A method for enhancing the hydrophobicity of PVDF materials

Abstract

The present invention provides a preparation method for enhancing the hydrophobic properties of polyvinylidene fluoride (PVDF) materials. PVDF powder is directly dispersed in a mixed solution formed by water, and then subjected to hydrothermal treatment at a certain temperature to obtain a modified PVDF material with enhanced hydrophobic properties. Unlike conventional hydrophobic modification preparation methods, the advantage of the method of the present invention is that through a simple and easy-to-control hydrothermal treatment process, the surface structure of PVDF is regulated, the surface roughness is increased, and the surface contact angle of the material is changed, thereby achieving an improvement in the hydrophobicity of the PVDF material, thereby effectively increasing the material's anti-wetting properties. This method is simple, easy to operate, and easy to mass produce. The modified PVDF material can be applied to many fields such as self-cleaning surfaces, antifouling coatings, medical dressings, waterproof electronic products, and filter membranes to improve product performance.

Description

Technical Field

[0001] The invention belongs to the technical field of nano-micro material preparation, relates to material modification and regulation, and is a method for enhancing the hydrophobicity of PVDF materials. Background Art

[0002] Polyvinylidene fluoride (PVDF), composed of fluorine and carbon atoms, is a semi-crystalline polymer. Compared to other fluoropolymers, it exhibits higher crystallinity and surface tension, and possesses excellent hydrophobicity, biocompatibility, and chemical stability. Due to its inherent surface properties and hydrophobicity, PVDF offers applications in microphase separation and self-cleaning surfaces, including high separation efficiency, simple processing, minimal environmental pollution, and strong versatility.

[0003] Enhancing the hydrophobicity of PVDF is beneficial to improving the application performance of the material and expanding its application prospects. Common methods for improving the hydrophobicity of PVDF materials include plasma surface grafting, surface coating, chemical copolymerization or surface modification. For example, PVDF is super-hydrophobically modified by low-temperature plasma grafting CF4. The surface roughness of the modified membrane is significantly improved due to the etching of CF4, thereby improving the hydrophobicity of the membrane (Wei Xing et al., Super-hydrophobic CF4 plasma modified PVDF membrane and its DCMD performance, Journal of Nanjing University of Technology (Natural Science Edition), 2012, 34(04):96-100); Surface chemical copolymerization or surface modification is used to increase the crystallinity of the membrane surface polymer and change the hydrophobicity of the membrane surface (Li Hongbin et al., Research progress in the preparation technology of hydrophobic separation membranes, New Chemical Materials, 2018, 46(10):230-234 ); silicon dioxide and ethanol are mixed into a homogeneous solution by the sol-gel method, and a hydrophobic sol is obtained after cooling, which reduces the surface free energy of the membrane material, increases the membrane contact angle, and improves the hydrophobicity (Li Wenxiu et al., Preparation of hydrophobic SiO2 membrane for separation of CH4 / CO2, Materials Engineering, 2013, (02): 78-82); membrane materials with different roughness are prepared by laser etching method, and the hydrophobicity is changed in terms of chemical composition and surface structure (Jin Meihua et al., Preparation of super-hydrophobic polydimethylsiloxane membrane and study on its surface adsorption, Journal of Chemistry of Universities, 2007, (05): 996-998). The above methods require multiple steps such as special equipment processing and compounding with other hydrophobic materials, and the process is relatively complicated. Therefore, it is valuable to develop a simple method to enhance the hydrophobicity of PVDF materials.

[0004] This patent provides a simple and easy preparation method for enhancing the hydrophobic properties of PVDF materials. Through hydrothermal treatment, the surface structure of PVDF is manipulated, changing the material's surface contact angle to achieve enhanced hydrophobicity. This method is simple and easy to operate. The modified PVDF material is suitable for applications such as self-cleaning surfaces, antifouling coatings, medical dressings, and filtration membranes, enhancing product hydrophobicity and performance. Summary of the Invention

[0005] The present invention obtains a PVDF material with enhanced hydrophobicity through a simple and easy hydrothermal reaction method. The preparation method adopts the following technical scheme:

[0006] A certain amount of PVDF powder is dispersed in a certain amount of water, stirred in a hot water bath environment of about 40℃~80℃, and after uniform dispersion, the obtained mixed solution is transferred to a hydrothermal reactor. After reacting at a certain temperature for a period of time, the product is taken out, centrifuged, washed with water, washed with alcohol, dried, and ground to obtain a powder product, which is the modified PVDF material.

[0007] The modified PVDF material prepared by this method has significantly enhanced hydrophobicity. The preparation method has the following main features:

[0008] This method is suitable for PVDF materials with different molecular weights, ranging from 400 to 1,200,000.

[0009] The hydrothermal synthesis temperature range of the method is 100°C to 160°C.

[0010] The hydrothermal synthesis time of the method ranges from 6 hours to 48 hours.

[0011] A certain amount of polytetrafluoroethylene or other fluorine-containing polymer powder is dispersed in a certain amount of water, and the modified fluorine-containing polymer material is prepared using the same method as above.

[0012] Unlike the complex methods previously reported, the method provided by the present invention requires only hydrothermal treatment, is simple and easy to operate, and is suitable for industrial large-scale production. The materials obtained by this method have a wide range of applications and great market value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 SEM comparison of PVDF raw material (a) and modified PVDF material (b);

[0014] Figure 2 Comparison of contact angles of PVDF raw material (a) and modified PVDF material (b). DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the examples, but the present invention is not limited to the following examples.

[0016] Example 1

[0017] 1.3658 g of PVDF powder with a molecular weight of 400 was dispersed in 65 ml of water and stirred in a water bath at about 40°C. After uniform dispersion, the resulting mixture was transferred to a hydrothermal reactor and reacted at 140°C for 6 hours. The product was taken out and centrifuged. After washing with water, washing with alcohol, drying, and grinding, a powder product was obtained, which is the modified PVDF material.

[0018] Example 2

[0019] 10.2738 g of PVDF powder with a molecular weight of 400 was dispersed in 200 ml of water and stirred in a water bath at about 40°C. After uniform dispersion, the resulting mixture was transferred to a hydrothermal reactor and reacted at 140°C for 24 hours. The product was taken out and centrifuged. After washing with water, washing with alcohol, drying, and grinding, a powder product was obtained, which is the modified PVDF material.

[0020] Example 3

[0021] 1.0245 g of PVDF powder with a molecular weight of 500,000 was dispersed in 50 ml of water and stirred in a water bath at about 60°C. After uniform dispersion, the resulting mixture was transferred to a hydrothermal reactor and reacted at 150°C for 6 hours. The product was taken out and centrifuged. After washing with water, washing with alcohol, drying, and grinding, a powder product was obtained, which is the modified PVDF material.

[0022] Example 4

[0023] Disperse 0.6829 g of PVDF powder with a molecular weight of 1200000 in 65 ml of water, stir in a water bath at about 80°C, and after uniform dispersion, transfer the resulting mixture to a hydrothermal reactor. After reacting at 100°C for 48 hours, take out the product, centrifuge it, wash it with water, wash it with alcohol, dry it, and grind it to obtain a powder product, which is the modified PVDF material.

[0024] Example 5

[0025] Disperse 0.3415 g of PVDF powder with a molecular weight of 1200000 in 50 ml of water, stir in a water bath environment at about 80°C, and after uniform dispersion, transfer the resulting mixture to a hydrothermal reactor. After reacting at 160°C for 24 hours, take out the product, centrifuge it, wash it with water, wash it with alcohol, dry it, and grind it to obtain a powder product, which is the modified PVDF material.

[0026] Example 6

[0027] 1.2729 g of polytetrafluoroethylene powder with a molecular weight of 30,000 was dispersed in 50 ml of water and stirred in a water bath at about 70°C. After uniform dispersion, the obtained mixture was transferred to a hydrothermal reactor and reacted at 160°C for 24 hours. The product was taken out, centrifuged, washed with water, washed with alcohol, dried, and ground to obtain a powder product, which is the modified polytetrafluoroethylene material.

Claims

1. A method for enhancing the hydrophobicity of PVDF materials, characterized in that: The method comprises the following steps: dispersing a certain amount of polyvinylidene fluoride (PVDF) powder in a certain amount of water, stirring in a water bath at 40°C to 80°C, transferring the obtained mixed solution to a hydrothermal reactor after uniform dispersion, reacting at a certain temperature for a period of time, taking out the product, centrifuging it, washing it with water, washing it with alcohol, drying it, and grinding it to obtain a powder product, which is the modified PVDF material; After treatment with the above method, the hydrophobicity of the modified PVDF material was significantly improved.

2. A method for enhancing the hydrophobicity of PVDF material according to claim 1, characterized in that: The method is suitable for PVDF materials with different molecular weights, and the molecular weight range of the PVDF material is 400 to 1,200,000.

3. The method for enhancing the hydrophobicity of PVDF material according to claim 1, characterized in that: The hydrothermal synthesis temperature range of the method is 100°C to 160°C.

4. The method for enhancing the hydrophobicity of PVDF material according to claim 1, characterized in that: The hydrothermal synthesis time of the method ranges from 6 hours to 48 hours.

5. The method for enhancing the hydrophobicity of PVDF material according to claim 1, characterized in that: The PVDF material obtained by this method can be used in the preparation of self-cleaning surfaces, antifouling coatings, medical dressings, waterproof electronic products, filter membranes and many other fields to improve the hydrophobicity of the product and its performance.

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