Graphene oxide reinforced epoxy vitrimer nanocomposites and methods of making the same

Abstract

The application discloses a kind of graphene oxide reinforced epoxy vitrimer nanocomposites and preparation method thereof, belong to high polymer nanocomposite technical field.The composite material uses epoxy vitrimer containing dynamic disulfide bond as matrix, adds 1wt.% graphene oxide, and is prepared using solvent method.Graphene oxide is dispersed in matrix with excellent dispersibility, and interface is combined strongly;The conductivity of the composite material is about 10⁻ 9 S / m, maintains good insulating property; the storage modulus is significantly improved, and GOc is enhanced optimally; high-temperature stress relaxation is fast, and the composite material has the characteristics of reworkability, recyclability, self-repairing and shape memory.The application has simple process and controllable performance, and can be used in the fields of aerospace, automobile lightweight, electronic packaging, recyclable structural composite materials and the like.

Description

Technical Field

[0001] This invention relates to the field of polymer nanocomposite technology, specifically to a graphene oxide-reinforced epoxy vitrimer nanocomposite and its preparation method. Background Technology

[0002] Traditional epoxy resin is one of the most widely used thermosetting polymer materials, characterized by high mechanical strength, resistance to chemical corrosion, good electrical insulation, and excellent adhesion. It holds an irreplaceable position in aerospace, automotive manufacturing, electronic packaging, and structural bonding. However, once cured, traditional epoxy resin forms a permanent three-dimensional cross-linked network that cannot be melted, dissolved, reprocessed, or recycled. Its waste is difficult to degrade, resulting in serious resource waste and environmental pressure.

[0003] Vitrimer (vitriminated polymer), with its dynamic covalent network, undergoes reversible bond exchange under external stimuli (such as heating). This allows the material to maintain the mechanical strength of thermosetting materials while possessing the reprocessing, recyclability, repairability, weldability, and shape memory properties of thermoplastics, making it an ideal green system to replace traditional thermosetting materials. Epoxy vitrimer, cured with 4-aminophenyl disulfide, exhibits rapid stress relaxation and network rearrangement at intermediate temperatures due to its dynamic disulfide bond structure, demonstrating excellent industrialization potential.

[0004] Graphene oxide (GO) possesses high specific surface area, high Young's modulus, and excellent interfacial compatibility, and can significantly improve the mechanical, thermal, and structural stability of polymer matrices even at low addition levels. However, current technologies have the following limitations:

[0005] 1) The dispersion and interfacial bonding mechanism of graphene oxide with different aspect ratios in epoxy vitrimer are unclear;

[0006] 2) There is a lack of systematic research on the effects of graphene oxide on the modulus, glass transition temperature, and stress relaxation behavior of epoxy vitrimer.

[0007] 3) It is difficult to simultaneously achieve integrated high-performance Vitrimer-based nanocomposites with high modulus, fast stress relaxation, and good recyclability.

[0008] Therefore, this invention provides a graphene oxide-reinforced epoxy vitrimer nanocomposite material and its preparation method, effectively solving the above-mentioned technical problems. Summary of the Invention

[0009] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0010] Given the unclear dispersion and interfacial bonding mechanisms of graphene oxide with different aspect ratios in epoxy vitrimer; the lack of systematic research on the influence of graphene oxide on the modulus, glass transition temperature, and stress relaxation behavior of epoxy vitrimer; and the difficulty in simultaneously achieving high modulus, fast stress relaxation, and good recyclability in integrated high-performance vitrimer-based nanocomposites, this invention is proposed.

[0011] Therefore, the purpose of this invention is to provide a graphene oxide / epoxy vitrimer nanocomposite material with high mechanical strength, good interfacial bonding, rapid stress relaxation, reprocessability and recyclability, and stable electrical insulation, and to provide a repeatable and industrially scalable preparation method.

[0012] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0013] A graphene oxide-reinforced epoxy vitrimer nanocomposite material is characterized by being composed of epoxy resin, 4-aminophenyl disulfide curing agent, and graphene oxide; wherein the amount of graphene oxide added is 1 wt.% of the matrix weight; and the matrix is ​​an epoxy vitrimer network containing dynamic disulfide bonds.

[0014] Preferably, the graphene oxide is commercial graphene oxide GOC or graphene oxide GOH synthesized by the modified Hummers method.

[0015] Preferably, the graphene oxide exhibits better dispersion in the epoxy vitrimer matrix than in a conventional epoxy resin matrix.

[0016] Preferably, the electrical conductivity of the composite material is 10⁻ 9 It is on the order of S / m and is an insulating material.

[0017] Preferably, adding 1 wt.% GOC increases the energy storage modulus of epoxy vitrimer by approximately 30%.

[0018] Preferably, the composite material exhibits rapid stress relaxation at 120°C and possesses reprocessable, recyclable, and self-healing properties.

[0019] Preferably, the method for preparing the graphene oxide-reinforced epoxy Vitrimer nanocomposite material is characterized by comprising the following steps:

[0020] (1) Graphene oxide was dispersed in acetone and sonicated for 30 min to obtain a dispersion;

[0021] (2) Add epoxy resin and stir at 80°C for 18 hours to remove acetone;

[0022] (3) Add 4-aminophenyl disulfide curing agent and stir evenly;

[0023] (4) Vacuum degassing at 80℃ for 1 hour;

[0024] (5) Pour into a mold, cure at 120℃ for 2.5h, then at 150℃ for 2h to obtain the composite material.

[0025] Preferably, the graphene oxide-reinforced epoxy vitrimer nanocomposite material is used in recyclable structural composite materials, self-healing materials, shape memory materials, automotive lightweight materials, aerospace materials, and electronic packaging materials.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1) Strong interface bonding, even dispersion, and not easy to agglomerate;

[0028] 2) Significant mechanical enhancement is achieved with a low addition amount (1 wt.%);

[0029] 3) The dynamic disulfide bond network endows the material with rapid stress relaxation, reprocessability, recyclability, and self-healing properties;

[0030] 4) Stable electrical insulation, suitable for electronic packaging and structural insulation components;

[0031] 5) The preparation process is simple and the conditions are mild, making it suitable for industrial production. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0033] Figure 1. FT-IR and Raman spectra of GOc and GOH;

[0034] Figure 2. SEM images of GOC and GOH;

[0035] Figure 3. Raman spectra of epoxy / GO and vitrimer / GO;

[0036] Figure 4. SEM image of the cross-section of the nanocomposite material;

[0037] Figure 5. Conductivity comparison bar chart;

[0038] Figure 6. Comparison of Tg measured by DSC and DMTA;

[0039] Figure 7. Comparison of energy storage modulus at 30℃;

[0040] Figure 8. Stress relaxation curves at 80℃ and 120℃. Detailed Implementation

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0042] Secondly, the present invention will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure will be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include the three-dimensional spatial dimensions of length, width, and depth.

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0044] This invention discloses a graphene oxide-reinforced epoxy Vitrimer nanocomposite material and its preparation method. The graphene oxide-reinforced epoxy Vitrimer nanocomposite material is composed of an epoxy Vitrimer matrix and a graphene oxide filler.

[0045] Matrix: Epoxy resin (Araldite LY564) + 4-aminophenyl disulfide (4-AFD), forming a dynamic disulfide cross-linking network;

[0046] Filler: Graphene oxide, added at 1 wt.%;

[0047] Graphene oxide is selected from:

[0048] GOc: Commercial graphene oxide with thicker sheets, smooth surface, and low aspect ratio;

[0049] GOH: An improved Hummers method for synthesizing graphene oxide, resulting in thinner sheets, more wrinkles, and a higher aspect ratio.

[0050] Preparation method

[0051] 1) Add 136 mg of graphene oxide to 100 ml of acetone and sonicate for 30 min to obtain a uniform dispersion;

[0052] 2) Add 10 g of epoxy resin and mechanically stir at 80°C for 18 hours to allow the acetone to evaporate completely;

[0053] 3) Add 4.38g of 4-AFD curing agent and stir until homogeneous;

[0054] 4) Vacuum degassing at 80℃ for 1 hour to remove air bubbles;

[0055] 5) Pour into a mold, cure at 120℃ for 2.5h, then at 150℃ for 2h to obtain graphene oxide / epoxy Vitrimer nanocomposite material.

[0056] In contrast, the traditional epoxy system uses Aradur 2954 as the curing agent, with a mixing ratio of 100:35 and a curing regime of 80℃ / 1h + 160℃ / 4h.

[0057] Performance characteristics

[0058] 1) Structural characteristics: Graphene oxide has better dispersibility in Vitrimer than epoxy resin; GOc has better dispersibility than GOH; Graphene oxide forms H…S hydrogen bonds with Vitrimer, resulting in strong interfacial bonding.

[0059] 2) Electrical properties: Conductivity approximately 5.0 × 10⁻ 9 S / m is an excellent insulating material.

[0060] 3) Thermal properties: Pure Vitrimer has a Tg of approximately 138-143℃; the addition of 1wt.% GO slightly reduces the Tg, improves chain segment mobility, and facilitates reprocessing.

[0061] 4) Mechanical properties: 1 wt.% GO significantly improves the modulus; GOC increases the modulus of vitrimer by about 30%, with the best reinforcement effect.

[0062] 5) Stress relaxation: The relaxation rate of the Vitrimer system is much faster than that of traditional epoxy; GOC / Vitrimer has the fastest relaxation rate at 120℃, and has the ability to be quickly reprocessed.

[0063] Example 1:

[0064] GOc / epoxy vitrimer nanocomposite (1 wt.%)

[0065] 1) Add 136mg of commercial GOC to 100ml of acetone and sonicate for 30 minutes;

[0066] 2) Add 10g of Araldite LY564 epoxy resin and stir at 80℃ for 18 h to remove acetone;

[0067] 3) Add 4.38g of 4-AFD and stir well;

[0068] 4) Degas at 80℃ for 1 hour;

[0069] 5) Curing at 120℃ for 2.5 hours and then at 150℃ for 2 hours yields the sample.

[0070] Example 2:

[0071] GOH / epoxy vitrimer nanocomposite material (1 wt.%)

[0072] Same as in Example 1, except that GOC is replaced with GOH prepared by the modified Hummers method.

[0073] Example 3:

[0074] Comparison of GOC / Traditional Epoxy Resin

[0075] Same as in Example 1, except that the curing agent was replaced with Aradur 2954 (3.5g), and the curing regime was 80℃ / 1h + 160℃ / 4h.

[0076] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A graphene oxide-reinforced epoxy Vitrimer nanocomposite material, characterized in that, It is composed of epoxy resin, 4-aminophenyl disulfide curing agent and graphene oxide; the amount of graphene oxide added is 1 wt.% of the weight of the matrix; the matrix is ​​an epoxy vitrimer network containing dynamic disulfide bonds.

2. The nanocomposite material according to claim 1, characterized in that, The graphene oxide is commercial graphene oxide GOC or graphene oxide GOH synthesized by the modified Hummers method.

3. The nanocomposite material according to claim 1, characterized in that, The graphene oxide exhibits better dispersion in the epoxy vitrimer matrix than in the conventional epoxy resin matrix.

4. The nanocomposite material according to claim 1, characterized in that, The electrical conductivity of the composite material is 10⁻ 9 It is on the order of S / m and is an insulating material.

5. The nanocomposite material according to claim 1, characterized in that, Adding 1 wt.% GOC increases the energy storage modulus of epoxy vitrimer by approximately 30%.

6. The nanocomposite material according to claim 1, characterized in that, The composite material exhibits rapid stress relaxation at 120°C and possesses reprocessable, recyclable, and self-healing properties.

7. A method for preparing the graphene oxide-reinforced epoxy Vitrimer nanocomposite material according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Graphene oxide was dispersed in acetone and sonicated for 30 min to obtain a dispersion; (2) Add epoxy resin and stir at 80°C for 18 hours to remove acetone; (3) Add 4-aminophenyl disulfide curing agent and stir evenly; (4) Vacuum degassing at 80℃ for 1 hour; (5) Pour into a mold, cure at 120℃ for 2.5h, then at 150℃ for 2h to obtain the composite material.

8. The application of the graphene oxide-reinforced epoxy vitrimer nanocomposite material according to any one of claims 1-6 in recyclable structural composite materials, self-healing materials, shape memory materials, automotive lightweight materials, aerospace materials, and electronic packaging materials.

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