ASYMMETRIC HYDROPHOBIC POLYOLEFIN HOLLOW FIBER MEMBRANE, PREPARING METHOD, AND USE OF THE SAME

Abstract

An asymmetric hydrophobic polyolefin hollow fiber membrane includes a support layer and a separation layer, the separation layer including an outer surface, the outer surface including a quantity of first pores with a certain pore size; presence of the first pores facilitates an anesthetic gas such as sevoflurane and remifentanil to permeate through the hollow fiber membrane into the human blood, allowing for the patient to maintain sedated throughout a surgical process; meanwhile, the first pores facilitate reduction of dosage of the anesthetic in the surgery, thereby reducing surgical costs and avoid overdosage of the anesthetic causing secondary impairment to the patient; in addition, the hollow fiber membrane offers a long plasma permeation duration, a high tensile strength and a high elongation at break to satisfy application needs, particularly suitable for human blood oxygenation including anesthetic gas and the gas-liquid separation areas.

Claims

1. An asymmetric hydrophobic polyolefin hollow fiber membrane, comprising a support layer and a separation layer, the support layer comprising an inner surface facing a lumen of the hollow fiber membrane, the separation layer comprising an outer surface, the outer surface being located at the side of the separation layer opposite the support layer, wherein: the outer surface comprises a plurality of first pores, the first pores having a pore size of 10 nm to 300 nm in a first direction of the outer surface and a pore size of 10 nm to 300 nm in a second direction of the outer surface; wherein the first direction of the outer surface is parallel to an axial direction of the hollow fiber membrane, and the second direction of the outer surface is parallel to a radial direction of the hollow fiber membrane the first pores at the outer surface have a pore density of 4 to 45 pores/1 μm.sup.2; the outer surface of the hollow fiber membrane has a surface energy of 10 mN/m to 45 mN/m under 20° C.; and the hollow fiber membrane has a tensile strength of at least 100CN and an elongation at break of at least 150%.

2. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, wherein the first pores have a pore size of 150 nm to 300 nm in the first direction of the outer surface, the first pores have a pore size of 10 nm to 90 nm in the second direction of the outer surface; wherein the first direction is parallel to the axial direction of the hollow fiber membrane, and the second direction is parallel to the radial direction of the hollow fiber membrane; and the first pores have a pore density of 4 to 35 pores/1 μm.sup.2.

3. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, wherein the separation layer has a thickness of 0.1 μm to 2 μm, accounting for 0.5 to 5% of total thickness of the hollow fiber membrane.

4. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, wherein the separation layer is porous, and a mean pore size of the separation layer is 10 nm to 60 nm.

5. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, wherein the hollow fiber membrane has an O.sub.2 permeation rate of 1 to 50 L/min.Math.bar.Math.m.sup.2; the hollow fiber membrane has a gas separation factor α of 1 to 4 between CO.sub.2 and O.sub.2 and a gas separation factor α of at least 150 between O.sub.2 and an anesthetic gas.

6. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 5, wherein the hollow fiber membrane has an O.sub.2 permeation rate of 10 to 40 L/min.Math.bar.Math.m.sup.2 and a CO.sub.2 permeation rate of 15 to 80 L/min.Math.bar.Math.m.sup.2.

7. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 5, wherein the hollow fiber membrane has a gas separation factor α of at least 200 between O.sub.2 and the anesthetic gas, wherein the anesthetic gas is selected from the group consisting of at least one of sevoflurane, xenon, remifentanil, and propofol.

8. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, wherein the hollow fiber membrane has a plasma permeation duration of at least 48 h.

9. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, further comprising a transition layer disposed between the support layer and the separation layer, the transition layer having a thickness of 10 nm to 50 nm and a mean pore size of 100 nm to 300 nm.

10. The asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, wherein the hollow fiber membrane has a thickness of 30 μm to 50 μm and an inner diameter of 100 μm to 300 μm; and the hollow fiber membrane has a volumetric porosity of 30% to 60%.

11. A method of preparing the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1, comprising: step 1: heating to plasticize a polyolefin polymer comprising only carbon and hydrogen, followed by dissolving the plasticized polyolefin polymer in a solvent system comprising compound A and compound B, and mixing under an environment higher than a critical delamination temperature, resulting in a homogeneous casting solution, wherein compound A is a solvent for polyolefin polymer, and compound B is a non-solvent for polyolefin polymer and elevates separation temperature for a phase comprising the polyolefin polymer and the compound A; the solvent system has a range exhibiting a homogeneous solution at an elevated temperature, a critical delamination temperature upon cooling, a miscibility gap in a liquid state of aggregation lower than the critical delamination temperature, and a cold curing temperature; step 2: extruding the casting solution in a die having a temperature higher than the critical delamination temperature to form a molding having an inner surface and an outer surface; step 3: placing the molding in an air section for preliminary phase separation; step 4: cooling the molding with a coolant comprising compound A at a cooling temperature of 5° C. to 60° C. for 20 ms to 75 ms; step 5: quenching the molding with a quenchant comprising compound A at a quenching temperature of 40° C. to 80° C. for 2 h to 5 h, whereby a nascent membrane is obtained upon end of the quenching; step 6: removing compound A and compound B from the nascent membrane to obtain a prototype membrane.

12. The method of preparing the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 11, wherein the polyolefin polymer is selected from the group consisting of at least one of polyethylene, polypropylene, and poly(4-methyl-1-pentene); and a concentration of the polyolefin polymer in the casting solution is 30% to 50%.

13. The method of preparing the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 11, wherein the compound A is selected from the group consisting of one or more of dehydrated castor oil fatty acid, methyl-12-hydroxystearate, paraffin oil, dibutyl sebacate, and dibutyl phthalate; the compound B is selected from the group consisting of one or more of dioctyl adipate, castor oil, mineral oil, palm oil, rapeseed oil, olive oil, dimethyl phthalate, dimethyl carbonate, and glyceryl triacetate; and a mass ratio of compound A to compound B is 1-5:1.

14. The method of preparing the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 11, wherein in step 3, the molding stays in the air section for 1.5 ms to 20 ms; the air section has a temperature of 50° C. to 150° C. and a relative humidity of not greater than 50%.

15. The method of preparing the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 11, wherein before the molding is subjected to cooling treatment in step 4, the molding resultant from the preliminary phase separation in step 3 is pre-cooled with a treating solution comprising compound A at a precooling temperature ranging from 120° C. to 160° C. for a precooling duration of 2 ms to 10 ms.

16. The method of preparing the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 11, wherein after the prototype membrane is obtained in step 5, the prototype membrane is placed under an environment of 120° C. to 180° C. for high-temperature setting and stretched by 0.5% to 10% to relieve stress, whereby a finished membrane is obtained.

17. A method comprising using the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1 for human blood oxygenation comprising an anesthetic gas.

18. A method comprising using the asymmetric hydrophobic polyolefin hollow fiber membrane according to claim 1 for gas-liquid separation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] FIG. 1 is a scanning electron microscope SEM image of the longitudinal section proximal to the outer surface side of a hollow fiber membrane prepared according to Example 1, wherein the magnification is 20000×;

[0053] FIG. 2 is a further magnified SEM image of the longitudinal section proximal to the outer surface side of the hollow fiber membrane prepared according to Example 1, wherein the magnification is 50000×;

[0054] FIG. 3 is a SEM image of the outer surface of the hollow fiber membrane prepared according to Example 1, wherein the magnification is 20000×;

[0055] FIG. 4 is a further magnified SEM image of the outer surface of the hollow fiber membrane prepared according to Example 1, wherein the magnification is 50000×;

[0056] FIG. 5 is a SEM image of an inner surface of the hollow fiber membrane prepared according to Example 2, wherein the magnification is 20000×;

[0057] FIG. 6 is a further magnified SEM image of the inner surface of the hollow fiber membrane prepared according to Example 1, wherein the magnification is 50000×;

[0058] FIG. 7 is a SEM image of a longitudinal section proximal to the outer surface of a hollow fiber membrane prepared according to Example 4, wherein the magnification is 20000×;

[0059] FIG. 8 is a further magnified SEM image of the longitudinal section proximal to the outer surface of the hollow fiber membrane prepared according to Example 4, wherein the magnification is 50000×;

[0060] FIG. 9 is a SEM image of the outer surface of the hollow fiber membrane prepared according to Example 4, wherein the magnification is 20000×;

[0061] FIG. 10 is a further magnified SEM image of the hollow fiber membrane prepared according to Example 4, wherein the magnification is 50000×;

[0062] FIG. 11 is a SEM image of an inner surface of the hollow fiber membrane prepared according to Example 4, wherein the magnification is 20000×;

[0063] FIG. 12 is a further magnified SEM image of the inner surface of the hollow fiber membrane prepared according to Example 4, wherein the magnification is 50000×.

DETAILED DESCRIPTION

[0064] Hereinafter, the present disclosure will be further detailed through embodiments with reference to the accompanying drawings.

Example 1

[0065] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0066] Step 1: feeding 40 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 45 wt. % methyl-12-hydroxystearate and 15 wt. % dioctyl adipate to form a mixture, and then stirring and mixing under 230° C. to obtain a homogeneous casting solution;

[0067] Step 2: extruding the casting solution out of a die with a temperature of 215° C. to obtain a molding having an inner surface and an outer surface;

[0068] Step 3: placing the molding in an air section for preliminary phase separation for 10 ms; wherein the air section has a temperature of 100° C. and a relative humidity of 30%;

[0069] Step 4: cooling the molding with a coolant comprising methyl-12-hydroxystearate at a cooling temperature of 40° C. for 55 ms;

[0070] Step 5: then, quenching the molding with a quenchant comprising methyl-12-hydroxystearate at a quenching temperature of 60° C. for 4 h, whereby a nascent membrane is obtained upon end of the quenching;

[0071] Step 6: extracting the nascent membrane for 24 h with 60° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0072] Step 7: subjecting the prototype membrane to high-temperature setting under 150° C., and stretching by 3% to relieve stress, thereby obtaining a finished membrane.

Example 2

[0073] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0074] Step 1: feeding 31 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 46 wt. % dibutyl sebacate and 23 wt. % castor oil to form a mixture, and then stirring and mixing under 255° C. to obtain a homogeneous casting solution;

[0075] Step 2: extruding the casting solution out of a die with a temperature of 230° C. to obtain a molding having an inner surface and an outer surface;

[0076] Step 3: placing the molding in an air section for preliminary phase separation for Sins; wherein the air section has a temperature of 105° C. and a relative humidity of 25%;

[0077] Step 4: cooling the molding with a coolant comprising the solvent system (46 wt. % dibutyl sebacate and 23 wt. % castor oil) used when preparing the casting solution at a cooling temperature of 50° C. for 35 ms;

[0078] Step 5: then, quenching the molding with a quenchant comprising the solvent system (46 wt. % dibutyl sebacate and 23 wt. % castor oil) used when preparing the casting solution at a quenching temperature of 55° C. for 3 h, whereby a nascent membrane is obtained upon end of the quenching;

[0079] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0080] Step 7: subjecting the prototype membrane to high-temperature setting under 140° C., and stretching by 5% to relieve stress, thereby obtaining a finished membrane.

Example 3

[0081] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0082] Step 1: feeding 48 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 39 wt. % dibutyl phthalate and 13 wt. % dioctyl adipate to form a mixture, and then stirring and mixing under 245° C. to obtain a homogeneous casting solution;

[0083] Step 2: extruding the casting solution out of a die with a temperature of 220° C. to obtain a molding having an inner surface and an outer surface;

[0084] Step 3: placing the molding in an air section for preliminary phase separation for 15 ms; wherein the air section has a temperature of 80° C. and a relative humidity of 35%;

[0085] Step 4: cooling the molding with a coolant comprising dibutyl phthalate at a cooling temperature of 30° C. for 60 ms;

[0086] Step 5: then, quenching the molding with a quenchant comprising dibutyl phthalate at a quenching temperature of 50° C. for 5 h, whereby a nascent membrane is obtained upon end of the quenching;

[0087] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0088] Step 7: subjecting the prototype membrane to high-temperature setting under 170° C., and stretching by 2% to relieve stress, thereby obtaining a finished membrane.

Example 4

[0089] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0090] Step 1: feeding 45 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 40 wt. % methyl-12-hydroxystearate and 15 wt. % dimethyl phthalate to form a mixture, and then stirring and mixing under 235° C. to obtain a homogeneous casting solution;

[0091] Step 2: extruding the casting solution out of a die with a temperature of 220° C. to obtain a molding having an inner surface and an outer surface;

[0092] Step 3: placing the molding in an air section for preliminary phase separation for 8 ms; wherein the air section has a temperature of 110° C. and a relative humidity of 20%; then, precooling the molding with a coolant comprising the solvent system (comprising 40 wt. % methyl-12-hydroxystearate and 15 wt. % dimethyl phthalate) used when preparing the casting solution at a precooling temperature of 140° C. for 6 ms;

[0093] Step 4: cooling the molding with the coolant comprising the solvent system (comprising 40 wt. % methyl-12-hydroxystearate and 15 wt. % dimethyl phthalate) used when preparing the casting solution at a cooling temperature of 40° C. for 60 ms;

[0094] Step 5: then, quenching the molding with a quenchant comprising the solvent system (comprising 40 wt. % methyl-12-hydroxystearate and 15 wt. % dimethyl phthalate) used when preparing the casting solution at a quenching temperature of 70° C. for 4 h, whereby a nascent membrane is obtained upon end of the quenching;

[0095] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0096] Step 7: subjecting the prototype membrane to high-temperature setting under 160° C., and stretching by 1% to relieve stress, thereby obtaining a finished membrane.

Example 5

[0097] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0098] Step 1: feeding 20 wt. % polypropylene and 20 wt. % polyethylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 40 wt. % dibutyl sebacate and 20 wt. % palm oil, and then stirring and mixing under 245° C. to obtain a homogeneous casting solution;

[0099] Step 2: extruding the casting solution out of a die with a temperature of 220° C. to obtain a molding having an inner surface and an outer surface;

[0100] Step 3: placing the molding in an air section for preliminary phase separation for 6 ms; wherein the air section has a temperature of 80° C. and a relative humidity of 35%;

[0101] Step 4: cooling the molding with a coolant comprising dibutyl sebacate at a cooling temperature of 35° C. for 50 ms;

[0102] Step 5: then, quenching the molding with a quenchant comprising dibutyl sebacate at a quenching temperature of 55° C. for 4.5 h, whereby a nascent membrane is obtained upon end of the quenching;

[0103] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0104] Step 7: subjecting the prototype membrane to high-temperature setting under 145° C., and stretching by 6% to relieve stress, thereby obtaining a finished membrane.

Example 6

[0105] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0106] Step 1: feeding 30 wt. % poly (4-methyl-1-pentene) (PMP) and 10 wt. % polyethylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 45 wt. % dehydrated castor oil fatty acid and 15 wt. % dioctyl adipate to form a mixture, and then stirring and mixing under 240° C. to obtain a homogeneous casting solution;

[0107] Step 2: extruding the casting solution out of a die with a temperature of 215° C. to obtain a molding having an inner surface and an outer surface;

[0108] Step 3: placing the molding in an air section for preliminary phase separation for 7 ms; wherein the air section has a temperature of 60° C. and a relative humidity of 10%;

[0109] Step 4: cooling the molding with a coolant comprising the solvent system (comprising 45 wt. % dehydrated castor oil fatty acid and 15 wt. % dioctyl adipate) used when preparing the casting solution at a cooling temperature of 25° C. for 75 ms;

[0110] Step 5: then, quenching the molding with a quenchant comprising the solvent system (comprising 45 wt. % dehydrated castor oil fatty acid and 15 wt. % dioctyl adipate) used when preparing the casting solution at a quenching temperature of 45° C. for 5 h, whereby a nascent membrane is obtained upon end of the quenching;

[0111] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

Example 7

[0112] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0113] Step 1: feeding 30 wt. % poly (4-methyl-1-pentene) (PMP) and 10 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 40 wt. % dehydrated castor oil fatty acid and 20 wt. % mineral oil to form a mixture, and then stirring and mixing under 250° C. to obtain a homogeneous casting solution;

[0114] Step 2: extruding the casting solution out of a die with a temperature of 225° C. to obtain a molding having an inner surface and an outer surface;

[0115] Step 3: placing the molding in an air section for preliminary phase separation for 14 ms; wherein the air section has a temperature of 130° C. and a relative humidity of 20%;

[0116] Step 4: cooling the molding with a coolant comprising dehydrated castor oil fatty acid at a cooling temperature of 35° C. for 50 ms;

[0117] Step 5: then, quenching the molding with dehydrated castor oil fatty acid as quenchant at a quenching temperature of 45° C. for 3.5 h, whereby a nascent membrane is obtained upon end of the quenching;

[0118] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0119] Step 7: subjecting the prototype membrane to high-temperature setting under 170° C. for high-temperature setting, and stretching by 6% to relieve stress, thereby obtaining a finished membrane.

Example 8

[0120] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0121] Step 1: feeding 20 wt. % poly (4-methyl-1-pentene) (PMP) and 20 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 40 wt. % methyl-12-hydroxystearate and 20 wt. % dimethyl phthalate to form a mixture, and then stirring and mixing under 240° C. to obtain a homogeneous casting solution;

[0122] Step 2: extruding the casting solution out of a die with a temperature of 220° C. to obtain a molding having an inner surface and an outer surface;

[0123] Step 3: placing the molding in an air section for preliminary phase separation for 12 ms; wherein the air section has a temperature of 120° C. and a relative humidity of 30%; then, precooling the molding with a coolant comprising the solvent system (comprising 40 wt. % methyl-12-hydroxystearate and 20 wt. % dimethyl phthalate) used when preparing the casting solution at a precooling temperature of 130° C. for 5 ms;

[0124] Step 4: cooling the molding with the coolant comprising the solvent system (comprising 40 wt. % methyl-12-hydroxystearate and 20 wt. % dimethyl phthalate) used when preparing the casting solution at a cooling temperature of 45° C. for 65 ms;

[0125] Step 5: then, quenching the molding with a quenchant comprising the solvent system (comprising 40 wt. % methyl-12-hydroxystearate and 20 wt. % dimethyl phthalate) used when preparing the casting solution at a quenching temperature of 65° C. for 4 h, whereby a nascent membrane is obtained upon end of the quenching;

[0126] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0127] Step 7: subjecting the prototype membrane to high-temperature setting under 150° C. for high-temperature setting, and stretching by 1% to relieve stress, thereby obtaining a finished membrane.

Comparative Example 1

[0128] A method of preparing an asymmetric hydrophobic polyolefin hollow fiber membrane, comprising steps of:

[0129] Step 1: feeding 40 wt. % polypropylene into a twin-screw extruder, heating till being plasticized, followed by adding a solvent system comprising 45 wt. % methyl-12-hydroxystearate and 15 wt. % dioctyl adipate to form a mixture, and then stirring and mixing under 230° C. to obtain a homogeneous casting solution;

[0130] Step 2: extruding the casting solution out of a die with a temperature of 215° C. to obtain a molding having an inner surface and an outer surface;

[0131] Step 3: placing the molding in an air section for preliminary phase separation for 10 ms; wherein the air section has a temperature of 100° C. and a relative humidity of 30%;

[0132] Step 4: cooling the molding with a coolant comprising dioctyl adipate at a cooling temperature of 40° C. for 55 ms;

[0133] Step 5: then, quenching the molding with a quenchant comprising dioctyl adipate at a quenching temperature of 60° C. for 4 h, whereby a nascent membrane is obtained upon end of the quenching;

[0134] Step 6: extracting the nascent membrane for 24 h with 65° C. isopropanol to remove compound A and compound B, whereby a prototype membrane is obtained;

[0135] Step 7: subjecting the prototype membrane to high-temperature setting under 150° C., and stretching by 3% to relieve stress, thereby obtaining a finished membrane.

Structural and Performance Testing for Test Samples

[0136] 1. Structural Characterization. The membrane body structure of each test sample is subjected to morphology characterization using a SEM (Hitachi S-5500) to obtain relevant data. Specific results are set forth in the table below.

TABLE-US-00001 Overall Separation- Test Inner Membrane Volumetric layer Samples Diameter/μm Thickness/μm porosity/% thickness/μm Example 1 195.6 40.3 46 1.1 Example 2 150.2 32.5 54 0.6 Example 3 261.7 48.2 41 1.9 Example 4 232.4 44.6 48 1.6 Example 5 217.3 38.4 51 0.8 Example 6 172.9 41.5 44 1.4 Example 7 206.1 39.2 37 0.9 Example 8 192.8 40.8 40 1.2 Comparative 209.4 43.1 32 2.2 Example 1 Proportion of separation- layer thickness to the total Mean Mean thickness pore size pore of the of the Thickness size of Test hollow fiber separation of transition transition Samples membrane/% layer/nm layer/nm layer/nm Example 1 2.73% 36 \ \ Example 2 1.85% 23 \ \ Example 3 3.94% 51 \ \ Example 4 3.59% 43 42 237 Example 5 2.08% 28 \ \ Example 6 3.37% 39 \ \ Example 7 2.30% 31 \ \ Example 8 2.94% 34 27 164 Comparative 5.10% \ \ \ example 1

[0137] Examples 1-3, Examples 5-7 and Comparative Example 1 do not comprise a precooling step in preparing a hollow fiber membrane, such that the resultant hollow fiber membranes do not have a transition layer; Examples 4 and 8 comprise a precooling step in preparing a hollow fiber membrane, such that the resultant hollow fiber membranes have a transition layer; in addition, compared with Example 1, Comparative Example 1 uses a non-solvent compound B as the coolant, which leads to a too fast curing speed for the separated phase, resulting in a dense separation layer for the resultant hollow fiber membrane. Without pores at the outer surface of the hollow fiber membrane, an anesthetic gas cannot permeate through the hollow fiber membrane prepared according to Comparative Example 1.

TABLE-US-00002 Pore size range Pore size range of the first of the first Pore density pores at the pores at the of the first outer surface outer surface pores at the Test in the first in the second outer surface Samples direction/nm direction/nm (pores/1 μm.sup.2) Example 1 180-270 15-70 22 Example 2 100-250 12-50 31 Example 3 200-290 20-85 13 Example 4 190 = 280 18-75 16 Example 5 160-250 10-65 29 Example 6 195-285  25-100 15 Example 7 185-280 14-60 26 Example 8 180-295 17-75 20 Comparative \ \ \ Example 1

[0138] The table unveils that the hollow fiber membranes prepared in Examples 1-8 of the disclosure all have a quantity of first pores with a certain pore size at their respective outer surface, which facilitates permeation of the anesthetic gas without affecting plasma permeation duration, such that the resultant hollow fiber membranes are particularly suitable for blood oxygenation comprising an anesthetic gas; in contrast, the hollow fiber membrane prepared according to Comparative Example 1 does not have pores at its outer surface, such that the anesthetic gases cannot permeate through the resultant hollow fiber membrane.

2. Property Testing

[0139] Tensile Strength and Elongation at Break Testing: each sample is stretched using a stretcher at a uniform speed under room temperature (where the stretching velocity is 50 mm/min and the distance between the upper and lower fixtures is 30 mm) till being broken, whereby the tensile strength and the elongation at break are measured. The testing is repeated three times. The mean value of the measured tensile strengths and the mean value of the measured elongations at break are computed as the final tensile strength value and the final elongation at break of the membrane.

TABLE-US-00003 Surface Energy of the Outer Surface of Test Test Sample under Tensile Elongation Samples 20° C. (mN/m) Strength/CN at Break/% Example 1 32 181 214 Example 2 34 188 235 Example 3 33 172 243 Example 4 31 140 276 Example 5 36 200 187 Example 6 26 110 452 Example 7 28 230 161 Example 8 24 160 268 Comparative 34 190 201 Example 1

[0140] Surface Energy Testing: the surface energy testing for the outer surface of each hollow fiber membrane is performed as such using a Dyne pen under 20° C.: drawing the Dyne pen over the outer surface of the hollow fiber membrane in a 10 cm-long ink pass, and observing whether over 90% of the ink pass has been drawn back into droplets in less than 2 s till the ink pass stops drawing back and droplets appear; the measured surface energy of the ink is the surface energy of the outer surface of the membrane.

[0141] The table unveils that the hollow fiber membranes prepared according to Examples 1-8 all have a relatively high tensile strength and a relatively high elongation at break, which may satisfy industrial requirements; meanwhile, the hollow fiber membranes have a strong hydrophobic property.

[0142] The hollow fiber membranes resulting from Examples 1-8 are subjected to gas permeation rate testing. The testing manner is described as follows:

[0143] One side of each membrane sample of 0.1 m.sup.2 is subjected to a to-be-tested gas (oxygen, carbon dioxide, and anesthetic gases) at the temperature of 25° C. under 1bar; the to-be-tested gas is charged into the lumen of the hollow fiber membrane; the volumetric flow rate of the gas permeated through the membrane wall of the test sample is measured using a flowmeter (Japan KOFLOC/4800); the testing is repeated three times from the inside of the membrane to the outside of the membrane and three times from the outside of the membrane to the inside of the membrane; the mean value of the six measurements is computed as the gas permeation rate of the membrane.

[0144] Unit of the Gas Permeation Rate: L/(min.Math.bar.Math.m.sup.2)

TABLE-US-00004 Gas Gas Gas Separation Separation O.sub.2 CO.sub.2 Separation Factor α Factor α Test Permeation Permeation Factor α (O.sub.2/ (O.sub.2/ Sample Rate Rate (CO.sub.2/O.sub.2) sevoflurane) remifentanil) Example 25 42 1.68 320 450 1 Example 30 52 1.73 277 442 2 Example 28 47 1.68 362 492 3 Example 20 36 1.80 285 412 4 Example 16 31 1.94 306 395 5 Example 7 15 2.14 261 368 6 Example 10 22 2.20 293 421 7 Example 12 27 2.25 304 437 8

[0145] The table unveils that the hollow fiber membranes prepared according to Examples 1-8 all have a relatively high oxygen permeation rate and a relatively high carbon dioxide permeation rate, which facilitates quick discharge of the carbon dioxide out of the blood and facilitates quick permeation of the oxygen through the hollow fiber membranes into the blood; meanwhile, the anesthetic gases may permeate through the hollow fiber membranes into the patient's blood at a certain permeation rate, such that the patent maintains sedated throughout a surgical process, thereby ensuring smooth proceeding of the surgery.

Testing on Plasma Permeation Duration of the Hollow Fiber Membranes

[0146] The plasma permeation duration of each test sample is measured by: letting a 37° C. phospholipid solution (1.5 g/L-α-lecithin dissolved in 500 ml normal saline solution) flow across the surface of each membrane sample at 61/(min*m.sup.2) under 1.0bar; letting air flow across the opposite side of the membrane sample and then pass through a cold trap; measuring the weight of the liquid aggregated in the cold trap as a function of time. The duration till noticeable increase of the weight, i.e., till the liquid is first noticeably aggregated in the cold trap, is determined as the plasma permeation duration.

[0147] The testing unveils that the plasma permeation durations of the hollow fiber membranes prepared according to Examples 1-8 are all over 48 hours, indicating that the hollow fiber membranes prepared according to the present disclosure have a very long service life and may ensure smooth proceeding of a surgery.

[0148] FIGS. 1-6 are SEM images of the hollow fiber membrane prepared according to Example 1, which unveil that the separation layer of the hollow fiber membrane prepared according to Example 1 is porous, and the outer surface of the hollow fiber membrane has a quantity of first pores with a certain pore size, which facilitate permeation of an anesthetic gas.

[0149] FIGS. 7-12 are SEM images of the hollow fiber membrane prepared according to Example 4, which unveil that the separation layer of the hollow fiber membrane prepared according to Example 4 is porous, and the outer surface of the hollow fiber membrane has a quantity of first pores with a certain pore size, which facilitate permeation of an anesthetic gas.

[0150] The hollow fiber membranes prepared according to the disclosure are particularly suitable for blood oxygenation comprising an anesthetic and also suitable for gas-liquid separation.

[0151] What have been described above are only preferred embodiments of the disclosure. The protection scope of the disclosure is not limited to the examples described above, and any technical solution under the idea of the disclosure falls within the protection of the disclosure. It is noted that to those improvements and modifications made by a person of normal skill in the art without departing from the principle of the disclosure shall also be deemed as falling within the protection scope of the disclosure.