Nanometer ZIF-8 modified polyurethane film coating and preparation method thereof

Abstract

The invention discloses a nano ZIF-8 modified polyurethane film coating and a preparation method thereof, and belongs to the field of high-performance composite film coatings. In the preparation method disclosed by the invention, the growth of ZIF-8 particles is limited by utilizing a low-temperature environment, the dispersion degree of ZIF-8 in PU is improved, the mechanical property of the composite coating is improved by utilizing the mechanical property of an inorganic substance shown by MOF, the crosslinking effect with the PU coating is enhanced by virtue of an organic functional group in the MOF, the combination of the MOF in the PU film coating is improved, and a long-range ordered structure of PU is blocked; according to the method, the use of large-scale instruments and equipment such as electrostatic spinning is avoided, and the method is simple, easy to implement and low in energy consumption. The problems that an existing modified PU film coating is poor in mechanical performance, complex in preparation method and the like in practical application are solved.

Description

Technical Field

[0001] The invention belongs to the field of high-performance composite film coatings, and specifically relates to a nano ZIF-8 modified polyurethane film coating and a preparation method thereof. Background Art

[0002] Polyurethane (PU) has excellent film-forming properties, adhesive properties, biodegradability and good biocompatibility. The film material prepared by it has great application prospects. Polyurethane is a high molecular polymer formed by the addition polymerization of isocyanate and polyhydroxy compounds, and its performance is between plastic and rubber. However, polyurethane contains a large number of strong polar groups such as -NCO, -OH, urea, etc., and its surface is relatively large, the elastic modulus is not high, the mechanical properties are poor, and the durability is low. Therefore, the mechanical properties and thermal stability of the PU matrix can be improved by modifying polyurethane with inorganic fillers such as titanium dioxide, silicon dioxide, nanoclay and nano zinc oxide, but there are still problems such as easy agglomeration and poor dispersibility, which will produce obvious color difference, and the abrasion resistance needs to be improved. Therefore, preparing nanofillers with good dispersibility and uniform distribution in composite film coatings will become a difficulty and breakthrough point in current research.

[0003] Metal-Organic Frameworks (MOFs) can simultaneously have organic functional groups that are easy to combine with PU matrix, and have the high strength performance of inorganic materials. Therefore, it is of great significance to use ZIF-8 materials as filling materials for thin films. However, the traditional method of modifying PU film coating mainly adopts electrostatic spinning method, which requires the use of large instruments and equipment, and the method is relatively cumbersome. In addition, the coordination constant of ZIF-8 is large, and it is easy to grow into large-sized grains, which is not conducive to the composite with PU matrix. Therefore, it is of great significance to explore a simple and effective composite method to comprehensively improve the mechanical properties and corrosion resistance of nano ZIF-8 modified polyurethane (PU) film coating. Summary of the invention

[0004] The purpose of the present invention is to provide a nano ZIF-8 modified polyurethane film coating and a preparation method thereof, so as to solve the problems of poor mechanical properties and complicated preparation methods of existing modified PU film coatings in practical applications.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a nano ZIF-8 modified polyurethane film coating, comprising:

[0007] S1: dissolving Zn(NO3)2·6H2O in methanol to obtain solution A, and dissolving l-dimethylimidazole in methanol to obtain solution B;

[0008] S2: low temperature treatment of solution A and solution B, and pouring the low temperature treated solution A into solution B and stirring to form a white turbid liquid C;

[0009] S3: Centrifuge the white turbid liquid C, collect the solid product, wash it with methanol and ethanol by centrifugation, and then dry it to obtain a white powder of ZIF-8;

[0010] S4: Ultrasonic dispersion of ZIF-8 white powder in polyurethane solution, stirring, and standing until no bubbles are present, to obtain a mixed solution D;

[0011] S5: Pour the mixed solution D onto a plate, scrape it flat, and let it stand to dry to obtain a ZIF-8 modified polyurethane film coating.

[0012] Preferably, in S1, 9 to 11 mmol Zn(NO3)2·6H2O is dissolved in 90 to 110 mL methanol to obtain solution A.

[0013] Preferably, in S1, 70-90 mmol of dimethylimidazole is dissolved in 90-110 mL of methanol to obtain solution B.

[0014] Preferably, the low temperature treatment of solution A and solution B in S2 is to place solution A and solution B in a refrigerator at 4° C. for 2 hours, respectively, until the solution temperature becomes constant.

[0015] Preferably, in S2, the low-temperature treated solution A is poured into solution B, and stirred continuously in a cold water bath at 4° C. for 20 to 50 minutes to form a white turbid liquid C.

[0016] Preferably, in S3, methanol and ethanol are centrifuged and washed at 8000 rpm for 6 times, and then vacuum dried at 65° C. for 10 hours.

[0017] Preferably, in S4, the concentration of the polyurethane solution is 12%.

[0018] Preferably, in S4, the mixture is stirred in a water bath at 60° C. for 20 to 30 minutes, and then allowed to stand at room temperature for 8 to 12 hours to remove bubbles, thereby obtaining a mixed solution D.

[0019] Preferably, in S5, the mixed solution D is poured onto a glass plate, flattened with a four-sided film applicator, and left to dry at room temperature for 24 hours to obtain a ZIF-8 modified polyurethane film coating.

[0020] A nano ZIF-8 modified polyurethane film coating is prepared by any one of the above-mentioned preparation methods.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) It avoids the use of large-scale instruments and equipment such as electrospinning, and the method is simple, easy and has low energy consumption.

[0023] 2) Using the mechanical properties of inorganic materials exhibited by ZIF-8 to improve the mechanical properties of composite coatings, such as Figure 3 shown.

[0024] 3) By using the organic functional groups in MOF to enhance the cross-linking effect with the PU coating, the combination of MOF in the PU film coating is improved, the long-range ordered structure of PU is blocked, and the impedance and corrosion resistance are increased. Figure 4 shown.

[0025] 4) Use low temperature environment to limit the growth of ZIF-8 particles and improve the dispersion of ZIF-8 in PU, such as Figure 2 shown. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 This is a SEM photo of the PU / ZIF-8 composite film synthesized by the present invention;

[0028] Figure 2 The XRD pattern of the PU / ZIF-8 composite film synthesized by the present invention;

[0029] Figure 3 It is the stress-strain diagram of the PU / ZIF-8 composite film synthesized by the present invention;

[0030] Figure 4 This is a graph showing the corrosion resistance of PU / ZIF-8 synthesized in the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0034] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0035] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0038] The present application discloses a method for preparing a nano ZIF-8 modified polyurethane film coating, comprising:

[0039] S1: dissolving Zn(NO3)2·6H2O in methanol to obtain solution A, and dissolving l-dimethylimidazole in methanol to obtain solution B;

[0040] S2: low temperature treatment of solution A and solution B, and pouring the low temperature treated solution A into solution B and stirring to form a white turbid liquid C;

[0041] S3: Centrifuge the white turbid liquid C, collect the solid product, wash it with methanol and ethanol by centrifugation, and then dry it to obtain a white powder of ZIF-8;

[0042] S4: Ultrasonic dispersion of ZIF-8 white powder in polyurethane solution, stirring, and standing until no bubbles are present, to obtain a mixed solution D;

[0043] S5: Pour the mixed solution D onto a plate, scrape it flat, and let it stand to dry to obtain a ZIF-8 modified polyurethane film coating; the SEM photo of the obtained ZIF-8 modified polyurethane film coating is shown in Figure 1 .

[0044] See also Figure 2 , XRD diagram of the PU / ZIF-8 composite film synthesized by the present invention, the present application utilizes a low temperature environment to limit the growth of ZIF-8 particles and improve the dispersion of ZIF-8 in PU, see Figure 3 , stress-strain diagram of the PU / ZIF-8 composite film synthesized by the present invention, the present application utilizes the mechanical properties of inorganic substances exhibited by MOF to improve the mechanical properties of the composite coating; see Figure 4 , the corrosion resistance performance diagram of PU / ZIF-8 synthesized by the present invention, the present application uses the organic functional groups in MOF to enhance the cross-linking effect with the PU coating, improves the combination of MOF in the PU film coating, blocks the long-range ordered structure of PU, and increases the impedance and corrosion resistance of the film coating; this method avoids the use of large-scale instruments and equipment such as electrospinning, and the method is simple, easy and has low energy consumption.

[0045] In some embodiments, a method for preparing a nano ZIF-8 modified polyurethane film coating comprises the following steps:

[0046] Step 1: Weigh 9-11 mmol Zn(NO3)2·6H2O and dissolve it in 90-110 mL methanol to obtain solution A, weigh 70-90 mmol dimethylimidazole and dissolve it in 90-110 mL methanol to obtain solution B, and stir at room temperature for 10-20 minutes until fully dissolved.

[0047] Step 2: Place solutions A and B in a 4°C refrigerator for 2 hours until the solution temperature becomes constant.

[0048] Step 3: Slowly pour the low-temperature treated solution A into solution B, and stir continuously in a cold water bath at 4°C for 20 to 50 minutes to gradually form a white turbid liquid C.

[0049] Step 4: The white turbid liquid C was centrifuged to collect the solid product, which was washed by centrifugation with methanol and ethanol (8000 rpm) for 6 times, and then dried in vacuo at 65° C. for 10 hours.

[0050] Step 5: Ultrasonic dispersion of the obtained ZIF-8 white powder in a 12% PU solution was performed, and the mixture was stirred in a 60°C water bath for 20 to 30 minutes, and then allowed to stand at room temperature for 8 to 12 hours to remove bubbles, thereby obtaining a mixed solution D.

[0051] Step 6: Pour the mixed solution D onto a glass plate, smooth it with a four-sided applicator, and let it stand and dry at room temperature for 24 hours to obtain a ZIF-8 modified polyurethane film coating.

[0052] Embodiment 1:

[0053] Step 1: Weigh 10 mmol Zn(NO3)2·6H2O and dissolve it in 100 mL methanol to obtain solution A, weigh 80 mmol dimethylimidazole and dissolve it in 100 mL methanol to obtain solution B, and stir at room temperature for 10 minutes until fully dissolved.

[0054] Step 2: Place solutions A and B in a 4°C refrigerator for 30 minutes until the solution temperature becomes constant.

[0055] Step 3: Slowly pour the low-temperature treated solution A into solution B, and stir continuously in a cold water bath at 4°C for 30 minutes to gradually form a white turbid liquid C.

[0056] Step 4: The white turbid liquid C was centrifuged to collect the solid product, which was washed by centrifugation with methanol and ethanol (8000 rpm) for 6 times, and then dried in vacuo at 65° C. for 10 hours.

[0057] Step 5: Ultrasonic dispersion of the obtained ZIF-8 white powder in a 12% PU solution was performed, and the mixture was stirred in a 60°C water bath for 25 minutes, and then allowed to stand at room temperature for 10 hours to remove bubbles, thereby obtaining a mixed solution D.

[0058] Step 6: Pour the mixed solution D onto a glass plate, smooth it with a four-sided applicator, and let it stand and dry at room temperature for 24 hours to obtain a ZIF-8 modified polyurethane film coating.

[0059] Embodiment 2:

[0060] Step 1: Weigh 9 mmol Zn(NO3)2·6H2O and dissolve it in 90 mL methanol to obtain solution A. Weigh 90 mmol dimethylimidazole and dissolve it in 110 mL methanol to obtain solution B. Stir at room temperature for 20 minutes until fully dissolved.

[0061] Step 2: Place solutions A and B in a 4°C refrigerator for 30 minutes until the solution temperature becomes constant.

[0062] Step 3: Slowly pour the low-temperature treated solution A into solution B, and stir continuously in a cold water bath at 4°C for 50 minutes to gradually form a white turbid liquid C.

[0063] Step 4: The white turbid liquid C was centrifuged to collect the solid product, which was washed by centrifugation with methanol and ethanol (8000 rpm) for 6 times, and then dried in vacuo at 65° C. for 10 hours.

[0064] Step 5: Ultrasonic dispersion of the obtained ZIF-8 white powder in a 12% PU solution was performed, and the mixture was stirred for 30 minutes in a 60°C water bath, and then allowed to stand at room temperature for 12 hours to remove bubbles, thereby obtaining a mixed solution D.

[0065] Step 6: Pour the mixed solution D onto a glass plate, smooth it with a four-sided applicator, and let it stand and dry at room temperature for 24 hours to obtain a ZIF-8 modified polyurethane film coating.

[0066] Embodiment 3:

[0067] Step 1: Weigh 11 mmol Zn(NO3)2·6H2O and dissolve it in 110 mL methanol to obtain solution A, weigh 70 mmol dimethylimidazole and dissolve it in 90 mL methanol to obtain solution B, and stir at room temperature for 10 minutes until fully dissolved.

[0068] Step 2: Place solutions A and B in a 4°C refrigerator for 30 minutes until the solution temperature becomes constant.

[0069] Step 3: Slowly pour the low-temperature treated solution A into solution B, and stir continuously in a cold water bath at 4°C for 20 minutes to gradually form a white turbid liquid C.

[0070] Step 4: The white turbid liquid C was centrifuged to collect the solid product, which was washed by centrifugation with methanol and ethanol (8000 rpm) for 6 times, and then dried in vacuo at 65° C. for 10 hours.

[0071] Step 5: Ultrasonic dispersion of the obtained ZIF-8 white powder in a PU solution with a concentration of 12%, stirring for 20 minutes in a 60°C water bath, and then standing at room temperature for 8 hours to remove bubbles, to obtain a mixed solution D.

[0072] Step 6: Pour the mixed solution D onto a glass plate, smooth it with a four-sided applicator, and let it stand and dry at room temperature for 24 hours to obtain a ZIF-8 modified polyurethane film coating.

[0073] In summary, the present invention discloses a nano ZIF-8 modified polyurethane thin film coating and a preparation method, which belongs to the field of high-performance composite thin film coatings. In the present invention, the growth of ZIF-8 particles is restricted by a low temperature environment, the dispersion of ZIF-8 in PU is improved, the mechanical properties of the inorganic material exhibited by MOF are used to improve the mechanical properties of the composite coating, the cross-linking effect with the PU coating is enhanced by means of the organic functional groups in MOF, the combination of MOF in the PU thin film coating is improved, the long-range ordered structure of PU is blocked, and the impedance and corrosion resistance of the thin film coating are increased. The method avoids the use of large-scale instruments and equipment such as electrospinning, and the method is simple, easy to operate and has low energy consumption.

[0074] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a nano ZIF-8 modified polyurethane film coating, characterized in that: include: S1: dissolving Zn(NO3)2·6H2O in methanol to obtain solution A, and dissolving l-dimethylimidazole in methanol to obtain solution B; S2: low temperature treatment of solution A and solution B, and pouring the low temperature treated solution A into solution B and stirring to form a white turbid liquid C; S3: Centrifuge the white turbid liquid C, collect the solid product, wash it with methanol and ethanol by centrifugation, and then dry it to obtain a white powder of ZIF-8; S4: Ultrasonic dispersion of ZIF-8 white powder in polyurethane solution, stirring, and standing until no bubbles are present, to obtain a mixed solution D; S5: Pour the mixed solution D onto a plate, scrape it flat, and let it stand to dry to obtain a ZIF-8 modified polyurethane film coating.

2. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In the S1, 9-11 mmol Zn(NO3)2·6H2O is dissolved in 90-110 mL methanol to obtain solution A.

3. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In the S1, 70-90 mmol of dimethylimidazole is dissolved in 90-110 mL of methanol to obtain solution B.

4. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: The low temperature treatment of solution A and solution B in S2 is to place solution A and solution B in a refrigerator at 4° C. for 2 hours, respectively, until the solution temperature is constant.

5. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In the above S2, the low temperature treated solution A is poured into the solution B, and the mixture is stirred in a cold water bath at 4°C for 20 to 50 minutes to form a white turbid liquid C.

6. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In S3, methanol and ethanol were centrifuged and washed 6 times at 8000 rpm, and then vacuum dried at 65°C for 10 hours.

7. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In the step S4, the concentration of the polyurethane solution is 12%.

8. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In the S4, the mixture is stirred in a water bath at 60° C. for 20 to 30 minutes, and then allowed to stand at room temperature for 8 to 12 hours to remove bubbles, thereby obtaining a mixed solution D.

9. The method for preparing a nano ZIF-8 modified polyurethane film coating according to claim 1, characterized in that: In the above S5, the mixed solution D is poured onto a glass plate, flattened with a four-sided film applicator, and left to dry at room temperature for 24 hours to obtain a ZIF-8 modified polyurethane film coating.

10. A nano ZIF-8 modified polyurethane film coating, characterized in that: The method is prepared by any one of claims 1 to 9.

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