Recyclable strong-adhesion ionic polymer and application thereof

Abstract

The invention discloses a recoverable strong-adhesion ionic polymer and application thereof. The ionic polymer is formed by dehydrating and polymerizing an ionic compound monomer; the structure of the ionic compound monomer is shown in the specification, wherein X <-> is an anion, R1 is a cation group, R is a central group, Y is a linking group, Ar is an aromatic group, and n is an integer between 1 and 6. Specific ionic compounds are used as monomers, and the independent ionic compound monomers form a three-dimensional polymer network based on dynamic covalent bonds through dehydration and mutual crosslinking; the ionic polymer shows excellent adhesion in a macroscopic adhesion performance test, and can be controllably degummed under the action of a small molecular alcohol solvent, so that the performance of the ionic polymer meets specific production requirements.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a recyclable, strongly adhesive ionomer and its applications. Background Technology

[0002] Polyionic liquids are a class of polymer materials polymerized from small-molecule ionic liquids as monomer compounds. They combine the excellent properties of polymers and ionic liquids, exhibiting superior chemical stability, ionic conductivity, and non-flammability. Furthermore, by adjusting the composition of anions, cations, and substituents in the monomer compounds, the physicochemical properties of polyionic liquids can be directionally controlled to meet the needs of different application scenarios, thus demonstrating broad application potential in numerous fields.

[0003] Adhesives are substances that can bond two or more materials together and give the joint a certain strength after curing. The adhesive strength is affected by the forces between the adhesive and the adherends, as well as the intermolecular forces within the adhesive itself. Furthermore, its chemical structure and aggregate structure also significantly influence its bonding performance.

[0004] To improve the adhesive properties of adhesives, traditional adhesives often employ covalent cross-linking to increase cohesive energy. Epoxy resin adhesives, for example, have become one of the most widely used types of adhesives, possessing extremely high adhesive performance. However, once cured, these adhesives are difficult to remove, making them unsuitable for applications requiring disassembly and maintenance. Furthermore, epoxy adhesives are mostly single-use, non-recyclable, and non-reusable, requiring disposal as waste after their service life, resulting in environmental problems and resource waste. In applications requiring disassembly, replacement, or maintenance, such as energy and electronic devices, adhesives with both high adhesive performance and controllable debonding are crucial.

[0005] However, existing adhesives often fail to simultaneously achieve both high adhesion and controllable debonding performance. Therefore, researching and developing a polyionic liquid adhesive that possesses both high-strength adhesion and controllable debonding under mild conditions has significant application value and market potential. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a recyclable, highly adhesive ionic polymer and its applications. Using specific ionic compounds as monomers, these monomers cross-link through dehydration to form a three-dimensional polymer network based on dynamic covalent bonds. This ionic polymer exhibits excellent adhesion in macroscopic adhesive performance tests and can be controllably degummed under the action of small-molecule alcohol solvents, thus meeting specific production requirements. This invention solves the problem that existing adhesives often cannot simultaneously achieve both high adhesion and controllable degumming performance.

[0007] To address the aforementioned technical problems, a first aspect of the present invention provides a recyclable, strongly adhesive ionic polymer, wherein the ionic polymer is formed by the dehydration polymerization of an ionic compound monomer; the ionic compound monomer has the following structure: ; Among them, X － R is an anion, R1 is a cationic group, R is a central group, Y is a linking group, Ar is an aromatic group, and n is an integer between 1 and 6.

[0008] Traditional ionic compounds typically exist in liquid or crystalline states at room temperature and pressure. Theoretically, their direct use as adhesives fails to meet bonding requirements, as neither state can balance the conflict between cohesive energy and interfacial adhesion energy. This invention introduces boric acid into the ionic monomer of the ionic polymer to form a dynamic covalent cross-linked structure. Through the self-assembly of multiple hydrogen bonds, the ionic polymer can form an internal aggregate structure, not only forming strong hydrogen bonds with various substrate surfaces, thus generating excellent interfacial adhesion, but also constructing a rich dynamic non-covalent cross-linked network within the material. This network, synergistically with electrostatic interactions, significantly enhances the cohesive energy of the adhesive. This interfacial-bulk combination mechanism results in the prepared ionic polymer exhibiting superior macroscopic adhesive properties when used as an adhesive.

[0009] Furthermore, the type of end group selected during the ionization reaction and the target anion chosen in the anion exchange step both affect the water solubility and glass transition temperature of the ionic compound. Therefore, the physicochemical properties of ionomer adhesives can be controlled and adjusted by flexibly combining cations with different end groups and different types of anions.

[0010] Furthermore, the X － Selected from Cl － ,Br － I － CH3COO － CF3COO － BF4 － PF6 － OTf － NTf2 － One or two of them.

[0011] Furthermore, R1 is selected from one or two of the following groups: .

[0012] Furthermore, the R is selected from one of the following groups: .

[0013] Furthermore, the Y is selected from one or two of the following groups: .

[0014] Furthermore, the Ar is selected from one or two of the following structures: .

[0015] Furthermore, the temperature for the dehydration polymerization is 60-100℃.

[0016] A second aspect of the present invention provides an adhesive comprising the ionic polymer described in the first aspect.

[0017] Furthermore, the adhesive is degummed and recovered by rinsing or soaking with small molecule alcohol solvents.

[0018] Furthermore, the small molecule alcohol solvent is selected from one or more of methanol, ethanol, and isopropanol.

[0019] The beneficial effects of this invention are: This invention introduces dynamic covalent bonds and multiple hydrogen bonds into ionic compound monomers, enabling discrete ionic compound units to form a three-dimensional network structure with dynamic physical cross-linking. When applied to adhesives, this structure exhibits significantly enhanced adhesion in macroscopic adhesion tests.

[0020] The ionomer adhesive of this invention has high bonding strength. It can be degummed and recycled under mild conditions using small molecule alcohol solvents such as methanol, ethanol, and isopropanol. The preparation method is highly operable and suitable for industrial production applications. Attached Figure Description

[0021] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is the infrared absorption spectrum of the ion polymer obtained in Example 1 of the present invention; Figure 2 This is the infrared absorption spectrum of the ion polymer obtained in Example 2 of the present invention; Figure 3 This is the infrared absorption spectrum of the ion polymer obtained in Example 3 of the present invention; Figure 4 This is the infrared absorption spectrum of the ion polymer obtained in Example 4 of the present invention; Figure 5 These are the thermogravimetric curves of the ionic polymers obtained in Examples 1-3 of this invention; Figure 6 The results of differential scanning calorimetry (DSC) analysis of the ionic polymers obtained in Examples 1-3 are shown. Figure 7 The shear strength data of the ionomer obtained in Example 1 on ceramic, stainless steel, epoxy resin and glass substrates; Figure 8 The macroscopic load-bearing capacity test is performed on the ionomer obtained in Example 1 after bonding it to a ceramic substrate. Figure 9 Images of the ionomer adhesive obtained in Example 1 bonded to a glass substrate before and after ethanol rinsing; Figure 10 The ionic polymer obtained in Example 1 was recovered by ethanol solvent and then bonded to ceramic and stainless steel substrates. The shear strength data of the bond was measured at room temperature. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This embodiment relates to a recyclable, strongly adhesive ionic polymer, which is formed by the dehydration polymerization of ionic compound monomers; the ionic compound monomers have the following structure: ; Among them, X － R is an anion, R1 is a cationic group, R is a central group, Y is a linking group, Ar is an aromatic group, and n is an integer between 1 and 6.

[0025] This embodiment introduces boric acid into the ionic monomer of the ionic polymer to form a dynamic covalent cross-linked structure. Through the self-assembly of multiple hydrogen bonds, the ionic polymer can form an internal aggregate structure, which not only forms strong hydrogen bonds with the surface of various substrate materials, thus generating excellent interfacial adhesion, but also constructs a rich dynamic non-covalent cross-linked network within the material. This network, in synergy with electrostatic interactions, significantly enhances the cohesive energy of the adhesive. This interfacial-bulk interaction mechanism enables the prepared ionic polymer to exhibit excellent macroscopic adhesive properties when used as an adhesive. Furthermore, this embodiment allows for the controllable adjustment of the physicochemical properties of the ionic polymer adhesive by flexibly combining cations with different end groups and different types of anions.

[0026] As a preferred embodiment, the X － Selected from Cl － ,Br － I － CH3COO － CF3COO －BF4 － PF6 － OTf － NTf2 － One or two of the following groups; wherein R1 is selected from one or two of the following groups: .

[0027] In a preferred embodiment, R is selected from one of the following groups: .

[0028] In a preferred embodiment, Y is selected from one or two of the following groups: .

[0029] In a preferred embodiment, Ar is selected from one or two of the following structures: .

[0030] In a preferred embodiment, the temperature of the dehydration polymerization is 70-100°C.

[0031] Another embodiment relates to an adhesive comprising the ionomer described in the above embodiments.

[0032] In a preferred embodiment, the adhesive is degummed and recovered by rinsing or soaking with a small molecule alcohol solvent; the small molecule alcohol solvent is selected from one or more of methanol, ethanol, and isopropanol. Example 1

[0033] This embodiment relates to a method for preparing a recyclable, highly adhesive ionomer, comprising the following steps: (1) Weigh 1 mmol of diethyl adipate and 1 mmol of 1-(3-aminopropyl)imidazolium and dissolve them in 20 ml of tetrahydrofuran. Stir the mixture continuously at room temperature for 24 h. After the reaction is complete, the product is obtained as a precipitate. The product is collected directly and washed with tetrahydrofuran. After vacuum drying, a urea-containing trimer is obtained with a yield of 98%.

[0034] (2) Weigh 2 mmol of 4-(bromomethyl)phenylboronic acid and 1 mmol of the urea-containing trimer obtained in step (1) and dissolve them in 20 mL of acetonitrile. Under the condition of continuously passing an inert gas into the flask, the mixture is stirred continuously at 90 °C for 48 h. After the reaction is completed and cooled, the mixture is precipitated in ethyl acetate and the product is collected. After vacuum drying, an ionic compound with a halogen anion is obtained with a yield of 95%.

[0035] (3) Weigh 1 mmol of the halogen anion obtained in step (2) and dissolve it in 100 ml of deionized water to obtain mixture A; separately weigh 1 mmol of sodium tetrafluoroborate (NaBF4) and dissolve it in 150 ml of deionized water to obtain mixture B. Mix the two solutions A and B at room temperature and stir for about 12 h. Collect the mixture and wash the precipitate with deionized water to obtain the ionic compound monomer with the following structural formula: .

[0036] (4) Dehydration polymerization: The ionic compound monomer obtained in step (3) is vacuum dried and polymerized at 80°C to finally obtain the ionic polymer PIL-1 with a yield of 97%.

[0037] NMR data of ionic compound monomers: 1 H NMR (400 MHz, DMSO- d 6) δ 9.27 (t, J = 1.6Hz, 2H), 8.12 (s, 2H), 7.99 – 7.59 (m, 10H), 7.48 – 7.29 (m, 6H), 5.42 (s,4H), 4.17 (t, J = 7.2 Hz, 4H), 3.04 (p, J = 6.2 Hz, 4H), 2.11 – 1.87 (m, 4H), 1.47 (t, J = 3.6 Hz, 4H), 1.35 – 1.22 (m, 4H). 13 C NMR (100 MHz, DMSO) δ172.73, 136.82, 135.92, 135.16, 127.60, 124.75, 122.44, 120.49, 52.50, 47.37,39.99, 35.66, 30.25, 26.84. Example 2

[0038] The difference between this embodiment and Example 1 is that 4-(bromomethyl)phenylboronic acid is replaced with 3-(bromomethyl)phenylboronic acid, while other steps and parameters remain unchanged. This method prepares an ionic monomer and an ionic polymer, PIL-2. The structural formula of the ionic monomer is: .

[0039] The NMR data of the ionic compound monomer are as follows: 1 H NMR (400 MHz, DMSO-D6): δ9.39 (s, 2H), 8.14 (s, 2H), 7.85 – 7.68 (m, 4H), 7.62 – 7.21 (m, 12H), 5.44 (s, 4H), 4.18(t, J = 6.8 Hz, 4H), 3.31 – 2.98 (m, 8H), 1.90 (t, J = 6.8 Hz, 4H), 1.48 –1.23 (m, 4H). 13 C NMR (100 MHz, DMSO-D6): δ 172.72, 136.82, 135.25, 129.47, 129.19, 128.69, 124.74, 123.39, 122.96, 121.54, 52.44, 47.42, 40.02, 36.48, 30.49, 26.87. Example 3

[0040] The difference between this embodiment and Example 1 is that diethyl adipate in step (1) is replaced with hexamethylene diisocyanate, while other steps and parameters remain unchanged. This process prepares an ionic monomer and an ionic polymer, PIL-3. The structural formula of the ionic monomer is: .

[0041] The NMR data of the ionic compound monomer are as follows: 1 H NMR (400 MHz, DMSO-D6): δ 9.16 (s, 2H),8.14 (s, 4H), 7.88 – 7.30 (m, 12H), 5.90 (dt, J = 14.4, 5.8 Hz, 4H), 5.41 (s,4H), 4.16 (t, J = 6.8 Hz, 4H), 2.98 (dq, J = 13.9, 6.4 Hz, 8H), 1.90 (p, J =6.8 Hz, 4H), 1.35 – 1.28 (m, 4H), 1.24 – 1.19 (m, 4H). 13 C NMR (100 MHz, DMSO-D6): δ158.68, 136.84, 135.15, 127.60, 124.74, 123.38, 123.01, 122.45, 121.54, 120.49, 52.47, 47.43, 36.49, 31.25, 31.15, 30.48, 26.66. Example 4

[0042] The difference between this embodiment and Example 1 is that sodium tetrafluoroborate in step (3) is replaced with sodium hexafluorophosphate, while other steps and parameters remain unchanged. The ionic compound monomer and ionic polymer PIL-4 are prepared. The structural formula of the ionic compound monomer is: .

[0043] The NMR data of the ionic compound monomer are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 9.26 (t, J = 1.6Hz, 2H), 8.12 (s, 2H), 7.92 (t, J = 5.8 Hz, 2H), 7.88 – 7.74 (m, 8H), 7.50 –7.31 (m, 6H), 5.40 (s, 4H), 4.19 (t, J = 7.2 Hz, 4H), 3.11 (p, J = 6.2 Hz,4H), 2.09 – 1.88 (m, 4H), 1.46 (t, J = 3.6 Hz, 4H), 1.35 – 1.23 (m, 4H). 13 CNMR (100 MHz, DMSO) δ 172.78, 136.85, 135.97, 135.21, 127.58, 124.77, 123.11,122.48, 52.57, 47.33, 40.01, 35.68, 30.23, 26.89. Test case Figure 1-4 The infrared absorption spectra of the ionic polymers obtained in Examples 1-4 are shown respectively. It can be seen that the polymers obtained in Examples 1-4 formed a cross-linked network structure.

[0044] Figure 5 The thermogravimetric curves of the ionic polymers obtained in Examples 1-3 are shown. The results show that PIL-1, PIL-2, and PIL-3 all have high thermal stability, and their initial decomposition temperatures are all around 250 °C.

[0045] Figure 6 The results of differential scanning calorimetry (DSC) tests on the ionic polymers obtained in Examples 1-3 show that PIL-2 has the lowest glass transition temperature and PIL-3 has the highest, indicating that the type of end-group substituents and the hydrogen bond density have a significant impact on the phase transition temperature of the material and can be adjusted as needed.

[0046] Figure 7 The ionomer obtained in Example 1 was subjected to single-lap shear tests on ceramic, stainless steel, epoxy resin, and glass substrates (adhesion area of ​​1 cm²). 2 ), at room temperature 100 mm min -1 The shear strength data of the bond was measured at the test speed. The data results show that PIL-1 has the highest bond strength on the stainless steel substrate.

[0047] Two stainless steel sheets were bonded together using the ionomer obtained in Example 1. A rope was fixed to one end of the bond, and a weight was suspended from the other end. The bonding surface of the ceramic sheet was 0.5 cm in size. 2 After the adhesive has fully cured, the ceramic tile bonded joint can suspend a weight of 25 kg, such as... Figure 8 As shown.

[0048] The ionomer adhesive prepared in Example 1, when bonded to a glass substrate, can be removed within 30 seconds after rinsing with 5 ml of ethanol. Figure 9 As shown.

[0049] After bonding with the ionomer adhesive prepared in Example 1, the adhesive was debonded with ethanol and the solution was recovered. After drying at 80 °C, single-lap shear tests were performed on ceramic and stainless steel substrates. The shear strength data of the bond was measured at room temperature. Figure 10 As shown in the data, the results indicate that the ionomers on stainless steel and ceramic substrates still exhibit high bonding strength after solvent recovery.

[0050] In summary, this invention introduces dynamic covalent bonds and multiple hydrogen bonds into ionic compound monomers, enabling the discrete ionic compound units to form a three-dimensional network structure with dynamic physical cross-linking. When applied to adhesives, this results in significantly enhanced adhesion in macroscopic adhesion tests. The ionic polymer adhesive of this invention has high adhesive strength and can be degummed and recycled under mild conditions using small molecule alcohol solvents such as methanol, ethanol, and isopropanol. The preparation method is highly operable and suitable for industrial production applications.

[0051] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A recyclable, highly adhesive ionomer, characterized in that, The ionic polymer is formed by the dehydration polymerization of ionic compound monomers; the ionic compound monomers have the following structure: ； Among them, X － R is an anion, R1 is a cationic group, R is a central group, Y is a linking group, Ar is an aromatic group, and n is an integer between 1 and 6.

2. The recyclable, strongly adhesive ionomer as described in claim 1, characterized in that, The X － Selected from Cl － ,Br － I － CH3COO － CF3COO － BF4 － PF6 － OTf － NTf2 － One or two of them.

3. The recyclable, strongly adhesive ionomer as described in claim 1, characterized in that, The R1 is selected from one or two of the following groups: 。 4. The recyclable, strongly adhesive ionomer as described in claim 1, characterized in that, The R is selected from one of the following groups: 。 5. The recyclable, strongly adhesive ionomer as described in claim 1, characterized in that, The Y is selected from one or two of the following groups: 。 6. The recyclable, strongly adhesive ionomer as described in claim 1, characterized in that, The Ar is selected from one or two of the following structures: 。 7. The recyclable, strongly adhesive ionomer as described in claim 1, characterized in that, The dehydration polymerization temperature is 60-100℃.

8. An adhesive, characterized in that, Includes the ionic polymer according to any one of claims 1-7.

9. The adhesive as described in claim 8, characterized in that, The adhesive is degummed and recovered by rinsing or soaking with small molecule alcohol solvents.

10. The adhesive as claimed in claim 8, characterized in that, The small molecule alcohol solvent is selected from one or more of methanol, ethanol, and isopropanol.

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