Method for enhancing hydrophobic property of PVDF (Polyvinylidene Fluoride) material

Abstract

The invention provides a preparation method for enhancing the hydrophobic property of a polyvinylidene fluoride (PVDF) material. The preparation method comprises the following steps: directly dispersing PVDF powder in water to form a mixed solution, and carrying out hydrothermal treatment at a certain temperature to obtain the modified PVDF material with enhanced hydrophobicity. Different from a conventional hydrophobic modification preparation method, the method disclosed by the invention has the advantages that the hydrophobic property of the PVDF material is improved by regulating the surface structure of the PVDF, increasing the surface roughness and changing the surface contact angle of the material through a simple and easily-controlled hydrothermal treatment process, so that the wetting resistance of the material is effectively improved. The method is simple and convenient in process, easy to operate and easy in mass production, the modified PVDF material can be applied to the fields of self-cleaning surfaces, antifouling coatings, medical dressings, waterproof electronic products, filtering membranes and the like, and the product performance is improved.

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) is composed of fluorine atoms and carbon atoms. It is a semi-crystalline polymer. Compared with other fluoropolymers, it has higher crystallinity and surface tension performance, and has excellent hydrophobicity, biocompatibility, chemical stability and other characteristics. Due to its own surface properties and hydrophobicity, PVDF material has high separation efficiency, simple process, low environmental pollution, and strong versatility in the fields of microphase separation and self-cleaning surface.

[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 grafting CF4 with low-temperature plasma. 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 polymer on the membrane surface and change the hydrophobicity of the membrane surface (Li Hongbin et al., Research Progress in Preparation Technology of Hydrophobic Separation Membranes, New Chemical Materials, 2018, 46(10):230-234 ); using the sol-gel method to mix silicon dioxide and ethanol into a homogeneous solution, and obtaining a hydrophobic sol after cooling, the surface free energy of the membrane material is reduced, the membrane contact angle is increased, and the hydrophobicity is improved (Li Wenxiu et al., Preparation of hydrophobic SiO2 membrane for separation of CH4 / CO2, Materials Engineering, 2013, (02): 78-82); using laser etching method to prepare membrane materials with different roughness, changing the hydrophobicity 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 of preparation 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 regulated, the surface contact angle of the material is changed, and the hydrophobic properties are improved. The process of this method is simple and easy to operate. The modified PVDF material is suitable for self-cleaning surfaces, antifouling coatings, medical dressings, filtration membranes and many other fields to improve the hydrophobicity and application performance of the product. Summary of the invention

[0005] The present invention obtains a PVDF material with enhanced hydrophobicity by a simple and easy hydrothermal reaction method, and 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 at about 40℃~80℃, and after uniform dispersion, the obtained mixed solution is transferred to a hydrothermal reactor. After reacting for a period of time at a certain temperature, 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 hydrophobicity of the modified PVDF material prepared by this method is significantly enhanced. The preparation method has the following main features:

[0008] The 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 by the same method as above.

[0012] Different from the complexity of the previously reported methods, the method provided by the present invention only requires hydrothermal treatment, the process is simple and easy to operate, and is a method suitable for industrial mass production. The material obtained by the method has 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 in conjunction with 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, stirred in a water bath at about 40°C, and after uniform dispersion, the obtained mixture was transferred to a hydrothermal reactor. After reacting at 140°C for 6 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 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, stirred in a water bath at about 40°C, and after uniform dispersion, the obtained mixture was transferred to a hydrothermal reactor. After reacting at 140°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 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, stirred in a water bath at about 60°C, and after uniform dispersion, the obtained mixture was transferred to a hydrothermal reactor. After reacting at 150°C for 6 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 PVDF material.

[0022] Example 4

[0023] 0.6829 g of PVDF powder with a molecular weight of 1200000 was dispersed in 65 ml of water, stirred in a water bath at about 80°C, and after uniform dispersion, the obtained mixture was transferred to a hydrothermal reactor. After reacting at 100°C for 48 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 PVDF material.

[0024] Example 5

[0025] 0.3415 g of PVDF powder with a molecular weight of 1200000 was dispersed in 50 ml of water, stirred in a water bath at about 80°C, and after uniform dispersion, the obtained mixture was transferred to a hydrothermal reactor. After reacting 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 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, stirred in a water bath at about 70°C, and after uniform dispersion, the obtained mixed solution was transferred to a hydrothermal reactor, 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 includes the following steps: dispersing a certain amount of polyvinylidene fluoride (PVDF) powder in a certain amount of water, stirring in a water bath environment at about 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 being treated by the above method, the hydrophobicity of the modified PVDF material is 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. A 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. A 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. A 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 many fields such as the preparation of self-cleaning surfaces, antifouling coatings, medical dressings, waterproof electronic products, filtration membranes, etc., to improve the hydrophobicity of the product and its performance.

6. A method for enhancing the hydrophobicity of PVDF material according to claim 1, characterized in that: This method is applicable to other fluorinated polymer powders including polytetrafluoroethylene to improve the hydrophobicity of the material.

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