Preparation and use methods of organic-inorganic hybrid phenolic structure adhesive

Abstract

The invention discloses a preparation method and a use method of an organic-inorganic hybrid phenolic structure adhesive, and belongs to the technical field of high polymer materials and application thereof. The method comprises the following steps: carrying out surface modification on PEEK by using nitric acid and a silane coupling agent to prepare MPEEK; the MPEEK is uniformly mixed with the nano-SiO2 and the phenolic resin, so that the nano-SiO2 modified phenolic resin is obtained. Compared with the prior art, the method has the beneficial effects that the mechanical property is obviously improved; the shear strength is improved by 9.1%; the thermal stability is enhanced; good adhesive strength (6.43 MPa) is still kept in a high-temperature environment of 400 DEG C; the solvent resistance is high, and the performance is not obviously reduced after the coating is soaked in various polar and non-polar solvents for 24 hours; the obtained structural adhesive is superior to a traditional PF adhesive in the aspects of shear strength, thermal decomposition temperature, interface wettability and the like. The adhesive is suitable for various base materials such as steel, aluminum and ceramic, and the bonding interface is stable.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and their applications, and particularly relates to a preparation and use method of an organic-inorganic hybrid phenolic structural adhesive. Background Art

[0002] Since the early 20th century, phenolic resin (PF) has become one of the most important thermosetting adhesives in industry due to its excellent heat resistance, chemical stability, and film-forming properties. PF adhesives are widely used in wood processing, electronic packaging, aerospace, and automotive manufacturing. However, the high crosslink density and rigid molecular structure of the PF system itself lead to significant brittleness of the cured material, with poor impact and shear resistance, limiting its reliability in high-load, high-vibration, and complex environments.

[0003] To improve the toughness and ductility of PF adhesives, researchers have proposed various modification schemes. On the one hand, thermoplastic polymers (such as nitrile rubber, polyetheramide, and PEEK) can be blended or chemically grafted to form a two-phase structure, achieving energy absorption and crack passivation. However, excessive introduction of thermoplastic components can lead to decreased crosslinking efficiency and reduced heat resistance. On the other hand, nano-inorganic fillers (such as SiO2, Al2O3, carbon nanotubes, and silanized silica) are also widely used in PF modification due to their high surface area and toughening properties. Nanoparticles improve the fracture toughness and thermal stability of the material through physical barrier and interfacial energy absorption. However, poor dispersion and insufficient interfacial compatibility often lead to filler agglomeration, forming defects and weakening the overall performance improvement.

[0004] Furthermore, existing technologies often focus on single modification strategies, ignoring the synergistic effects of organic and inorganic components at the microscopic interface level. The key technical challenge in the field of PF structural adhesives remains how to construct organic-inorganic hybrid networks that exhibit strong interfacial interactions while balancing high toughness and high temperature resistance.

[0005] Therefore, it is urgent to develop a new organic Inorganic hybrid modification technology, through chemical functionalization modification and nano-inorganic network construction, achieves a dual improvement in the high toughness and high-temperature stability of PF adhesives, thereby meeting the reliability requirements of structural adhesives under extreme conditions in cutting-edge engineering applications. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems of traditional phenolic resin structural adhesives such as high brittleness, poor toughness, and poor thermal stability, and to provide a preparation and use method of an organic-inorganic hybrid phenolic structural adhesive with high mechanical strength and thermal stability. This method introduces silane-modified polyetheretherketone (MPEEK) and nano-silica (nano-SiO2) into the PF system to construct an organic-inorganic hybrid thermosetting structural adhesive to improve the mechanical strength, thermal stability and interface bonding performance of the adhesive, and is used for high-strength bonding in high-temperature and multi-environment adaptability scenarios.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing an organic-inorganic hybrid phenolic structural adhesive, comprising:

[0009] Step 1: Surface modification of PEEK using nitric acid and silane coupling agent to produce MPEEK;

[0010] Step 2: Combine MPEEK and nano SiO2 and phenolic resin are mixed evenly.

[0011] Furthermore, step one is specifically as follows: immersing the PEEK powder in a 30 vol% nitric acid solution and ultrasonically dispersing it for at least 30 minutes, washing the treated PEEK with anhydrous ethanol at least three times to remove residual nitric acid and drying it at 60±5°C for 12 hours, immersing the dried PEEK powder in an ethanol solution with a mass fraction of KH560 of 5 wt% and treating it at 60°C for 30 minutes to 2 hours, and after treatment, washing the sample with anhydrous ethanol at least three times and drying it at 60±5°C for 12 hours to obtain surface-modified PEEK (MPEEK).

[0012] Furthermore, in step 2, the MPEEK: nano The mass ratio of SiO2:phenolic resin is 5:0~5:100.

[0013] A method for using the adhesive prepared by the above preparation method, the method comprising: forming a stable organic Inorganic hybrid network structure.

[0014] Furthermore, the multi-step thermal curing process is specifically 80±5℃ for 1h±10 min, 120±5℃ for 1h±10 min, 150±5℃ for 1h±10 min, and 180±5℃ for 2h±10 min.

[0015] The beneficial effects of the present invention compared to the prior art are:

[0016] 1. Significant improvement in mechanical properties: shear strength increased by 9.1%;

[0017] 2. Enhanced thermal stability: maintains good adhesion (6.43 MPa) even at 400°C.

[0018] 3. Strong solvent resistance: No significant performance degradation after immersion in a variety of polar and non-polar solvents for 24 hours;

[0019] 4. The obtained structural adhesive is superior to traditional PF adhesives in shear strength, thermal decomposition temperature, interface wettability, etc.

[0020] 5. Wide adaptability: Applicable to various substrates such as steel, aluminum, ceramics, etc., with stable bonding interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The tensile shear strength diagram of steel bonded with different adhesives;

[0022] Figure 2 This is a graph of the shear strength of steel plates bonded after 24 hours of adhesive treatment with different solvents;

[0023] Figure 3 This is the shear strength diagram of the adhesive on different substrates;

[0024] Figure 4 This is the shear strength diagram of the bonded steel plates after the adhesive was treated at different temperatures for 30 minutes;

[0025] Figure 5 SEM images after online shear strength tests at different temperatures. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments described herein are only partial examples of the present invention and are not all possible implementation methods. Based on the technical content disclosed in the present invention, other implementation methods that can be derived by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0027] Example 1:

[0028] PEEK powder was immersed in a 30 vol% nitric acid solution and ultrasonically dispersed for at least 30 min. The treated PEEK was washed with anhydrous ethanol at least three times to remove residual nitric acid and dried at 60±5 ℃ for 12 h. The dried PEEK powder was immersed in an ethanol solution with a mass fraction of KH560 (5 wt%) and treated at 60 ℃ for 2 min. After treatment, the sample was washed with anhydrous ethanol at least three times and dried at 60±5 ℃ for 12 h to obtain surface-modified PEEK (MPEEK). It was then blended with nano-SiO2 and phenolic resin in a mass ratio of 5:1:100, and phosphoric acid was added as a curing catalyst. The mass ratio of phenolic resin to phosphoric acid was 100:2.

[0029] Example 2:

[0030] The difference between this embodiment and embodiment 1 is that: MPEEK, nano The mass ratio of SiO2 and phenolic resin is 5:3:100.

[0031] Example 3:

[0032] The difference between this embodiment and embodiment 1 is that: MPEEK, nano The mass ratio of SiO2 and phenolic resin is 5:5:100.

[0033] Example 4:

[0034] The difference between this embodiment and embodiment 1 is that: MPEEK, nano The mass ratio of SiO2 and phenolic resin is 5:0:100, that is, no nano SiO2.

[0035] After polishing the steel sheets with 80-grit sandpaper, they were bonded using the adhesives prepared in Examples 1 to 4, and then subjected to multi-stage heat curing treatment (80°C for 1 hour, 120°C for 1 hour, 150°C for 1 hour, and 180°C for 2 hours). The final tensile shear strength test results were 21.87 MPa, 22.51 MPa, 23.82 MPa, and 22.50 MPa, respectively. Figure 1 ), while the shear strength of pure PF glue is 21.83 Mpa, indicating that the adhesive prepared by the method of the present invention has higher bonding strength.

[0036] Shear strength of steel plates bonded with the adhesive of Example 3 after being placed in air, water, 10 wt% NaCl, acid, alkali, ethanol, and ethyl acetate for 24 h ( Figure 2), the shear strengths after treatment were 23.82MPa, 23.31MPa, 22.89MPa, 22.92MPa, 20.59MPa, 23.55MPa, and 23.40MPa, respectively, indicating that the adhesive has excellent environmental resistance.

[0037] Shear strength of steel, aluminum alloy, titanium alloy, wood, glass, SiC, and PI bonded with the adhesive of Example 3 ( Figure 3 ), the shear strengths after treatment were 23.82MPa, 17.24MPa, 8.94MPa, 9.83MPa, 14.58MPa, 5.88Mpa (substrate fracture), and 15.45MPa, respectively, indicating that the adhesive has a wide range of material applicability.

[0038] The shear strength of the steel plates bonded with the adhesive of Example 3 after being treated at 100°C, 200°C, 300°C, and 400°C for 30 minutes ( Figure 4 ) and its SEM image ( Figure 5 ), indicating that the adhesive has excellent high temperature resistance.

Claims

1. A method for preparing an organic-inorganic hybrid phenolic structural adhesive, characterized in that: The method is: Step 1: Surface modification of PEEK using nitric acid and silane coupling agent to produce MPEEK; Step 2: Combine MPEEK and nano SiO2 and phenolic resin are mixed evenly.

2. The method for preparing an organic-inorganic hybrid phenolic structural adhesive according to claim 1, wherein: The step 1 specifically comprises: immersing the PEEK powder in a 30 vol% nitric acid solution and ultrasonically dispersing it for at least 30 minutes, washing the treated PEEK with anhydrous ethanol at least three times to remove residual nitric acid, and drying it at 60±5°C for 12 hours, immersing the dried PEEK powder in an ethanol solution with a mass fraction of 5 wt% KH560 and treating it at 60°C for 30 minutes to 2 hours, and after the treatment, washing the sample with anhydrous ethanol at least three times and drying it at 60±5°C for 12 hours to obtain surface-modified PEEK (MPEEK).

3. The method for preparing an organic-inorganic hybrid phenolic structural adhesive according to claim 1, wherein: In step 2, the MPEEK: nano The mass ratio of SiO2:phenolic resin is 5:0~5:

100.

4. A method for using the adhesive prepared by the preparation method according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: forming a stable organic-inorganic hybrid network structure through a multi-step thermal curing process.

5. The method according to claim 4, characterized in that: The multi-step thermal curing process is specifically: maintaining at 80±5°C for 1h±10 min, maintaining at 120±5°C for 1h±10 min, maintaining at 150±5°C for 1h±10 min, and maintaining at 180±5°C for 2h±10 min.

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