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, etc., so as to save precipitation and reduce manufacturing cost , The preparation method is simple and easy to implement

Active Publication Date: 2008-01-23
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 adjusting the amount of chemical imidization reagents, so that polyimide nanofiltration membranes can be prepared by phase inversion.

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
Comparison scheme
Effect test

Embodiment 1

[0021] Synthesis of polyamic acid: 5g (0.025mol) of 4,4'-diaminodiphenyl ether (ODA) was dissolved in 80-mL of N,N-dimethylacetamide, electromagnetic stirring, under nitrogen protection 5.45 g (0.025 mol) of pyromellitic dianhydride (PMDA) was added in batches to the solution, and stirred and reacted at room temperature for 8 hours to obtain a polyamic acid solution with a concentration of 13.1 wt%.

[0022] Polyamic acid solution film-making process: Take 25 g of the above-mentioned synthesized polyamic acid solution, add 2.0 g of polyvinylpyrrolidone additive, mix well, filter with 300-mesh stainless steel mesh, and let the filtrate stand for degassing for 24 hours. Under dust-free conditions, at 25°C and relative humidity of 50%, apply the above-mentioned solution on a glass plate or a porous bottom layer, control the thickness of the film to about 25 μm, control the volatilization time for 25 seconds, and then immerse in water or ethanol Film formation in the coagulation b...

Embodiment 2

[0026] The synthesis of polyamic acid: the diphenylmethanediamine (MDA) of 4.9568g (0.025mol) is dissolved in the N-methylpyrrolidone of 80-mL, electromagnetic stirring, in solution, add 8.0558g (0.025mol) in batches under nitrogen protection mol) of benzophenone tetra-acid dianhydride (BTDA), stirred and reacted at room temperature for 8 hours to obtain a polyamic acid solution, and the concentration of this solution was 13.99 wt%.

[0027] Polyamic acid solution film-making process: Take 25 g of the above-mentioned synthesized polyamic acid solution, add 2.3 g of polyethylene glycol additive, mix well, filter with 300 mesh stainless steel mesh, and let the filtrate stand for degassing for 24 hours. Under dust-free conditions, at 25°C and relative humidity of 50%, apply the above-mentioned solution on a glass plate or a porous bottom layer, control the thickness of the film to about 25 μm, control the volatilization time for 25 seconds, and then immerse in water or ethanol Fi...

Embodiment 3

[0031] The synthesis of polyamic acid: the 3 of 5.658g (0.025mol), 3 ' dimethyl diphenylmethanediamine (DMMDA) is dissolved in the dimethylformamide of 80-mL, electromagnetic stirring, in the solution under nitrogen protection 11.106 g (0.025 mol) of hexafluorodianhydride (6FDA) was added in batches, stirred and reacted at room temperature for 8 hours to obtain a polyamic acid solution with a concentration of 17.32 wt%.

[0032] Polyamic acid solution film-making process: Take 25g of the polyamic acid solution synthesized above, add 1.8g of polyvinyl alcohol additive, mix well, filter with 300-mesh stainless steel mesh, and let the filtrate stand for degassing for 24 hours. Under dust-free conditions, at 25°C and relative humidity of 50%, apply the above-mentioned solution on a glass plate or a porous bottom layer, control the thickness of the film to about 25 μm, control the volatilization time for 25 seconds, and then immerse in water or ethanol Film formation in the coagula...

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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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Patent Type & Authority Patents(China)
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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