Preparation method of polyimide nanometer filtering membrane

A technology of polyimide nano and polyamic acid, which is applied in the field of preparation of polyimide nanofiltration membrane, can solve the problems of uncontrolled polyimide material solubility, and achieve the goal of eliminating precipitation and reducing solvent The effect of the amount and type of expansion

Active Publication Date: 2007-02-14
PETROCHINA CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there is no attempt to control the degree of imidization and then control the solubility of polyimide materials by adj

Method used

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  • Preparation method of polyimide nanometer filtering membrane
  • Preparation method of polyimide nanometer filtering membrane
  • Preparation method of polyimide nanometer filtering membrane

Examples

Experimental program
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Effect test

Example Embodiment

[0020] Example 1

[0021] Synthesis of polyamic acid: Dissolve 5g (0.025mol) of 4,4'-diaminodiphenyl ether (ODA) in 80mL of N,N-dimethylacetamide, stir electromagnetically, and under the protection of nitrogen 5.45g (0.025mol) of pyromellitic dianhydride (PMDA) was added to the solution in batches, and the reaction was stirred at room temperature 8 A polyamic acid solution was obtained within hours, and the concentration of the solution was 13.1 wt%.

[0022] Polyamic acid solution membrane preparation process: Take 25 g of the above-synthesized polyamic acid solution, add 2.0 g of polyvinylpyrrolidone additive, and after mixing uniformly, filter with a 300-mesh stainless steel mesh, and let the filtrate stand for 24 hours to degas. Under dust-free conditions, at 25°C and 50% relative humidity, coat the obtained solution on a glass plate or porous bottom layer. The thickness of the film is controlled to be about 25μm, and the volatilization time is controlled for 25 seconds, and t...

Example Embodiment

[0025] Example 2

[0026] Synthesis of polyamic acid: Dissolve 4.9568g (0.025mol) of diphenylmethanediamine (MDA) in 80mL of N-methylpyrrolidone, stir electromagnetically, and add 8.0558g (0.025 mol) to the solution in batches under the protection of nitrogen. mol) of benzophenone tetracarboxylic dianhydride (BTDA), stirred and reacted at room temperature for 8 hours to obtain a polyamic acid solution, and the concentration of the solution was 13.99 wt%.

[0027] Polyamic acid solution membrane preparation process: Take 25g of the above-synthesized polyamic acid solution, add 2.3g of polyethylene glycol additive, and after mixing uniformly, filter with a 300-mesh stainless steel mesh, and leave the filtrate to stand and degas for 24 hours. Under dust-free conditions, at 25°C and 50% relative humidity, coat the obtained solution on a glass plate or porous bottom layer. The thickness of the film is controlled to be about 25μm, and the volatilization time is controlled for 25 seconds...

Example Embodiment

[0030] Example 3

[0031] Synthesis of polyamic acid: Dissolve 5.658g (0.025mol) of 3,3'dimethyldiphenylmethanediamine (DMMDA) in 80mL of dimethylformamide, stir electromagnetically, and add to the solution under the protection of nitrogen 11.106g (0.025mol) of hexafluorodianhydride (6FDA) was added in batches, and the reaction was stirred at room temperature 8 A polyamic acid solution was obtained within hours, and the concentration of the solution was 17.32wt%.

[0032] Polyamic acid solution membrane production process: take 25 g of the above-synthesized polyamic acid solution, add 1.8 g of polyvinyl alcohol additive, and after mixing uniformly, filter with a 300-mesh stainless steel mesh, and let the filtrate stand for 24 hours to degas. Under dust-free conditions, at 25°C and 50% relative humidity, apply the solution obtained above on a glass plate or porous bottom layer. The thickness of the film is controlled to be about 25μm, the volatilization time is controlled for 25 se...

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Abstract

The present invention relates to a preparation process of nanofiltering polyimide membrane for recovering lubricant oil acetone-benzene dewaxing solvent. The preparation process includes the following steps: preparing polyamic acid solution, adding additive for phase transfer to prepare nanofiltering polyamic acid membrane, imidating the membrane chemically, solvent exchanging and heat treatment. Or, the preparation process may include the following steps: the first preparing partially imidated polyimide capable of being dissolved in some solvents, preparing film casting solution, filming in a phase transfer process, solvent exchanging and heat treatment. The present invention has low preparation cost, and the prepared nanofiltering polyimide membrane has lubricant oil intercepting rate greater than 90 % and mixed acetone-benzene solvent flux greater than 12 L/sq m .hr at the conditions of -18 deg.c and 3 MPa.

Description

technical field [0001] The invention relates to a preparation method of a polyimide nanofiltration membrane used for recovering lubricating oil ketone-benzene dewaxing solvent. Background technique [0002] As known to those skilled in the art, solvent dewaxing has long dominated the production of lube base stocks. The solvent after dewaxing (ie, methyl ethyl ketone and toluene) is separated from the mixture of lubricating oil and solvent through a distillation process for recycling. Due to the frequent freezing-heating-vaporization-condensation-freezing of solvent , resulting in a large amount of energy consumption, becoming a bottleneck in the expansion of lubricating oil and paraffin production. [0003] Those skilled in the art try to open up a new approach with high efficiency and low energy consumption for this process by means of membrane separation. Membrane separation technology is applied to the dewaxing process, which can directly separate part of the cold solve...

Claims

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Application Information

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IPC IPC(8): B01D71/64
Inventor 孔瑛张志华史德青于宏伟王云芳胡胜杨金荣武志峰张媛媛柳越男
Owner PETROCHINA CO LTD
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