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Method for preparing polyvinylidene fluoride alloy film by adopting compound thermally induced phase separation process

A technology of polyvinylidene fluoride and alloy membrane, which is applied in the direction of semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc. It can solve the problems of unfriendly environment, influence of cortex structure, and influence of body pore structure, etc., so as to reduce production cost , good mechanical strength

Active Publication Date: 2015-03-18
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of the single diluents used in TIPS are non-water-soluble latent solvents, which are insoluble in water, so they must be extracted with other extractants after film formation, which is a complicated process and is not friendly to the environment.
A homogeneous solution can be formed at high temperature, but solid-liquid phase separation usually occurs during the cooling process, and the formed membrane is generally spherical and loose in structure, the strength of the membrane is not high, and the water flux is also affected to a certain extent
[0005] Composite Thermally Induced Phase Separation (c-TIPS) uses the principle that polymers form a homogeneous solution at high temperature, and the homogeneous solution undergoes thermally induced phase separation (TIPS) and non-solvent-induced phase separation (NIPS) film formation at the same time when the temperature is lowered. , that is, during the film forming process, water is both an extractant and a coolant (hereinafter referred to as the coolant), and the surface solvent of the film-forming liquid will exchange with the coolant water to cause non-solvent-induced phase separation It mainly occurs on the surface of the membrane and affects the structure of the cortex; at the same time, the high-temperature casting liquid and the extraction coolant water undergo heat-induced exchange, resulting in thermally-induced phase separation and affecting the pore structure of the body

Method used

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  • Method for preparing polyvinylidene fluoride alloy film by adopting compound thermally induced phase separation process
  • Method for preparing polyvinylidene fluoride alloy film by adopting compound thermally induced phase separation process

Examples

Experimental program
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Embodiment 1

[0024] Accurately weigh 84.5g of caprolactam, 13.5g of polyvinylidene fluoride with a molecular weight of 320,000, and 1.5g of polyethylene oxide with a molecular weight of 50,000. Stir the above three materials evenly and pour them into a 250mL beaker. , using an oil bath to heat, the temperature of the oil bath used is 120°C, heating to completely dissolve the raw materials, and keeping it at 120°C for 45 minutes, then stirring the solution with an electric stirrer for 30 minutes, and then standing in the oil bath for defoaming to obtain Casting solution, and then keep the casting solution at 120°C for preservation. Pour the obtained film-casting solution into the template and scrape to form a film, and quickly put the freshly scraped film into water at a predetermined temperature of 35°C until the film and the film plate are naturally separated; the polyvinylidene fluoride alloy film is obtained, The thickness of the polyvinylidene fluoride alloy film is 145 μm, and the thi...

Embodiment 2

[0027] Accurately weigh 84.7g of caprolactam, 12g of polyvinylidene fluoride with a molecular weight of 320,000, and 3g of polyethylene oxide with a molecular weight of 50,000. Stir the above three raw materials evenly and pour them into a 250mL beaker. Heating in an oil bath, the temperature of the oil bath used is 130 °C, heating to completely dissolve the raw materials, and keeping at 130 °C for 1.5 hours, then stirring the solution with an electric stirrer for 30 minutes, and then standing in the oil bath for defoaming to obtain a cast film solution, and then the casting solution was kept at 130°C. Pour the obtained film casting solution into the template and scrape to form a film, and quickly put the freshly scraped film into water at a predetermined temperature of 30°C until the film and the film plate are naturally separated; the polyvinylidene fluoride alloy film is obtained. The thickness of the polyvinylidene fluoride alloy film is 140 μm, and the thickness of the sk...

Embodiment 3

[0030] Accurately weigh 80.5g of caprolactam, 18.2g of polyvinylidene fluoride with a molecular weight of 320,000, and 2g of polyethylene oxide with a molecular weight of 50,000. Stir the above three materials evenly and pour them into a 250mL beaker. Under the condition of slow nitrogen protection, Heating in an oil bath, the temperature of the oil bath used is 130°C, heating to completely dissolve the raw materials, and keeping at 130°C for 2 hours, then stirring the solution with an electric stirrer for 45 minutes, and then standing in the oil bath for defoaming to obtain a cast film solution, and then the casting solution was kept at 130°C. Pour the obtained film-casting liquid into the template and scrape to form a film, and quickly put the freshly scraped film into water at a predetermined temperature of 15°C until the film and the film plate are naturally separated; the polyvinylidene fluoride alloy film is obtained, The thickness of the polyvinylidene fluoride alloy fi...

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Abstract

The invention discloses a method for preparing a polyvinylidene fluoride alloy film by adopting a compound thermally induced phase separation process. The method comprises the following steps: uniformly mixing polyvinylidene fluoride, a hydrophilic polymer and caprolactam; heating to a dissolving temperature in the presence of nitrogen, and keeping the temperature for 1.5-3h; after completely dissolving polyvinylidene fluoride, hydrophilic polymer and caprolactam, mixing at a dissolving temperature for 0.5-1.5h, standing to obtain a casting solution, and storing the casting solution at the dissolving temperature; and preparing the casting solution into a film, rapidly placing the scraped film in water with a preset temperature, naturally separating the film from a film plate by using water as a cold extraction agent to obtain the polyvinylidene fluoride alloy film. The method is simple in process, free from pollution, and relatively low in cost; the prepared polyvinylidene fluoride alloy film has excellent chemical stability, high mechanical strength and pollution resistance, is easily cleaned, provides a high-performance alloy film product for an MBR process in the fields of sewage treatment and water resource recycling, and is widely applied to the fields such as industries, medical treatment and sewage treatment.

Description

technical field [0001] The invention belongs to the technical field of polymer material manufacturing, and in particular relates to a method for preparing a polyvinylidene fluoride alloy film by a composite heat-induced phase separation method. Background technique [0002] Polyvinylidene fluoride (PVDF) has outstanding solvent resistance, acid and alkali resistance, ultraviolet resistance and weather resistance, and is an excellent membrane material. The polyvinylidene fluoride membrane prepared by this membrane material has been well applied in sewage purification treatment and biochemical pharmaceutical industry. Due to the hydrophobicity of PVDF, simple PVDF membranes are easily polluted by organic matter in water during application, and are not easy to clean. The polyvinylidene fluoride alloy membrane is a polymer porous membrane prepared by blending a hydrophilic polymer compound with PVDF. The blended gold membrane can improve the hydrophilic performance of the PVDF ...

Claims

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Application Information

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IPC IPC(8): B01D71/34B01D67/00
Inventor 蔡新海肖通虎
Owner NINGBO UNIV