Hyperbranched-like pressure-sensitive adhesive with underwater and under-oil broad-spectrum adhesion capability as well as preparation method and application of hyperbranched-like pressure-sensitive adhesive

Abstract

The invention provides a hyperbranched-like pressure-sensitive adhesive with underwater and under-oil broad-spectrum bonding capability as well as a preparation method and application of the hyperbranched-like pressure-sensitive adhesive. 4, 4 '-diaminodicyclohexylmethane and N, N'-methylene bisacrylamide are adopted and heated in a polar solvent, an out-of-order hyperbranched polymer is formed through a Michael addition reaction, after product molecules are aggregated, a flexible supramolecular polymer with nanoscale water / oil phase separation can be formed, and the flexible supramolecular polymer has the water absorption / oil absorption characteristic. The hyperbranched pressure-sensitive adhesive can rapidly absorb and remove an interface water layer and an interface oil layer on the surface of a base material, and rapid and tight attachment of a product and the base material is achieved; meanwhile, the flexible nanophase separation structure can rotate along with the polarity of the binding face, evolution is matched with the polarity type of the base material, and broad-spectrum bonding is achieved.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil, its preparation method, and its application. Background Art

[0002] Underwater and underwater (or collectively referred to as underwater bonding) bonding is a major bottleneck in the design of adhesive materials and a cutting-edge research area in the field of polymer materials. Applications include biomedical bonding, underwater in-situ repair, oil well exploration, building waterproofing, and liquid transportation leak sealing. The adhesive stress between the adhesive and the substrate mainly depends on the intermolecular forces (including van der Waals forces, electrostatic adsorption forces, and dispersion forces) generated by the liquid adhesive wetting the substrate before curing, and the adhesive nail structure formed after curing. Under certain conditions, the adhesive can also diffuse into the substrate or bond with it, thus generating adhesive stress. However, in underwater and underwater environments, an interfacial liquid layer (interfacial water layer, oil layer) inevitably adheres to the surface of the substrate, preventing the adhesive molecules from wetting the substrate and greatly affecting the adhesive strength, which is a major bottleneck in the field of adhesive materials.

[0003] Current strategies for underwater and oil-based bonding include: ① constructing covalent bond structures on the surfaces of the adhesive and the substrate; ② utilizing the rapid water absorption mechanism of dry gels to remove the interfacial water layer; and ③ constructing superhydrophobic adhesives to repel the interfacial water layer. However, these methods have extremely high requirements for the compatibility between the adhesive and the substrate, and lack broad applicability. Furthermore, single-formulation adhesives are difficult to use simultaneously in underwater and oil-based environments, becoming a bottleneck problem limiting the practical application of these technologies. Summary of the Invention

[0004] This invention addresses the aforementioned bottlenecks by designing a polymer structure using 4,4'-diaminodicyclohexylmethane and N,N'-methylenebisacrylamide as raw materials. A disordered hyperbranched polymer (RQHP) is prepared from hydrophobic / hydrophilic monomers via Michael addition, constructing a supramolecular adhesive with hydrophilic / hydrophobic aggregate states. This adhesive possesses both water and oil absorption capabilities, enabling rapid removal of interfacial water / oil layers. Furthermore, the flexible structure of the RQHP facilitates the movement of hydrophilic / hydrophobic regions within the supramolecular adhesive, adapting to the polarity of the substrate surface. This promotes wetting between the adhesive and the substrate, enhances intermolecular interaction strength, and achieves broad-spectrum, strong adhesion between the adhesive and various substrates underwater and in oil. This solves the current bottleneck problem of underwater adhesives lacking broad substrate applicability and not being able to function simultaneously underwater and in oil.

[0005] One objective of this invention is to provide a hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil, comprising at least one hyperbranched polymer containing the repeating unit structure shown in formula (I):

[0006]

[0007] In equation (Ⅰ), the repeated R are the same or different, and are independently H or

[0008] The hyperbranched pressure-sensitive adhesive provided by this invention, which has broad-spectrum adhesion capabilities both underwater and in oil, is obtained by reacting 4,4'-diaminodicyclohexylmethane (HDDM) and N,N'-methylenebisacrylamide (MBA).

[0009] In the hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil provided by the present invention, the number-average molecular weight of the hyperbranched polymer is 5000-50000 Da, preferably 6500-32000 Da.

[0010] This invention constructs a quasi-hyperbranched polymer structure possessing both hydrophilic and hydrophobic segments through the Michael addition reaction of MBA and HDDM monomers. MBA and HDDM are chemically linked via a Michael addition reaction of amino groups with double bonds. Since both primary and tertiary amines in the monomer structures can undergo addition reactions with double bonds, a disordered quasi-hyperbranched structure can be formed. In the aforementioned quasi-hyperbranched structural unit, HDDM linked with only one MBA has two hydrophobic cyclohexane structures, making it a hydrophobic segment in the system; while in structures linked with two or more MBAs, the introduction of more hydrophilic amide bonds makes it a hydrophilic segment. Simultaneously, the linkage between the two monomers is a saturated CH bond, possessing flexible movement capabilities. Therefore, the end groups and end segments in the quasi-hyperbranched polymer structure can move freely within a confined space, thus forming a hydrophilic / hydrophobic microphase separation. At this point, the hydrophilic / hydrophobic properties of the polymer surface can evolve spontaneously with the external contact interface.

[0011] A second objective of this invention is to provide a method for preparing a hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities. Preferably, this method is used to prepare the hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities described in the first objective of this invention. The preparation method includes: adding components including 4,4'-diaminodicyclohexylmethane (HDDM) and N,N'-methylenebisacrylamide (MBA) to a solvent, heating and reacting the mixture, and then performing post-treatment to obtain the hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities.

[0012] In the above-mentioned preparation method of hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil:

[0013] The molar ratio of 4,4'-diaminodicyclohexylmethane to N,N'-methylenebisacrylamide is (0.8-1.8):2, preferably (1-1.5):2;

[0014] The solvent is selected from polar solvents, preferably at least one of alcohol solvents, and more preferably at least one of methanol, ethanol, glycerol, and 1,4-butanediol;

[0015] The amount of solvent used is not particularly limited and can be adjusted within a wide range. For example, based on a total mass of 100g of 4,4'-diaminodicyclohexylmethane and N,N'-methylenebisacrylamide, the volume of solvent used is 30-800mL, preferably 50-500mL.

[0016] The conditions for the heating reaction are: reaction temperature 35-40℃, reaction time 18-28h;

[0017] The heating reaction optionally includes a post-treatment step. Preferably, the post-treatment includes precipitation and washing steps. The precipitation step includes adding a precipitation solvent, stirring, and then allowing the mixture to stand. Preferably, the precipitation solvent is selected from at least one of acetone, ethyl acetate, and petroleum ether. The amount of the precipitation solvent is not particularly limited and can be adjusted within a wide range, as long as the polymer obtained after the reaction precipitates. For example, for 100g of the obtained hyperbranched polymer, the volume of the precipitation solvent is 80-350mL. The washing step includes adding a washing solvent. Specifically, the solid product precipitated after adding the precipitation solvent and stirring is washed with the washing solvent. Preferably, the washing solvent is selected from at least one of cyclohexane and n-hexane. The amount of the washing solvent is not particularly limited and can be adjusted within a wide range, as long as small molecule impurities in the polymer are removed. For example, for 100g of the obtained hyperbranched polymer, the volume of the washing solvent is 50-200mL.

[0018] A third objective of this invention is to obtain a hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities using the preparation method described in the second objective of this invention. Preferably, the hyperbranched polymer in the hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities has a branching degree of 1.1 to 1.5. The hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities is a pale yellow, semi-transparent, viscous liquid that can be applied to bonding various substrate surfaces.

[0019] The hyperbranched polymer prepared in this invention exhibits the following characteristics: if the branching degree is too high, the molecular structure will be closer to complete hyperbranching, the branch radius will be reduced, and hydrophilic / hydrophobic segments will be difficult to aggregate; if the branching degree is too low, a linear structure will be formed, and the hydrophilic / hydrophobic regions will no longer exist. This invention controls the degree of branching by adjusting the molar ratio of the two monomers. Since HDDM is a tetrafunctional monomer, its molar ratio needs to be less than that of MBA. In this invention, the molar ratio of MBA to HDDM is preferably controlled between 2:1 and 2:1.5, and its branching degree can be controlled by adjusting the molar ratio of the two monomers. 1 Characterized by ¹H NMR. Using the above methods, the branching degree of the hyperbranched polymer products ranged from 1.1 to 1.5, effectively adjusting their solvent swelling capacity, hydrophilic / hydrophobic variation, and underwater adhesion strength. The reaction between MBA and HDDM is shown below:

[0020]

[0021] The hyperbranched pressure-sensitive adhesive provided by this invention has broad-spectrum adhesion capabilities both underwater and in oil, and exhibits dynamic exchange between hydrophilic and hydrophobic phases. It can rapidly absorb water under the physical cross-linking action of the hydrophobic phase and rapidly absorb oil under the physical cross-linking action of the hydrophilic phase.

[0022] The fourth objective of this invention is to provide a hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities as described in the first objective of this invention, or a hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities as described in the third objective of this invention, for use in underwater and oil-based environments.

[0023] The hyperbranched pressure-sensitive adhesive provided by this invention has broad-spectrum adhesion capabilities both underwater and in oil. When using it, it can be optionally dissolved in a commonly used volatile solvent (such as anhydrous ethanol) first, and then dripped or spread on the surface of the substrate. After drying, it can be pressed into contact with the object to be bonded.

[0024] This invention provides a hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil. Its raw materials are 4,4'-diaminodicyclohexylmethane (HDDM) and N,N'-methylenebisacrylamide (MBA), which, upon heating in a polar solvent, form a random quasi-hyperbranched polymer (RQHP) through a Michael addition reaction. After aggregation, the product molecules form a flexible hyperbranched polymer with nanoscale water / oil phase separation, exhibiting both water and oil absorption properties. This flexible hyperbranched polymer can rapidly absorb and remove interfacial water and oil layers from the substrate surface, achieving rapid and tight adhesion between the product and the substrate. Simultaneously, the flexible nanoscale phase separation structure (end-group structure) in the flexible hyperbranched polymer can rotate according to the polarity of the bonding surface, evolving to match the polarity of the substrate, thus achieving broad-spectrum adhesion.

[0025] The alkyl segments in the hyperbranched polymer provided by this invention are cyclohexyl structures with greater flexibility, greater steric hindrance, and less tendency to crystallize. This ensures that the product remains viscous at room temperature and can rapidly absorb water under the physical crosslinking of the hydrophobic phase and oil under the physical crosslinking of the hydrophilic phase. This type of hyperbranched polymer simultaneously possesses water and oil absorption capabilities, enabling rapid removal of interfacial water and oil layers, achieving rapid adhesion underwater, underwater, and in water-oil mixtures. Furthermore, the hyperbranched structure in the hyperbranched polymer promotes the movement of the hydrophilic / hydrophobic phases, achieving adaptive switching of the material's hydrophilicity / hydrophobicity and increasing adhesion strength to the substrate. By adjusting the ratio of hydrophilic / lipophilic monomers in the formulation, this invention can address the needs of adhesion under different water / oil ratios.

[0026] The hyperbranched pressure-sensitive adhesive provided by this invention has broad-spectrum underwater and oil-based bonding capabilities. It can rapidly absorb water and oil, and simultaneously remove the interfacial water and oil layers. Furthermore, the hyperbranched polymer structure can rapidly adapt to the polarity of the substrate, enabling broad-spectrum underwater and oil-based bonding to various substrates (ceramics, polyethylene, polypropylene, glass, aluminum alloys, wood, etc.). This invention has extremely important scientific significance and practical value. Attached Figure Description

[0027] Figure 1 The adhesion of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of this invention is shown in pure water.

[0028] Figure 2 This is a schematic diagram of the underwater bonding tensile-shear strength test method for the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of the present invention.

[0029] Figure 3 The bonding performance of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of this invention under liquid paraffin immersion.

[0030] Figure 4 The tensile strength of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of the present invention under pressure for 10 seconds and 10 minutes underwater and in liquid paraffin.

[0031] Figure 5 The surface morphology of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of this invention changes over time when exposed to a humid environment (30°C, 90% relative humidity).

[0032] Figure 6a ~c represent the surface morphology of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of this invention in a dry state, and in water and liquid paraffin, respectively, under scanning electron microscopy.

[0033] Figure 7 The swelling of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of this invention after immersion in pure water and liquid paraffin is shown on the x-axis as immersion time (minutes) and y-axis as swelling index (%).

[0034] Figure 8 This shows the change in the hydrophilicity and hydrophobicity of the surface of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of the present invention as the hydrophilicity and hydrophobicity of the external contact surface change.

[0035] Figure 9 The changes in the water contact angle of the hyperbranched pressure-sensitive adhesive (RQHP) prepared in Example 1 of this invention after it came into contact with hydrogel (calcium alginate hydrogel) and oleogel (oil-extended styrene-butadiene rubber) are shown. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0037] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0038] Example 1

[0039] A hyperbranched polymer was synthesized using MBA (15.4 g, Macklin AR) and HDDM (10.5 g, Macklin, 98%) at a molar ratio of 2:1. 30 mL of methanol was used as the solvent, and a 100 mL round-bottom flask was used as the reaction vessel. The reaction temperature was set at 30℃ (Chenghui Instrument Factory, XE-50 water bath), and the reaction time was 24 hours. After the reaction, the product was a colorless, transparent, and homogeneous liquid. 50 mL of acetone was added to the flask, and after stirring and standing for 30 minutes, a milky white, opaque, viscous precipitate gradually formed from the hyperbranched polymer. After removing the supernatant, 20 mL of cyclohexane was added for a second wash to remove small molecules, resulting in a high-purity hyperbranched polymer product (RQHP), a pale yellow, semi-transparent, viscous liquid. The number-average molecular weight of the obtained hyperbranched polymer product was 6800 Da. 1 Characterized by H NMR, the product obtained is a hyperbranched pressure-sensitive adhesive containing a hyperbranched polymer with a branching degree of 1.1-1.3.

[0040] Add 20 mL of anhydrous ethanol to the round-bottom flask containing the product. After stirring for 10 minutes, the product dissolves, forming a pale yellow, transparent, and clear solution. The above solution is then dropped onto the surfaces of glass, aluminum sheets, wood, ceramics, polyethylene sheets, and polypropylene sheets (0.2 mL / cm²). 2 After being placed in a 35°C forced-air drying oven for 30 minutes, the solvent evaporates, and the hyperbranched polymer adhesive adheres to the surface of various substrates, appearing colorless and transparent, and can be used for underwater / oil-based in-situ bonding applications.

[0041] Example 2

[0042] Hyperbranched polymers were synthesized using a molar ratio of MBA (15.4 g, Macklin AR) to HDDM (15.75 g, Macklin, 98%) of 2:1.5. The solvent was 30 mL (methanol), and the reaction vessel was a 100 mL round-bottom flask. The reaction temperature was set at 30℃ (Chenghui Instrument Factory, XE-50 water bath), and the reaction time was 24 hours. After the reaction, the product was a colorless, transparent, and homogeneous liquid. 50 mL of acetone was added to the flask, and after stirring and standing for 30 minutes, a milky white, opaque, viscous precipitate gradually formed from the hyperbranched polymer. After removing the supernatant, 20 mL of cyclohexane was added for a second wash to remove small molecules, yielding a high-purity hyperbranched polymer product (RQHP), a pale yellow, semi-transparent, viscous liquid. The number average molecular weight of the obtained hyperbranched polymer product was 28000 Da. 1 Characterized by H NMR, the product obtained is a hyperbranched pressure-sensitive adhesive containing a hyperbranched polymer with a branching degree of 1.2-1.4.

[0043] Add 20 mL of anhydrous ethanol to the round-bottom flask containing the product. After stirring for 10 minutes, the product dissolves, forming a pale yellow, transparent, and clear solution. The above solution is then dropped onto the surfaces of glass, aluminum sheets, wood, ceramics, polyethylene sheets, and polypropylene sheets (0.2 mL / cm²). 2 After being placed in a 35°C forced-air drying oven for 30 minutes, the solvent evaporates, and the hyperbranched polymer adhesive adheres to the surface of various substrates, appearing colorless and transparent, and can be used for underwater / oil-based in-situ bonding applications.

[0044] Example 3

[0045] A hyperbranched polymer was synthesized using MBA (15.4 g, Macklin AR) and HDDM (12.6 g, Macklin, 98%) at a molar ratio of 2:1.2. 30 mL of methanol was used as the solvent, and a 100 mL round-bottom flask was used as the reaction vessel. The reaction temperature was set at 30℃ (Chenghui Instrument Factory, XE-50 water bath), and the reaction time was 24 hours. After the reaction, the product was a colorless, transparent, and homogeneous liquid. 50 mL of acetone was added to the flask, and after stirring and standing for 30 minutes, a milky white, opaque, viscous precipitate gradually formed from the hyperbranched polymer. After removing the supernatant, 20 mL of cyclohexane was added for a second wash to remove small molecules, resulting in a high-purity hyperbranched polymer product (RQHP), a pale yellow, semi-transparent, viscous liquid. The number-average molecular weight of the obtained hyperbranched polymer product was 12700 Da. 1 Characterized by H NMR, the product obtained is a hyperbranched pressure-sensitive adhesive containing a hyperbranched polymer with a branching degree of 1.3-1.5.

[0046] Add 20 mL of anhydrous ethanol to the round-bottom flask containing the product. After stirring for 10 minutes, the product dissolves, forming a pale yellow, transparent, and clear solution. The above solution is then dropped onto the surfaces of glass, aluminum sheets, wood, ceramics, polyethylene sheets, and polypropylene sheets (0.2 mL / cm²). 2 After being placed in a 35°C forced-air drying oven for 30 minutes, the solvent evaporates, and the hyperbranched polymer adhesive adheres to the surface of various substrates, appearing colorless and transparent, and can be used for underwater / oil-based in-situ bonding applications.

[0047] Test examples: Adhesion performance test and immersion performance test of hyperbranched pressure-sensitive adhesives

[0048] The hyperbranched polymer product (RQHP) obtained in Example 1 was dissolved in ethanol, coated onto the bottom of a chrome-plated weight, and completely dried. Then, it was pressed against the surfaces of different substrates (polyethylene PE, polypropylene PP, glass, aluminum sheet, wood chip, ceramic) in water, liquid paraffin (Beijing Reagent Factory, analytical grade), seawater (from Tanggu area, Tianjin), ice-seawater (from Tanggu area, Tianjin), and vegetable oil (Luhua brand, 5S grade pressed first-class peanut oil). The adhesion tensile and shear strength between RQHP and the substrate surface was tested after pressing for 1 minute and 10 minutes (INSTRON 5900 testing machine, USA). The results are shown in Tables 1 and 2.

[0049] Table 1. Adhesion tensile and shear strength of RQHP with various substrates in water

[0050]

[0051] Table 2. Adhesion tensile and shear strength of RQHP with different substrates in liquid paraffin and vegetable oil

[0052]

[0053] This invention aims to design a physically cross-linked, hyperbranched pressure-sensitive adhesive with an adaptive structure that rapidly absorbs water and oil. First, the rapid swelling of the dry gel absorbs aqueous / oil-based liquids adhering to the bonding surface, enabling intermolecular contact and wetting between the adhesive and the substrate. Subsequently, the hyperbranched structure of the polymer allows the ends to move freely within a confined space, forming a hydrophilic / hydrophobic nanophase separation structure. This structure then rotates and rearranges according to the polarity of the adhered interface, adapting to the polarity of the bonded interface and achieving broad-spectrum adhesion to hydrophilic / hydrophobic interfaces (adhesion effect as shown in the image). Figure 1 , 3 As shown, it can generate a tensile shear strength of 207 kPa after being in contact with glass underwater for 10 seconds, and can generate a tensile shear strength of 162 kPa after being in contact with glass in liquid paraffin for 10 seconds.

[0054] Figure 5 This study demonstrates the morphological changes of a glass slide coated with a hyperbranched pressure-sensitive adhesive after it was removed from a drying oven and placed in a laboratory environment (30°C, 90% relative humidity). When the hyperbranched pressure-sensitive adhesive was completely dry, it was transparent overall, indicating that no significant phase separation had occurred within the material, and it was in a homogeneous amorphous state. After being placed in a room temperature environment for 30 seconds, a white hazy structure appeared at the edge of the coated area, indicating significant phase separation due to the absorption of moisture from the air. As the time of exposure to air continued to increase, the white hazy structure at the edge expanded, eventually making the entire coated surface white and translucent. This indicates that: ① due to the absorption of moisture from the air, the hyperbranched polymer partially formed hydrophilic structures and partially formed hydrophobic structures, resulting in phase separation; ② the phase separation distribution was extremely uniform; and ③ the phase separation scale was extremely small (translucent).

[0055] Figure 6a Figure ~c shows the cross-sectional morphology of the freeze-dried quasi-hyperbranched polymer under different placement conditions. For the fully dried quasi-hyperbranched polymer, numerous raised bright spots with a scale of 20-30 nm are distributed on its surface, showing a significant difference from the surrounding polymer substrate. This indicates that even in the fully dried state, due to the vastly different affinity / repulsion of the chain segment structure, a uniform phase-separated structure at the nanoscale can still be generated. Since the phase separation scale at this point is less than 1 / 4 of the visible light wavelength, its corresponding macroscopic structure is completely transparent, as shown in Figure ~c. Figure 6a As shown. After the surface is immersed in water for 10 seconds, the size of the bright spots further increases to about 150nm; at this point, it is close to 1 / 4 of the wavelength of visible light, and macroscopically it appears to be semi-transparent, as shown. Figure 6bAs shown, when a dry surface is immersed in liquid paraffin for 10 seconds, a patchy, bright area appears on the surface, significantly different from the area after immersion in water. This indicates that the hydrophobic phase can absorb the liquid paraffin, resulting in phase separation. Figure 6c As shown. By Figure 6a The results showed that, under conditions involving air and moisture, hydrophilic / hydrophobic phase separation regions did indeed appear inside the hyperbranched polymer.

[0056] Figure 7 The swelling curves of the hyperbranched polymer-like material are shown. A completely dried hyperbranched polymer-like material can absorb 50% of its own weight in deionized water within 30 seconds, demonstrating an extremely rapid water absorption rate; within 600 seconds, it can absorb 148% of its own weight in deionized water, representing 75% of its maximum swelling index (203%). Furthermore, the hyperbranched polymer-like material can also rapidly absorb oil; a dried hyperbranched polymer can absorb 18% of its own weight in liquid paraffin within 30 seconds. These results indicate that the hyperbranched polymer-like material-like material possesses both water and oil absorption capabilities, enabling it to remove interfacial water and oil layers from the surface of the substrate being bonded.

[0057] Figure 8 This study demonstrates the changes in the hydrophilicity and hydrophobicity of a hyperbranched polymer surface under external stimuli. The transient contact angle of the completely dry hyperbranched polymer surface with deionized water was 76%. However, after immersing the material in deionized water for 10 minutes, the contact angle significantly decreased to 43°. When the material was immersed in liquid paraffin for 10 minutes, the contact angle significantly increased to 102°, higher than the value in the dry state. After a subsequent immersion in pure water, the contact angle significantly decreased to 31°. These results indicate that the nanoscale phase separation within the hyperbranched polymer exhibits strong mobility, spontaneously moving according to the polarity of the surfaces it contacts, thereby altering the hydrophilicity and hydrophobicity of the material surface. Therefore, this hyperbranched polymer possesses the ability to change its structural properties in response to changes in external surface properties.

[0058] Figure 9This study demonstrates the changes in the properties of a hyperbranched polymer-like material laid flat on a tin foil surface upon contact with different hydrophilic / hydrophobic surfaces. The hyperbranched polymer is soluble in methanol and, after being laid flat, gradually dries, exhibiting a pale white, semi-transparent state. Sodium alginate-calcium chloride hydrogel sheets (2 wt% sodium alginate + 1 M CaCl2) and oil-extended styrene-butadiene rubber oleogel sheets (70 wt% naphthenic oil) were prepared. These sheets were cut according to the structures shown in the figure and attached to the surface of the hyperbranched polymer. After being attached for 10 minutes, the sheets were peeled off. Subsequently, the surface morphology of the hyperbranched polymer showed significant differences in color intensity depending on whether the hydrogel or oleogel was attached, indicating different phase separation structures formed after water / oil absorption. A water droplet test was then performed on the surface of the hyperbranched polymer. The results showed that in the hydrogel-attached areas, water droplets spread rapidly, exhibiting strong hydrophilicity; while in the oleogel-attached areas, water droplets were significantly convex, indicating strong hydrophobicity. The above phenomena further demonstrate that the hyperbranched polymer provided by the present invention has the ability to "evolve its hydrophilic and hydrophobic properties according to the properties of the external contact surface", and has strong adhesion to both hydrophilic and hydrophobic surfaces.

Claims

1. A hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil, comprising at least one hyperbranched polymer containing repeating unit structures as shown in formula (I): In equation (Ⅰ), the repeated R are the same or different, and are independently H or 2. The hyperbranched pressure-sensitive adhesive according to claim 1, characterized in that, The hyperbranched polymer is obtained by reacting 4,4'-diaminodicyclohexylmethane and N,N'-methylenebisacrylamide.

3. The hyperbranched pressure-sensitive adhesive according to claim 1 or 2, characterized in that, The number-average molecular weight of the hyperbranched polymer is 5000-50000 Da, preferably 6500-32000 Da.

4. A method for preparing a hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities, preferably used for preparing the hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities as described in any one of claims 1 to 3, wherein the preparation method comprises: The components, including 4,4'-diaminodicyclohexylmethane and N,N'-methylenebisacrylamide, are added to a solvent and heated to react, resulting in the hyperbranched pressure-sensitive adhesive with broad-spectrum adhesion capabilities both underwater and in oil.

5. The preparation method according to claim 4, characterized in that, The molar ratio of 4,4'-diaminodicyclohexylmethane to N,N'-methylenebisacrylamide is (0.8–1.8):2, preferably (1–1.5):2; and / or, The solvent is selected from polar solvents, preferably at least one of alcohol solvents, more preferably at least one of methanol, ethanol, glycerol, and 1,4-butanediol; and / or, Based on a total mass of 100g of 4,4'-diaminodicyclohexylmethane and N,N'-methylenebisacrylamide, the volume of the solvent used is 30-800mL, preferably 50-500mL.

6. The preparation method according to claim 4, characterized in that, The conditions for the heating reaction are: reaction temperature 35–40°C, reaction time 18–28 h; and / or, The heating reaction may optionally include a post-treatment step, preferably including precipitation and washing steps.

7. The preparation method according to claim 6, characterized in that, The precipitation process in the post-treatment includes the steps of adding a precipitation solvent, stirring, and then allowing it to stand. Preferably, the precipitation solvent is selected from at least one of acetone, ethyl acetate, and petroleum ether; and / or, The post-processing cleaning includes the step of adding a cleaning solvent for cleaning. Preferably, the cleaning solvent is selected from at least one of cyclohexane and n-hexane.

8. A hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities obtained by the preparation method according to any one of claims 4 to 7, preferably wherein the degree of branching of the hyperbranched polymer in the hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities is 1.1 to 1.

5.

9. The hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities according to claim 8, characterized in that, The aforementioned hyperbranched pressure-sensitive adhesive exhibits dynamic exchange between hydrophilic and hydrophobic phases. Under the physical cross-linking action of the hydrophobic phase, it can rapidly absorb water, and under the physical cross-linking action of the hydrophilic phase, it can rapidly absorb oil.

10. The application of a hyperbranched pressure-sensitive adhesive with broad-spectrum underwater and oil-based adhesion capabilities as described in claim 8 or 9 in underwater and oil-based environments.

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