Self-repairing hydrophobic silicon dioxide as well as preparation method and application thereof

Abstract

The invention discloses self-repairing hydrophobic silicon dioxide which comprises microspheres 1, microspheres 2 uniformly loaded on the surfaces of the microspheres 1 and octa-epoxy cyclohexyl ethyl cage-shaped polysilsesquioxane uniformly loaded on the surfaces of the microspheres 2, wherein the microspheres 1 comprise porous silicon dioxide and a polydopamine layer coated on the surface of the porous silicon dioxide, and octadecylamine is adsorbed in the porous silicon dioxide; the microspheres 2 are porous silicon dioxide grafted with amino groups. The invention further discloses a preparation method and application of the self-repairing hydrophobic silicon dioxide. The silicon dioxide disclosed by the invention has good hydrophobicity and dispersity, and has a function of repairing hydrophobicity.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon dioxide, and in particular to a self-repairing hydrophobic silicon dioxide and a preparation method and application thereof. Background Art

[0002] Silica has multiple functions such as reinforcement and matting, and is widely used in coatings. However, there are a large number of active hydroxyl groups in silica, which are hydrophilic and easy to agglomerate, and cannot be evenly dispersed in the coating. These factors limit the use of silica in coatings. At present, silica is often hydrophobically modified to improve its easy agglomeration and hydrophilic problems, but the hydrophobic properties of existing hydrophobic silica still need to be further improved, and the hydrophobicity of existing coatings is often destroyed during use and cannot be restored. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a self-healing hydrophobic silica and a preparation method and application thereof. The self-healing hydrophobic silica of the present invention has good hydrophobicity and dispersibility, and has the function of repairing hydrophobicity.

[0004] The present invention provides a self-repairing hydrophobic silica, comprising: a microsphere 1, a microsphere 2 uniformly loaded on the surface of the microsphere 1, and an octaepoxycyclohexylethyl caged polysilsesquioxane uniformly loaded on the surface of the microsphere 2;

[0005] Among them, microsphere 1 includes porous silica and a polydopamine layer coated on the surface of the porous silica, and octadecylamine is adsorbed in the porous silica; microsphere 2 is porous silica grafted with amino groups.

[0006] Preferably, the particle size of the microsphere 1 is 4-6 μm.

[0007] Preferably, the particle size of the microspheres 2 is 0.2-0.5 μm.

[0008] Preferably, the porous silica grafted with amino groups refers to porous silica modified with a silane coupling agent containing amino groups.

[0009] The amino group-containing silane coupling agent may be 3-aminopropyltriethoxysilane or the like.

[0010] The above-mentioned octaepoxycyclohexylethyl cage polysilsesquioxane can be purchased from the market.

[0011] The present invention also proposes a method for preparing the above-mentioned self-healing hydrophobic silica, comprising the following steps: mixing porous silica adsorbed with octadecylamine with a dopamine buffer, performing a primary reaction, and performing solid-liquid separation to obtain microsphere 1; mixing microsphere 1, microsphere 2, and a first organic solvent, performing a secondary reaction, and performing solid-liquid separation to obtain an intermediate; mixing the intermediate, octacyclohexylethyl caged polysilsesquioxane, and a second organic solvent, performing a tertiary reaction, and performing solid-liquid separation to obtain self-healing hydrophobic silica.

[0012] The present invention first coats a polydopamine layer on the surface of porous silica adsorbed with octadecylamine, the polydopamine is easily oxidized to form a quinone bond, and then reacts with the porous silica grafted with amino groups, so that microspheres 2 are uniformly loaded on the surface of microspheres 1, and then the remaining amino groups on the surface of microspheres 2 react with octaepoxycyclohexylethyl caged polysilsesquioxane to uniformly load the nano-scale caged polysilsesquioxane on the surface of microspheres 2; by controlling the particle sizes of microspheres 1 and microspheres 2 and coordinating with the nano-scale caged polysilsesquioxane, the final product is raspberry-shaped and has a micro-nano structure with a step distribution, thereby greatly improving the hydrophobicity of the product, and the product has epoxy groups on the outside, which can further improve the hydrophobicity and dispersibility, and the epoxy groups can react with a variety of groups in the coating, thereby improving the mechanical properties of the coating.

[0013] The microsphere 1 is coated with octadecylamine. When the micro-nanostructure is damaged, the octadecylamine in the microsphere 1 can be released and react with the quinone bond in polydopamine to expose a long hydrophobic alkyl chain on the coating surface, thereby repairing the damaged part and continuously maintaining the hydrophobicity of the coating.

[0014] Preferably, the solvent of the dopamine buffer is Tris-HCl buffer with a pH of 8-8.5.

[0015] Preferably, the concentration of dopamine is 3-5 mg / ml.

[0016] Preferably, the temperature of the primary reaction is room temperature and the time is 4-5 hours.

[0017] Preferably, the weight ratio of microsphere 1 to microsphere 2 is 1:3-4.

[0018] Preferably, the temperature of the secondary reaction is 40-60° C. and the time is 18-24 h.

[0019] Preferably, the weight ratio of the intermediate and the octaepoxycyclohexylethyl cage-like polysilsesquioxane is 1:5-7.

[0020] Preferably, the temperature of the three reactions is 40-60°C and the time is 8-12h.

[0021] Preferably, the first organic solvent is ethanol.

[0022] Preferably, the second organic solvent is isopropanol.

[0023] The present invention also proposes the application of the self-repairing hydrophobic silica in coatings.

[0024] The above-mentioned coating can be epoxy resin coating, polyurethane coating, polyacrylate coating, etc.

[0025] The present invention controls the particle sizes of microspheres 1 and 2 and cooperates with nano-scale caged polysilsesquioxane, so that the final product is raspberry-shaped and has a micro-nano structure with a step distribution, and this structure can greatly improve the hydrophobicity; and the microsphere 1 is coated with octadecylamine. When the above micro-nano structure is damaged, the octadecylamine in the microsphere 1 can be released and react with the quinone bond in the polydopamine, exposing a hydrophobic long alkyl chain on the surface of the coating, repairing the damaged part, and continuously maintaining the hydrophobicity of the coating; and the present invention has good dispersibility and will not agglomerate. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described in detail below through specific embodiments.

[0027] Example 1

[0028] A self-repairing hydrophobic silica, comprising: a microsphere 1, a microsphere 2 uniformly loaded on the surface of the microsphere 1, and an octaepoxycyclohexylethyl caged polysilsesquioxane uniformly loaded on the surface of the microsphere 2;

[0029] Among them, microsphere 1 includes porous silica and a polydopamine layer coated on the surface of the porous silica, and octadecylamine is adsorbed in the porous silica; microsphere 2 is porous silica modified by 3-aminopropyltriethoxysilane.

[0030] The preparation method of the self-repairing hydrophobic silica comprises the following steps:

[0031] 0.1 g of porous silica adsorbed with octadecylamine was added to 100 ml of Tris-HCl buffer at pH 8, and the mixture was stirred and mixed, and dopamine was added and mixed to make the concentration of dopamine 5 mg / ml, and then stirred and reacted at room temperature for 4 h, centrifuged, washed, and dried to obtain microspheres 1 with a particle size of 6 μm;

[0032] Add microsphere 1 to ethanol and disperse evenly to obtain dispersion 1; add microsphere 2 with a particle size of 0.5 μm to ethanol and disperse evenly by ultrasonic to obtain dispersion 2; mix dispersion 1 and dispersion 2 so that the weight ratio of microsphere 1 to microsphere 2 is 1:3, react at a temperature of 60° C. for 18 hours, centrifuge, wash, and dry to obtain an intermediate;

[0033] The intermediate was added to the isopropanol solution of octaepoxycyclohexylethyl caged polysilsesquioxane and mixed evenly, and the weight ratio of the intermediate to octaepoxycyclohexylethyl caged polysilsesquioxane was 1:7. The temperature was adjusted to 60° C. for reaction for 8 h, centrifuged, washed, and dried to obtain self-healing hydrophobic silica.

[0034] Example 2

[0035] A self-repairing hydrophobic silica, comprising: a microsphere 1, a microsphere 2 uniformly loaded on the surface of the microsphere 1, and an octaepoxycyclohexylethyl caged polysilsesquioxane uniformly loaded on the surface of the microsphere 2;

[0036] Among them, microsphere 1 includes porous silica and a polydopamine layer coated on the surface of the porous silica, and octadecylamine is adsorbed in the porous silica; microsphere 2 is porous silica modified by 3-aminopropyltriethoxysilane.

[0037] The preparation method of the self-repairing hydrophobic silica comprises the following steps:

[0038] 0.1 g of porous silica adsorbed with octadecylamine was added to 100 ml of Tris-HCl buffer at pH 8.5, and the mixture was stirred and mixed. Dopamine was added and mixed to make the concentration of dopamine 3 mg / ml. The mixture was stirred and reacted at room temperature for 5 h, centrifuged, washed, and dried to obtain microspheres 1 with a particle size of 4 μm.

[0039] Add microsphere 1 to ethanol and disperse evenly to obtain dispersion 1; add microsphere 2 with a particle size of 0.2 μm to ethanol and disperse evenly by ultrasonic to obtain dispersion 2; mix dispersion 1 and dispersion 2 so that the weight ratio of microsphere 1 to microsphere 2 is 1:4, react at a temperature of 40° C. for 24 hours, centrifuge, wash, and dry to obtain an intermediate;

[0040] The intermediate was added to the isopropanol solution of octaepoxycyclohexylethyl caged polysilsesquioxane and mixed evenly, and the weight ratio of the intermediate to octaepoxycyclohexylethyl caged polysilsesquioxane was 1:5. The temperature was adjusted to 40° C. for reaction for 12 hours, centrifuged, washed, and dried to obtain self-healing hydrophobic silica.

[0041] Example 3

[0042] A self-repairing hydrophobic silica, comprising: a microsphere 1, a microsphere 2 uniformly loaded on the surface of the microsphere 1, and an octaepoxycyclohexylethyl caged polysilsesquioxane uniformly loaded on the surface of the microsphere 2;

[0043] Among them, microsphere 1 includes porous silica and a polydopamine layer coated on the surface of the porous silica, and octadecylamine is adsorbed in the porous silica; microsphere 2 is porous silica modified by 3-aminopropyltriethoxysilane.

[0044] The preparation method of the self-repairing hydrophobic silica comprises the following steps:

[0045] 0.1 g of porous silica adsorbed with octadecylamine was added to 100 ml of Tris-HCl buffer at pH 8.5, and the mixture was stirred and mixed. Dopamine was added and mixed to make the concentration of dopamine 4 mg / ml. The mixture was stirred and reacted at room temperature for 4.5 h, centrifuged, washed, and dried to obtain microspheres 1 with a particle size of 5 μm.

[0046] Add microsphere 1 to ethanol and disperse evenly to obtain dispersion 1; add microsphere 2 with a particle size of 0.3 μm to ethanol and disperse evenly by ultrasonic to obtain dispersion 2; mix dispersion 1 and dispersion 2 so that the weight ratio of microsphere 1 to microsphere 2 is 1:3.5, react at a temperature of 50° C. for 20 hours, centrifuge, wash, and dry to obtain an intermediate;

[0047] The intermediate was added to the isopropanol solution of octaepoxycyclohexylethyl caged polysilsesquioxane and mixed evenly, and the weight ratio of the intermediate to octaepoxycyclohexylethyl caged polysilsesquioxane was 1:6. The temperature was adjusted to 50° C. for reaction for 10 hours, centrifuged, washed, and dried to obtain self-healing hydrophobic silica.

[0048] The microspheres 1 and the intermediate prepared in Example 3 were used as comparative examples 1-2, respectively.

[0049] Take the products of Examples 1-3 and Comparative Examples 1-2, add them to acrylic resin coating (the formula of acrylic resin coating is: 70 parts of acrylic resin, 24 parts of diluent, 5 parts of film-forming aid, 0.5 parts of leveling agent, 0.5 parts of curing agent) in the same weight ratio and mix well to obtain each group of coatings.

[0050] The water contact angle of each group of coatings was measured respectively; each group of coatings was destroyed in the same way, and the water contact angle of the destroyed coatings was measured after 12 hours. The results are shown in Table 1.

[0051] Table 1 Test results

[0052] Test items Water contact angle of coating° 12h after destruction, the water contact angle of the coating Example 1 158 155 Example 2 159 156 Example 3 160 156 Comparative Example 1 58 98 Comparative Example 2 80 113

[0053] It can be seen from Table 1 that the hydrophobic silica of the present invention has good hydrophobic properties and has hydrophobic self-repairing properties.

[0054] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A self-repairing hydrophobic silica, characterized in that: include: Microsphere 1, microsphere 2 uniformly loaded on the surface of microsphere 1, and octaepoxycyclohexylethyl caged polysilsesquioxane uniformly loaded on the surface of microsphere 2; Among them, microsphere 1 includes porous silica and a polydopamine layer coated on the surface of the porous silica, and octadecylamine is adsorbed in the porous silica; microsphere 2 is porous silica grafted with amino groups.

2. The self-healing hydrophobic silica according to claim 1, characterized in that: The particle size of the microsphere 1 is 4-6 μm; preferably, the particle size of the microsphere 2 is 0.2-0.5 μm; preferably, the porous silica grafted with amino groups refers to porous silica modified by a silane coupling agent containing amino groups.

3. A method for preparing the self-healing hydrophobic silica as claimed in claim 1 or 2, characterized in that: The method comprises the following steps: mixing porous silica adsorbed with octadecylamine and dopamine buffer, performing a primary reaction, and performing solid-liquid separation to obtain microsphere 1; mixing microsphere 1, microsphere 2 and a first organic solvent, performing a secondary reaction, and performing solid-liquid separation to obtain an intermediate; and mixing the intermediate, octaepoxycyclohexylethyl caged polysilsesquioxane and a second organic solvent, performing a tertiary reaction, and performing solid-liquid separation to obtain self-healing hydrophobic silica.

4. The method for preparing the self-repairing hydrophobic silica according to claim 3, characterized in that: The solvent of the dopamine buffer is a Tris-HCl buffer with a pH of 8-8.5; preferably, the concentration of dopamine is 3-5 mg / ml.

5. The method for preparing the self-repairing hydrophobic silica according to claim 3 or 4, characterized in that: The temperature of one reaction is room temperature and the time is 4-5h.

6. The method for preparing the self-healing hydrophobic silica according to any one of claims 3 to 5, characterized in that: The weight ratio of microsphere 1 to microsphere 2 is 1:3-4; preferably, the temperature of the secondary reaction is 40-60° C., and the time is 18-24 hours.

7. The method for preparing the self-healing hydrophobic silica according to any one of claims 3 to 6, characterized in that: The weight ratio of the intermediate and octaepoxycyclohexylethyl cage-shaped polysilsesquioxane is 1:5-7.

8. The method for preparing the self-healing hydrophobic silica according to any one of claims 3 to 7, characterized in that: The temperature of the three reactions is 40-60°C and the time is 8-12h.

9. The method for preparing the self-healing hydrophobic silica according to any one of claims 3 to 8, characterized in that: The first organic solvent is ethanol; preferably, the second organic solvent is isopropanol.

10. Use of the self-healing hydrophobic silica as claimed in claim 1 or 2 in coatings.