioxide and nano-crystalline cellulose are uniformly mixed to form a solid mixture, and an ethanol solution is used to dissolve and disperse the solid mixture to prepare a dip coating solution, and finally the polyurethane foam is placed in the dip coating solution for at least one dip coating and drying treatment to prepare a super-hydrophobic polyurethane foam, and the dip coating and drying treatment includes sequentially ultrasonic treatment and drying treatment. Here, the number of dip coating and drying treatments can be once, twice, or multiple times.

[0043] In this embodiment, the polyurethane foam prepared by reacting polyester polyol with isocyanate is placed in a dipping solution containing nano-silicon dioxide and nano-crystalline cellulose, and the polyurethane foam is ultrasonically treated to uniformly infiltrate the nano-crystalline cellulose and part of the nano-silicon dioxide into the surface of the polyurethane foam, thereby ensuring that the nano-silicon dioxide in the dipping solution is coated on the surface of the polyurethane foam through nanofiber crystallization, thereby increasing the adhesion amount and adhesion uniformity of the silicon dioxide on the surface of the polyurethane foam, thereby improving the hydrophobic properties of the super-hydrophobic polyurethane foam.

[0044] In this embodiment, the preparation principle of the super-hydrophobic polyurethane foam is as follows: nano-crystalline cellulose contains abundant hydroxyl groups, which can form hydrogen bonds with the amino groups on the surface of the polyurethane foam, and can also form hydrogen bonds with the outer oxygen atoms of silica, that is, silica is uniformly and stably attached to the surface of the polyurethane foam through nano-crystalline cellulose, and because the outer oxygen atoms of silica can also combine with the amino groups on the surface of the polyurethane foam to form hydrogen bonds, the hydrophobic properties of the super-hydrophobic polyurethane foam are further improved.

[0045] In this embodiment, the mass ratio of the polyester polyol to the isocyanate in the polyurethane foam is any value in the range of 2:1-2:1.5, that is, the mass ratio of the polyester polyol to the isocyanate in the polyurethane foam can be 2:1, 2:1.1, 2:1.2, 2:1.3, 2:1.4 or 2:1.5, or any value in the range of 2:1-2:1.5. By setting the mass ratio of the polyester polyol to the isocyanate in the polyurethane foam within the above range, the cross-linking degree of the prepared polyurethane foam is moderate, and the hardness and softness can be balanced, while taking into account both comfort and support, so as to ensure its structural stability during the oil-water separation process.

[0046] In this embodiment, the mass ratio of nano-scale silicon dioxide to nano-crystalline cellulose in the dipping solution is any value in the range of 5: 1-10: 1, that is, the mass ratio of nano-scale silicon dioxide to nano-crystalline cellulose in the dipping solution can be 5: 1, 6: 1, 7: 1, 8: 1, 9: 1 or 10: 1, or any value in the range of 5: 1-10: 1. By setting the mass ratio of nano-scale silicon dioxide to nano-crystalline cellulose in the dipping solution within the above range, that is, ensuring that the content of nano-scale silicon dioxide is much greater than the content of nano-crystalline cellulose, the nano-crystalline cellulose can be stably attached to the polyurethane foam while also being able to attach more nano-scale silicon dioxide, so that the nano-scale silicon dioxide is attached to the polyurethane foam as much as possible, thereby improving the hydrophobic properties of the super-hydrophobic polyurethane foam.

[0047] In a further embodiment, the ultrasonic treatment time is any value between 50 min and 90 min, that is, the ultrasonic treatment time after the polyurethane foam is soaked in the dipping solution can be 50 min, 60 min, 70 min, 80 min or 90 min, or any value between 50 min and 90 min. In this embodiment, the polyurethane foam is soaked in the dipping solution and then subjected to ultrasonic treatment for the time within the above range, so that the nano-scale silicon dioxide and nano-crystalline cellulose in the dipping solution can be evenly dispersed on the surface of the polyurethane foam, thereby improving the distribution uniformity of the nano-scale silicon dioxide.

[0048] In a further embodiment, the temperature of the drying treatment is any value in 40 ℃-60 ℃, and the time of the drying treatment is any value in 4h-8h, that is, the polyurethane foam is soaked in the dipping solution and after ultrasonic treatment, the temperature of the drying treatment can be 40 ℃, 45 ℃, 50 ℃, 55 ℃ or 60 ℃, or any value in 40 ℃-60 ℃, and the time of the drying treatment can be 4h, 5h, 6h, 7h or 8h, or any value in 4h-8h. By setting the temperature and time of the drying treatment within the above range, the volatilization rate of the solvent and the deposition and curing process of the solid mixture on the foam surface can be balanced, and the temperature is too high to cause the solvent to volatilize too fast and cause the uneven aggregation of nano materials or the surface damage of the foam, and the coating after dipping can also be prevented from being completely dried due to the low temperature, which affects the hydrophobicity and surface stability of the super-hydrophobic polyurethane foam.

[0049] In a further embodiment, step S200 further includes:

[0050] The ethanol solution added with the solid mixture is subjected to magnetic stirring and ultrasonic dispersion treatments in sequence.

[0051] In this embodiment, after the solid mixture is added to the ethanol solution, the mixed solution is subjected to magnetic stirring and ultrasonic dispersion to fully disperse the nano-silicon dioxide in the solid mixture in the ethanol solution, thereby improving the distribution uniformity of the nano-silicon dioxide in the dip-coating solution and facilitating the subsequent uniform distribution of the silicon dioxide in the super-hydrophobic polyurethane foam.

[0052] In a further embodiment, before step S300, the following steps are further included:

[0053] Pre-treat polyurethane foam.

[0054] In this embodiment, before the polyurethane foam is immersed in the dipping solution, the step of pretreating the polyurethane foam includes sequentially soaking the polyurethane foam in an acetone solution, soaking in an anhydrous ethanol solution, ultrasonic cleaning and drying, that is, using the acetone solution to dissolve the incompletely reacted organic reagent in the polyurethane foam, and using anhydrous ethanol to dissolve the acetone solution, and finally using ultrasonic cleaning of the anhydrous ethanol solution in the polyurethane foam to reduce the effect of impurities on the surface of the polyurethane foam on the adhesion ability of nanocrystalline cellulose, thereby improving the bonding stability between the nanocrystalline cellulose and the polyurethane foam.

[0055] In a further embodiment, the polyester polyol mixed solution includes polyester polyol, catalyst, foaming agent, foam stabilizer and deionized water, wherein the polyester polyol is any one of polyethylene terephthalate, polyethylene adipate and polyethylene carbonate. In this embodiment, the hydroxyl group of the polyester polyol reacts with the isocyanate group in the isocyanate to form a polyurethane skeleton, and the curling group generates a large number of bubbles under the action of the foaming agent and forms a foam structure. As the reaction proceeds, the molecular weight of the polyurethane increases continuously, and the foam gradually changes from a liquid state to a solid state. The bubbles are fixed in the cured polyurethane matrix to form a stable porous structure, and finally a polyurethane foam with specific properties is obtained. Here, the catalyst can be any one of triethylenediamine, dimethylaminoethyl or stannous octoate, the blowing agent can be azodicarbonamide or toluenesulfonyl hydrazide, the foam stabilizer can be polydimethylsiloxane-polyether copolymer or polyethylene oxide-polypropylene oxide block copolymer, and deionized water can react with isocyanate to form carbon dioxide gas, and form foam under the action of the blowing agent, thereby increasing the foam content of the polyurethane foam.

[0056] In a further embodiment, the mass ratio of the catalyst to the polyester polyol in the polyester polyol mixed solution is any value in the range of 0.005-0.01, that is, the mass ratio of the catalyst to the polyester polyol in the polyester polyol mixed solution can be 0.005, 0.006, 0.007, 0.008, 0.009 or 0.01, or any value in the range of 0.005-0.01. The catalyst is used to accelerate the reaction rate of the isocyanate group in the isocyanate with the hydroxyl group in the polyester polyol, which not only promotes the formation of foam, but also controls the structure of the foam, for example, the porosity and stability of the foam. By setting the catalyst in the polyester polyol within the above range, the reaction rate of the isocyanate group in the isocyanate with the polyester polyol can be accelerated, and the formation rate of the polyurethane foam can be increased.

[0057] In a further embodiment, the mass ratio of the blowing agent to the polyester polyol in the polyester polyol mixed solution is any value in the range of 0.06-0.1, that is, the mass ratio of the blowing agent to the polyester polyol can be 0.06, 0.07, 0.08, 0.09 or 0.1, or any value in the range of 0.06-0.1. The blowing agent is used to generate a foam structure, usually by initiating the release of gas to form bubbles. By setting the mass ratio of the blowing agent to the polyester polyol within the above range, the yield of carbon dioxide generated by the isocyanate reaction converted into bubbles can be increased, thereby improving the porous structure in the polyurethane foam.

[0058] In a further embodiment, the isocyanate is any one of diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, and isophorone diisocyanate. In this embodiment, different isocyanates have different molecular structures and reaction characteristics, that is, the polyurethane foam produced when different isocyanates react with polyester polyols also has different performances in hardness, elasticity, chemical resistance, heat resistance, etc., and the type of isocyanate can be selected according to the requirements of the tissue foam.

[0059] The present invention also provides a super hydrophobic polyurethane foam, which is prepared according to any one of the above preparation methods, and the super hydrophobic polyurethane foam comprises polyurethane foam, nanocrystalline cellulose and nano-scale silicon dioxide. The preparation method of the super hydrophobic polyurethane foam is not described here one by one.

[0060] In this embodiment, nano-scale silicon dioxide is evenly distributed on the surface of the super-hydrophobic polyurethane foam, which has strong oleophilic and hydrophobic properties and can be used for complete separation of oil and water.

[0061] The present application will be further described in detail below with reference to specific embodiments.

[0062] In some embodiments, a polyester polyol mixed solution is first reacted with isocyanate to prepare a polyurethane foam, nano-silicon dioxide and nano-crystalline cellulose are evenly mixed to form a solid mixture, an ethanol solution is used to dissolve and disperse the solid mixture to prepare a dipping solution, and the polyurethane foam is placed in the dipping solution for at least one dipping and drying treatment to prepare a super-hydrophobic polyurethane foam, the dipping and drying treatment comprising ultrasonic treatment and drying treatment in sequence, the ultrasonic treatment time is any value between 50 min and 90 min, the drying treatment temperature is any value between 40°C and 60°C, the drying treatment time is any value between 4h and 8h, the mass ratio of polyester polyol to isocyanate in the polyurethane foam is any value between 2:1 and 2:1.5, and the mass ratio of nano-silicon dioxide to nano-crystalline cellulose in the dipping solution is any value between 5:1 and 10:1.

[0063] Example 1

[0064] Firstly, polyurethane foam is prepared by reacting polyethylene terephthalate with diphenylmethane diisocyanate, wherein the mass ratio of polyethylene terephthalate to diphenylmethane diisocyanate is 2:1. Then, nano-scale silicon dioxide and nano-crystalline cellulose with a mass ratio of 7:1 are dissolved in an ethanol solution to prepare a dipping solution. The polyurethane foam is immersed in the dipping solution and ultrasonically treated for 60 minutes. Then, it is baked at 50°C for 6 hours to prepare a superhydrophobic polyurethane foam.

[0065] Comparative Example 1

[0066] The only difference between Comparative Example 1 and Example 1 is that the dipping solution does not include nano-sized silicon dioxide.

[0067] Comparative Example 2

[0068] The only difference between Comparative Example 2 and Example 1 is that nanocrystalline cellulose is not included in the dipping solution.

[0069] First, the lipophilicity of the super-hydrophobic polyurethane foam was characterized. Table 1 shows the adsorption rate of soybean oil by the polyurethane foam in Example 1 and Comparative Examples 1-2 according to the present invention.

[0070] Table 1. Adsorption rate of soybean oil by polyurethane foam in Example 1 and Comparative Examples 1-2

[0071]

[0072]

[0073] As shown in Table 1, the super-hydrophobic polyurethane foam in Example 1 has a higher adsorption rate to soybean oil, and can still maintain a certain adsorption rate after repeated use, showing good lipophilicity and durability. Comparative Example 1 has a good adsorption effect on soybean oil, but the adsorption rate of Comparative Example 2 is the lowest among the three, and the adsorption effect is poor, indicating that only silicon dioxide is used to dip-coat polyurethane foam, and silicon dioxide cannot be uniformly adsorbed on the polyurethane skeleton, and scattered silicon dioxide can block the polyurethane gap and affect the oil absorption effect, while using nano-crystalline cellulose and nano-silicon dioxide mixed solution to dip-coat polyurethane foam, silicon dioxide can be uniformly and stably adsorbed on the polyurethane skeleton, and the gap is clear, so that it has strong lipophilicity and super-hydrophobicity.

[0074] Then, the contact angle test was performed on the super hydrophobic polyurethane foam in Example 1 and Comparative Examples 1-2. Table 2 shows the contact angle test results of the super hydrophobic polyurethane foam in Example 1 and Comparative Examples 1-2 according to the present invention. Figure 2 3 is a schematic structural diagram of the contact angle of the super-hydrophobic polyurethane foam prepared according to Example 1 of the present invention.

[0075] Table 2. Contact angle test results of super hydrophobic polyurethane foam in Example 1 and Comparative Examples 1-2

[0076] Contact angle Example 1 152.3° Comparative Example 1 68.5° Comparative Example 2 128.7°

[0077] As shown in Table 2, the contact angles of the super-hydrophobic polyurethane foams prepared in Example 1, Comparative Example 1 and Comparative Example 2 were 152.3° (refer to Figure 2 ), 68.5°, 128.7°. Since the contact angle of the super-hydrophobic polyurethane foam to water is greater than 150°, it shows super-phobicity, and less than 90°, it shows hydrophilicity. Therefore, the super-hydrophobic polyurethane foam prepared in Example 1 has excellent hydrophobic properties.

[0078] Finally, the super hydrophobic polyurethane foam prepared in Example 1 was subjected to an oil-water separation test. Figure 3 is a diagram showing the oil-water separation results of the super-hydrophobic polyurethane foam prepared according to Example 1 of the present invention, Figure 4 is a scanning electron microscope image of the overall structure of the super-hydrophobic polyurethane foam prepared according to Example 1 of the present invention, Figure 5 3 is a scanning electron microscope image of the super-hydrophobic polyurethane foam skeleton prepared according to Example 1 of the present invention.

[0079] like Figure 3 As shown, a mixed solution of water and soybean oil marked with methyl blue is placed in a funnel, and a super-hydrophobic polyurethane foam is installed at the bottom of the funnel. It can be found that the soybean oil flows into the conical flask through the polyurethane foam under the action of gravity, while the water cannot pass through the polyurethane foam and stays in the funnel, indicating that the super-hydrophobic polyurethane foam prepared in Example 1 has excellent oil-water separation performance.

[0080] like Figure 4 and Figure 5 As shown, the network structure of the super hydrophobic polyurethane foam prepared in Example 1 is evenly distributed, indicating that an excellent three-dimensional porous structure is successfully prepared.

[0081] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a super hydrophobic polyurethane foam, characterized in that, include: Polyurethane foam is prepared by reacting a polyester polyol mixed solution with isocyanate; Mixing nano-sized silicon dioxide and nano-crystalline cellulose uniformly to form a solid mixture, and dissolving and dispersing the solid mixture using an ethanol solution to prepare a dipping solution; The polyurethane foam is placed in the dipping solution and subjected to at least one dipping and drying treatment to prepare a super-hydrophobic polyurethane foam, wherein the dipping and drying treatment includes sequentially performing an ultrasonic treatment and a drying treatment; wherein, The mass ratio of the polyester polyol to the isocyanate in the polyurethane foam is any value in the range of 2:1-2:1.5, and the mass ratio of the nano-scale silicon dioxide to the nano-crystalline cellulose in the dipping solution is any value in the range of 5:1-10:

1.

2. The preparation method according to claim 1, characterized in that: The ultrasonic treatment time is any value between 50 min and 90 min.

3. The preparation method according to claim 2, characterized in that: The temperature of the drying treatment is any value between 40° C. and 60° C., and the time of the drying treatment is any value between 4 h and 8 h.

4. The preparation method according to claim 3, characterized in that: The step of dissolving and dispersing the solid mixture with an ethanol solution to prepare a dip coating solution further comprises: The ethanol solution added to the solid mixture is sequentially subjected to magnetic stirring and ultrasonic dispersion treatments.

5. The preparation method according to claim 4, characterized in that: Before the step of placing the polyurethane foam into the dipping solution for at least one dipping and drying process, the step further includes: The polyurethane foam is pretreated.

6. The preparation method according to claim 5, characterized in that: The polyester polyol mixed solution comprises polyester polyol, a catalyst, a foaming agent, a foam stabilizer and deionized water; wherein, The polyester polyol is any one of polyethylene terephthalate, polyethylene adipate and polyethylene carbonate.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the catalyst to the polyester polyol in the polyester polyol mixed solution is any value in the range of 0.005-0.

01.

8. The preparation method according to claim 6, characterized in that: The mass ratio of the foaming agent to the polyester polyol in the polyester polyol mixed solution is any value in the range of 0.06-0.

1.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The isocyanate is any one of diphenylmethane diisocyanate, polyphenylmethane polyisocyanate and isophorone diisocyanate.

10. A super hydrophobic polyurethane foam, characterized in that: The super-hydrophobic polyurethane foam is prepared according to the preparation method described in any one of claims 1 to 9, wherein the super-hydrophobic polyurethane foam comprises polyurethane foam, nano-crystalline cellulose and nano-scale silica.

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