CN106669460B - Polytetrafluoroethylene superfine fiber tubular membrane - Google Patents
Polytetrafluoroethylene superfine fiber tubular membrane Download PDFInfo
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- CN106669460B CN106669460B CN201510767112.4A CN201510767112A CN106669460B CN 106669460 B CN106669460 B CN 106669460B CN 201510767112 A CN201510767112 A CN 201510767112A CN 106669460 B CN106669460 B CN 106669460B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/04—Tubular membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
- B01D71/36—Polytetrafluoroethene
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- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention provides a polytetrafluoroethylene fiber tubular membrane which comprises a polytetrafluoroethylene material body, wherein polytetrafluoroethylene is fibrous, the fiber diameter is 30-200 nm, the body is provided with a pore cavity with the pore diameter of 10-1000 nm and a cavity wall formed by surrounding the pore cavity in a three-dimensional space, the pore cavity is uniformly distributed, all the pore cavities are communicated in a three-dimensional mode, the pore cavity is uniformly distributed on a porous material in any unit volume, the porosity is more than 65%, and the light transmittance is more than 45%. The invention provides a specific and definite measuring mode for the pore space distribution uniformity of the polytetrafluoroethylene fiber tubular membrane, and defines the pore distribution uniformity of the porous material and the multi-level structure thereof under the scale of small unit level volume, and the porous structure is highly uniform, thereby ensuring the uniformity and consistency of all performances of the porous material.
Description
Technical Field
The invention relates to a porous material, in particular to a polytetrafluoroethylene fiber tubular membrane.
Background
The solid porous material containing a certain number of holes is a material with a network structure formed by through or closed holes. Compared with continuous medium materials, porous materials generally have the advantages of low relative density, high specific strength, high specific surface area, light weight, sound insulation, heat insulation, good permeability and the like. According to the difference of pore size, porous materials can be divided into microporous (pore size less than 2 nm), mesoporous (pore size 2-50 nm) and macroporous (pore size greater than 50 nm).
The porous materials are classified into metal porous materials and non-metal porous materials according to the material thereof. The non-metal porous material has the characteristics of large specific surface area, small density, small heat conductivity, small relative density, large porosity and the like, and has wide application prospects in the fields of catalysts (including carriers), adsorbents, heat preservation, heat insulation, sewage and waste gas treatment, filtering of liquid and gas (even bacteria), light building materials, environmental protection, soil improvement, chemical engineering and the like. The polytetrafluoroethylene porous membrane material has the advantages of high temperature stability, high chemical stability, high electric insulation, high flame retardance, high self-lubrication performance and the like, and is wide in application range. However, due to the randomness, irregularity of the pore structure, it still does not meet many application properties.
In many applications, the porous material is required to be uniform, the pore size and the distribution of pores are uniform, so that the performance is uniform, but in practice, many porous materials cannot meet the requirement, and the uniformity is complemented; although some materials are self-claimed to achieve higher uniformity, the uniformity is still the uniformity under the scale of large volume, if the material is measured by the scale of small volume, for example, a plurality of three-dimensional bodies with the volume not more than one cubic centimeter are randomly selected on the material, the quality of the three-dimensional bodies is respectively measured, the uniformity difference is still very large, and therefore, various properties of the polytetrafluoroethylene porous membrane material, such as strength, elastic modulus, flux and the like, are not uniform, and the function of the polytetrafluoroethylene porous membrane material is seriously influenced.
Disclosure of Invention
The invention aims to provide a polytetrafluoroethylene fiber tubular membrane with a proper and controllable structure and uniform height.
The purpose of the invention is realized by the following measures:
a polytetrafluoroethylene fiber tubular membrane comprises a polytetrafluoroethylene material body, wherein polytetrafluoroethylene is fibrous, the fiber diameter is 30-200 nm, the body is provided with a pore cavity with the aperture of 10-1000 nm and a cavity wall formed by surrounding the pore cavity in a three-dimensional space, the pore cavity is uniformly distributed, all the pore cavities are three-dimensionally communicated, the pore cavity is uniformly distributed, namely, all the pore cavities are uniformly distributed on a porous material under any unit volume, the porosity is more than 65%, and the light transmittance is more than 45%.
Specifically, the polytetrafluoroethylene fiber tubular membrane is provided with a pore cavity with the aperture of 30-1000 nm and a cavity wall formed by surrounding the pore cavity in a three-dimensional space, wherein a lower-level pore cavity with the aperture of 10-100 nm is arranged on the cavity wall, the pore cavities at all levels are respectively communicated in three dimensions, and the pore cavities at all levels are communicated with each other; the pore cavities are uniformly distributed, and the uniform distribution of the pore cavities means that all the pore cavities are uniformly distributed under any unit volume on the porous material.
Specifically, the unit-scale volume means a unit-scale volume on the order of cubic centimeters or cubic millimeters or less.
More specifically, the uniform distribution of the cavities means that three-dimensional bodies having a volume not greater than one cubic centimeter and the same size are arbitrarily taken on the porous material, and the masses of the three-dimensional bodies are substantially equivalent.
More specifically, the above-mentioned substantial equivalence means that a plurality of three-dimensional bodies having a volume of not more than one cubic centimeter and the same size are arbitrarily taken on the porous material, the masses thereof are respectively referred to, and the average value of the masses thereof is obtained, and the absolute value of the deviation of the mass of any one of the three-dimensional bodies from the average value of the masses is not more than 4% of the average value of the masses of the three-dimensional bodies.
Further, three-dimensional bodies of the same size having a volume of no more than one cubic millimeter are optionally taken on the multi-stage material and their masses are substantially equivalent.
More specifically, the substantial equivalence of the masses means that a plurality of three-dimensional bodies with the same size and the volume of not more than one cubic millimeter are taken on the porous material, the masses are respectively called, the average value of the masses of the three-dimensional bodies is obtained, and the absolute value of the deviation of the mass of any three-dimensional body relative to the average value of the masses is not more than 4% of the average value of the masses of the three-dimensional bodies.
Preferably, the polytetrafluoroethylene fiber tubular membrane is made of a multi-stage porous material, the body is composed of cavities graded according to the pore size of the material and cavity walls surrounding the cavities in a three-dimensional space, lower-stage cavities are arranged on the cavity walls, the cavities at all stages are communicated in three dimensions respectively, and the cavities at all stages are communicated with one another. More specifically, the next stage porous material forms the walls of the previous stage lumen. The cavity wall of the upper-level pore cavity is formed by compounding the lower-level multi-level porous materials or the lower-level multi-level porous materials, so that the material can meet specific functional requirements.
Specifically, each stage of the porous material of the material body is a continuous structure. The maximum outer boundary of each stage of porous material is equivalent to the spatial boundary of the whole material body. That is, each stage of porous material can exist in the body as a stage of independent porous material and has independent physicochemical properties. The structure can lead the physicochemical properties of porous materials at all levels to be different, has different physicochemical properties in the whole space of relatively fixed materials, and better meets the function requirements in various aspects.
Advantageous effects
1. The invention provides a polytetrafluoroethylene fiber tubular membrane with a porous structure, and the structural form, the hierarchical structural form of pore cavities and the uniform structure of the pore cavities of the polytetrafluoroethylene fiber tubular membrane are determined so that the polytetrafluoroethylene fiber tubular membrane can meet various functional requirements.
2. The invention provides a specific and definite measuring mode for the pore space distribution uniformity of the polytetrafluoroethylene fiber tubular membrane, and defines the pore distribution uniformity of the porous material and the multi-level structure thereof under the scale of small unit level volume, and the porous structure is highly uniform, thereby ensuring the uniformity and consistency of all performances of the porous material.
3. The polytetrafluoroethylene fiber tubular membrane is three-dimensionally communicated, comprises three-dimensionally communicated holes of each stage, is mutually three-dimensionally communicated with the holes of each stage, has good connectivity, and can fully meet the functional requirements of materials.
4. The polytetrafluoroethylene fiber tubular membrane is a hydrophobic surface with a multi-stage rough structure. The surface water contact angle can reach over 160 degrees.
5. The polytetrafluoroethylene fiber tubular membrane has the advantages of bright membrane color, bright and smooth luster, no need of support, stable shape and controllable thickness, and is applied to the membrane distillation process, and the flux is controllable>42L/m2H, the retention rate is more than 99.8%.
Detailed Description
The detailed embodiments are given on the premise of the technical solution of the present invention, but the scope of the present invention is not limited to the following embodiments. It will be apparent that various substitutions and alterations can be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims, based on common technical knowledge and/or common usage in the art.
Example 1
The polytetrafluoroethylene fiber tubular membrane has a secondary pore structure, wherein uniformly distributed and mutually communicated secondary pores are arranged on the wall of a uniformly distributed and mutually communicated primary pore, the two pores are mutually communicated, and the communication is three-dimensional. Each stage of porous material of the material body is a continuous structure. The total effective porosity is 75%, the fiber diameter is 150 +/-20 nm, the average pore diameter of the macropores is 0.40 mu m, and the wall of the macropores is provided with through pores with the average pore diameter of 30 nm.
9 pieces of three-dimensional bodies of the same size of 10mm × 10mm × 10mm were arbitrarily machined from the porous material, and the mass was measured on a Mettler-Torledo XP26 Microbalance balance, and the results are shown in Table 1, in which the absolute value of the deviation from the mean value is expressed in percentage, and the absolute value of the deviation from the mean value is divided by the mean value of the mass, as can be seen from Table 1, the mass deviation is not more than 4%.
And (3) light transmittance measurement: and scanning 380-780nm wave bands by adopting an LCD5200 photoelectric characteristic tester according to the distribution characteristics of all wave bands of sunlight published by GBT2680-1994 to calculate the light transmittance of the sample to visible light.
TABLE 1
| Part number | Mass (mg) | Absolute value of deviation from average (%) |
| 1 | 655.131 | 0.3% |
| 2 | 666.763 | 1.4% |
| 3 | 646.919 | 1.6% |
| 4 | 661.415 | 0.6% |
| 5 | 657.179 | 0.0% |
| 6 | 643.106 | 2.2% |
| 7 | 667.490 | 1.5% |
| 8 | 660.103 | 0.4% |
| 9 | 657.861 | 0.1% |
| Mass average value | 657.330 |
The preparation method of the polytetrafluoroethylene porous material comprises the following steps:
(1) uniformly mixing polytetrafluoroethylene emulsion with the solid content of 65%, chitosan with the particle size of 30nm and 7% (mass ratio) polyvinyl alcohol solution, and mixing the components according to the weight ratio of 45: 25: 3, preparing a spinning solution;
(2) preparing a polytetrafluoroethylene precursor film in an oriented electrostatic spinning fiber device by adopting an electrostatic spinning method under a vacuum condition; treating at 100 deg.C for 30min under vacuum condition;
(3) winding 5 layers of the precursor film obtained in the step (2) on a cylindrical supporting die with the diameter of 4-25mm, sending the precursor film into a tubular furnace for sintering in vacuum or protective atmosphere, wherein the sintering adopts program temperature control segmented continuous sintering, the temperature is increased from room temperature to 200 ℃ at the speed of 3 ℃/min, and the temperature is maintained at 200 ℃ for 60 min; heating to 300 deg.C at a rate of 3 deg.C/min, and maintaining at 300 deg.C for 40 min; heating to 400 deg.C at a rate of 3 deg.C/min, and maintaining at 400 deg.C for 60 min.
(4) And (3) performing temperature-programmed cooling after sintering, and performing subsequent treatment according to a conventional technology to obtain a porous polytetrafluoroethylene fiber tubular membrane with a two-stage pore structure, wherein the thickness of the porous polytetrafluoroethylene fiber tubular membrane is 158 micrometers, the diameter of the tubular membrane is 4-25mm, and the light transmittance is 60%.
The polytetrafluoroethylene fiber tubular membrane is free of support, stable in form, controllable in thickness, capable of being used for gas-liquid separation and liquid-liquid separation, capable of achieving accurate classified filtration, and suitable for filtration of binary or multi-element gas (liquid), large in flux, high in retention rate, not prone to being polluted (such as pollution of a multi-element liquid infiltration membrane), and efficient and long-acting. The film water contact angle was 166 °.
For example, the total flux can reach 42kg/m in the membrane distillation of an acid/alcohol-water-non-volatile solute system2H or more, the retention rate of non-volatile solute in the system is more than 99.8%, and the separation factor of volatile alcohol/acid = [ mass fraction of alcohol/acid in distillate × (1-mass fraction of raw material liquid alcohol/acid) ]]Div [ raw material solution alcohol/acid mass fraction x (1-distillate alcohol/acid mass fraction)]Up to 10 or more.
Example 2
The polytetrafluoroethylene fiber tubular membrane has a three-stage pore structure, wherein uniformly distributed and mutually communicated second-stage pores are arranged on the wall of a uniformly distributed and mutually communicated first-stage pore and are mutually communicated, and the two-stage pores are also mutually communicated, and the communication is three-dimensional. Each stage of porous material of the material body is a continuous structure. The total effective porosity is 85%, the fiber diameter is 180 +/-20 nm, the average pore diameter of the macropores is 1000nm, the wall of the macropores is provided with through secondary pores with the average pore diameter of 60nm, and the wall of the secondary pores is provided with through tertiary pores with the average pore diameter of 10 nm.
Any 9 pieces of 10mm × 10mm × 10mm three-dimensional bodies of the same size were mechanically processed on the porous material, and the mass was measured on a mertler-toledo XP26 Microbalance balance, and the results are shown in table 1, in which the absolute value of the deviation from the mean value is expressed in percentage, and the absolute value of the deviation from the mean value is divided by the mean value of the mass, as can be seen from table 2, the mass deviation is not more than 4%.
TABLE 2
| Part number | Mass (mg) | Absolute value of deviation from average (%) |
| 1 | 520.735 | 0.3% |
| 2 | 504.772 | 2.7% |
| 3 | 528.525 | 1.8% |
| 4 | 521.513 | 0.5% |
| 5 | 526.519 | 1.5% |
| 6 | 501.381 | 3.4% |
| 7 | 512.440 | 1.3% |
| 8 | 526.384 | 1.4% |
| 9 | 528.103 | 1.8% |
| Mass average value | 520.735 |
The preparation method of the polytetrafluoroethylene porous material comprises the following steps:
(1) mixing PTFE fine powder and polyethylene glycol with the molecular weight of 1000, stirring and heating to 380 ℃, continuously stirring for 60min, rapidly cooling to room temperature for crushing, and crushing at the temperature below zero ℃ to obtain polytetrafluoroethylene particles;
(2) dispersing polytetrafluoroethylene particles with the particle size of 200nm to prepare emulsion with the solid content of 65%, uniformly mixing the emulsion with chitosan with the particle size of 100nm and polyvinyl alcohol solution with the mass ratio of 7%, and mixing the emulsion according to the weight ratio of 45: 25: 3, preparing a spinning solution;
(3) preparing a polytetrafluoroethylene precursor film in an oriented electrostatic spinning fiber device by adopting an electrostatic spinning method under a vacuum condition, and treating for 30min at 100 ℃ under the vacuum condition;
(4) winding 5 layers of the precursor film on a cylindrical support mold with the diameter of 4-25mm, sending the precursor film into a tubular furnace, sintering in vacuum or protective atmosphere, adopting program temperature control segmented continuous sintering, heating from room temperature to 200 ℃ at the speed of 3 ℃/min, and keeping the temperature at 200 ℃ for 60 min; heating to 310 ℃ at the speed of 3 ℃/min, and preserving the heat at 310 ℃ for 40 min; heating to 400 deg.C at a rate of 3 deg.C/min, and maintaining at 400 deg.C for 60 min.
(5) And (3) performing temperature-programmed cooling after sintering, and performing subsequent treatment according to a conventional technology to obtain the porous polytetrafluoroethylene fiber tubular membrane with a tertiary pore structure, wherein the thickness of the porous polytetrafluoroethylene fiber tubular membrane is 160 mu m, and the diameter of the porous polytetrafluoroethylene fiber tubular membrane is 4-25 mm.
The polytetrafluoroethylene fiber tubular membrane is free of support, stable in form, controllable in thickness, capable of being used for gas-liquid separation and liquid-liquid separation, capable of achieving accurate classified filtration, and suitable for filtration of binary or multi-element gas (liquid), large in flux, high in retention rate, not prone to being polluted (such as pollution of a multi-element liquid infiltration membrane), and efficient and long-acting. The film water contact angle was 168 °, and the light transmittance was 68%.
For example, the total flux can reach 42kg/m in the membrane distillation of a multi (or mixed) alcohol/acid-water-non-volatile solute system2H or more, the retention rate of non-volatile solute in the system is more than 99.9%, and the separation factor of volatile alcohol/acid = [ mass fraction of alcohol/acid in distillate × (1-mass fraction of raw material liquid alcohol/acid) ]]Div [ raw material solution alcohol/acid mass fraction x (1-distillate alcohol/acid mass fraction)]Up to 10 or more.
Claims (1)
1. A polytetrafluoroethylene fiber tubular membrane has a secondary pore structure, wherein uniformly distributed and mutually communicated secondary pores are arranged on the wall of a uniformly distributed and mutually communicated primary pore, the two pores are mutually communicated, and the communication is three-dimensional; each stage of porous material of the material body is a continuous structure; the total effective porosity is 75%, the fiber diameter is 150 +/-20 nm, the average pore diameter of the macropores is 0.40 mu m, and the wall of the macropores is provided with through pores with the average pore diameter of 30 nm;
the preparation method of the polytetrafluoroethylene tubular membrane comprises the following steps:
(1) uniformly mixing polytetrafluoroethylene emulsion with the solid content of 65%, chitosan with the particle size of 30nm and 7wt% of polyvinyl alcohol solution, and mixing the components according to the weight ratio of 45: 25: 3, preparing a spinning solution;
(2) preparing a polytetrafluoroethylene precursor film in an oriented electrostatic spinning fiber device by adopting an electrostatic spinning method under a vacuum condition; treating at 100 deg.C for 30min under vacuum condition;
(3) winding 5 layers of the precursor film obtained in the step (2) on a cylindrical supporting die with the diameter of 4-25mm, sending the precursor film into a tubular furnace for sintering in vacuum or protective atmosphere, wherein the sintering adopts program temperature control segmented continuous sintering, the temperature is increased from room temperature to 200 ℃ at the speed of 3 ℃/min, and the temperature is maintained at 200 ℃ for 60 min; heating to 300 deg.C at a rate of 3 deg.C/min, and maintaining at 300 deg.C for 40 min; heating to 400 deg.C at a rate of 3 deg.C/min, and maintaining at 400 deg.C for 60 min;
(4) and (3) performing temperature-programmed cooling after sintering, and performing subsequent treatment according to a conventional technology to obtain a porous polytetrafluoroethylene fiber tubular membrane with a two-stage pore structure, wherein the thickness of the porous polytetrafluoroethylene fiber tubular membrane is 158 micrometers, the diameter of the tubular membrane is 4-25mm, and the light transmittance is 60%.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510767112.4A CN106669460B (en) | 2015-11-11 | 2015-11-11 | Polytetrafluoroethylene superfine fiber tubular membrane |
| PCT/CN2016/105253 WO2017080465A1 (en) | 2015-11-11 | 2016-11-09 | Polytetrafluoroethylene ultra-fine fiber tubular membrane |
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| CN201510767112.4A CN106669460B (en) | 2015-11-11 | 2015-11-11 | Polytetrafluoroethylene superfine fiber tubular membrane |
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| CN109395599A (en) * | 2017-08-18 | 2019-03-01 | 重庆润泽医药有限公司 | A kind of polytetrafluoroethyltubular tubular membrane and preparation method thereof |
| CN109402873A (en) * | 2017-08-18 | 2019-03-01 | 重庆润泽医药有限公司 | A kind of macromolecule semi-permeable material |
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| CN103894077A (en) * | 2014-04-10 | 2014-07-02 | 江南大学 | Composite filter membrane with multidimensional pore structure and preparation method thereof |
| CN104906968A (en) * | 2014-03-13 | 2015-09-16 | 成都百途医药科技有限公司 | Teflon membrane and preparation method thereof |
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| GB1527592A (en) * | 1974-08-05 | 1978-10-04 | Ici Ltd | Wound dressing |
| JP4659241B2 (en) * | 2001-03-19 | 2011-03-30 | ジャパンゴアテックス株式会社 | Polytetrafluoroethylene membrane and method for producing the same |
| CN101530750A (en) * | 2009-04-20 | 2009-09-16 | 浙江理工大学 | Preparation method of polytetrafluoroethylene superfine fiber porous membrane |
| CN102151493A (en) * | 2011-03-18 | 2011-08-17 | 上腾新材料科技（苏州）有限公司 | Method for preparing nano polytetrafluoroethylene microporous membrane |
| CN103212308A (en) * | 2012-08-01 | 2013-07-24 | 上海市凌桥环保设备厂有限公司 | Polytetrafluoroethylene millipore membrane for purifying PM2.5 |
| CN105013344B (en) * | 2014-04-22 | 2017-12-08 | 成都百途医药科技有限公司 | A kind of preparation method of super-hydrophobic polytetrafluoroethylfiber fiber film |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104906968A (en) * | 2014-03-13 | 2015-09-16 | 成都百途医药科技有限公司 | Teflon membrane and preparation method thereof |
| CN103894077A (en) * | 2014-04-10 | 2014-07-02 | 江南大学 | Composite filter membrane with multidimensional pore structure and preparation method thereof |
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