A modified polymethylvinylsiloxane, its preparation and application, and an adhesive material.

Abstract

The application provides a modified polymethylvinylsiloxane and preparation and application thereof, and an adhesive material, and belongs to the field of polymers. The application provides a modified polymethylvinylsiloxane, the structure of which is shown in formula I, wherein R is an ethanol, propionic acid or ethyl acetate substituent; 2<=n<=6. The modified polymethylvinylsiloxane obtained by the application can be used as an adhesive material, and when used as the adhesive material, the adhesive strength thereof on a surface with roughness R a <=50 µm is higher than 120 kPa, while the contradiction between super-softness, super-high tensile strength (elongation at break >=800%), a wide temperature range (-100°C~150°C) and reversible strong adhesion on a rough surface is solved, and excellent comprehensive performance is exhibited. Formula I.

Description

TECHNICAL FIELD

[0001] The application provides a modified polymethylvinylsiloxane as well as preparation and application thereof, and an adhesive material, and belongs to the field of polymers. BACKGROUND

[0002] The adhesive material has an irreplaceable role in the fields of industrial production, daily life, biomedicine, and cutting-edge technology, such as packaging of flexible electronic devices, grasping of soft robots, biomedical dressings, and sealing and bonding in extreme environments. With the continuous expansion and deepening of application scenarios, more stringent requirements are put forward for the comprehensive performance of the adhesive material.

[0003] However, the adhesive material in the prior art is generally difficult to achieve coordination and compromise in multiple key performances, and there are obvious technical bottlenecks: (1) the contradiction between mechanical properties and adhesive properties. Traditional high-strength adhesive materials (such as epoxy resin, cyanoacrylate, etc.) are generally high in modulus and large in brittleness, and cannot be reused. Although soft materials (such as silicone gel) are low in modulus, their cohesive strength is often insufficient, and they are prone to cohesive failure, resulting in low adhesive strength and generally poor tensile properties. (2) Surface adaptability problem. High-performance adhesive materials (such as pressure-sensitive adhesive) need to be in close contact with smooth and clean surfaces to achieve effective adhesion. In actual applications, many surfaces (such as biological tissues, rough metal surfaces, fabrics, and microstructured surfaces, etc.) are rough and non-ideal. When the surface roughness increases, the adhesive material is difficult to effectively fill the surface grooves, the contact area decreases, and the adhesive performance is significantly reduced. (3) Limitations in performance stability at extreme temperatures. Traditional hydrogels lose their adhesion properties below the freezing point (0 °C) because water in the material freezes, making the material hard and brittle. Conventional acrylate or rubber-based adhesives lose their adhesion properties below −40 °C because they approach the glass transition temperature or crystallization temperature, resulting in a significant increase in modulus. (4) The contradiction between strong adhesion and reversibility. In order to achieve strong adhesion to rough surfaces, traditional materials often rely on the viscous flow of high molecular weight to wet the surface, or through chemical cross-linking to solidify. When peeling, the cohesive force is often less than the adhesive force, resulting in bulk damage and interface residue, and the material cannot be reused. Existing reversible adhesive materials (such as biomimetic gecko dry adhesive tape) mainly rely on microstructures to generate van der Waals forces, but they require a very high degree of flatness of the substrate. On rough surfaces, the microarray cannot form effective contact, resulting in a significant decrease in adhesion performance.

[0004] In summary, existing adhesive materials struggle to simultaneously resolve the contradictions between ultra-softness (adapting to roughness), ultra-high tensile strength (adapting to large deformations), a wide temperature range (−100 °C~150 °C), and reversible strong adhesion to rough surfaces. This technological bottleneck severely restricts the application of adhesive materials in extreme environments (such as polar scientific expeditions, deep space exploration, and industrial high-temperature transfer). Therefore, there is an urgent need to develop a novel ultra-soft, ultra-stretchable adhesive material that, through molecular structure design, achieves strong and reversible adhesion to rough surfaces across a wide temperature range, thereby promoting the engineering applications of adhesive materials. Summary of the Invention

[0005] To address the aforementioned deficiencies, this invention provides a modified polymethylvinylsiloxane (PMVS). A modified PMVS with a novel structure is prepared by branching polar groups (hydroxyl, carboxyl, or ester groups, etc.) onto the side links of PMVS. Furthermore, it is indicated that PMVS can be used as an adhesive material, and when used as an adhesive material, it exhibits good performance in the roughness R within the temperature range of −100 °C to 150 °C. a It exhibits an adhesion strength of over 120 kPa on surfaces ≤50 µm, and simultaneously resolves the contradictions between ultra-softness (adapting to roughness), ultra-high tensile strength (elongation at break ≥800%), wide temperature range (−100 °C~150 °C), and reversible strong adhesion to rough surfaces, demonstrating excellent comprehensive performance.

[0006] The technical solution of the present invention:

[0007] The first technical problem to be solved by this invention is to provide a modified polymethylvinylsiloxane, the structure of which is shown in Formula I:

[0008]

[0009] Formula I

[0010] Wherein, R = ethanol, propionic acid or ethyl acetate substituent; 2≦n≦6; preferably 2, 3 or 6.

[0011] Furthermore, the modified polymethylvinylsiloxane is a substance with the following structural formula:

[0012] , or

[0013] Formula II Formula III

[0014]

[0015] Formula IV

[0016] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned modified polymethylvinylsiloxane. The preparation method is as follows: first, polymethylvinylsiloxane, a dithiol crosslinking agent, a polar group modifier, a photocatalyst, and a solvent are mixed evenly to obtain a viscous liquid; then, a Michael addition reaction is carried out under ultraviolet light irradiation at a wavelength of 254-550 nm to obtain the modified polymethylvinylsiloxane; wherein, the proportions of each raw material are: 140-150 parts by weight of polymethylvinylsiloxane, 1-3 parts by weight of dithiol crosslinking agent, 10-28 parts by weight of polar group modifier, 7-12 parts by weight of photocatalyst, and 98-105 parts by weight of solvent; the polar group modifier is at least one of ethyl mercaptoacetate, 3-mercaptopropionic acid, or β-mercaptoethanol.

[0017] Furthermore, the structural formula of the polymethylvinylsiloxane is shown in Formula V.

[0018]

[0019] Formula V

[0020] Among them, 5%≦m / (m+n)≦15%.

[0021] Furthermore, the vinyl content of the polymethylvinylsiloxane is 5 mol.%-15 mol.%.

[0022] Furthermore, the dithiol crosslinking agent is: 1,6-hexanedithiol, 1,2-ethanedithiol, or 1,3-propanedithiol.

[0023] Furthermore, the photocatalyst is selected from: 2-hydroxy-2-methyl-1-phenyl-1-propanone (tris(2,2′-bipyridine)ruthenium(II) chloride hexahydrate, tris[2-phenylpyridine-C2,N]iridium(III), tetrabromofluorescein disodium or Acid Red 94.

[0024] Furthermore, the solvent is: N,N-dimethylformamide, toluene, or tetrahydrofuran.

[0025] Furthermore, in the above preparation method, the raw materials also include a reinforcing agent, the amount of which is 2.8 to 12 parts by weight. The reinforcing agent is: fumed silica, ferric oxide, cerium oxide, aluminum oxide, or magnesium oxide.

[0026] The third technical problem to be solved by the present invention is to point out that the above-mentioned modified polymethylvinylsiloxane can be used as an adhesive material, a capture mechanism or a medical dressing.

[0027] The fourth technical problem to be solved by the present invention is to provide an adhesive material whose raw materials include the above-mentioned modified polymethylvinylsiloxane.

[0028] The beneficial effects of this invention are:

[0029] This invention, for the first time, prepares a modified polymethylvinylsiloxane (PMVS) with a novel structure by branching polar groups (hydroxyl, carboxyl, or ester groups, etc.) onto the side links of PMVS; and discovers that it can be used as an adhesive material, and when used as an adhesive material, it exhibits good performance in terms of roughness R within the temperature range of −100 °C to 150 °C. a It exhibits excellent adhesion and mechanical properties with an adhesion strength higher than 120 kPa on a surface ≤50 µm, a minimum Young's modulus of 6.3 kPa, and a maximum elongation at break of 1055.8%. Attached Figure Description

[0030] Figure 1 The infrared spectra of mercaptoethanol and hydroxyl-modified polymethyl vinyl siloxane obtained in Example 1 are shown. The absorption peaks corresponding to methylene, hydroxyl and mercapto groups in the molecular structure of mercaptoethanol and the absorption peaks corresponding to methyl, hydroxyl and siloxane bonds in the molecular structure of hydroxyl-modified polymethyl vinyl siloxane, as well as the vinyl and mercapto absorption peaks that disappear after the reaction, are observed in the infrared spectra, thus proving the successful synthesis of hydroxyl-modified polymethyl vinyl siloxane.

[0031] Figure 2 The infrared spectra of mercaptopropionic acid and carboxyl-modified polymethyl vinyl siloxane obtained in Example 2 are shown. The infrared spectra show the absorption peaks corresponding to methylene, carbonyl, hydroxyl and mercapto groups in the molecular structure of mercaptopropionic acid, as well as the absorption peaks corresponding to methyl, hydroxyl, carbonyl and siloxane bonds in the molecular structure of carboxyl-modified polymethyl vinyl siloxane, and the vinyl and mercapto absorption peaks that disappear after the reaction. This proves the successful synthesis of carboxyl-modified polymethyl vinyl siloxane.

[0032] Figure 3 The figures show the target surface morphology in the adhesion performance tests of Examples 1 and 2. As can be seen from the figures, the roughness of the target surface is 40.8 µm, indicating that the target surface exhibits high roughness.

[0033] Figure 4 The figure shows the adhesion properties of the hydroxyl-modified polymethylvinylsiloxane obtained in Example 1 at −100 °C, 25 °C, and 150 °C. As can be seen from the figure, the adhesion strengths of the hydroxyl-modified polymethylvinylsiloxane at −100 °C, 25 °C, and 150 °C can reach 139.4 kPa, 134.8 kPa, and 122.0 kPa, respectively. It is evident that the hydroxyl-modified polymethylvinylsiloxane exhibits excellent adhesion properties to rough surfaces over a wide temperature range (−100 °C to 150 °C).

[0034] Figure 5The figure shows the adhesion properties of the carboxyl-modified polymethylvinylsiloxane obtained in Example 2 at −100 °C, 25 °C, and 150 °C. As can be seen from the figure, the adhesion strengths of the carboxyl-modified polymethylvinylsiloxane at −100 °C, 25 °C, and 150 °C can reach 138.6 kPa, 132.0 kPa, and 137.0 kPa, respectively. It is evident that the carboxyl-modified polymethylvinylsiloxane exhibits excellent adhesion properties to rough surfaces over a wide temperature range (−100 °C to 150 °C).

[0035] Figure 6 The figures show the tensile curves of the hydroxyl-modified polymethylvinylsiloxane and carboxyl-modified polymethylvinylsiloxane obtained in Examples 1 and 2. As can be seen from the figures, the Young's modulus and elongation at break of the hydroxyl-modified polymethylvinylsiloxane are 24.9 kPa and 839.7%, respectively, while those of the carboxyl-modified polymethylvinylsiloxane are 6.3 kPa and 1055.8%, respectively. It is evident that both the hydroxyl-modified and carboxyl-modified polymethylvinylsiloxanes exhibit ultra-soft and ultra-tensile properties.

[0036] Figure 7 The reversible adhesion properties of the carboxyl-modified polymethylvinylsiloxane obtained in Example 2 at −100 °C (Figure a), 25 °C (Figure b), and 150 °C (Figure c) are shown. Detailed Implementation

[0037] This invention, for the first time, prepares a modified polymethylvinylsiloxane (PMVS) with a novel structure by branching polar groups (hydroxyl, carboxyl, or ester groups, etc.) onto the side links of PMVS; and discovers that it can be used as an adhesive material, and when used as an adhesive material, it exhibits good performance in terms of surface roughness R within the temperature range of -100 °C to 150 °C. a The adhesion strength on a surface ≤50 µm is higher than 120 kPa, the Young's modulus can be as low as 6.3 kPa, and the elongation at break can be as high as 1055.8%, exhibiting excellent adhesion and mechanical properties. It simultaneously solves the contradiction between ultra-softness (adapting to roughness), ultra-high tensile strength (elongation at break ≥800%), wide temperature range (−100 °C~150 °C), and reversible strong adhesion to rough surfaces, demonstrating excellent comprehensive performance.

[0038] The modified polymethylvinylsiloxane of this invention has the structural formula shown in Formula I:

[0039]

[0040] Formula I

[0041] Wherein, R = ethanol, propionic acid or ethyl acetate substituent; 2≦n≦6; preferably 2, 3 or 6.

[0042] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0043] Example 1

[0044] 14.5 g of polymethylvinylsiloxane (GS5210, Shanghai Silicon Oil New Materials), 0.2 g of hexamethylenedithiol (Aladdin), 1.1 g of mercaptoethanol (Aladdin), 0.7 g of alumina (MPA-06), 0.9 ml of 2-hydroxy-2-methyl-1-phenyl-1-propanone (Aladdin), and 10.2 g of tetrahydrofuran (Aladdin) were mixed at room temperature for 30 min to obtain a milky white viscous liquid. Then, the mixture was irradiated under 365 nm ultraviolet light for 10 min to obtain hydroxyl-modified polymethylvinylsiloxane.

[0045] according to Figure 1 The middle Fourier transform infrared spectrum shows that the hydroxyl-modified polymethyl vinyl siloxane contains chemical bonds such as silicon-oxygen bonds, methyl, methylene, and hydroxyl groups. After the reaction, the vinyl and mercapto groups disappear, thus proving that mercaptoethanol successfully reacted with polymethyl vinyl siloxane to obtain hydroxyl-modified polymethyl vinyl siloxane.

[0046] The morphology of its adhesive surface is as follows Figure 3 As shown. According to Figure 3 The surface morphology image shows that the target surface has a roughness of 40.8 µm, classifying it as a rough surface. Adhesion properties are as follows... Figure 4 As shown, the adhesive strength of hydroxyl-modified polymethylvinylsiloxane can reach 139.4 kPa, 134.8 kPa and 122.0 kPa at −100 °C, 25 °C and 150 °C, respectively, proving that it exhibits excellent adhesion performance to rough surfaces in a wide temperature range (−100 °C~150 °C).

[0047] Its mechanical properties are as follows Figure 6 As shown. According to Figure 6 The tensile curves show that the Young's modulus and elongation at break of the hydroxyl-modified polymethylvinylsiloxane are 24.9 kPa and 839.7%, respectively, exhibiting ultra-softness and ultra-tensile properties.

[0048] Example 2

[0049] 15.0 g of polymethylvinylsiloxane (Shanghai Silicon Oil New Materials, GS5210), 0.3 g of hexanedithiol (Aladdin), 2.7 g of mercaptopropionic acid (Aladdin), 0.8 g of cerium oxide (Aladdin), 1.0 ml of 2-hydroxy-2-methyl-1-phenyl-1-propanone (Aladdin), and 10.5 g of tetrahydrofuran (Aladdin) were mixed at room temperature for 30 min to obtain a pale yellow viscous liquid. Then, the mixture was irradiated under 365 nm ultraviolet light for 10 min to obtain carboxyl-modified polymethylvinylsiloxane.

[0050] according to Figure 2 The mid-Fourier transform infrared spectrum shows that the carboxyl-modified polymethyl vinyl siloxane contains chemical bonds such as silicon-oxygen bonds, methyl, methylene, carbonyl, and hydroxyl groups. Furthermore, the vinyl and mercapto groups disappear after the reaction, thus proving that mercaptopropionic acid successfully reacted with polymethyl vinyl siloxane to obtain carboxyl-modified polymethyl vinyl siloxane.

[0051] The morphology of its adhesive surface is as follows Figure 3 As shown. According to Figure 3 The surface morphology image shows that the target surface has a roughness of 40.8 µm, classifying it as a rough surface. Adhesion properties are as follows... Figure 5 As shown, the carboxyl-modified polymethylvinylsiloxane exhibits adhesion strengths of 138.6 kPa, 132.0 kPa, and 137.0 kPa at −100 °C, 25 °C, and 150 °C, respectively, demonstrating its excellent adhesion performance to rough surfaces across a wide temperature range (−100 °C to 150 °C).

[0052] In this invention, the testing method for the above-mentioned performance is as follows:

[0053] The adhesive properties of the adhesive material were characterized using a dynamic mechanical analyzer (Q850, TA instrument). A rough surface was fixed to the lower clamp of the dynamic mechanical analyzer's compression fixture using double-sided adhesive, and the adhesive material was fixed to the upper clamp. The temperature of the dynamic mechanical analyzer was stabilized at target temperatures (−100 °C, 25 °C, and 150 °C) using its temperature control device. A pre-compression of 5 N was applied to the adhesive material and held for 6 s. Then, the upper clamp was lifted upwards at a rate of 100 mm / min, and the stress-time curve was obtained, from which the adhesive strength was read.

[0054] The adhesive reversibility of the adhesive material was characterized using a dynamic mechanical analyzer (Q850, TA instrument). The test conditions and parameter settings were the same as those for the adhesive performance test, and the process was repeated five times to verify the adhesive reversibility of the adhesive material.

[0055] Its mechanical properties are as followsFigure 6 As shown. According to Figure 6 The tensile curves show that the Young's modulus and elongation at break of the carboxyl-modified polymethylvinylsiloxane are 6.3 kPa and 1055.8%, respectively, exhibiting ultra-softness and ultra-tensile properties.

[0056] Its adhesive reversibility is as follows Figure 7 As shown, according to Figure 7 The adhesion cycle curves show that carboxyl-modified polymethylvinylsiloxane exhibits good adhesion at −100 °C (…). Figure 7 a) 25 °C ( Figure 7 b) and 150 °C ( Figure 7 c) After five cycles of adhesion and deadhesion to the target surface, it still exhibits strong adhesion properties, demonstrating its reversible adhesion.

[0057] It should be noted that while the preferred embodiments of the present invention are given in the specification and accompanying drawings, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of the present invention; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of the present invention. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of the present invention specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A modified polymethylvinylsiloxane, characterized by, The structure is shown as formula I: ； Formula I Wherein, R = ethanol, propionic acid or ethyl acetate substituent; 2 ≦ n ≦ 6.

2. The modified polymethylvinylsiloxane according to claim 1, characterized in that, The modified polymethylvinylsiloxane is a substance shown in the following structural formula: , or Formula II Formula III ； Formula IV.

3. The method for producing the modified polymethylvinylsiloxane according to claim 1 or 2, characterized by, The preparation method is: first, mixing polymethylvinylsiloxane, bimer capto crosslinking agent, polar group modifier, photocatalyst and solvent uniformly to obtain a viscous liquid; then, under the irradiation of ultraviolet light with a wavelength of 254-550 nm, a Michael addition reaction is carried out to obtain the modified polymethylvinylsiloxane; wherein, the amount ratio of each raw material is: polymethylvinylsiloxane 140-150 parts by weight, bimer capto crosslinking agent 1-3 parts by weight, polar group modifier 10-28 parts by weight, photocatalyst 7-12 parts by weight, solvent 98-105 parts by weight; the polar group modifier is at least one of ethyl mercaptoacetate, 3-mercapto propionic acid or beta-mercaptoethanol.

4. The method for producing a modified polymethylvinylsiloxane according to claim 3, wherein The vinyl content of the polymethylvinylsiloxane is 5 mol%-15 mol%.

5. The method for preparing modified polymethylvinylsiloxane according to claim 3, characterized in that, The bimer capto crosslinking agent is 1,6-hexanedithiol, 1,2-ethanedithiol or 1,3-propanedithiol.

6. The method for preparing modified polymethylvinylsiloxane according to claim 3, characterized in that, The photocatalyst is selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, tris[2-phenylpyridine-C2,N]iridium(III), disodium tetra bromo fluorescein or acid red 94.

7. The method for preparing modified polymethylvinylsiloxane according to claim 3, characterized in that, The solvent is N,N-dimethylformamide, toluene or tetrahydrofuran.

8. The method for preparing modified polymethylvinylsiloxane according to claim 3, characterized in that, In the preparation method, the preparation raw material further includes a reinforcing agent, and the addition amount of the reinforcing agent is 2.8-12 parts by weight, and the reinforcing agent is fumed silica, diiron trioxide, cerium oxide, aluminum oxide or magnesium oxide.

9. Use of the modified polymethylvinylsiloxane of claim 1 or 2 in an adhesive material, a capturing mechanism or a medical dressing.

10. An adhesive material, characterized by The raw material of the adhesive material includes the modified polymethylvinylsiloxane of claim 1 or 2. The structure is shown as formula I: Formula I Wherein, R = ethanol, propionic acid or ethyl acetate substituent; 2 ≦ n ≦ 6. The modified polymethylvinylsiloxane is a substance shown in the following structural formula: Formula II Formula III Formula IV. The preparation method is: first, mixing polymethylvinylsiloxane, bimer capto crosslinking agent, polar group modifier, photocatalyst and solvent uniformly to obtain a viscous liquid; then, under the irradiation of ultraviolet light with a wavelength of 254-550 nm, a Michael addition reaction is carried out to obtain the modified polymethylvinylsiloxane; wherein, the amount ratio of each raw material is: polymethylvinylsiloxane 140-150 parts by weight, bimer capto crosslinking agent 1-3 parts by weight, polar group modifier 10-28 parts by weight, photocatalyst 7-12 parts by weight, solvent 98-105 parts by weight; the polar group modifier is at least one of ethyl mercaptoacetate, 3-mercapto propionic acid or beta-mercaptoethanol. The vinyl content of the polymethylvinylsiloxane is 5 mol%-15 mol%. The bimer capto crosslinking agent is 1,6-hexanedithiol, 1,2-ethanedithiol or 1,3-propanedithiol. The photocatalyst is selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, tris[2-phenylpyridine-C2,N]iridium(III), disodium tetra bromo fluorescein or acid red 94. The solvent is N,N-dimethylformamide, toluene or tetrahydrofuran. In the preparation method, the preparation raw material further includes a reinforcing agent, and the addition amount of the reinforcing agent is 2.8-12 parts by weight, and the reinforcing agent is fumed silica, diiron trioxide, cerium oxide, aluminum oxide or magnesium oxide.

9. Use of the modified polymethylvinylsiloxane of claim 1 or 2 in an adhesive material, a capturing mechanism or a medical dressing. The raw material of the adhesive material includes the modified polymethylvinylsiloxane of claim 1 or 2.

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