Repairable, readily dissolvable organosilicon elastomers containing boron-oxygen bonds and methods of making the same

Abstract

The present application relates to a kind of boron-oxygen bond-containing repairable, easily soluble silicone elastomer and its preparation method.The present application is generated by the condensation reaction of boron hydroxyl group and Schiff base reaction of amino polysiloxane derivative A, chain extender aldehyde group-containing monomer derivative B and 3-amino phenylboronic acid C, and the main chain of organic polysiloxane containing boron-oxygen bond and dynamic imine bond, using amino and hydroxyl and hydroxyl and hydroxyl form multiple hydrogen bond, preparation repairable, easily soluble silicone elastomer.The silicone elastomer prepared by the present application has good mechanical properties, solubility and self-repairing performance in heat and water and high self-repairing efficiency, and can be applied in flexible display, flexible sensing, wearable electronic products, electronic skin and other fields.

Description

Technical Field

[0001] This invention belongs to the field of flexible materials, and specifically relates to a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] With the continuous development of polymer materials and electronic science, the demand for various flexible electronic devices in people's daily lives is increasing. Among these, the most prominent research areas are flexible displays, flexible sensors, wearable electronics, and electronic skin. These flexible electronic devices often require an ideal stretchable elastomer as a substrate. Organosilicon elastomers, as an organosilicon polymer material, are ideal for various flexible electronic devices due to their excellent chemical and thermodynamic stability, non-toxicity, non-flammability, and excellent flexibility over a wide temperature range. Traditional methods of crosslinking organosilicon elastomers using peroxides and hydrosilylation form permanent covalent crosslinked networks, resulting in a loss of self-healing properties and poor solubility. How to enable damaged organosilicon elastomers to repair themselves and restore their mechanical properties remains a challenge. However, organosilicon elastomers prepared based on dynamic chemical bonds, such as disulfide bonds, reversible acylhydrazones, metal coordination bonds, and reversible DA reactions, can easily achieve self-repair through the reversible destruction of these dynamic chemical bonds. For example, patent CN 109749086 A discloses a method for preparing a self-healing organosilicon elastomer. The method includes: synthesizing a polysiloxane containing 1,2-dithiocyclopentyl group by chain extension reaction of a 1,2-dithiocyclopentyl derivative A and an amino-containing polysiloxane derivative B; and realizing the reversible crosslinking of the organosilicon elastomer by utilizing the dynamic disulfide bond effect of the terminal dithiocyclopentyl group of the polysiloxane to prepare a self-healing organosilicon elastomer. However, the inventors found that there is still room for research on the mechanical properties and degradability of the material. Summary of the Invention

[0004] To overcome the above problems, this invention provides a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds and its preparation method. The organosilicon elastomer achieves reversible crosslinking by using 3-aminophenylboronic acid condensation to form boron-oxygen bonds and reacting with a Shiff base to generate dynamic imine bonds. Furthermore, the self-healing properties of the organosilicon elastomer are further endowed by various hydrogen bonds, resulting in high tensile strength and rapid dissolution by amino and methylamino reagents. The preparation method of this invention is simple, efficient, practical, and easy to promote.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a boron-oxygen bond-containing repairable and easily soluble organosilicon elastomer involves dispersing an amino-containing polysiloxane derivative A, an aldehyde-containing monomer derivative B, and 3-aminophenylboronic acid in an organic solvent, reacting them at 25℃~40℃ for 12~16h, and then casting them into a mold to obtain the boron-oxygen bond-containing repairable and easily soluble organosilicon elastomer.

[0007] The general formula of the structural unit containing amino-containing polysiloxane derivative A is as follows:

[0008]

[0009] Where n is a natural number greater than zero; R1 is usually methyl, phenyl, or trifluoropropyl; the structural formula of R2 is Where y = 0 to 10;

[0010] The general formula of the aldehyde-containing monomer derivative B is as follows:

[0011] OHC-R3-CHO

[0012] Wherein, R3 is —(CH2). z —or benzene ring, where Z is a natural number.

[0013] This invention reveals that while organosilicon elastomers prepared via peroxide crosslinking and hydrosilylation crosslinking possess good mechanical properties, these materials exhibit poor self-healing properties (only swelling, not dissolving) and complex preparation processes. Therefore, this invention utilizes the condensation of 3-aminophenylboronic acid to form boron-oxygen bonds and the reaction with a Shiff base to generate dynamic imine bonds, achieving reversible crosslinking of organosilicon elastomers. The introduction of boron-oxygen bonds enables self-healing not only under conventional conditions but also in water; the introduction of dynamic imine bonds endows them with self-healing and solubility properties at high temperatures. Furthermore, 3-aminophenylboronic acid can construct a ternary structure through the formation of boron-oxygen bonds, thereby forming a ternary crosslinked network, increasing the crosslinking density of the organosilicon elastomer. The mechanical properties of the material can be controlled by adjusting the amount of 3-aminophenylboronic acid used to adjust the crosslinking density.

[0014] In some embodiments, the molar ratio of amino to aldehyde groups in the amino-containing polysiloxane derivative A and the aldehyde-containing monomer derivative B is 1:1, which effectively facilitates the Schiff base reaction and ensures complete reaction of the amino and aldehyde groups. Adding 3 wt% to 5 wt% of 3-aminophenylboronic acid C can induce a three-dimensional cross-linked structure in the polymer, allowing unreacted amino and hydroxyl groups, as well as hydroxyl groups to form multiple hydrogen bonds.

[0015] This application research found that if the amount of 3-aminophenylboronic acid is too large, it may cause solid precipitation; if the amount of 3-aminophenylboronic acid is too small, the effect may be insignificant. Therefore, in some embodiments, the amount of 3-aminophenylboronic acid is 3wt% to 5wt% so that the organosilicon elastomer has good repair and dissolution properties, as well as good mechanical properties and stability.

[0016] 3-Aminophenylboronic acid can form boron-oxygen bonds through dehydration, achieving a cross-linking effect, enabling the polymer to form a three-dimensional structure, improving its processability, and giving it the ability to self-heal in water, increasing the cross-linking density, and improving mechanical properties.

[0017] This application does not specifically limit the structure of the amino-containing polysiloxane derivative A. In some embodiments, the amino-containing polysiloxane derivative A is at least one of α,ω-diaminopropyl polydimethylsiloxane, α,ω-diaminopropyl polymethylphenylsiloxane, or α,ω-diaminopropyl polymethyltrifluoropropylsiloxane, which can obtain better self-healing and easy-to-dissolve properties.

[0018] In some embodiments, the molecular weight of the amino-containing polysiloxane derivative A is 1,000 to 30,000, preferably 2,000 to 20,000.

[0019] In the synthesis of organosilicon elastomers, chain extenders are commonly used to extend the chain of prepolymers to increase their relative molecular mass.

[0020] In some embodiments, the aldehyde-containing monomer derivative B chain extender is glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, or terephthalaldehyde, which causes the amino and aldehyde groups to undergo a Schiff base reaction to form an imine bond, thereby endowing the organosilicon elastomer with better thermal repair and solubility properties.

[0021] The present invention also provides a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds prepared by any of the above methods.

[0022] This invention also provides a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds, the structural formula of which is as follows:

[0023]

[0024] Where n is a natural number greater than zero; R1 is usually methyl, phenyl, or trifluoropropyl; the structural formula of R2 is Where y = 0 to 10; R3 is —(CH2) z —or benzene ring, where Z is a natural number.

[0025] In some embodiments, the molecular weight of the boron-oxygen bond-containing repairable, soluble organosilicon elastomer ranges from 3,000 to 90,000.

[0026] The present invention also provides the application of any of the above-mentioned boron-oxygen bond-containing repairable and soluble organosilicon elastomers in the manufacture of flexible displays, flexible sensors, wearable electronic products or electronic skin.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) Compared with the prior art, the present invention utilizes the condensation polymerization of 3-aminophenylboronic acid to form boron-oxygen bonds and the reaction of Shiff base to generate dynamic imine bonds to achieve reversible crosslinking of organosilicon elastomers. Furthermore, by controlling the content of 3-aminophenylboronic acid C, the crosslinking density is adjusted to give it good mechanical properties, solubility and self-healing properties in water.

[0029] (2) The operation method of this application is simple, low-cost, universal, and easy to scale up production. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0031] Figure 1 The FT-IR image of the organosilicon elastomer prepared in Example 1;

[0032] Figure 2 Optical microscope images of the organosilicon elastomer prepared in Example 1 before and after self-healing;

[0033] Figure 3 Stress-strain curves of organosilicon elastomers with different contents of 3-aminophenylboronic acid prepared in Example 1;

[0034] Figure 4 Stress-strain curves of the silicone elastomer prepared in Example 1 before and after self-healing under different conditions;

[0035] Figure 5 Photographs showing the degradation process of the organosilicon elastomer prepared in Example 1. Detailed Implementation

[0036] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] As described in the background section, current self-healing silicone elastomer materials still suffer from poor mechanical properties and unsatisfactory solubility. This invention proposes a repairable and easily soluble silicone elastomer containing boron-oxygen bonds. It comprises an amino-containing polysiloxane derivative A, a chain extender containing an aldehyde-based monomer derivative B, and 3-aminophenylboronic acid, which undergo a condensation reaction of amino and aldehyde groups to form reversible dynamic imine bonds, boron-oxygen bonds, and hydrogen bonds, thus preparing a self-healing and easily degradable silicone elastomer.

[0039] The specific steps are as follows:

[0040] Step 1: Dissolve amino-containing polysiloxane derivative A, chain extender aldehyde-containing monomer derivative B, and 4-aminophenylboronic acid C in tetrahydrofuran, mix thoroughly under normal pressure, and heat to react.

[0041] Step 2: Heat and dry the above prepolymer until constant weight is achieved, and the product is obtained.

[0042] The general formula of the structural unit containing amino-containing polysiloxane derivative A is as follows:

[0043]

[0044] Where n is a natural number greater than zero; R1 is usually methyl, phenyl, or trifluoropropyl; the structural formula of R2 is Where y = 0 to 10;

[0045] The general formula of the aldehyde-containing monomer derivative B chain extender is as follows:

[0046] OHC-R3-CHO

[0047] Wherein, R3 is —(CH2). z —or a benzene ring, where Z is a natural number. For example, glyoxal: OHCCHO, malondialdehyde: Butylene dialdehyde: Glutaraldehyde: terephthalaldehyde:

[0048] The structural formulas of the 3-aminophenylboronic acid C are as follows:

[0049]

[0050] The present invention also provides a method for preparing a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds, which is formed by condensation reaction of amino-containing polysiloxane derivative A, chain extender containing aldehyde monomer derivative B, and 3-aminophenylboronic acid and Shiff base reaction to form a reversible dynamic imine bond, boron-oxygen bond, and hydrogen bond to construct a reversible cross-linked network.

[0051] To achieve the self-healing properties of organosilicon elastomers, aldehyde groups are introduced onto the amino groups at the ends of the organopolysiloxane backbone, forming reversible dynamic imine bonds via a Shiff base reaction. 3-Aminophenylboronic acid is introduced into the system to form reversible boron-oxygen bonds. Multiple hydrogen bonds are formed between unreacted amino and hydroxyl groups, and between hydroxyl groups, thus achieving the self-healing properties of the organosilicon elastomer. Furthermore, the imine and boron-oxygen bonds on the backbone form a cross-linking network, further enhancing the repair performance of the organosilicon elastomer.

[0052] Preferably, A is one or more of α,ω-diaminopropyl polydimethylsiloxane, α,ω-diaminopropyl polymethylphenylsiloxane, and α,ω-diaminopropyl polymethyltrifluoropropylsiloxane.

[0053] Preferably, the molecular weight of A is 1,000 to 30,000, more preferably 2,000 to 20,000.

[0054] Preferably, the chain extender B is one or more of glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, and terephthalaldehyde.

[0055] Preferably, the amount of 3-aminophenylboronic acid C used is 3% to 5% of the total mass of the system.

[0056] Preferably, the condensation reaction of the amino group and the aldehyde group is carried out at a temperature of 25°C to 40°C.

[0057] Preferably, the study found that common organic synthesis reactions were used: the condensation reaction of 3-aminophenylboronic acid and the Shiff base reaction, which have simple, mild reaction conditions and are easy to operate.

[0058] The present invention also provides polysiloxanes with imine bonds and boron-oxygen bonds in the main chain prepared by any of the above methods.

[0059] The polysiloxanes with imine and boron-oxygen bonds in their main chain as described above can be used to prepare organosilicon elastomer materials, which also have good mechanical properties, solubility properties, and self-healing properties in heat and water.

[0060] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0061] In the following examples, α,ω-aminopropyl polysiloxane (Mn: 2000, 5000, 10000) is a commercially available polymer purchased from Jiashan Jiangnan Textile Materials Co., Ltd., and other raw materials are also commercially available products.

[0062] Example 1

[0063] 10g of α,ω-aminopropylpolysiloxane (Mn: 2000), 0.67g of terephthalaldehyde (98% purity), and 0.53g of 3-aminophenylboronic acid were dissolved in an appropriate amount of tetrahydrofuran (monomer concentration maintained at approximately 0.1g / ml). The mixture was stirred thoroughly at 40℃ and reacted for 12 hours. The solution was then poured into a polytetrafluoroethylene mold and dried at a constant temperature until constant weight was obtained, yielding an organosilicon elastomer. The organosilicon elastomer was cut into dumbbell shapes (length × width × thickness: 50 × 4 × 0.8mm). 3 The sample was broken at a tensile rate of 50 mm / min using an Instron 3343 electronic universal testing machine at room temperature. The fracture surfaces of the sample were then brought into full contact. The sample was then placed in a 100°C vacuum drying oven for 15 minutes for repair before testing, or repaired at room temperature under a certain pressure for 12 hours, or repaired in water at room temperature for 30 minutes.

[0064] Figure 1-5 The images show FT-IR images of silicone elastomers, optical microscope images before and after self-healing under different self-healing conditions, stress-strain curves of silicone elastomers with different 3-aminophenylboronic acid contents, stress-strain curves before and after self-healing under different self-healing conditions, and photographs of the actual dissolution process.

[0065] like Figure 1 As shown, the silicone elastomer is at 1624 cm⁻¹ -1 The presence of imine bonds (C=N) indicates the formation of dynamic imine bonds in the elastomer. For example... Figure 2 As shown, the top image is an optical microscope image of a crack cut into the surface of a silicone elastomer. The bottom images, from left to right, are optical microscope images of the silicone elastomer after repairing the crack at room temperature for 12 hours, in water at room temperature for 30 minutes, and at 100°C for 15 minutes. The optical microscope clearly and accurately observes that the silicone elastomer has a strong self-healing ability. Figure 3 As shown, the elastomers prepared with three different contents of 3-aminophenylboronic acid exhibit different tensile properties. The elastomer with 3 wt% 3-aminophenylboronic acid in the total system mass has an elongation at break of 295%, while the elastomer with 5 wt% 3-aminophenylboronic acid in the total system mass has a tensile strength of 2.84 MPa. Figure 4 As shown, under conditions of 100℃ for 15 minutes, the repair efficiency of silicone elastomers can reach 95%. Figure 5As shown, due to the presence of dynamic imine bonds, when a 0.1g piece of organosilicon elastomer is placed in an excess of aniline, it can be clearly seen that the sample is completely dissolved after 15 minutes, demonstrating its good solubility.

[0066] Example 2

[0067] Repeat the steps described in Example 1, except that 0.67g of terephthalaldehyde is replaced with 1.0g of glutaraldehyde (50wt%).

[0068] Example 3

[0069] Repeat the steps described in Example 1, except that 10g of α,ω-aminopropyl polysiloxane (Mn: 2000) is replaced with 27.5g of α,ω-aminopropyl polysiloxane (Mn: 5000).

[0070] Example 4

[0071] Repeat the steps described in Example 1, except that 10g of α,ω-aminopropyl polysiloxane (Mn: 2000) is replaced with 55g of α,ω-aminopropyl polysiloxane (Mn: 10000).

[0072] Example 5

[0073] Repeat the steps described in Example 1, except that 0.67g of terephthalaldehyde is replaced with 0.725g of glyoxal (40wt%).

[0074] Example 6

[0075] Repeat the steps described in Example 1, except that 0.67g of terephthalaldehyde is replaced with 0.36g of malondialdehyde (purity 98%).

[0076] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds, characterized in that, Amino-containing polysiloxane derivative A, aldehyde-containing monomer derivative B, and 3-aminophenylboronic acid are dispersed in an organic solvent and reacted at 25℃~40℃ for 12~16h. The mixture is then cast into a mold to obtain a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds. The general formula of the structural unit containing amino-containing polysiloxane derivative A is as follows: Where n is a natural number greater than zero; R1 is methyl, phenyl, or trifluoropropyl; the structural formula of R2 is , where y = 0 ~ 10; The general formula of the aldehyde-containing monomer derivative B is as follows: Wherein, R3 is —(CH2). z —or a benzene ring, where Z is a natural number; The molecular weight of the amino-containing polysiloxane derivative A is 1000~30000; The repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds is characterized by the following structural formula: Where n is a natural number greater than zero; R1 is methyl, phenyl, or trifluoropropyl; the structural formula of R2 is , where y = 0~10; R3 is —(CH2) z —or a benzene ring, where Z is a natural number; The molecular weight range of the boron-oxygen bond-containing repairable and easily soluble organosilicon elastomer is 3000-90000; The amount of 3-aminophenylboronic acid used is 4.7% of the total mass of the system; The silicone elastomer can self-heal in water.

2. The method for preparing the boron-oxygen bond-containing repairable and easily soluble organosilicon elastomer as described in claim 1, characterized in that, In the amino-containing polysiloxane derivative A and the aldehyde-containing monomer derivative B, the molar ratio of amino to aldehyde groups is 1:1 to 1.

1.

3. The method for preparing the boron-oxygen bond-containing repairable and easily soluble organosilicon elastomer as described in claim 1, characterized in that, The amino-containing polysiloxane derivative A is one or more of α,ω-diaminopropyl polydimethylsiloxane, α,ω-diaminopropyl polymethylphenylsiloxane, or α,ω-diaminopropyl polymethyltrifluoropropylsiloxane.

4. The method for preparing the repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds as described in claim 1, characterized in that, The molecular weight of the amino-containing polysiloxane derivative A is 2000~20000.

5. The method for preparing a repairable and easily soluble organosilicon elastomer containing boron-oxygen bonds as described in claim 1, characterized in that, The aldehyde-containing monomer derivative B is at least one of glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, and terephthalaldehyde.

6. The application of the boron-oxygen bond-containing repairable and easily soluble organosilicon elastomer prepared by the preparation method according to any one of claims 1-5 in the manufacture of flexible displays, flexible sensors, wearable electronic products or electronic skin.

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