Ionic polymer adhesive prepared based on PET degradation and preparation method thereof

Abstract

The invention discloses an ionic polymer adhesive prepared based on PET degradation and a preparation method of the ionic polymer adhesive. The preparation method comprises the following steps: carrying out aminolysis or ester exchange reaction on PET and a small molecule of which one end is provided with amino or hydroxyl and the other end is provided with an organic cation precursor to obtain an intermediate; carrying out ionization reaction on the intermediate and halogenated hydrocarbon to obtain an organic ionic compound; mixing the organic ion compound solution with a salt solution containing target anions for anion exchange reaction to obtain an organic ion monomer compound; and heating the organic ionic monomer compound for polymerization reaction to obtain the ionic polymer adhesive prepared based on PET degradation. According to the preparation method, PET is converted into a small molecule compound through aminolysis / ester exchange reaction, an organic ion monomer compound is prepared through ionization reaction and anion exchange reaction, a three-dimensional polymer network is formed through dehydration polymerization and mutual cross-linking, the adhesive property is excellent, and meanwhile recycling and repeated bonding can be achieved under specific conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to an ionic polymer adhesive prepared based on PET degradation and a preparation method thereof. BACKGROUND

[0002] Polyethylene terephthalate (PET) is one of the most widely used plastics, commonly found in beverage bottles, food packaging and textiles. Its lightweight, durable and low-cost characteristics make it dominant in the packaging field. However, its recycling is severely insufficient, with a long-term recycling rate of less than 30%. The imperfect recycling system, high sorting cost and lower economic efficiency of recycled materials jointly restrict the recycling of PET.

[0003] As a key material in modern industry, adhesives have penetrated into many fields such as electronic equipment, automobile manufacturing, aerospace and daily consumer goods, playing an irreplaceable role in bonding and sealing. However, traditional adhesives are difficult to separate and degrade after the end of product life, exacerbating resource waste and environmental pollution. Developing recyclable adhesives with repeatable bonding, easy separation or degradation under specific conditions is becoming an important direction of concern and research in academia and industry.

[0004] Organic ionic polymers can effectively make up for the performance deficiencies of traditional adhesives in specific application scenarios due to their conductivity, electrochemical stability and non-flammability. However, traditional ionic compounds usually exist in liquid or crystalline state at room temperature and pressure, which theoretically cannot meet the bonding requirements if used directly as adhesives. Both of these two forms cannot balance the contradiction between cohesive energy and interfacial adhesion energy.

[0005] Therefore, it has great application potential to convert waste PET into high-performance adhesive with repeatable bonding, easy separation and recyclability through degradation. SUMMARY

[0006] The present application aims to solve the problems in the prior art, and provides an ionic polymer adhesive prepared based on PET degradation and a preparation method thereof. PET is converted into small molecule compounds through aminolysis / ester exchange reaction, and organic ionic monomer compounds are prepared through ionization reaction and anion exchange reaction. The organic ionic monomer compounds are crosslinked to form a three-dimensional polymer network through dehydration, thereby showing excellent adhesion in macroscopic bonding performance test. At the same time, the organic ionic polymer adhesive can be recycled and reused under specific conditions, so that its performance meets the specific production requirements.

[0007] To solve the above technical problems, the first aspect of the present application provides a method for preparing an ionic polymer adhesive based on PET degradation, comprising the following steps: S1, in an organic solvent, a small molecule with amine group or hydroxyl group at one end and organic cation precursor at the other end is subjected to aminolysis or ester exchange reaction with PET to obtain an intermediate; S2, in an organic solvent, the intermediate and a halogenated hydrocarbon are subjected to an ionization reaction to obtain an organic ionic compound; S3, a solution of the organic ionic compound is mixed with a solution of a salt containing a target anion to perform an anion exchange reaction to obtain an organic ionic monomer compound; wherein the target anion is selected from one or more of CH3COO － , CF3COO － , BF4 － , PF6 － , OTf － , NCN2 － , and NTf2 － ; S4, the organic ionic monomer compound is heated to perform a polymerization reaction to obtain an ionic polymer adhesive based on PET degradation.

[0008] The present application uses waste PET as raw material, and prepares an organic ionic monomer compound through PET degradation, ionization reaction, and anion exchange reaction. The organic ionic monomer compounds are crosslinked to form a three-dimensional polymer network through dehydration, and the ionic polymer used as an adhesive exhibits excellent macroscopic bonding performance. Meanwhile, the ionic polymer adhesive can be recycled and reused under specific conditions, so that the performance of the ionic polymer adhesive meets the specific production requirements.

[0009] Further, in S1, the small molecule is selected from one or more of the following compounds: .

[0010] Further, in S2, the halogenated hydrocarbon is selected from one or more of the following compounds: .

[0011] The present application selects specific small molecules and halogenated hydrocarbons to form an internal aggregation structure through multiple hydrogen bonds by self-assembly. The ionic polymer not only can form strong hydrogen bond interactions with the surfaces of various substrate materials, thereby producing excellent interfacial adhesion, but also can construct a rich dynamic non-covalent crosslinking network inside the material, which cooperates with electrostatic interactions to significantly improve the cohesive energy of the adhesive. This interfacial and bulk combined mechanism makes the prepared ionic polymer used as an adhesive exhibit excellent macroscopic bonding performance.

[0012] In addition, the type of end group selected in the ionization reaction and the target anion selected in the anion exchange step will affect the water solubility, glass transition temperature and other properties of the ionic compound. Therefore, by flexibly matching different end groups of cations and different types of anions, the physical and chemical properties of the ionic polymer adhesive can be controlled and adjusted.

[0013] Further, in S1, the temperature of the aminolysis or ester exchange reaction is 70-100 DEG C, and the time is 20-30h.

[0014] Further, in S2, the ionization reaction conditions are: inert atmosphere protection, temperature 25-110 DEG C, and time 5-72h.

[0015] Further, in S4, the temperature of the polymerization reaction is 50-200 DEG C, and the time is 1-24h.

[0016] Further, in S1 and S2, the organic solvent is independently selected from one or more of anhydrous ethanol, methanol, tetrahydrofuran, ethyl acetate, acetonitrile, toluene, acetone, dichloromethane, chloroform, and N,N-dimethylformamide.

[0017] Further, in S3, the solvent of the organic ionic compound solution and the salt solution containing the target anion is independently selected from one or more of deionized water, acetone and tetrahydrofuran.

[0018] The second aspect of the present application provides the adhesive prepared by the method of the first aspect.

[0019] Further, the adhesive is degummed and recovered by flushing or soaking with a small molecule alcohol solvent.

[0020] The beneficial effects of the present application are: The present application converts PET into small molecule compounds through aminolysis / ester exchange reaction, prepares organic ionic monomer compounds through ionization reaction and anion exchange reaction, and forms a three-dimensional polymer network through dehydration and mutual crosslinking between the organic ionic monomer compounds; through the self-assembly of multiple hydrogen bonds, the ionic polymer can form an internal aggregation structure, which not only can form strong hydrogen bond interaction with the surface of various types of base materials, thereby producing excellent interfacial adhesion; at the same time, these hydrogen bonds also construct a rich dynamic non-covalent crosslinking network inside the material, which cooperates with electrostatic interaction, significantly improves the cohesive energy of the adhesive, and exhibits excellent macroscopic bonding performance for the adhesive, and the adhesive has excellent adhesion.

[0021] The adhesive obtained by the method can be recycled and reused under specific conditions, and the performance of the organic ionic polymer adhesive meets specific production requirements; in addition, the waste PET is used as a raw material, which has important significance in solving environmental pollution and resource recycling. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described below are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is the infrared absorption spectrum of the adhesive obtained in Example 1 of the present application; Figure 2 is the infrared absorption spectrum of the adhesive obtained in Example 2 of the present application; Figure 3 is the shear strength test result of the adhesive obtained in Example 1 of the present application on different substrates; Figure 4 is the macroscopic weighing test of the adhesive obtained in Example 1 of the present application after bonding the substrate; Figure 5 is the shear strength data of the adhesive obtained in Example 1 of the present application on ceramic and stainless steel substrates after recovery with ethanol solvent. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be described clearly and completely in combination with specific embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] The present embodiment relates to a method for preparing an ionic polymer adhesive based on PET degradation, comprising the following steps: S1, in an organic solvent, a small molecule with amine group or hydroxyl group at one end and organic cation precursor at the other end is subjected to aminolysis or ester exchange reaction with PET to obtain an intermediate; S2, in an organic solvent, the intermediate and a halogenated hydrocarbon are subjected to an ionization reaction to obtain an organic ionic compound; S3, the organic ionic compound solution is mixed with a salt solution containing target anions to perform an anion exchange reaction to obtain an organic ionic monomer compound; wherein the target anion is selected from CH3COO － , CF3COO － , BF4－ PF6 － OTf － NCN2 － and NTf2 － ; one or more of them; S4, heating the organic ionic monomer compound to perform a polymerization reaction to obtain the ionic polymer adhesive prepared based on PET degradation.

[0026] This embodiment takes waste PET as raw material, and prepares organic ionic monomer compounds through PET degradation, ionization reaction and anion exchange reaction. The organic ionic monomer compounds are crosslinked to form a three-dimensional polymer network through dehydration, and the ionic polymer used for adhesive exhibits excellent macroscopic bonding performance. Meanwhile, the ionic polymer adhesive can be recycled and reused under specific conditions, so that the performance of the organic ionic polymer adhesive meets specific production requirements.

[0027] As a preferred embodiment, in S1, the small molecule is selected from one or more of the following compounds: .

[0028] As a preferred embodiment, in S2, the halogenated hydrocarbon is selected from one or more of the following compounds: .

[0029] This embodiment selects specific small molecules and halogenated hydrocarbons, and the ionic polymer can form an internal aggregation structure through self-assembly of multiple hydrogen bonds. The ionic polymer not only can form strong hydrogen bond with the surface of various substrate materials, thereby producing excellent interfacial adhesion, but also can construct a rich dynamic non-covalent crosslinking network in the material, which cooperates with electrostatic interaction to significantly improve the cohesive energy of the adhesive. This interfacial and bulk combined mechanism makes the prepared ionic polymer used for adhesive exhibit excellent macroscopic bonding performance. In addition, the type of end group selected during the ionization reaction and the target anion selected in the anion exchange step will affect the water solubility, glass transition temperature and other properties of the ionic compound. Therefore, by flexibly matching different cations with different types of anions, the physical and chemical properties of the ionic polymer adhesive can be controllably adjusted.

[0030] As a preferred embodiment, in S1, the temperature of the aminolysis or ester exchange reaction is 70-100℃, and the time is 20-30h; in S2, the ionization reaction conditions are: inert atmosphere protection, temperature 25-110℃, time 5-72h; in S4, the temperature of the polymerization reaction is 50-200℃, and the time is 1-24h.

[0031] In a preferred embodiment, in S1 and S2, the organic solvent is independently selected from one or more of anhydrous ethanol, methanol, tetrahydrofuran, ethyl acetate, acetonitrile, toluene, acetone, dichloromethane, chloroform, and N,N-dimethylformamide; in S3, the solvents of the organic ionic compound solution and the salt solution containing the target anion are independently selected from one or more of deionized water, acetone, and tetrahydrofuran.

[0032] Another embodiment provides an adhesive prepared by the method described in the above embodiments, wherein the adhesive is degummed and recovered by rinsing or soaking in a small molecule alcohol solvent, wherein the small molecule alcohol solvent is selected from one or more of methanol, ethanol, and isopropanol.

[0033] Example 1

[0034] This embodiment relates to a method for preparing ionomer adhesives based on PET degradation, comprising the following steps: (1) Weigh 1 mmol PET and 1 mmol 1-(3-aminopropyl)imidazolium and dissolve them in 20 ml ethyl acetate. Stir continuously at 80 °C for 24 h. After the reaction is complete, the product is obtained in the form of a precipitate. The product is collected directly and washed with ethyl acetate. After vacuum drying, the imidazolium-containing raw material is obtained with a yield of 87%.

[0035] (2) Weigh 2 mmol of 4-(bromomethyl)phenylboronic acid and 1 mmol of the PET degradation imidazole-containing raw material obtained in step (1) and dissolve them in 20 mL of acetonitrile. Under the condition of continuously purging inert gas Ar 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 organic ionic compound with halogen anion is obtained with a yield of 71%.

[0036] (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 lithium bis(trifluoromethanesulfonyl)imide (LiNTf2) and dissolve it in 150 ml of deionized water to obtain mixture B. Mixtures A and B are mixed at room temperature and stirred for about 12 h. The precipitate is collected and washed with deionized water, then vacuum dried to finally obtain the imidazole-type bis(trifluoromethanesulfonyl)imide salt ionic monomer compound with a yield of 93%. The structural formula is: .

[0037] The NMR characterization of ionic monomeric compounds is as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 9.30 (d, J=1.8 Hz, 2H), 8.73 – 8.65 (m, 2H), 8.12 (s, 4H), 7.93 (s, 4H), 7.88 – 7.78 (m,8H), 7.36 (d, J = 7.8 Hz, 4H), 5.42 (s, 4H), 4.25 (t, J = 6.0 Hz, 4H), 3.30(t, J = 6.0 Hz, 4H), 2.09 (p, J = 6.8 Hz, 4H). 13 C NMR (100 MHz, DMSO- d 6) δ166.34, 137.07, 136.91, 136.80, 135.17, 127.65, 127.62, 123.37, 123.09,122.43, 119.95, 52.51, 47.50, 36.56, 30.04. (4) Weigh 1 mmol of the ionic monomer compound obtained in step (3) and heat it to 60°C under vacuum for 30 minutes to obtain the ionic polymer adhesive PIL-1 with a yield of 100%.

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

[0039] The NMR characterization of ionic monomeric compounds is as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 9.31 (d, J =1.8 Hz, 2H), 8.70 – 8.65 (m, 2H), 8.14 (s, 4H), 7.90 (s, 4H), 7.85 – 7.70 (m,6H), 7.30-7.40 (m, 4H), 7.23-6.91 (m, 2H), 5.40 (s, 4H), 4.26 (t, J = 6.0 Hz, 4H), 3.31 (t, J = 6.0 Hz, 4H), 2.16 (p, J = 6.8 Hz, 4H).13 C NMR (101 MHz, DMSO) δ 166.31, 138.31, 136.84, 136.02, 135.47, 135.15, 128.16, 127.59,123.38, 123.02, 122.31, 120.97, 119.95, 52.47, 47.44, 36.49, 30.48.

[0040] Example 3

[0041] The difference between this embodiment and Example 1 is that lithium bis(trifluoromethanesulfonyl)imide in step (3) is replaced with lithium hexafluorophosphate (LiPF6), while other steps and parameters remain unchanged. This prepares an ionic monomer compound and an ionic polymer adhesive PIL-3. The structural formula of the ionic monomer compound is: .

[0042] The NMR characterization of ionic monomeric compounds is as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 9.31 (d, J =1.6 Hz, 2H), 8.72 – 8.63 (m, 2H), 8.12 (s, 4H), 7.93 (s, 4H), 7.88 – 7.78 (m,8H), 7.36 (d, J = 7.6 Hz, 4H), 5.42 (s, 4H), 4.25 (t, J = 6.0 Hz, 4H), 3.30(t, J = 6.0 Hz, 4H), 2.09 (p, J = 6.8 Hz, 4H). 13 C NMR (101 MHz, DMSO) δ166.72, 137.45, 137.29, 137.18, 136.37, 135.55, 128.03, 128.01, 125.13,123.75, 123.47, 122.81, 52.89, 47.88, 36.93, 30.42.

[0043] Test case Figures 1-2 The infrared absorption spectra of the ionic polymers obtained in Examples 1 and 2 are shown respectively, indicating that the cross-linked polymers were successfully obtained.

[0044] Figure 3The adhesive obtained in Example 1 was subjected to a single-lap shear test on copper, aluminum, stainless steel, ceramic, glass, epoxy resin, acrylic, and polytetrafluoroethylene substrates (adhesion area 1 cm²). 2 ), at room temperature for 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 high bond strength, especially the highest bond strength on ceramic substrates.

[0045] Two stainless steel sheets were bonded together using the adhesive obtained in Example 1. A rope was fixed to one end of the bonded joint, 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 surface can suspend a weight of 20kg, such as... Figure 4 As shown.

[0046] The adhesive obtained in Example 1 was degummed with ethanol, and the recovered solution was dried at 80°C. Single-lap shear tests were then performed on ceramic and stainless steel substrates. The shear strength at the bond joint was measured at room temperature. The results showed that the adhesive still exhibited high bonding strength on stainless steel and ceramic substrates after PIL-1 solvent recovery. Figure 5 As shown.

[0047] In summary, this invention converts PET into small molecule compounds through aminolysis / ester exchange reactions, and prepares organic ionic monomer compounds through ionization and anion exchange reactions. These organic ionic monomer compounds cross-link with each other through dehydration to form a three-dimensional polymer network. Through the self-assembly of multiple hydrogen bonds, the ionic polymers can form internal aggregate structures, not only forming strong hydrogen bonds with various substrate materials, thus generating excellent interfacial adhesion, but also constructing a rich dynamic non-covalent cross-linked network within the material. This network, synergistic with electrostatic interactions, significantly enhances the cohesive energy of the adhesive, resulting in superior macroscopic bonding properties and excellent adhesion. The adhesives obtained by this invention can be recycled and reused under specific conditions, allowing the performance of organic ionic polymer adhesives to meet specific production needs. Furthermore, using waste PET as a raw material is of great significance in addressing environmental pollution and resource recycling.

[0048] 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 method for preparing an ionomeric adhesive based on PET degradation, characterized by, The method comprises the following steps: S1. In an organic solvent, aminolysis or transesterification reaction of a small molecule with amine group or hydroxyl group at one end and organic cation precursor at the other end with PET to obtain an intermediate; S2. In an organic solvent, ionization reaction of the intermediate and halogenated hydrocarbon to obtain an organic ionic compound; S3, mixing the organic ionic compound solution with a salt solution containing a target anion to perform an anion exchange reaction to obtain an organic ionic monomer compound; wherein the target anion is selected from one or more of CH3COO － , CF3COO － , BF4 － , PF6 － , OTf － , NCN2 － , and NTf2 － . S4. Polymerization reaction of the organic ionic monomer compound by heating to obtain an ionic polymer adhesive prepared based on PET degradation.

2. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, characterized in that, In S1, the small molecule is selected from one or more of the following compounds:

3. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, wherein, In S2, the halogenated hydrocarbon is selected from one or more of the following compounds:

4. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, wherein, In S1, the temperature of the aminolysis or transesterification reaction is 70-100℃, and the time is 20-30h.

5. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, wherein, In S2, the ionization reaction conditions are: inert atmosphere protection, temperature 25-110℃, and time 5-72h.

6. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, wherein, In S4, the temperature of the polymerization reaction is 50-200℃, and the time is 1-24h.

7. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, wherein, In S1 and S2, the organic solvent is independently selected from one or more of the following: anhydrous ethanol, methanol, tetrahydrofuran, ethyl acetate, acetonitrile, toluene, acetone, dichloromethane, chloroform, and N,N-dimethylformamide.

8. The method for preparing an ionomeric adhesive based on PET degradation according to claim 1, wherein, In S3, the solvents of the organic ionic compound solution and the salt solution containing target anions are independently selected from one or more of the following: deionized water, acetone, and tetrahydrofuran.

9. An adhesive prepared by the method of any one of claims 1-8.

10. The adhesive according to claim 9, wherein The adhesive is degummed by flushing or soaking with a small-molecule alcohol solvent and recovered.

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