Method for providing surface modification compositions with improved byproduct removal
阅读说明：本技术 利用改进的副产物去除来提供表面改性组合物的方法 (Method for providing surface modification compositions with improved byproduct removal ) 是由 J·特奥 C·卡梅拉斯 P·科萨拉朱 M·P·霍尔 于 2018-07-12 设计创作，主要内容包括：一种形成表面改性组合物的方法,该方法具有对有机溶剂和其用于将不溶性反应副产物从该组合物去除的蒸发的减少需求。纯化的组合物可用于形成具有改善的生物相容性的制品,例如医疗制品(例如纺丝中空纤维)。(A method of forming a surface modification composition having a reduced need for organic solvents and evaporation thereof for removing insoluble reaction byproducts from the composition. The purified compositions can be used to form articles, such as medical articles (e.g., spun hollow fibers), having improved biocompatibility.)
1. A method, comprising:
forming a first solution by phase-converting at least a portion of a surface-modifying composition to a liquid state, the surface-modifying composition comprising:
a) at least one polymer or oligomer, and
b) i) fluorotelomer alcohols and ii) insoluble reaction by-products of isocyanates,
wherein the insoluble reaction by-product is substantially insoluble in the polymer or oligomer; and
removing at least a portion of the insoluble reaction by-products present in the first solution from the first solution to obtain a second solution;
wherein the polymer or oligomer comprises a polymer or oligomer backbone covalently attached to at least one surface active group.
2. The method of claim 1, wherein the first solution is formed by dissolving at least a portion of the surface modification composition in at least one solvent.
3. The method of claim 1, wherein the first solution is formed by melting the polymer or oligomer of the surface modification composition.
4. The method of claim 1, wherein the insoluble reaction by-product is a fluorotelomer alcohol-terminated diisocyanate.
5. The method of claim 1, wherein the fluorotelomer alcohol (FTOH) is 4:2FTOH, 5:2FTOH, 6:2FTOH, 7:2FTOH, 8:2FTOH, 9:2FTOH, 10:2FTOH, or a combination thereof.
6. The method of claim 1, wherein the fluorotelomer alcohol is a 6:2 fluorotelomer alcohol.
7. The method of claim 1, wherein the isocyanate has two or more isocyanate functional groups.
8. The method of claim 1, wherein the isocyanate is a diisocyanate, triisocyanate, or combination thereof.
9. The method of claim 1, wherein the insoluble reaction by-product is an insoluble trimeric reaction by-product.
10. The method of claim 1 wherein a) is a polymer having a polymer backbone comprising polyurethane and fluorinated end groups.
11. The method of claim 1 wherein a) is a polymer having a molecular weight of about 4,000 to about 15,000.
12. The method of claim 1, wherein a) is SMM1, SMM2, SMM3, SMM4, SMM5, SMM6, SMM7, SMM8, SMM9, SMM10, SMM11, SMM12, SMM13, or SMM14, or any combination thereof.
13. The method of claim 2, wherein at least one solvent is present in an amount such that the insoluble reaction by-products are dissolved in the first solution in an amount of less than 10 wt% by weight of the surface modification composition.
14. The method of claim 2, wherein the at least one solvent is present in an amount such that the insoluble reaction by-products are dissolved in the first solution in an amount of less than 1 wt% by weight of the surface modification composition.
15. The method of claim 2, wherein the solvent is at least one of Dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), Dimethylsulfoxide (DMSO), Tetrahydrofuran (THF), N-ethylpyrrolidone, N-octylpyrrolidone, Dimethylformamide (DMF), butyrolactone, or any combination thereof.
16. The method of claim 1, 2 or 3, wherein the removing comprises filtration, centrifugation or other liquid-solid separation means.
17. The method of claim 1, wherein the insoluble reaction by-product is present in the second solution in an amount of less than 5 wt% by weight of the surface modification composition.
18. The method of claim 1, wherein substantially insoluble comprises a solubility of less than 10 weight percent in a polymer or oligomer.
19. The method of claim 1, wherein the polymer or oligomer is one or a combination of several polyurethanes with a fluorochemical compound attached to a terminal position of the polymer or oligomer.
20. The method of claim 1, wherein the polymer or oligomer is a material capable of improving the hemocompatibility of a polymer surface.
21. The method of claim 20, wherein the polymer or oligomer of a material capable of improving the hemocompatibility of a polymer surface is SMM (surface modifying macromolecule) or SMA (surface modifying additive).
22. The method of claim 1, wherein:
the surface modification composition comprises the polymer or oligomer in an amount of about 50 wt% to about 99 wt% relative to the total weight of the surface modification composition present in the first solution.
23. The method of claim 1, wherein:
the surface modification composition comprises the insoluble reaction by-product in an amount of about 1 wt% to about 50 wt% relative to the total weight of the surface modification composition present in the first solution.
24. The method of claim 1, wherein:
the ratio of the wt.% of the polymer or oligomer to the wt.% of the insoluble reaction by-products in the first solution is in the range of about 1: 1 to about 99: 1, respectively, based on the total weight of the first solution.
25. The method of claim 2, wherein:
the first solution contains DMAC in an amount from about 0 wt% to about 90 wt%, based on the total weight of the first solution.
26. The method of claim 2, wherein:
the total weight of DMAC and surface modification composition present in the first solution is in the range of about 0 wt% to 20 wt%, based on the total weight of the first solution.
27. The method of claim 2, wherein:
the first solution contains DMAC in an amount from about 0 wt% to about 50 wt%, based on the total weight of the first solution.
28. The method of claim 2, wherein:
the first solution contains DMAC in an amount of about 0 to 75 wt.%, based on the total weight of solvents present in the first solution.
29. The method of claim 2, wherein:
DMAC is the only solvent present in the first solution.
30. The method of claim 1, wherein:
the first solution contains the surface modification composition in an amount of about 10 wt% to about 100 wt%, based on the total weight of the first solution.
31. The method of claim 1 or 2, wherein:
the surface modification composition is the only non-solvent component present in the first solution.
32. The method of claim 1 or 2, wherein:
in the second solution, the polymer or oligomer is present in an amount of about 5 wt% to about 99.9 wt%, based on the total weight of the second solution.
33. The method of claim 2, wherein:
in the second solution, the ratio of the wt.% of the polymer or oligomer to the wt.% of the insoluble reaction by-products, based on the total weight of the second solution, is in the range of about 50: 1 to about 999: 1, respectively.
34. The method of claim 1, 2 or 3, wherein:
the removing removes about 11 wt% to 100 wt% of the total weight of the insoluble reaction byproducts present in the first solution.
35. A method, comprising:
forming a first solution by dissolving at least a portion of a surface modifying composition in Dimethylacetamide (DMAC), the surface modifying composition comprising:
a) at least one polymer or oligomer, and
b) i) fluorotelomer alcohols and ii) insoluble reaction by-products of isocyanates;
wherein the insoluble reaction by-product is substantially insoluble in DMAC; and
removing at least a portion of the insoluble reaction by-products present in the first solution from the first solution to obtain a second solution;
wherein the polymer or oligomer comprises a polymer or oligomer backbone covalently attached to at least one surface active group.
36. The method of claim 1, 2, 27 or 35, further comprising:
combining the second solution with an additional amount of DMAC to obtain a diluted solution;
combining the diluted solution with a base polymer to obtain a mixture; and
the mixture was filtered to obtain a dope.
37. The method of claim 36, wherein the base polymer is at least one of Polysulfone (PSF), Polyethersulfone (PES), Polyarylsulfone (PAS), Polyarylsulfone (PAES), polyvinylidene fluoride (PVDF), Polyacrylonitrile (PAN), or any copolymer thereof.
38. The method of claim 36, wherein:
the diluted solution contains DMAC in an amount of about 50 wt% to about 99 wt%, based on the total weight of the diluted solution.
39. The method of claim 36, wherein:
the total weight of DMAC and surface modification composition present in the diluted solution is in the range of about 50% to 100% by total weight of the diluted solution.
40. The method of claim 36, wherein:
the diluted solution contains DMAC in an amount of about 50 wt% to about 75 wt%, based on the total weight of the diluted solution.
41. The method of claim 36, wherein:
the diluted solution contains DMAC in an amount of about 1 to 100 wt.%, based on the total weight of solvent present in the diluted solution.
42. The method of claim 36, wherein:
DMAC is the only solvent present in the diluted solution.
43. The method of claim 36, wherein:
the diluted solution contains the surface modification composition in an amount of about 0.1 wt% to about 15 wt%, based on the total weight of the diluted solution.
44. The method of claim 36, wherein:
the diluted solution contains the surface-modifying composition in an amount of about 0.1 wt% to 100 wt%, based on the total weight of non-solvent components present in the diluted solution.
45. The method of claim 36, wherein:
the surface modification composition is the only non-solvent component present in the diluted solution.
46. The method of claim 36, wherein:
the base polymer comprises a mixture of polyvinylpyrrolidone (PVP) and Polysulfone (PS).
47. The method of claim 36, further comprising contacting the dope with a precipitation fluid to precipitate the dope.
Background
The present application claims benefit of prior U.S. provisional patent application No.62/532,397 filed 2017, 7, and 14, under 35u.s.c. § 119(e), which is incorporated herein by reference in its entirety.
The present invention relates to a process for producing Surface Modified Compositions (SMC) with improved by-product removal and their use in the manufacture of articles using them.
Membranes with selective permeability are widely used in various products, such as filter media used in the medical field. Membranes in the form of hollow fibers are particularly suitable for the preparation of high area/volume membranes, such as hollow fiber membranes suitable for hemodialysis, hemofiltration or hemodiafiltration. A variety of polymers, including polysulfone, polyethersulfone, cellulose acetate, polyamide, polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, polyolefin, and the like, have been used to form such hollow fiber membranes.
U.S. patent No. 8,318,867 describes surface-modifying macromolecules with fluorinated end groups (SMM). The' 867 patent indicates that SMM can be used in hollow fiber membrane filtration made from polyethylene, polypropylene, or silicone base polymers for fluid or gas separation in membrane and non-woven applications such as surgical drapes, surgical gowns, face masks, body wraps, bandages, and other protective garments for medical technicians (e.g., workwear, lab gowns), and in implantable medical devices (e.g., central venous catheters). The' 867 patent further shows the synthesis of SMM with fluorinated end groups, which are washed in methanol, and then the polymer is transferred to a rotary evaporator and dried. Us patent No. 8,071,683 describes the synthesis of surface-modified macromolecules with fluorinated end groups (SMM), which are repeatedly washed with methanol, then twice in THF/EDTA (tetrahydrofuran/ethylenediaminetetraacetic acid) to remove residual catalyst, followed by multiple successive washes in THF/MeOH to remove unreacted monomers, low molecular weight byproducts and catalyst residues, then the SMM is dried in a flow oven and then dried under vacuum. The' 683 patent also describes a synthetic SMM with fluorinated end groups that is continuously washed in IPA/EDTA (isopropanol/EDTA) solution followed by another wash in IPA/hexane to remove unreacted monomers, low molecular weight byproducts, and catalyst residues to provide a polymer that is subsequently dried under vacuum prior to use.
There is a need for surface modification compositions that are produced with the removal of by-products and that do not require and expense for the evaporation of organic solvents. The composition can improve the biocompatibility of the polymer surface.
Disclosure of Invention
It is a feature of the present invention to provide a method for preparing a composition comprising a surface-modifying macromolecule that meets the above and/or other needs.
Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention relates to a method comprising forming a first solution by phase-converting at least a portion of a surface-modifying composition comprising a) a polymer or oligomer and b) an insoluble reaction byproduct of i) a fluorotelomer alcohol and ii) an isocyanate to a liquid state, wherein the insoluble reaction byproduct is substantially insoluble in the polymer or oligomer; and removing at least a portion of the insoluble reaction by-products present in the first solution from the first solution to obtain a second solution, wherein the polymer or oligomer is a polymer or oligomer backbone covalently attached to at least one surface active group.
The present invention further relates to a process comprising forming a first solution by dissolving at least a portion of a surface modification composition comprising a) a polymer or oligomer and b) an insoluble reaction by-product of i) a fluorotelomer and ii) an isocyanate in Dimethylacetamide (DMAC), wherein the insoluble reaction by-product is substantially insoluble in DMAC; and removing at least a portion of the insoluble reaction by-products present in the first solution from the first solution to obtain a second solution, wherein the polymer or oligomer is a polymer or oligomer backbone covalently attached to at least one surface active group.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.
Drawings
Fig. 1 is a process flow diagram of a method for producing a surface modification composition containing a polymer/oligomer reaction product using insoluble reaction byproduct removal, wherein the resulting surface modification composition may be used in medical component formation, according to an example of the present application.
FIG. 2 is a process flow diagram of a conventional method for preparing surface-modified macromolecules using solvent evaporation.
Fig. 3 is a process flow diagram of a method of making a surface modification composition containing a fluoropolymer/oligomer product utilizing removal of insoluble reaction byproducts according to an example of the present application, wherein the resulting surface modification composition is used directly in hollow fiber production.
Fig. 4 shows a reaction scheme for the synthesis of surface-modified macromolecules (SMM1) in which SMM1 product can be separated from the trimeric by-products of the reaction scheme using a method according to an example of the present application.
Fig. 5 shows the general chemical structure of surface-modifying macromolecules (SMM) and the specific chemical structure of surface-modifying macromolecules (SMM1, SMM6, and SMM8) that can be separated from reaction byproducts using methods according to examples of the present application.
Detailed Description
A method is disclosed for providing Surface Modification Compositions (SMC) utilizing reaction byproduct removal without the need for solvent evaporation. The resulting surface-modified composition can be used directly to prepare products. The resulting purified surface-modifying composition can be used to improve the biocompatibility of the surface of products made therefrom. The present invention can provide a method of removing reaction by-products from the synthesis of surface modifying compositions, such as Surface Modifying Macromolecules (SMM), that does not involve the need for organic solvent washing and/or evaporative solvent washing. The need for an energy intensive and expensive process for solvent evaporation can be eliminated by the process of the present invention. The disclosed methods can provide a solution that can be formed into articles having improved surface properties, such as extruded or molded medical articles (e.g., spun hollow fibers).
As used herein, "surface modification" refers to compositions or materials comprising "surface modifier" compounds, such as the Surface Modifying Macromolecules (SMM) described herein or described in U.S. patent nos. 6,127,507, 8,071,683, and 8,318,867, which are all incorporated herein by reference in their entirety. The surface modifying agent can also be described as a polymer or oligomer backbone covalently attached to at least one surface active group. "surface active group" refers to a lipophilic group covalently linked to a surface modifying agent.
In the process of the present invention, the first solution may be formed by phase-converting at least a portion of the surface modifying composition to a liquid state, wherein the surface modifying composition comprises a polymer or oligomer reaction product that is a surface modifying agent and an insoluble reaction by-product, and removing at least a portion of the insoluble reaction by-product present in the first solution to obtain a second solution comprising the polymer or oligomer reaction product in a purified form or at a higher concentration. For the purposes of the present invention, a 'phase transition' may be considered a transition without the need for a change in phase or physical state with the polymeric or oligomeric reaction product. It is often the case that the starting surface-modifying composition is a solid (e.g., a paste or powder) at room temperature (e.g., 20 to 25 ℃). As used herein, 'phase transformation' is or may include changing, transforming, or maintaining a first portion of a surface modifying composition in a liquid state such that a different portion of the surface modifying composition is or remains insoluble (e.g., is or remains in a solid state) or has a different density, viscosity, or other difference to allow separation from the first portion. As a specific example, the polymer or oligomer reaction product is or is converted or changed or converted or maintained in a liquid state, while the insoluble reaction by-product or portion thereof is a solid or is not converted or changed or not changed to a liquid state. Phase inversion as described herein can be achieved by any means, such as selectively using a solvent that changes the desired polymer or oligomer reaction product to a liquid (e.g., the selective solvent dissolves or makes more soluble the desired polymer or oligomer reaction product without doing so for insoluble reaction byproducts or portions thereof). Phase transformation as described herein can also be achieved by, for example, selective melting, such as selective heating to a temperature such that the desired polymer or oligomer reaction product becomes liquid (i.e., the selective melting causes the desired polymer or oligomer reaction product to become liquid without doing so for insoluble reaction byproducts or portions thereof). If the surface modification composition is initially a liquid, the reverse approach can be followed, i.e., the surface modification composition can be subjected to temperatures to have the desired polymer or oligomer in a different physical state (i.e., a different species or phase state) than the undesired reaction by-products or portions thereof. The polymer or oligomer reaction product may be a material that can improve biocompatibility, such as hemocompatibility of the polymer surface. The material may be SMM (surface modifying macromolecules) or SMA (surface modifying additives). The polymer or oligomer may be a polymer or oligomer backbone covalently attached to at least one surface active group. Insoluble reaction byproducts can be removed by selectively placing the polymer or oligomer reaction product in a liquid state (in view of the fact that the reaction byproducts are/remain insoluble relative to the polymer or oligomer and other portions of the SMC), and separating the polymer or oligomer phase from the insoluble byproduct phase in the liquid SMC. Such removal of insoluble reaction byproducts from the surface modification composition may include the use of selective dissolution in a solvent, selective hot melt or other methods that selectively place the desired polymer or oligomer reaction product in a liquid state rather than the undesired reaction byproducts. The material in the liquid state can be separated from the insoluble solid by-product material by filtration, centrifugation, decantation, or other liquid-solid separation methods. As used herein, "purified" may refer to the surface modifying agent-containing portion of the surface modifying composition that has been separated from insoluble reaction byproducts present therein.
As an option, the solvent may be used to dilute the polymer or oligomer reaction product to a level sufficient that the polymer or oligomer reaction product can pass through the microporous filter while trapping insoluble reaction byproducts at/in the filter. The term "solvent" is used herein in its usual meaning, wherein it indicates a substance capable of dissolving another substance (solute) to form a homogeneously dispersed mixture thereof in a liquid or flowable state on a molecular level. As a preferred option, the solvent that can be used to selectively dissolve the polymer or oligomer reaction product can be an organic solvent that can also be used to form a dope (spin dope) or have other functions that can be used in downstream product manufacturing stages of surface modifier purification.
Alternatively, the SMC may be heated to a temperature at which its portion comprising the polymer or oligomer melts to a liquid state while the reaction by-products remain insoluble, and the polymer or oligomer in the liquid state may be separated from the insoluble unmelted reaction by-products, such as by filtration, decantation, or any other liquid-solid separation method.
Referring to fig. 1, a method identified by
In
For comparison, fig. 2 shows a prior method of isolating surface-modifying macromolecules (SMM) from a reaction solution, where the SMM is dissolved in methanol or ethanol and hexane or a mixture of hexane and other organic solvents (e.g., isopropanol) is added and the byproducts are filtered out of the SMM-containing composition, which also contains alcohol, hexane and any other organic solvents, which then must be evaporated from the SMM-containing composition. This process is expensive and energy intensive including solvent evaporation.
Fig. 3 shows a method according to a more specific example of the present application, identified by
As an option, the surface modification composition may be a reaction solution obtained from SMM synthesis that may contain as reaction product materials two major components that may be about 50 wt.% to about 99 wt.% fluoropolymer/oligomer reaction product and about 1 wt.% to about 50 wt.% reaction by-products, and specifically may be about 75 wt.% to about 95 wt.% fluoropolymer/oligomer reaction product and about 25 wt.% to about 5 wt.% reaction by-products, or other amounts, based on the total weight of the surface modification composition (prior to any selective solvent or melt processing). For the reaction chemistry of the SMM1 synthesis shown in fig. 4, the reaction solution may contain the two major components as reaction product materials in amounts according to the ranges described above, more specifically may be about 85 wt.% to about 90 wt.% fluoropolymer/oligomer reaction product (e.g., about 87 wt.%) and about 10 wt.% to about 15 wt.% trimer reaction by-product (e.g., about 13 wt.%). The ratio of weight% fluoropolymer/oligomer reaction product to weight% reaction by-products in the reaction solution (i.e., the surface modification composition prior to any optional solvent or melt treatment) may be in the range of from about 1: 1 to about 99: 1, or from about 2: 1 to about 9.5: 1, or from about 3: 1 to about 9: 1, or other ratios thereof.
As noted, the trimer by-product is undesirable. The method of the present invention (as shown in fig. 3) provides a method of removing trimer byproducts from a surface modification composition to separate desired SMM1 or other SMM therein from the trimer byproducts without the need to use solvent washing and solvent evaporation. In this regard, steps 302A and 302B illustrate two options for forming a first solution comprising a surface-modifying composition in a liquid state that contains insoluble reaction byproducts. The first solution may contain the surface modification composition in an amount of from about 10 wt% to about 100 wt%, or from 85 wt% to about 99.99 wt%, or from about 95 wt% to about 99.99 wt%, based on the total weight of the first solution. The first solution may contain SMM in an amount of about 10 wt% to about 99.99 wt%, or 85 wt% to about 99.99 wt%, or about 95 wt% to about 99.99 wt%, based on the total weight of the first solution. The surface modification composition may comprise all or substantially all of the non-solvent components present in the first solution.
In option 302A shown in fig. 3, a first solution is formed by dissolving at least a portion of the Surface Modification Composition (SMC) in a solvent that selectively or preferentially dissolves SMM1 or other desired SMM products as compared to the undesired trimer byproducts or other reaction byproducts. This process step can take advantage of the poor solubility of the trimer by-product in some solvents as well as the excellent solubility of the fluoropolymer/oligomer product in the same solvent. As an option, the surface modification composition may be the only non-solvent component present in the first solution. The trimer by-product is not a fluoropolymer or oligomer having two or more repeating units in the polyurethane backbone. The trimer is highly fluorinated in its central part relative to the individual HDI units. Compared to fluoropolymer/oligomer reaction products, trimers have very low solubility in some organic solvents (such as polar aprotic solvents). As an option, the organic solvent that can be used as a selective solvent for the fluoropolymer/oligomer reaction product relative to the trimer by-product can be Dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), Dimethylsulfoxide (DMSO), Tetrahydrofuran (THF), N-ethylpyrrolidone, N-octylpyrrolidone, Dimethylformamide (DMF), butyrolactone, or other solvents, or any combination thereof. Preferably, the solvent comprises DMAC. As an option, the first solution may contain DMAC in an amount of about 0 wt.% to 90 wt.%, or about 0.01 wt.% to about 15 wt.%, or about 0.01 wt.% to about 5 wt.%, based on the total weight of the first solution. As an option, the first solution may comprise one solvent or two or more different solvents capable of dissolving the fluoropolymer/oligomer reaction product. As an option, the first solution may contain DMAC as a solvent in an amount of about 1 wt% to 99.9 wt%, or about 1 wt% to about 50 wt%, or about 5 wt% to about 25 wt%, based on the total weight of solvent present in the first solution. As a preferred option, DMAC is the only solvent present in the first solution (i.e., the solvent present is 100% DMAC). As an option, the total weight of the DMAC and the surface modification composition present in the first solution may be in the range of from about 0 wt% to 100 wt%, from 0 wt% to about 75 wt%, or from 0 wt% to about 20 wt%, or from about 1 wt% to about 50 wt%, or from about 1 wt% to about 20 wt%, or from about 5 wt% to about 20 wt%, based on the total weight of the first solution.
The trimer by-product is preferably substantially insoluble in the surface modification composition treated with the selective solvent, while the fluoropolymer/oligomer reaction product is substantially soluble therein. For purposes herein, the term "substantially insoluble" as used herein to describe the solubility of reaction byproducts in a surface modification composition containing a reaction solution and an added selective solvent means that no more than 10 weight percent (e.g., 0 to 10 weight percent) of the reaction byproducts are soluble in the solvent-treated SMC. As an option, a solvent can be selected in which the reaction by-products (such as trimer by-products) have a solubility in the solvent of no more than about 10 wt.%, or no more than about 5 wt.%, or no more than about 2 wt.%, or no more than 1 wt.%, or other low solubility therein. The fluoropolymer/oligomer reaction product may be highly soluble, such as at least about 90 wt.%, or at least 95 wt.%, or at least 98 wt.%, or at least 99 wt.% soluble, or other high solubility therein, in the same solvent.
In option 302B shown in fig. 3, the first solution is formed by heat treating a surface modification composition containing a fluoropolymer/oligomer reaction product and a trimer byproduct or other reaction byproduct such that the fluoropolymer/oligomer product (e.g., SMM) is converted to a less viscous or liquid state, such as by melting, and the reaction byproduct remains insoluble therein. This can be accomplished with a fluoropolymer/oligomer product (e.g., SMM) having a lower softening temperature, a lower melting temperature, or both, relative to the reaction by-products (e.g., trimers). The method does not require the addition of a solvent to selectively reduce SMM viscosity relative to reaction byproducts.
In step 303, the insoluble trimer by-product may be filtered off or otherwise separated from the fluoropolymer/oligomer product in the solution to which the selective solvent was added in step 302A (if used in place of step 302B) to provide another solution in which the fluoropolymer/oligomer product is present in a more purified form. As a preferred option for step 302A, a selective solvent, such as DMAC, may be used to dilute the SMM (e.g., SMM1) in the surface modification composition to a level just sufficient for the SMM to be pushed through a filter, such as a membrane filter, while trapping insoluble trimers in the filter. As used herein, the term filtration is a mechanical method of separating solids (e.g., insoluble trimer reaction by-products from the reaction of excess isocyanate reactant and fluorotelomer alcohol) from liquids (e.g., SMM and any solvent) by passing the feed stream through a microporous membrane or other porous structure that retains the solids and allows the liquids to pass through. For the use of step 302A, the contents of the filtered SMM may depend on the amount of solvent used. As an option, about 0.3X to about 0.5X solvent (per 1X SMM) or about 0.35X to about 0.45X solvent (per 1X SMM), or about 0.4X solvent (per 1X SMM), such as about 0.4X DMAC (per 1X SMM1), may be used to dissolve the SMMs in the surface-modifying composition (e.g., reaction solution). The additional use of DMAC may make it easier to filter the surface-modified composition, but may also increase the trimer content carried in the solution passing through the filter. The filtered SMM (e.g., SMM1) solution that has been in a solvent (e.g., DMAC) can be used directly to make a dope or other polymer-containing mass that can be extruded or molded into an article.
As an option, if the filter is used to separate insoluble reaction byproducts from a solution containing fluoropolymer/oligomer reaction products, the filter may be a membrane, such as a microporous membrane. In the case where step 302A is used prior to filtration in step 303, the membrane preferably has good resistance to the organic solvent used and low levels of extractables. As an option, in usingIn the case of step 302A, the membrane material used in the filtration step 303 may be an organic polymer, such as a fluoropolymer or an aromatic polymer having these properties. As an option, the fluoropolymer membrane material may be based on a copolymer of Ethylene and Chlorotrifluoroethylene (ECTFE), Polytetrafluoroethylene (PTFE), or similar material. The ECTFE membrane material can be prepared fromObtained from Solvay. As other options, the membrane filter material may be a microporous metallic material (e.g., stainless steel) or a ceramic material. Porous membrane structures are generally classified according to their effective pore size or according to their retention (i.e., the size of particles that cannot pass through the pores of the porous membrane structure). Thus, for example, if they retain dissolved substances such as ions, protein viruses or soluble macromolecules, the structures used as filters are classified as ultrafilters, whereas if they pass dissolved substances and retain only undissolved particles, they are classified as microporous structures. By this classification, the filter used in the present invention may be a 'microporous structure' as the membrane preferably retains insoluble particles of reaction by-products and allows soluble reaction products (such as soluble SMM) to pass through the membrane. As an option, the microporous structure used in the method of the present invention may have an average pore size of about 0.05 microns to about 10 microns (μm). Porous membranes can be described as a pore volume separated by pore walls and a solid matrix. The membrane may be a flat sheet membrane or other structure. The porous structures used as membrane filters may have a pore size difference at both of their surfaces, i.e. they are isotropic or symmetric when both surfaces have similar pore sizes, and they are anisotropic or asymmetric when both surfaces have different pore sizes. The solvent-treated reaction solution may be invaded into the pores of the membrane using positive pressure to displace existing air or flowable liquid contents therein.
As an option where step 302B is used, the separation of the lower viscosity portion of the SMC containing fluoropolymer/oligomer product (e.g., SMM) from the solid trimer by-product may be accomplished by filtration using a filter formed from a material that can allow the SMC to be heated to a temperature to selectively phase-convert the fluoropolymer/oligomer product (e.g., SMM) contents. In this regard, as an option, the membrane filter material may be a microporous metallic material (e.g., stainless steel), ceramic, or an organic polymeric material having a softening point and a melting point higher than the fluoropolymer/oligomer product (e.g., SMM), or other heat resistant microporous membrane material. As an option, the heated reaction solution may be allowed to stand (without agitation) long enough to allow insoluble byproducts to precipitate at or near the bottom of the vessel containing the fluid mixture, and then the lower viscosity portion of the mixture containing the fluoropolymer/oligomer product (e.g., SMM) is decanted.
The separation and removal of the insoluble trimer by-product from the fluoropolymer/oligomer product in step 303 in the solution of step 302A or 302B provides another solution of the surface modification composition in which the fluoropolymer/oligomer product is present in a more purified form than the solution prior to filtration or other liquid-solid separation step. An advantage of the present invention is that the solution obtained from the filtration or other liquid-solid separation step can be directly used for further processing in connection with the production of extruded or moulded parts, such as shown in
As an option, the removal of reaction byproducts (such as trimer byproducts) from the surface modification composition removes from about 1 wt.% to 100 wt.%, or from about 10 wt.% to about 100 wt.%, or from about 50 wt.% to about 100 wt.%, or from about 75 wt.% to about 100 wt.%, or from about 90 wt.% to about 100 wt.%, or from about 95 wt.% to about 100 wt.% of the total weight of insoluble reaction byproducts present in the solution (based on the weight prior to any solvent addition and liquid-solid separation). According to the methods of the present invention, the content of reaction byproducts (such as trimer byproducts) in a solution that has been solvent treated or heat treated and filtered or otherwise subjected to liquid-solid separation can be reduced to about 5 wt.% or less (e.g., 0 to 5.0 wt.%), or about 1.0 wt.% or less, or about 0.8 wt.% or less, or about 0.5 wt.% or less, or about 0.25 wt.% or less, or 0.1 wt.% or less, or other reductions, based on the total weight of the solution that has been solvent treated or heat treated and filtered or otherwise subjected to liquid-solid separation. The polymer or oligomer reaction product may be present in an amount of from about 5 wt.% to about 99.9 wt.%, or from about 10 wt.% to about 99.9 wt.%, or from about 50 wt.% to about 99.9 wt.%, or from about 75 wt.% to about 99.9 wt.%, or from about 90 wt.% to about 99.9 wt.%, based on the total weight of the solution that has been solvent treated or heat treated and filtered or otherwise subjected to liquid-solid separation. In a solution that has been treated with a solvent or melted and filtered or otherwise subjected to a second solution of liquid-solid separation, the ratio of the weight% of the polymer or oligomer to the weight% of the insoluble reaction by-products, based on the total weight of the solution, may range from about 50: 1 to about 999: 1, or from about 75: 1 to about 750: 1, or from about 100: 1 to about 500: 1.
In step 304, additional solvent (for spinning) may be added to the solvent (if used) added in step 302A along with one or more film-forming base polymers and optional additives. From methods and apparatus of these types of steps commonly used in the industry, such as shown in U.S. patent nos. 9,353,220, 8,784,664, and 6,113,785 and U.S. patent application publication No. 2006/0205309 (which are all incorporated herein by reference in their entirety), mixing, filtration, and spinning steps for making spun hollow fibers may be suitable. The dope may be prepared by combining the solution obtained after removal of the insoluble reaction by-products with an additional amount of solvent (such as DMAC) to obtain a diluted solution with the base polymer to obtain a mixture which may be filtered to obtain the dope. As an option, the base polymer may be at least one of Polysulfone (PSF), Polyethersulfone (PES), Polyarylsulfone (PAS), Polyarylsulfone (PAES), polyvinylidene fluoride (PVDF), Polyacrylonitrile (PAN), or any copolymer thereof. As an option, hydrophilic monomers such as polyvinylpyrrolidone, polyethylene glycol, or combinations thereof may be included. As an option, the diluted solution may contain DMAC in an amount of from about 50 wt% to about 99 wt%, or from about 50 wt% to about 75 wt%, or from about 69 wt% to about 95 wt%, or from about 65 wt% to about 90 wt%, based on the total weight of the diluted solution. The diluted solution may contain DMAC in an amount of from about 1 to 100 wt.%, or from about 10 to about 100 wt.%, or from about 25 to about 100 wt.%, or from about 50 to about 100 wt.%, or from about 75 to about 100 wt.%, or from about 90 to about 100 wt.%, based on the total weight of solvent present in the diluted solution. As an option, DMAC may be the only solvent present in the diluted solution. The total weight of DMAC and surface modification composition present in the diluted solution may optionally be from about 50 wt% to 100 wt%, or from about 60 wt% to about 99 wt%, or from about 70 wt% to about 95 wt%, or from about 75 wt% to about 90 wt%, based on the total weight of the diluted solution. As an option, the diluted solution may contain the surface modification composition in an amount of from about 0.1 wt% to about 15 wt%, or from 0.5 wt% to about 15 wt%, or from about 1 wt% to about 15 wt%, or from about 3 wt% to about 12 wt%, based on the total weight of the diluted solution. As an option, the diluted solution may contain the surface-modifying composition in an amount of about 0.1 wt% to 100 wt%, about 1 wt% to about 100 wt%, or about 10 wt% to about 99 wt%, or about 25 wt% to about 99 wt%, or about 50 wt% to about 95 wt%, or about 60 wt% to about 90 wt%, based on the total weight of the non-solvent components present in the diluted solution. The dope can be wet spun or dry spun into dialysis grade hollow fibers or other products.
Fig. 5 shows the general chemical structure of SMM and several specific SMMs (SMM1, SMM6, SMM8) that can be separated from reaction byproducts using the method of the present invention. In SMM6, x and y are each 1 or greater, and in SMM8, n is 1 or greater. Other SMMs in the surface-modifying composition comprising reaction by-products may also be treated according to the invention, such as SMM2, SMM3, SMM4, SMM5, SMM7, SMM8, SMM9, SMM10, SMM11, SMM12, SMM13, or SMM14, or any combination thereof. Synthetic methods for forming these SMMs and others are shown, for example, in incorporated U.S. patent nos. 8,071,683 and 8,318,867, with the modification that the reaction solution is not washed with an organic solvent or evaporated solvent, but rather the by-product removal method of the present invention is used on the reaction product.
As an option, SMMs purified by the methods of the present invention can be constructed by an appropriately designed combination of isocyanates (e.g., diisocyanates or triisocyanates), polyols, and fluoroalcohol monomers to form a wide range of polyurethanes using catalysts in the polymerization. These reactants for the synthesis of SMM may include, but are not limited to, the component reagents described below. As the isocyanate, a diisocyanate may be used, which may be one or more of HDI ═ hexamethylene diisocyanate, HMDI ═ 4,4' -methylenebis (cyclohexyl isocyanate), IPDI ═ isophorone diisocyanate, TMXDI ═ m-tetramethylene xylene diisocyanate, or others, or a triisocyanate may be used, which may be one or more of HDI isocyanurate, IPDI trimer isocyanurate, or others, or any combination thereof. The polyol may be one or more of PPO ═ polypropylene oxide, HLBH ═ hydrogenated hydroxyl terminated polybutadiene, PCN ═ poly (2, 2-dimethyl-1-3-propyl carbonate) diol, PHCN ═ poly (hexamethylene carbonate) diol, PEB ═ poly (ethylene-co-butylene) diol, LBHP ═ hydroxyl terminated polybutadiene polyol, PEGA ═ poly (diethylene glycol) adipate, PTMO ═ poly (tetrahydrofuran) diol, PDP ═ diethylene glycol-phthalic anhydride polyester polyol, SPH ═ 1, 6-hexanediol-phthalic anhydride polyester polyol, SPN ═ neopentyl glycol-phthalic anhydride polyester polyol, BPAE ═ bisphenol a ethoxylated glycol, or others, or any combination thereof. The fluorinated end capping groups may be derived from one or more fluorine-containing telomer alcohols (FTOH). The fluorotelomer alcohols may have the structure F (CF)2)z-CH2CH2-OH (wherein z ═ 4,6, 8, 10 or 12 or other values of z), or F (CF)2)z-CH(CH3) -OH, wherein z ═ 5, 7, 9 or 11 or other values of z. As an option, the fluorotelomer alcohol (FTOH) can be 4:2FTOH, 5:2FTOH, 6:2FTOH, 7:2FTOH, 8:2FTOH, 9:2FTOH, 10:2FTOH, or other FTOH, or any combination or mixture thereof. In a preferred option, the fluorotelomer alcohol can be 1H,1H,2H,2H perfluoro-1-octanol (6: 2F)TOH), 1H,2H perfluorodecanol, 1H, 5H-perfluoro-1-pentanol, 1H perfluorobutanol, or any mixture of these. In a more preferred option, the fluorotelomer is 6:2FTOH (1H,1H,2H, 2H-perfluoro-1-octanol). The polymerization catalyst may be a non-tin based catalyst, such as a bismuth catalyst, for example a bismuth carboxylate catalyst or other catalyst.
The invention will be further elucidated by the following theoretical examples, which are intended to be exemplary of the invention. In this non-limiting illustration, the process of the present invention is carried out according to the process scheme shown in FIG. 3.
The general synthesis schemes shown in incorporated U.S. patent nos. 8,071,683 and 8,318,867 for synthesizing SMMs may be adapted as indicated herein to synthesize various SMMs. To synthesize SMM1, for example, a polyol such as polypropylene oxide may be reacted with a molar excess (e.g., molar HDI > molar PPO) of a diisocyanate such as HDI in an organic solvent such as Dimethylacetamide (DMAC) or toluene in the presence of a catalyst (e.g., bismuth catalyst) at about 60-75 ℃ to form a prepolymer. The prepolymer ends may then be capped with a molar excess (e.g., moles FTOH > moles prepolymer) of perfluorotelomer alcohol (FTOH) at about 40-50 ℃. Since the reaction may be moisture sensitive, the reaction is preferably carried out under a nitrogen atmosphere under anhydrous conditions. SMM1 in the resulting reaction solution (if the synthesis is performed in DMAC as solvent) may be precipitated by the addition of water, or SMM1 in the resulting reaction solution may be precipitated by the addition of methanol if the reaction is performed in toluene. The chemical structure of SMM1 is shown in fig. 4. A reaction solution containing about 87 wt.% SMM1 and about 13 wt.% trimer may be produced from this multi-step reaction scheme. Precipitated SMM1 does not require washing in hexane or other organic solvents that need to be evaporated. In contrast, SMM1 may be selectively dissolved in DMAC or other solvent, such as added to the reaction solution at a ratio of 0.4 DMAC/1X SMM1, where the SMM1 is substantially dissolved in the added solvent (e.g., ≧ 98 wt% dissolved) and the trimeric by-product is substantially insoluble in the added solvent (e.g., < 2 wt% solubility). The trimer by-product can be filtered from the solvent-treated reaction solution by using a microporous membrane having an average pore size of between about 0.05 microns and about 10 microns (μm), which allows the dissolved SSM1 to pass completely through under the positive pressure provided on the inlet side of the membrane. The solution passing through the membrane can be used directly for spinning dope formulations and spinning of hollow fibers therein. To provide the dope, the solution passing through the membrane may have additional solvent added (e.g., about 71X DMAC/1X SMM1 or other amounts, as shown herein), and further film forming polymers such as polysulfone and polyvinylpyrrolidone (PVP) or others. The resulting combination can be mixed, filtered, and spun into hollow fibers using these types of procedures and equipment disclosed in the incorporated patents that are commonly used in the industry.
The present invention includes the following aspects/embodiments/features in any order and/or in any combination:
1. the invention relates to a method comprising:
forming a first solution by phase-converting at least a portion of a surface-modifying composition to a liquid state, the surface-modifying composition comprising:
a) at least one polymer or oligomer, and
b) i) fluorotelomer alcohols and ii) insoluble reaction by-products of isocyanates,
wherein the insoluble reaction by-product is substantially insoluble in the polymer or oligomer; and
removing at least a portion of the insoluble reaction by-products present in the first solution from the first solution to obtain a second solution;
wherein the polymer or oligomer comprises a polymer or oligomer backbone covalently attached to at least one surface active group.
2. The method of any preceding or subsequent embodiment/feature/aspect, wherein the first solution is formed by dissolving at least a portion of the surface modification composition in at least one solvent.
3. The method of any preceding or subsequent embodiment/feature/aspect, wherein the first solution is formed by melting the polymer or oligomer of the surface modification composition.
4. The method of any preceding or subsequent embodiment/feature/aspect, wherein the insoluble reaction by-product is a fluorotelomer alcohol-terminated diisocyanate.
5. The method of any preceding or subsequent embodiment/feature/aspect, wherein the fluorotelomer alcohol (FTOH) is 4:2FTOH, 5:2FTOH, 6:2FTOH, 7:2FTOH, 8:2FTOH, 9:2FTOH, 10:2FTOH, or a combination thereof.
6. The method of any preceding or subsequent embodiment/feature/aspect, wherein the fluorotelomer alcohol is 6:2 FTOH.
7. The method of any preceding or subsequent embodiment/feature/aspect, wherein the isocyanate has two or more isocyanate functional groups.
8. The method of any preceding or subsequent embodiment/feature/aspect, wherein the isocyanate is a diisocyanate, triisocyanate, or a combination thereof.
9. The method of any preceding or subsequent embodiment/feature/aspect, wherein the insoluble reaction byproduct is an insoluble trimeric reaction byproduct.
10. The method of any preceding or subsequent embodiment/feature/aspect, wherein a) is the polymer having a polymer backbone comprising polyurethane and fluorinated end groups.
11. The method of any preceding or subsequent embodiment/feature/aspect, wherein a) is a polymer having a molecular weight of from about 8,500 to about 20,000, or from about 4,000 to about 15,000.
12. The method of any preceding or subsequent embodiment/feature/aspect, wherein a) is SMM1, SMM2, SMM3, SMM4, SMM5, SMM6, SMM7, SMM8, SMM9, SMM10, SMM11, SMM12, SMM13, or SMM14, or any combination thereof.
13. The method of any preceding or subsequent embodiment/feature/aspect, wherein the at least one solvent is present in an amount such that insoluble reaction byproducts are dissolved in the first solution in an amount of less than 10 wt.%, based on the weight of the surface modification composition.
14. The method of any preceding or subsequent embodiment/feature/aspect, wherein the at least one solvent is present in an amount such that insoluble reaction byproducts are dissolved in the first solution in an amount of less than 1 wt.%, based on the weight of the surface modification composition.
15. The method of any preceding or subsequent embodiment/feature/aspect, wherein the solvent is at least one of Dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), Dimethylsulfoxide (DMSO), Tetrahydrofuran (THF), N-ethylpyrrolidone, N-octylpyrrolidone, Dimethylformamide (DMF), butyrolactone, or any combination thereof.
16. The method of any preceding or subsequent embodiment/feature/aspect, wherein removing comprises filtering, centrifuging, or other liquid-solid separation means.
17. The method of any preceding or subsequent embodiment/feature/aspect, wherein the insoluble reaction by-products are present in the second solution in an amount of less than 5 wt%, based on the weight of the surface modification composition.
18. The method of any preceding or subsequent embodiment/feature/aspect, wherein substantially insoluble comprises a solubility in the polymer or oligomer of less than 10 wt%.
19. The method of any preceding or subsequent embodiment/feature/aspect, wherein the polymer or oligomer is one or a combination of several polyurethanes with a fluorochemical compound attached to a terminal position of the polymer or oligomer.
20. The method of any preceding or subsequent embodiment/feature/aspect, wherein the polymer or oligomer is a material capable of improving the hemocompatibility of the polymer surface.
21. The method of any preceding or subsequent embodiment/feature/aspect, wherein the polymer or oligomer of the material capable of improving the blood compatibility of the polymer surface is SMM (surface modifying macromolecule) or SMA (surface modifying additive).
22. The method of any preceding or following embodiment/feature/aspect, wherein:
the surface modification composition comprises a polymer or oligomer in an amount of about 50 wt% to about 99 wt% relative to the total weight of the surface modification composition present in the first solution.
23. The method of any preceding or following embodiment/feature/aspect, wherein:
the surface modification composition comprises insoluble reaction by-products in an amount of about 1 wt% to about 50 wt% relative to the total weight of the surface modification composition present in the first solution.
24. The method of any preceding or following embodiment/feature/aspect, wherein:
the ratio of the weight% of the polymer or oligomer to the weight% of the insoluble reaction by-products in the first solution is in the range of about 1: 1 to about 99: 1, respectively, based on the total weight of the first solution.
25. The method of any preceding or following embodiment/feature/aspect, wherein:
the first solution contains DMAC in an amount from about 0 wt% to about 90 wt%, based on the total weight of the first solution.
26. The method of any preceding or following embodiment/feature/aspect, wherein:
the total weight of DMAC and the surface modification composition present in the first solution ranges from about 0 wt% to 20 wt%, based on the total weight of the first solution.
27. The method of any preceding or following embodiment/feature/aspect, wherein:
the first solution contains DMAC in an amount from about 0 wt% to about 50 wt%, based on the total weight of the first solution.
28. The method of any preceding or following embodiment/feature/aspect, wherein:
the first solution contains DMAC in an amount of about 0 to 75 wt.%, based on the total weight of solvent present in the first solution.
29. The method of any preceding or following embodiment/feature/aspect, wherein:
DMAC is the only solvent present in the first solution.
30. The method of any preceding or following embodiment/feature/aspect, wherein:
the first solution contains the surface modification composition in an amount of about 10 wt% to about 100 wt%, based on the total weight of the first solution.
31. The method of any preceding or following embodiment/feature/aspect, wherein:
the surface modification composition is the only non-solvent component present in the first solution.
32. The method of any preceding or following embodiment/feature/aspect, wherein:
in the second solution, the polymer or oligomer is present in an amount of about 5 wt% to about 99.9 wt%, based on the total weight of the second solution.
33. The method of any preceding or following embodiment/feature/aspect, wherein:
in the second solution, the ratio of the weight% of the polymer or oligomer to the weight% of the insoluble reaction by-products, based on the total weight of the second solution, is in the range of about 50: 1 to about 999: 1, respectively.
34. The method of any preceding or following embodiment/feature/aspect, wherein:
the removal removes about 1 wt% to 100 wt% of the total weight of insoluble reaction byproducts present in the first solution.
35. The invention further relates to a method comprising:
forming a first solution by dissolving at least a portion of a surface modifying composition in Dimethylacetamide (DMAC), the surface modifying composition comprising:
a)
at least one polymer or oligomer, and
b)
i) a fluorotelomer and ii) an insoluble reaction by-product of an isocyanate;
wherein the insoluble reaction by-product is substantially insoluble in DMAC; and
removing at least a portion of the insoluble reaction by-products present in the first solution from the first solution to obtain a second solution;
wherein the polymer or oligomer comprises a polymer or oligomer backbone covalently attached to at least one surface active group.
36. The method of any preceding or following embodiment/feature/aspect, further comprising:
combining the second solution with an additional amount of DMAC to obtain a diluted solution;
combining the diluted solution with a base polymer to obtain a mixture; and
the mixture was filtered to obtain a dope.
37. The method of any preceding or subsequent embodiment/feature/aspect, wherein the base polymer is at least one of Polysulfone (PSF), Polyethersulfone (PES), Polyarylsulfone (PAS), Polyarylethersulfone (PAES), polyvinylidene fluoride (PVDF), Polyacrylonitrile (PAN), or any copolymer thereof.
38. The method of any preceding or following embodiment/feature/aspect, wherein:
the diluted solution contains DMAC in an amount of about 50 wt% to about 99 wt%, based on the total weight of the diluted solution.
39. The method of any preceding or following embodiment/feature/aspect, wherein:
the total weight of DMAC and the surface modification composition present in the diluted solution is in the range of about 50% to 100% based on the total weight of the diluted solution.
40. The method of any preceding or following embodiment/feature/aspect, wherein:
the diluted solution contains DMAC in an amount of about 50 wt% to about 75 wt%, based on the total weight of the diluted solution.
41. The method of any preceding or following embodiment/feature/aspect, wherein:
the diluted solution contains DMAC in an amount of about 1 to 100 wt.%, based on the total weight of solvent present in the diluted solution.
42. The method of any preceding or following embodiment/feature/aspect, wherein:
DMAC is the only solvent present in the diluted solution.
43. The method of any preceding or following embodiment/feature/aspect, wherein:
the diluted solution contains the surface modification composition in an amount of about 0.1 wt% to about 15 wt%, based on the total weight of the diluted solution.
44. The method of any preceding or following embodiment/feature/aspect, wherein:
the diluted solution contains the surface-modifying composition in an amount of about 0.1 wt% to 100 wt%, based on the total weight of the non-solvent component present in the diluted solution.
45. The method of any preceding or following embodiment/feature/aspect, wherein:
the surface modification composition is the only non-solvent component present in the diluted solution.
46. The method of any preceding or following embodiment/feature/aspect, wherein:
the base polymer comprises a mixture of polyvinylpyrrolidone (PVP) and Polysulfone (PS).
47. The method of any preceding or subsequent embodiment/feature/aspect, further comprising contacting the dope with a precipitation fluid to precipitate the dope.
The invention may comprise any combination of these various features or embodiments above and/or below as set forth in sentences and/or paragraphs. Any combination of features disclosed herein is considered part of the invention and is not intended to be limiting with respect to the features that may be combined.
Applicants specifically incorporate the entire contents of all cited references in this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper limit or preferred value and any lower limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims and their equivalents.