Nano-material modified high-weather-resistance phenolic resin and preparation method thereof

Abstract

The invention relates to nano-material modified high-weather-resistance phenolic resin and a preparation method thereof. The method comprises the following steps: mixing vinyl trimethoxy silane (VTMS) and an ethanol solution, modifying nano titanium dioxide (NT), adding polyethylene glycol (PEG-400) into the mixed solution, and uniformly stirring and mixing by adopting a magnetic machine. And mixing phenolic resin with the composite modified solution for reaction to prepare the modified phenolic resin. The obtained phenolic resin has excellent adhesive property, weather resistance and mechanical property, also has good flowing property, and is suitable for the engineering bamboo processing and manufacturing industry.

Description

Technical Field

[0001] The invention belongs to the technical field of phenolic resins, and particularly relates to a nano material modified high-weather-resistant phenolic resin and a preparation method thereof. Background Art

[0002] As a new type of green and environmentally friendly material with excellent mechanical properties, engineering bamboo can be widely used in building structures, outdoor landscaping, furniture manufacturing and other fields through processing such as reorganization and gluing. In the processing of engineering bamboo, phenolic resin is often used as an adhesive for gluing and compounding bamboo veneers. However, due to the natural characteristics of bamboo and the outdoor service environment, the application of traditional phenolic resin adhesives in engineering bamboo still has problems such as insufficient weather resistance, weak interfacial adhesion, and an imbalance between mechanical properties and processing properties. Therefore, in order to address the above problems, it is urgent to develop a phenolic resin adhesive with high weather resistance, high adhesion, excellent toughness and fluidity, so as to promote the application of engineering bamboo in high-end fields such as outdoor load-bearing structures and bamboo buildings.

[0003] Research on needle-modified phenolic resins has been conducted both domestically and internationally. Patent ZL201510162837.0 discloses a nano-modified flame-retardant phenolic injection molding compound and its preparation method. The preparation process involves mixing multiple raw materials and controlling specific reaction conditions, such as mixing soluble magnesium and aluminum salts with water and then adding them dropwise to an aqueous solution of sodium dodecylbenzenesulfonate while maintaining a specific pH value. This increases the complexity of the process and the difficulty of production. Furthermore, for some special applications with extreme material performance requirements, further improvements may be required to meet higher performance standards. Patent CN202310540729 discloses an environmentally friendly modified light-colored phenolic resin and its preparation method. This patent introduces a functional monomer containing both thiourea and epoxy groups in its molecular structure to hinder the oxidation of phenolic groups to quinones, achieving efficient decolorization and improving the durability of the decolorization. However, a potential problem is that the synthesis and acquisition of the functional monomer can be complex, increasing the preparation cost and process difficulty. Furthermore, this method primarily improves decolorization performance; further optimization may be required in other performance areas. Patent CN119823336A discloses a low-temperature curing rosin-modified phenolic resin and its preparation method. This patent uses rosin, diphenylcyclooctyne-mercapto groups, and diphenylphosphoryl azide to modify a conventional phenolic resin to achieve low-temperature curing. However, the patent's limitations may include the impact of the quality and supply stability of raw materials, such as rosin, on product performance. Furthermore, the stability of the resin's performance in high-temperature environments after low-temperature curing may require further study.

[0004] NT has high strength and modulus, acting as a reinforcing phase. It forms a good interfacial bond with the phenolic resin matrix, effectively transferring stress when subjected to force, and improving the adhesive's mechanical properties, such as tensile strength and flexural strength. NT also has excellent thermal stability, maintaining its structural and performance stability even in high-temperature environments. It forms a heat-resistant network structure within the adhesive, preventing heat transfer and thermal decomposition of the resin molecules, thereby increasing the adhesive's heat resistance temperature and thermal decomposition onset temperature. NT also has excellent UV absorption and scattering capabilities, absorbing and scattering UV rays, reducing UV damage to phenolic resin molecules.

[0005] The VTMS molecule contains two functional groups with different properties. The trimethoxysilyl group hydrolyzes in the presence of water to form a silanol group, which reacts with the hydroxyl groups on the NT surface to form a stable chemical bond, thereby firmly connecting the silane coupling agent to the NT surface. The vinyl group, on the other hand, reacts with the active groups in the phenolic resin. In this way, VTMS acts as a bridge between the NT and the phenolic resin, enhancing the interfacial bonding between the two and enabling the nano-NT to better exert its reinforcing and modifying effects. Furthermore, VTMS can form an organic coating on the surface of the NT particles. This coating can reduce the surface energy between the nano-titanium dioxide particles, reduce agglomeration between the particles, and enable the nano-titanium dioxide to be more evenly dispersed in the phenolic resin glue.

[0006] Phenolic resins are inherently brittle and prone to cracking when subjected to external forces. PEG-400 has a long-chain molecular structure, and its flexible chain segments can be inserted into the molecular network of the phenolic resin. When the phenolic resin is subjected to external forces, the flexible chains of PEG-400 can absorb and disperse energy, reducing crack propagation and thereby improving the toughness and impact resistance of the glue. Furthermore, PEG-400 can reduce the viscosity of phenolic resin glues and increase their fluidity. This makes the phenolic resin easier to handle during application, allowing it to be evenly applied to the surface of the adherend, enhancing the wettability and contact area between the phenolic resin and the adherend, and thus improving the bonding effect. PEG-400 can affect the curing reaction of the phenolic resin to a certain extent. It may interact with the groups in the phenolic resin, changing the activation energy of the reaction, thereby regulating the curing speed of the phenolic resin.

[0007] It is of practical significance to prepare phenolic resin with high weather resistance, high adhesion, excellent mechanical properties and simple process. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a nanomaterial-modified highly weather-resistant phenolic resin and a preparation method thereof. The phenolic resin glue has the advantages of high weather resistance, high adhesion, excellent mechanical properties and simple process.

[0009] To achieve the above objectives, the technical solution of the present invention is:

[0010] A nanomaterial-modified high-weather-resistant phenolic resin and a preparation method thereof are characterized in that: VTMS generates silanol functional groups after hydrolysis and activation in an ethanol solution. These functional groups not only help disperse NT, but also react with the hydroxyl groups on the NT surface to form stable chemical bonds, thereby connecting VTMS to the NT surface. In addition, VTMS can also react with the phenolic resin to significantly enhance the interfacial bonding between NT and the resin. This improvement enables NT to better play its reinforcing and modifying role. On the other hand, PEG-400 has a long-chain molecular structure, and its flexible chain segments can be embedded in the molecular network of the phenolic resin and effectively improve the toughness and impact resistance of the resin by absorbing and dissipating the energy generated by external forces. The method comprises the following steps: (1) adding VTMS to an ethanol solution, adjusting its pH value with acetic acid, adding NT after thorough stirring, and continuing to stir; (2) adding PEG-400 to the above mixed solution and continuing to stir; (3) slowly dripping the above mixed solution into the phenolic resin and continuing to stir to obtain the modified phenolic resin.

[0011] Furthermore, it is characterized in that: in the step (1), after VTMS and ethanol solution (the volume ratio of anhydrous ethanol and water is 4:1) are fully mixed, the pH value is adjusted to 4-5 by acetic acid, NT (0.3wt%-0.5wt%, calculated as phenolic resin) is added thereto, and stirring is continued.

[0012] Furthermore, it is characterized in that: in the step (2), PEG-400 (3wt%-5wt%, calculated as phenolic resin) is added to the mixed solution and stirred continuously.

[0013] Furthermore, it is characterized in that: in the step (3), the mixed solution is slowly dripped into the phenolic resin, and the mixture is continuously stirred for 0.5h to 1h to obtain the modified phenolic resin, and then the bubbles in the system are removed by vacuum degassing.

[0014] Compared with the existing invention, the beneficial effects of the present invention are as follows:

[0015] NT can form a good interface with the phenolic resin matrix, effectively transfer stress when subjected to force, and improve the tensile strength, bending strength and other mechanical properties of the glue. NT also has good thermal stability and can maintain its structure and performance stability in high temperature environments. It can form a heat-resistant network structure inside the glue to prevent heat transfer and thermal decomposition of resin molecules.

[0016] NT also has excellent ultraviolet absorption and scattering capabilities, which can absorb and scatter ultraviolet rays and reduce the damage of ultraviolet rays to phenolic resin molecules.

[0017] The VTMS molecule contains two functional groups of different properties. The trimethoxysilyl group hydrolyzes in the presence of water to form a silanol group, which reacts with the hydroxyl groups on the nanostructured ...

[0018] VTMS can form an organic coating on the surface of NT particles. This coating can reduce the surface energy between nano-titanium dioxide particles, reduce the agglomeration of particles, and enable nano-titanium dioxide to be more evenly dispersed in the phenolic resin glue.

[0019] PEG-400 has a long-chain molecular structure, and its flexible chain segments can be inserted into the molecular network of the phenolic resin. When the phenolic resin is subjected to external forces, the flexible chains of PEG-400 can absorb and disperse energy, reducing the expansion of cracks, thereby improving the toughness and impact resistance of the adhesive.

[0020] PEG-400 can reduce the viscosity of phenolic resin adhesives and increase their fluidity. This makes the phenolic resin easier to apply, allowing for even coverage of the adherend surface. This enhances wettability and contact area between the phenolic resin and the adherend, ultimately improving the bonding effect. PEG-400 can also affect the curing reaction of phenolic resin to a certain extent. It may interact with the groups in the phenolic resin, changing the activation energy of the reaction and thereby regulating the curing speed of the phenolic resin. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0022] A nanomaterial-modified high-weather-resistant phenolic resin and a preparation method thereof are characterized in that: VTMS generates silanol functional groups after hydrolysis and activation in an ethanol solution. These functional groups not only help to disperse NT, but also react with the hydroxyl groups on the NT surface to form stable chemical bonds, thereby connecting VTMS to the NT surface. In addition, VTMS can also react with the phenolic resin to significantly enhance the interfacial bonding between NT and the resin, which improves the NT to better play its reinforcing and modifying role. On the other hand, PEG-400 has a long-chain molecular structure, and its flexible chain segments can be embedded in the molecular network of the phenolic resin and effectively improve the toughness and impact resistance of the resin by absorbing and dissipating the energy generated by external forces. The method comprises the following steps: (1) adding VTMS to an ethanol solution, adjusting its pH value with acetic acid, adding NT after thorough stirring, and continuing to stir; (2) adding PEG-400 to the above mixed solution and continuing to stir; (3) slowly dripping the above mixed solution into the phenolic resin and continuing to stir to obtain the modified phenolic resin.

[0023] Furthermore, it is characterized in that: in the step (1), after VTMS and ethanol solution (the volume ratio of anhydrous ethanol and water is 4:1) are fully mixed, the pH value is adjusted to 4-5 by acetic acid, NT (0.3wt%-0.5wt%, calculated as phenolic resin) is added thereto, and stirring is continued.

[0024] Furthermore, it is characterized in that: in the step (2), PEG-400 (3wt%-5wt%, calculated as phenolic resin) is added to the mixed solution and stirred continuously.

[0025] Furthermore, it is characterized in that: in the step (3), the mixed solution is slowly dripped into the phenolic resin, and the mixture is continuously stirred for 0.5h to 1h to obtain the modified phenolic resin, and then the bubbles in the system are removed by vacuum degassing.

[0026] Example 1

[0027] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.3wt%, 3wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0028] Example 2

[0029] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.4wt%, 3wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0030] Example 3

[0031] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.5wt%, 3wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0032] Example 4

[0033] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.3wt%, 4wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0034] Example 5

[0035] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.4wt%, 4wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0036] Example 6

[0037] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.5wt%, 4wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0038] Example 7

[0039] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.3wt%, 5wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0040] Example 8

[0041] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.4wt%, 5wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0042] Example 9

[0043] Based on phenolic resin, the weights of VTMS, NT, PEG-400, and ethanol solution are 1wt%, 0.5wt%, 5wt%, and 30wt%, respectively. The VTMS and ethanol solutions are thoroughly mixed using a magnetic stirrer, and the pH of the solution is adjusted with acetic acid. NT is then added to the mixed solution and stirred for 0.5-1 hour. PEG-400 is then added to the mixed solution and stirred for 0.5-1 hour. The stirred mixed solution is then slowly dripped into the phenolic resin and stirred for 0.5-1 hour using a magnetic stirrer. Vacuum degassing is then performed to remove air bubbles from the system.

[0044] Adhesion performance and aging tests.

[0045] Table 1 Phenolic resin bonding performance values

[0046] The above embodiments are only specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent transformations, improvements, etc. made based on the concept of the present invention without departing from the essence of the technical solution of the present invention shall be included in the protection scope of the present invention.

[0047] Mechanical properties testing.

[0048] Table 2 Mechanical properties and aging performance test of phenolic resin

[0049] Heat resistance test

[0050] Table 3 Phenolic resin heat resistance values

Claims

1. A nanomaterial-modified highly weather-resistant phenolic resin and a preparation method thereof, characterized in that: After hydrolysis and activation in an ethanol solution, VTMS generates silanol functional groups. These functional groups not only help disperse NT, but also react with the hydroxyl groups on the NT surface to form stable chemical bonds, thereby connecting VTMS to the NT surface. In addition, VTMS can react with phenolic resin, significantly enhancing the interfacial bonding between NT and the resin. This improvement enables NT to better play its reinforcing and modifying role. On the other hand, PEG-400 has a long-chain molecular structure, and its flexible chain segments can be embedded in the molecular network of phenolic resin and effectively improve the toughness and impact resistance of the resin by absorbing and dissipating the energy generated by external forces. The process includes the following steps: (1) adding VTMS to an ethanol solution, adjusting its pH value with acetic acid, stirring thoroughly, adding NT, and continuing to stir; (2) adding PEG-400 to the above mixed solution and continuing to stir; (3) slowly dripping the above mixed solution into the phenolic resin and continuing to stir to obtain the modified phenolic resin.

2. A nanomaterial-modified highly weather-resistant phenolic resin and a preparation method thereof according to claim 1, characterized in that: In step (1), VTMS and ethanol solution (the volume ratio of anhydrous ethanol to water is 4:1) are fully mixed, the pH value is adjusted to 4-5 by acetic acid, and NT (0.3wt%-0.5wt%, calculated as phenolic resin) is added thereto and stirred continuously.

3. A nanomaterial-modified highly weather-resistant phenolic resin and a preparation method thereof according to claim 1, characterized in that: In step (2), PEG-400 (3 wt%-5 wt%, calculated on the basis of phenolic resin) is added to the mixed solution and stirred continuously.

4. A nanomaterial-modified highly weather-resistant phenolic resin and a preparation method thereof according to claim 1, characterized in that: In step (3), the mixed solution is slowly dripped into the phenolic resin and stirred for 0.5 to 1 hour to obtain the modified phenolic resin, and then the bubbles in the system are removed by vacuum degassing.

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