SOLID-RETAINED POLYMER COMPOSITE ARTICLES AND METHODS OF FORMING - Patent application

Abstract

A solid-retained polymer composite article is disclosed. The polymer composite article includes a composite region having a first porous polymer including a plurality of pores and a retained solid. The composite region has at least a portion of the retained solid immobilized within some of the pores. In embodiments where the retained solid is a solid sorbent material, the article is configured to receive carbon dioxide through the first porous polymer capable of adsorbing to the solid sorbent.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 157,442, filed March 5, 2021, and U.S. Provisional Application No. 63 / 302,857, filed January 25, 2022, the disclosures of each of which are incorporated by reference in their entirety herein.

[0002] Field The present disclosure relates to solid-retained polymer composite articles, methods of forming the polymer composite articles by entrainment, and methods of using the polymer composite articles. In embodiments where the retained solid is a solid adsorbent material, the articles may be used for adsorption purposes, including adsorption for direct air capture (DAC) of carbon dioxide. [Background technology]

[0003] background Increasing carbon dioxide (CO2) levels due to greenhouse gas emissions have been shown to be harmful to the environment. As reported in the Climate.gov article “Climate Change: Atmospheric Carbon Dioxide,” the average carbon dioxide level in the atmosphere in 2019 was 409.8 ppm, the highest level recorded in the past 800,000 years. The rate at which atmospheric CO2 is increasing is also much higher than the rate in previous decades.

[0004] To mitigate the effects of climate change, it is necessary to not only reduce CO2 emissions to zero in the near future, but to make them negative. Several possibilities exist to achieve negative emissions, such as the combustion of biomaterials for power generation combined with CO2 capture from combustion flue gases and subsequent CO2 sequestration ("BECCS") or direct air capture of CO2 ("DAC").

[0005] Gas separation by adsorption has many different applications in industry, for example, the removal of specific components from a gas stream, where the desired product can be either the component removed from the gas stream, the remaining depleted stream, or both. This allows both minor and major components of the gas stream to be subjected to the adsorption process. One important gas separation application is in the capture of CO2 from gas streams such as flue gas, exhaust gas, industrial waste gas, biogas, and air. Air is considered a dilute feed stream for CO2.

[0006] Direct capture of CO2 from the atmosphere, called DAC, is one of several means of mitigating anthropogenic greenhouse gas emissions and has attractive economic prospects as a non-fossil, site-independent source of CO2 for commodity markets and the production of synthetic fuels. Specific advantages of capturing CO2 from the atmosphere include: a) DAC can address emissions from distributed sources (e.g., land, sea, and air vehicles) that represent a large proportion of global greenhouse gas emissions and that cannot currently be captured at the emission site in an economically viable manner, b) DAC can address traditional emissions and therefore can generate truly negative emissions, and c) DAC systems do not need to be attached to the emission source, are site-independent, and can be located at the site where the CO2 is further processed or used.

[0007] There is a growing drive to develop and improve these processes to make them more efficient, maximizing the amount of CO2 removed from the atmosphere while minimizing the energy required for the process.

[0008] FIG. 1 is a schematic diagram of the process involved in a conventional DAC system 10. An inlet feed stream 11 is provided that includes a mixture of CO2 molecules 16 in a non-CO2 diluent 18. For example, the inlet feed stream 11 can be an air stream. During the adsorption process, the inlet feed stream 11 is exposed to a sorbent 12. The CO2 molecules 16 adsorb to the sorbent 12 while the non-CO2 diluent 18 passes through the sorbent 12 and is exhausted from the system 10. The sorbent 12 then undergoes a desorption process to release the CO2 molecules 16 from the sorbent 12. The desorption process can involve moisture in the form of liquid water or water vapor, or a change in system temperature due to a reaction or energy supplied to the system. This desorption process is referred to as "swing" adsorption to define a cyclic process of repeated CO2 adsorption and desorption. If moisture swing adsorption is used, the sorbent 12 can be exposed to moisture in the form of water vapor or liquid water to cause desorption of the CO2 molecules 16. If temperature swing adsorption is used, heat can be applied to the sorbent 12 to cause desorption of the CO2 molecules 16. These moisture and / or temperature fluctuations can temporarily break the bonds that hold the molecules to the sorbent 12, thereby releasing the CO2 molecules 16. The desorbed CO2 molecules 16 can then be separated from the sorbent 12 and collected as product 14. The collected CO2 molecules 16 can then be concentrated and subjected to further necessary processing before being used or stored. It is important that the sorbent 12 used can repeatedly withstand the environment required to separate the CO2 molecules 16, e.g., high temperature and humidity conditions.

[0009] There are established publications and techniques for DAC. One example is the use of articles that include a substrate, such as a monolith, that supports or is coated with a sorbent material. Modifications are established by varying the type of substrate and the sorbent used. However, these previously established publications and methods are limited in their ability to efficiently cycle between adsorption and desorption states. They are also limited with respect to the durability of the articles. Additionally, articles can degrade when exposed to environments with high temperatures or high humidity levels, or a combination thereof, which can result in a shortened lifespan. Summary of the Invention

[0010] Abstract An entrained polymer composite article is disclosed. The entrained polymer composite article includes a composite region having a porous polymer including a plurality of pores and a solid material. The composite region has at least some of the solid material entrained, held and immobilized within some of the pores. When the article is entrained with a solid adsorbent material, the article can be configured to receive carbon dioxide through the porous polymer, which can be adsorbed onto the solid sorbent.

[0011] According to one example ("Example A"), a sorptive polymer composite article includes a first region having a solid sorbent and a first porous polymer, the first porous polymer including a plurality of pores, the first region having at least a portion of the solid sorbent immobilized within at least a portion of the pores of the first porous polymer, and the first region configured to receive carbon dioxide through the first porous polymer and adsorb carbon dioxide onto the solid sorbent.

[0012] According to a second example ("Example B"), a method of combining a solid sorbent and a first porous polymer includes providing a first porous polymer having a plurality of pores, providing a solid sorbent, combining the sorbent and the first porous polymer such that at least a portion of the sorbent is disposed within the pores of the first porous polymer, and immobilizing the solid sorbent within the pores of the first porous polymer.

[0013] According to a third example ("Example C"), an entrained polymer composite article includes a first porous polymer including a plurality of nodes, a plurality of fibrils connecting adjacent nodes, and a plurality of pores defined by the nodes and the fibrils, the first porous polymer having a first state in which the fibrils are substantially straight and a second state in which the fibrils are substantially wavy or tortuous and the pores are smaller in size than in the first state, and a plurality of solid particles are retained within the pores in the first state and immobilized within the pores in the second state. [Brief description of the drawings]

[0014] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] FIG. 1 is a schematic diagram of the processes involved in a DAC system.

[0015] [Diagram 2] FIG. 2 is an elevational view of a sorbent polymer composite article of the present disclosure.

[0016] [Figure 2A] FIG. 2A is a schematic elevational view of a first composite region of the first composite article of FIG.

[0017] [Figure 2B] 2B is a schematic elevational view of the first composite region of the first composite article of FIG. 2 in a compressed form.

[0018] [Figure 2C]FIG. 2C is a schematic elevational view of the first composite region of the first composite article of FIG. 2B in a further compressed form.

[0019] [Figure 2D] FIG. 2D is an elevational view of the first sorbent polymer composite article of FIG. 2 shown including an edge seal region of the present disclosure.

[0020] [Diagram 3] FIG. 3 is a flow chart illustrating a method of forming the sorbent polymer composite article of FIG.

[0021] [Figure 4A] FIG. 4A is an elevational view of a first region of a sorptive polymer composite article prior to the immobilization step.

[0022] [Figure 4B] FIG. 4B is an elevational view of a first region of the sorptive polymer composite article of FIG. 4A after a fixation step.

[0023] [Figure 5A] FIG. 5A is an elevational view of a first region and a second region of a sorbent polymer composite article during the combining process.

[0024] [Figure 5B] FIG. 5B is an elevational view of the sorptive polymer composite article of FIG. 6A during the immobilization process.

[0025] [Figure 6] 6A, 6B and 6C are SEM images of diamond particle retained polymer composite article samples according to Example 1.

[0026] [Figure 7] 7A, 7B, and 7C are SEM images of iron oxide particle-retained polymer composite article samples according to Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Detailed Description of the Invention Definitions and Terminology This disclosure is not intended to be interpreted in a limiting sense, for example, the terms used in this application should be read broadly in the context of the meaning that a specialist in the field would ascribe to such terms.

[0028] With respect to the term imprecision, the terms "about" and "approximately" may be used interchangeably to refer to measurements that include the stated measurements and also measurements that are reasonably close to the stated measurements. Measurements that are reasonably close to the stated measurements deviate from the stated measurements by a reasonably small amount, as understood and readily ascertained by one of ordinary skill in the relevant art. Such deviations may result from measurement errors, differences in calibration of measuring and / or manufacturing equipment, human error in reading and / or setting measurements, fine-tuning made to optimize performance and / or structural parameters taking into account differences in measurements relative to other components, specific implementation scenarios, imprecise adjustment and / or manipulation of objects by humans or machines, and the like. In cases where it is determined that a person of ordinary skill in the relevant art would not be able to readily ascertain the value of such reasonably small differences, the terms "about" and "approximately" may be understood to mean plus or minus 10% of the stated value.

[0029] The term "fibril," as used herein, describes an elongated piece of material, such as a polymer, whose length and width are substantially different from one another. For example, a fibril can resemble a string or piece of fiber, whose width (or thickness) is much shorter or less than its length.

[0030] The term "node" as used herein describes a connection point of at least two fibrils, which connection may be defined as a location where two fibrils contact each other, either permanently or temporarily. In some instances, a node may also be used to describe a volume of polymer larger than a fibril and where a fibril begins or ends without a clear continuation of the same fibril through the node. In some instances, a node is wider but shorter in length than a fibril.

[0031] As used herein, "nodes" and "fibrils" are usually, but not necessarily, connected or interconnected and may be used to describe objects having, for example, microscopic size. A "microscopic" object may be defined as an object having at least one dimension (width, length, or height) so substantially small that the object or details of the object are not visible to the naked eye or are difficult, if not impossible, to observe without the aid of a microscope, such as, but not limited to, a scanning electron microscope (SEM), or an appropriate type of magnifying device.

[0032] Description of Various Embodiments The present disclosure relates to solid-loaded polymer composite articles, methods of forming polymer composite articles by entrainment, and methods of using polymer composite articles. In embodiments in which the loaded solid is a solid adsorbent material, the article may be used to adsorb and separate one or more desired substances from a source stream. Although the use of the sorbent polymer composite article is described with respect to DAC of carbon dioxide from a dilute feed stream such as air, it can be used for other adsorption methods and applications. These methods include adsorption of substances from a variety of inputs, including, but not limited to, other gaseous feed streams (e.g., combustion exhaust) and liquid feed streams (e.g., seawater). The adsorbed substance is not limited to carbon dioxide. Other adsorbed substances can include, but are not limited to, other gas molecules (e.g., N2, CH4, CO, etc.), liquid molecules, solutes, etc. In certain embodiments, the input may be a dilute one that contains the adsorbed substance on the order of parts per million (ppm). The article can retain other solid materials for other uses, including pharmaceutical and biological uses.

[0033] 2 illustrates a first exemplary polymer composite article, specifically a sorptive polymer composite article 20, that includes a first composite region 28. The first composite region 28 includes a first porous polymer 22 and a retained solid, illustratively including a sorptive material 24. The retained solid can also optionally include a carrier 26. Each element of the first composite region 28 is described further below.

[0034] The first porous polymer 22 of the first composite region 28 can be one of expanded polytetrafluoroethylene (ePTFE), expanded (expanded, expanded, stretched or foamed) polyethylene (ePE), polytetrafluoroethylene (PTFE) or another suitable porous polymer. It will be understood that nonwoven materials such as nanospun, meltblown, spunbond and porous cast films can be various other suitable porous polymer forms. The first porous polymer 22 can be expanded by stretching the polymer at a controlled temperature and controlled stretching rate, causing the polymer to fibrillate. After expansion, the first porous polymer 22 can include a microstructure of a plurality of nodes 30 and a plurality of fibrils 34 connecting adjacent nodes 30. In these examples, the first porous polymer 22 includes pores 32 bounded by fibrils 34 and nodes 30. Exemplary node and fibril microstructures are described in U.S. Pat. No. 3,953,566 to Gore, which is incorporated herein by reference in its entirety. The pores 32 of the first porous polymer 22 can be considered micropores. Such pores can have a single pore size or can have a distribution of pore sizes. The average pore size can range from 0.1 microns to 100 microns in certain embodiments.

[0035] The sorptive material 24 of the first complex region 28 is a substrate having a surface configured to retain desired substances from an input as a thin film on the surface by adsorption. The sorptive material 24 varies based on which substances are targeted for adsorption. In various embodiments, the sorptive material 24 is a carbon dioxide sorptive material, including but not limited to an ion exchange resin (e.g., a strong base anion exchange resin such as Dowex® Marathon® A resin, Dow Chemical available from the Company), zeolites, activated carbon, alumina, metal-organic frameworks, polyethyleneimine (PEI), or another suitable carbon dioxide adsorbent material, such as desiccants, carbon molecular sieves, carbon adsorbents, graphite, activated alumina, molecular sieves, aluminophosphates, silicoaluminophosphates, zeolite adsorbents, ion-exchanged zeolites, hydrophilic zeolites, hydrophobic zeolites, modified zeolites, natural zeolites, faujasites, clinoptilolite, mordenite, metal-exchanged silicoaluminophosphates, monopolar resins, bipolar resins, aromatic crosslinked polystyrene matrices, brominated aromatic matrices, methacrylate ester copolymers, graphite-based adsorbents, carbon fibers, carbon nanotubes, nanomaterials, metal salt adsorbents, perchlorates, oxalates, alkaline earth metal particles, ETS, CTS, metal oxides, chemisorbents, amines, organometallic reactants, hydrotalcites, silicalites, zeolitic imadazolate frameworks, and Metal organic frameworks (MOFs), adsorbent compounds, and combinations thereof may be mentioned.

[0036] The sorbent material 24, 24' may be present in the first porous polymer 22 as a coating, a filler, entrained particles, and / or in another suitable form, as described further below. In the embodiment shown in FIG. 2, solid particles of the sorbent material 24 on the carrier 26 are entrained in the first porous polymer 22 such that the particles occupy and are retained within the pores 32 between the nodes 30 and the fibrils 34 of the first porous polymer 22. It is also within the scope of this disclosure for the first porous polymer 22 to be coated with the sorbent material 24' such that the sorbent material 24' forms a substantially continuous coating on the nodes 30 and / or fibrils 34 of the first porous polymer 22, as shown in FIG. 2D. It is further within the scope of this disclosure for the first porous polymer 22 to be filled with the sorbent material 24 such that the sorbent material 24 is incorporated into the nodes 30 and / or fibrils 34 of the first porous polymer 22.

[0037] The optional carrier 26 in the first composite region 28 is a material configured to increase the surface area of ​​the region it occupies, allowing for an increase in the surface area available for adsorption of the desired substance. The carrier 26 may include mesoporous silica, polystyrene beads, porous polymer beds or spheres, oxide supports, or another suitable carrier material. The carrier 26 may further include a porous film having a porous inorganic material therein, such as calcium sulfate, alumina, activated carbon, fumed silica, etc. As mentioned above, the carrier 26 may be present within the pores 32 of the first composite region 28 as high surface area particles coated or functionalized with the sorbent material 24. The combination of the carrier 26 coated with the sorbent material 24 increases the surface area available for adsorption. In these embodiments, the nodes 30 and fibrils 34 may or may not be coated with the sorbent material 24. When the nodes 30 and fibrils 34 are not coated, the original hydrophobicity of the first porous polymer 22 may be retained.

[0038] The first composite region 28 of the sorbent polymer composite article 20 includes a first side 72 (e.g., the upper side in FIG. 2 ) and a second side 74 (e.g., the lower side in FIG. 2 ). The sorbent polymer composite article 20 further includes a second region 36 including a second porous polymer 40, the second region 36 disposed adjacent to the first side 72 of the first composite region 28. In various embodiments, the sorbent polymer composite article also includes a third region 38 including a third porous polymer 48, the third region 38 disposed adjacent to the second side 74 of the first composite region 28. In this manner, the first composite region 28 can be sandwiched between the second region 36 on the first side 72 and the third region on the second side 74. The second porous polymer 40 of the second region 36 can include a plurality of nodes 42, a plurality of fibrils 46 connecting adjacent nodes 42, and a plurality of pores 44 each formed between each node 42 and fibril 46. Similarly, the third porous polymer 48 of the third region 38 may include a plurality of nodes 50, a plurality of fibrils 52 connecting adjacent nodes 50, and a plurality of pores 54 formed between each node 50 and fibril 52. The pores 44 of the second porous polymer 40 and / or the pores 54 of the third porous polymer 48 may be considered micropores, as further described above.

[0039] The first composite region 28, the second region 36, and the third region 38 of the sorbent polymer composite article 20 may be formed using different processes. In certain embodiments, the first composite region 28, the second region 36, and / or the third region 38 may be formed as separate layers and then bonded together. In this case, the first porous polymer 22 of the first composite region 28, the second porous polymer 40 of the second region 36, and / or the third porous polymer 48 of the third region 38 may be distinct structures. In other embodiments, the first composite region 28, the second region 36, and / or the third region 38 may be formed together and then subjected to different coating processes or surface treatments to distinguish the particular regions, as further described below. In this case, the first porous polymer 22 of the first composite region 28, the second porous polymer 40 of the second region 36, and / or the third porous polymer 48 of the third region 38 may be continuous or unitary structures.

[0040] The first composite region 28, the second region 36, and the third region 38 of the sorbent polymer composite article 20 can have different degrees of hydrophobicity. The hydrophobicity can be altered by various methods, such as the application of coatings or surface treatments, including, but not limited to, plasma etching and the application of fine topographical features. The first composite region 28 can have a first hydrophobicity, the second region 36 can have a second hydrophobicity, and the third region 38 can have a third hydrophobicity. The first hydrophobicity is less than each of the second and third hydrophobicities. The second hydrophobicity can be greater than, less than, or equal to the third hydrophobicity. The greater hydrophobicity of the second and third regions 36, 38 can reduce the permeability of liquid water through the respective regions 36, 38, thus forming a barrier between the surrounding liquid water and the components of the first composite region 28. This reduces degradation of the sorptive material 24, 24' in the first composite region 28 that can be caused by liquid water and improves the life and durability of the sorptive polymer composite article 20. The increased hydrophobicity of the second region 36 and the increased hydrophobicity of the third region 38 relative to the first hydrophobicity of the first composite region 28 can be attributed to the absence of the sorptive material 24, 24' in the second and third regions 36, 38.

[0041] In some embodiments, the first composite region 28 is sealed with a coating (not shown). In a particular example, the coating is configured to be a carbon adsorbent material similar to the sorptive material 24 described above.

[0042] The second porous polymer 40 of the second region 36 and the third porous polymer 48 of the third region 38 can be at least one of polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), expanded polyethylene (ePE), or other suitable porous polymers. The second porous polymer 40 of the second region 36 may be the same or different from the third porous polymer 48 of the third region 38. Additionally, the first porous polymer 22 of the first composite region 28, the second porous polymer 40 of the second region 36, and the third porous polymer 48 of the third region 38 may be the same or different.

[0043] In various embodiments, the thickness of the second region 36 is less than the thickness of the first composite region 28, and the thickness of the third region 38 is less than the thickness of the first composite region 28. The overall thickness of the sorbent polymer composite article 20 can be from about 0.1 mm to about 5.0 mm. In certain embodiments, the thickness of the first composite region 28 can make up a majority of the overall thickness, for example, about 70%, about 80%, about 90% or more of the overall thickness.

[0044] The pore characteristics of the porous polymers 22, 40, 48 of the first conjugate region 28, second region 36, and third region 38, respectively, can be varied. In certain embodiments, the second and third regions 36, 38 can have fewer and / or smaller pores 44, 54 than the first conjugate region 28 to selectively limit the permeation of undesirable fluids (e.g., water) into the first conjugate region 28 while allowing the permeation of desired molecules (e.g., CO2) into the first conjugate region 28. In contrast, the first conjugate region 28 can have more and / or larger pores 32 than the second and third regions 36, 38 to facilitate the movement of CO2 through the first conjugate region 28 for adsorption and desorption.

[0045] Additionally, the pore characteristics can vary among the different embodiments, and this variation in pore characteristics can depend on the overall thickness of the sorbent polymer composite article 20, as well as the individual thicknesses of the first composite region 28, the second region 36, and the third region 38.

[0046] FIG. 2A is a schematic elevational view of the first composite region 28 of the sorptive composite article 20 of FIG. 2. In this embodiment, the sorptive polymer composite article 20 (FIG. 2) is relatively thick, e.g., about 3 mm, with the first composite region 28 having a thickness T1 that is a majority of the total thickness of the sorptive polymer composite 20. The sorptive polymer composite article 20 can be loaded with a desired amount of sorptive material 24 (e.g., about 60% sorptive material 24) to maintain a relatively large porosity, where porosity is the relative ratio of the volume of the void space in the first composite region 28 to the total volume of the first composite region 28. In this manner, the sorptive polymer composite article 20 is relatively open in structure and the sorptive material 24 is relatively accessible. Because of the thickness T1 in this embodiment, the sorptive material 24 remains accessible to gas, although the distance required for gas diffusion may be greater. As a result, the initial rate of gas adsorbing onto the sorbent material 24 may be slower compared to thinner embodiments as described herein, but equilibrium of CO2 adsorbing onto the sorbent material 24 may be reached more quickly.

[0047] FIG. 2B is an alternative embodiment of the first composite region 28 of FIG. 2A, where the sorbent composite article 20 (FIG. 2) has a median thickness of, for example, about 0.5 mm. In this embodiment, the first composite region 28 has a thickness T2 that is a majority of the total thickness of the sorbent polymer composite article 20. In this case, if the amount of polymer 22 (FIG. 2) in the first composite region and the amount of sorbent material 24 are constant compared to the previous embodiment, the porosity will be relatively smaller than that of the first composite region 28 of FIG. 2A. Thus, the sorbent polymer composite article 20 maintains a porosity that allows gas to access the sorbent material 24, but is relatively less accessible than the sorbent material 24 of the embodiment of FIG. 2A. As a result, the initial rate of gas adsorbing into the sorbent material 24 may be faster due to the shorter diffusion distance, but the time to equilibrium of CO2 adsorption is increased compared to the embodiment of FIG. 2A.

[0048] FIG. 2C is an alternative embodiment of the first composite region 28 of FIGS. 2A and 2B, where the sorbent polymer composite article 20 (FIG. 2) is relatively thin, for example about 0.1 mm. In this embodiment, the first composite region 28 has a thickness T3 that is a majority of the total thickness of the sorbent polymer composite article 20. In this case, if the amount of polymer 22 (FIG. 2) and the amount of sorbent material 24 in the first composite region 28 are constant for the above two embodiments, the polymer 22 and available sorbent material 24 are more concentrated in the sorbent polymer composite article 20. The diffusion distance required for gas to pass through the article 20 is shorter due to the compressed thickness of the sorbent polymer composite article 20, but the sorbent material 24 is also less accessible to gas. As a result, the initial adsorption rate of gas into the sorbent material 24 is faster than in the previous embodiment, but it may take longer for the system to reach CO2 adsorption equilibrium.

[0049] 2, the pore characteristics of the sorbent polymer composite 20 can vary within each layer, but also across various embodiments as a result of varying various properties including the thickness of the sorbent polymer composite article 20, the thickness of the first composite region 28, the amount of sorbent material 24 and the amount of polymer 22 used within the sorbent polymer composite article 20. In this manner, the relationship between the diffusion length and the accessibility of the sorbent material 24 can be varied to maximize the functionality of the sorbent polymer composite article 20.

[0050] The ability to vary the hydrophobicity, thickness, porosity and other properties of the first composite region 28, the second region 36 and the third region 38 can increase the durability and adaptability of the sorbent polymer composite article 20. For example, increasing the porosity of the second region 36 and the third region 38 can decrease the permeability of fluids to the first region while allowing desired molecules, such as carbon dioxide, to pass through. Additionally, the use of a relatively thin and flexible sorbent polymer composite article 20 can allow the sorbent polymer composite article 20 to conform to different configurations for carbon dioxide adsorption and desorption.

[0051] In certain instances, the tensile strength of the entire sorbent polymer composite article 20 (first porous polymer 22 including sorbent material 24) is equal to or substantially equal to the strength of the first porous polymer 22 alone (without sorbent material 24). In a conventional filling process, the first porous polymer 22 may have strength based on how much filler (in this case, sorbent material 24) is incorporated into the microstructure of the first porous polymer 22. In the present disclosure, in contrast, the first porous polymer 22 is expanded before introducing the sorbent material 24, which allows the first porous polymer 22 to be fully formed without weakening the microstructure of the first porous polymer 22. The amount of sorbent material 24 added after expansion may be increased or decreased with little or no effect on the strength of the first porous polymer 22. Thus, the first porous polymer 22 may have a tensile strength after entrainment of the sorbent material 24 approximately equal to the original tensile strength of the first porous polymer 22 before the addition of the sorbent material 24. In this manner, the presence of the sorbent material 24 with the first porous polymer 22 in the sorbent polymer composite article 20 may not reduce the strength of the first porous polymer 22. As a result, the strength of the first porous polymer 22 may be controlled, which in turn may control the strength of the entire sorbent polymer composite article 20, regardless of how much sorbent material 24 is entrained in the sorbent polymer composite article 20. As is known in the art, tensile strength may be measured by stretching the first porous polymer 22 and / or the sorbent polymer composite article 20 and measuring the deformation at different force values.

[0052] The sorptive polymer composite article 20 of FIG. 2 can be used for a variety of adsorption methods. During the adsorption stage, an input feed stream (similar to the feed stream 11 of FIG. 1) can be directed across the sorptive polymer composite article 20 to adsorb the CO2 molecules. Then, during the desorption stage, the sorptive polymer composite article 20 can undergo a moisture swing and / or temperature swing process to desorb the CO2 molecules. As mentioned above, the polymer composite article 20 can also have other applications besides adsorption, where it is more commonly desirable to entrain the first porous polymer 22 with solid particles. This can include pharmaceutical applications to entrain the porous polymer with a therapeutic agent, or biological applications to entrain the porous polymer with cells.

[0053] FIG. 2D is an additional elevational view of the sorbent polymer composite article of FIG. 2, including an additional edge seal region 21. In an embodiment, the sorbent polymer composite article 20 includes this edge seal region 21 to protect the components of the sorbent polymer composite article 20. For example, if the sorbent polymer composite article 20 is cut or divided in any manner, such as for production or manufacturing purposes, it may leave the first composite region 28, and thus the sorbent material 24, 24' within the first composite region 28, exposed to external environmental elements such as water or steam that may be detrimental to the properties of the sorbent polymer composite article 20. Therefore, an embodiment with an edge seal region 21 may be desirable. As shown in FIG. 2D, the edge seal region 21 may connect the polymer 40 of the second region 36 and the polymer 48 of the third region 38, and is positioned to cover the exposed polymer 28 of the first composite region on at least one side.

[0054] In the illustrated embodiment of FIG. 2D, the edge seal region 21 is formed by applying an additional layer of sealing material 47 onto the sorbent polymer composite article 20. The sealing material 47 may be the same or different from the material of the second region 36 and the third region 36. For example, the sealing material 47 may be ePTFE (as shown in FIG. 2A), ePE, a silicone elastomer, or any other suitable non-porous and / or hydrophobic material that protects the first composite region 28. In other embodiments, the edge seal region 21 may be formed by extending the second region 36 and the third region 38 and bonding (e.g., sandwiching, gluing) the regions 36, 38. The addition of this edge sealing step benefits the composite by protecting the sorbent retained within the composite and strengthening the leading edge of the composite (the area most susceptible to damage from airborne debris and high-velocity impacts).

[0055] Figure 3 is a flow chart illustrating a method 100 for forming the first composite region 28 of the sorbent polymer composite article 20 of Figure 2. At block 102, the method 100 first involves providing a first porous polymer 22. The first porous polymer 22 can be ePTFE, PTFE or ePE, as discussed above, or any other suitable porous polymer.

[0056] At block 104, the method 100 includes providing a solid sorptive material 24 in the form of particles (e.g., a powder) including an optionally present carrier 26. The particles of the solid sorptive material 24 can have an average particle size of about 0.1 μm to about 100 μm, more specifically about 1 μm to about 10 μm.

[0057] At block 106, the method 100 then includes combining the particles of the solid sorptive material 24 with the first porous polymer 22, with some of the particles of the sorptive material 24 disposed within the pores 32 of the first porous polymer 22. In a wet entrainment embodiment, the combining step includes delivering a slurry (not shown) including particles of the sorptive material 24 and a liquid carrier (e.g., water) to the first porous polymer 22. The first porous polymer 22 can be immersed in and impregnated with the slurry, and then the liquid carrier can be removed leaving the particles of the sorptive material 24 in the pores 32. This wet entrainment process is similar to a liquid filtration process, and the retained sorptive material 24 of the wet entrainment process is similar to the residue of a filtration process. In a dry entrainment embodiment, the combining step includes applying the particles of the solid sorptive material 24 in dry particulate form to the first porous polymer 22 using a forced air flow (e.g., positive or negative pressure or a combination thereof). After the combining step of block 106, the pores 32 of the first porous polymer 22 can retain particles of the sorptive material 24. As a result, the pores 32 of the first porous polymer 22 can be filled with particles of the sorptive material 24. The amount of loading can be varied based on the pore size, particle size and pressure involved in the process, and the time in the process. Advantageously, both the wet and dry entrainment processes of block 106 can preserve the physical and chemical structure of the particles of the sorptive material 24. Thus, as discussed above, the wet and dry entrainment processes of block 106 can be suitable for use with a variety of solid particles other than the solid particles of the sorptive material 24 described herein, including drugs, therapeutic agents, and living cells.

[0058] At block 108, the method 100 further includes immobilizing the particles of the sorbent material 24 within the pores 32 of the expanded first porous polymer 22 of the first composite region 28. In a solvent shrinkage embodiment, this immobilization step can include applying a suitable solvent (e.g., isopropyl alcohol (IPA)) to the first porous polymer 22 and sorbent material 24 combination to soak the first porous polymer 22, followed by evaporation of the solvent. This solvent application and subsequent evaporation of the solvent is configured to shrink the fibrils 34, thereby tightening the pores 32 of the first porous polymer 22 of the first composite region 28 and trapping the particles of the solid sorbent material 24 within the pores 32, as shown and described below with respect to Figures 4A and 4B. In a heat shrinkage embodiment, the immobilization step can include applying heat to the combination of the solid sorbent material 24 and the first porous polymer 22. The application of heat causes the fibrils 34 to shrink, thereby tightening the pores 32 of the first porous polymer 22 and trapping the particles of the solid sorbent material 24 within the pores 32. This heating step should be performed at a temperature high enough to evaporate the solvent and shrink the fibrils 34, but low enough to avoid damaging the sorbent material 24, for example, from about 60° C. to about 200° C. It is also within the scope of the present disclosure to perform both the solvent shrinkage process and the heat shrinkage process. The fixation step can reduce the porosity of the first porous polymer 22. After the fixation step of block 108, the pores 32 of the first porous polymer 22 can be tightly filled (e.g., plugged) with the particles of the sorbent material 24.

[0059] Further, in various embodiments, the immobilization step can include attaching one or more coating regions 38 onto the first porous polymer 22, such as a second region 36 including a second porous polymer 40 and / or a third coating region 38 including a third porous polymer 48 (FIG. 2), such that the particles of the solid sorptive material 24 are trapped within the pores 32 of the first porous polymer 22. In certain examples, the porous polymers 40, 48 are PTFE, ePTFE, ePE, or other suitable porous polymers as described above. In various embodiments, attaching the second region 36 and / or the third region 38 onto the first porous polymer 22 and the solid sorptive material 24 can include laminating the second region 36 and / or the third region 38 to the first composite region 28. In various embodiments, the second region 36 and / or the third region 38 can be in the form of a polymer sheet. The concept of immobilization by coating with the second region 36 and / or the third region 38 is further described below with respect to FIGS. 5A and 5B.

[0060] 4A is a perspective view of the first composite region 28 of the sorptive polymer composite article 20 prior to immobilization in block 108 (FIG. 3). The first composite region 28 includes a first porous polymer 22 having a plurality of pores 32, a plurality of fibrils 34, and a plurality of nodes 30. In this state, the fibrils 34 are substantially straight. Each of the plurality of pores 32 comprises a pore size 60. The first porous polymer 22 of the first region 28 includes discrete regions of the sorptive material 24 located within the pores 32. Solid particles and / or carriers 26 of the sorptive material 24 are loosely packed within the pores 32, but may not yet be immobilized.

[0061] FIG. 4B is a perspective view of the first composite region 28 of the sorbent polymer composite article 20 of FIG. 4A after the immobilization step of block 108 described with reference to FIG. 3. In this state, the fibrils 34 are bent and / or wavy. Each of the plurality of pores 32 now has a pore size 62 smaller than the pore size 60 referred to in FIG. 4A. This contraction of the fibrils 34 and tightening of the pores 32 serves to immobilize the solid particles of the sorbent material 24 and / or carrier 26 that are tightly packed within the pores 32 of the first porous polymer 22. In certain instances where the solid particles are intended to absorb or adsorb, the process allows the particles to expand and contract repeatedly. The bent or wavy fibrils store length, allowing for cyclic changes in size or thickness without fibril breakage (tensile failure).

[0062] Another variation of the method 100 of FIG. 3 for forming a sorbent polymer composite article 20 is further described with reference to FIGS. 5A and 5B.

[0063] 5A is a schematic diagram of a portion of the sorbent polymer composite article 20 during the combining step of block 106 (FIG. 3). The sorbent polymer composite article 20 is shown with the third region 38 disposed adjacent the lower second side 74 of the first composite region 28, thereby sealing the lower second side 74 and leaving the upper first side 72 open. The sorbent material 24 may be provided in the form of dry particles and entrained in the forced flow 27 and introduced through the open first side 72 of the first porous polymer 22. The sorbent material 24 may be trapped between the nodes 30 and fibrils 34 of the first porous polymer 22 against the sealed second side 74, thereby retaining the sorbent material 24 within the pores 32 of the first porous polymer 22.

[0064] Figure 5B is a schematic diagram of the sorptive polymer composite article 20 during the immobilization step of block 108 (Figure 3). In addition to the third region 38 sealing the lower second side 74 of the first composite region 28 similar to Figure 5A, the sorptive polymer composite 20 further includes a second region 36 sealing the upper first side 72 of the first composite region 28, thereby immobilizing the sorptive material 24 within the polymer 20 of the first composite region 28 between the second region 36 and the third region 38. EXAMPLES

[0065] example Example 1 We first provided an expanded porous polymer sheet of ePTFE made according to the teachings of U.S. Patent No. 5,814,405 to Branca et al. Diamond dust particles, 2-6 μm in size, were mixed with a 70% IPA 30% H2O solvent. Using a syringe, the mixture of diamond particles and IPA was pulled through the ePTFE sheet. The mixture was then pushed back through the polymer sheet. This process was repeated 10 times. In this case, the particles were injected or entrained into the ePTFE membrane and during drying of the solvent, the fibrils contracted to hold / grip the particles, so that they no longer migrated. The amount of contraction can be varied based on the restraint of the membrane during the drying process.

[0066] 6A, 6B and 6C are SEM images of porous polymers containing diamond particles with sizes of about 2 μm to 6 μm held within the pores of the polymer made in this example. Figures 6A-6C are shown with notations indicating the magnification and scale of each SEM image. Figure 6A is at 100x magnification and the scale indicates a length of 500 μm for the image (so that the distance between two consecutive vertical markers represents 50 μm). Shown at the bottom of the image is 10.0 kV 5.5 mm x 100 k BSE-COMP 08 / 07 / 2020. Figure 6B is at 1000x magnification and the scale indicates a length of 50 μm for the image (so that the distance between two consecutive vertical markers represents 5 μm). Shown at the bottom of the image is 10.0 kV 5.5 mm x 1.00 k BSE-COMP 08 / 07 / 2020. FIG. 6C is at 1000x magnification with the scale indicating a length of 50 μm for the image (so that the distance between two consecutive vertical markers represents 5 μm). Shown at the bottom of the image is a 10.0 kV 4.8 mm x 1.00 k BSE-COMP 08 / 07 / 2020. FIGS. 6B and 6C are higher magnification SEMs taken from the same sample (FIG. 6A) with the polymer sheet and diamond particles disposed within the pores of the sheet to form the first region. FIGS. 6A and 6B show surface SEM images of ePTFE filled and / or embedded with diamond particles. FIG. 6C is a cross-sectional view of the diamond-filled polymer shown in FIGS. 6A-B, with diamond particles observable throughout the thickness of the ePTFE film and loose particles observable on one side of the film. These images show that diamond particles 90 are located within pores 93 between the polymer fibrils 92. In FIG. 6C, many of the diamond particles 90 have been pulled upward toward the top surface of the polymer, while some diamond particles 90 lie loosely toward the bottom surface of the polymer.

[0067] Example 2 We first provided an expanded porous polymer sheet of ePTFE made according to the teachings of U.S. Patent No. 5,814,405 to Branca et al. Iron oxide particles with an average size of about 0.5 μm (with aggregates of about 2-8 μm) were added to a liquid carrier (tap water) to form a slurry. The porous polymer membrane was wetted with IPA solvent. As in Example 1, the slurry of water and iron oxide particles was pulled through the membrane and then pushed back. This process was repeated 10 times. In this example, the sample was dried and then exposed to a temperature of about 200° C. This increase in temperature relieves residual stresses in the membrane. It should be noted that membranes with higher initial expansion properties may shrink more than other membranes with lower expansion properties.

[0068] Figures 7A, 7B and 7C are SEM images taken from a sample of porous polymer containing iron oxide particles <0.5 μm in size, with aggregates of approximately 2 μm to 8 μm, held within the pores of the polymer made in this example. Figures 7A-7C are shown with notations indicating the magnification and scale of each SEM image. Figures 7B and 7C are high magnification SEMs taken from the same sample of this example (shown in Figure 7A) containing iron oxide particles 94 located within the polymer. Figure 7A is at 100x magnification, with the scale indicating a length of 500 μm for the image (as the distance between two consecutive vertical markers represents 50 μm). Shown at the bottom of the image is a 10.0 kV 5.6 mm x 100 BSE-COMP 08 / 07 / 2020. Figure 7B is at 1000x magnification, with the scale indicating a length of 50 μm for the image (as the distance between two consecutive vertical markers represents 5 μm). Shown at the bottom of the image is a 10.0kV 5.6mmx1.00k BSE-COMP 08 / 07 / 2020. Figure 7C is at 1000x magnification with the scale indicating a length of 50μm for the image (so that the distance between two consecutive vertical markers represents 5μm). Shown at the bottom of the image is a 10.0kV 10.0mmx1.00k SE+BSE 08 / 07 / 2020. Figures 7A and 7B are SEM images of the surface of a polymer sheet including a first region having polymer and iron oxide particles 94. Figure 7C is a cross-sectional view of the iron oxide loaded polymer shown in Figures 7A-7B, where embedded iron oxide particles are observable throughout the thickness of the ePTFE film. These images show that the iron oxide particles 94 are located within the pores 93 between the fibrils 92 of the polymer. Compared to the larger particles 90 of Example 1 (FIG. 6C), the smaller particles 94 of this Example 2 (FIG. 7C) were more susceptible to being pulled completely through the ePTFE sheet.

[0069] Prediction example 3 It is envisaged that a laminate may be used to aid the infusion process. A membrane such as the Branca membrane of Examples 1 and 2 above may have an additional membrane laminated to one side. This membrane may be very thin and have a much smaller or denser microstructure than the Branca membrane. Particles are applied from the Branca membrane side using positive pressure from the Branca membrane side or negative pressure from the other side, or both. The solid particles penetrate the microstructure and stop at the interface of the denser porous region. When the Branca membrane is "full" of particles, the infusion process ends and is followed by a capping region and / or shrinkage process. This envisaged process is described in this disclosure with reference to Figures 5A and 5B and may be applied for use with this membrane.

Claims

1. 1. A sorptive polymer composite article comprising a first region comprising a solid sorbent and a first porous polymer, said first porous polymer being shrinkable and comprising a plurality of fibrils defining a plurality of pores, said first region having at least a portion of the solid sorbent immobilized within at least a portion of the pores of said first porous polymer upon shrinkage of said fibrils, and said first region being configured to receive carbon dioxide through said first porous polymer and adsorb carbon dioxide onto said solid sorbent.

2. The sorptive polymer composite article of claim 1 , wherein the solid sorbent is an ion exchange resin, a zeolite, activated carbon, alumina, a metal organic framework, or polyethyleneimine (PEI).

3. The sorbent polymer composite article of claim 1 or 2, further comprising a second region having a second porous polymer and a third region having a third porous polymer, wherein the second porous polymer in the second region and the third porous polymer in the third region are hydrophobic.

4. The sorbent polymer composite article of claim 3 , wherein said first porous polymer, said second porous polymer, and said third porous polymer are the same.

5. The sorbent polymer composite article of claim 1 , wherein said first region has a thickness of less than 5.0 mm.

6. The sorbent polymer composite article of claim 1 , wherein said first porous polymer of said first region is expanded polytetrafluoroethylene, polytetrafluoroethylene, or expanded polyethylene.

7. 2. The sorbent polymer composite article of claim 1, wherein the tensile strength of the first porous polymer after the solid sorbent is immobilized within at least a portion of the pores of the first porous polymer remains equal to the original tensile strength of the first porous polymer before the solid sorbent is immobilized within at least a portion of the pores of the first porous polymer.

8. The sorbent polymer composite article of claim 3 , wherein said second region is disposed on a first side of said first region and said third region is disposed on a second side of said first region.

9. The sorbent polymer composite article of claim 3, wherein the second porous polymer and the third porous polymer of the second region and the third region, respectively, are at least one of polytetrafluoroethylene, expanded polytetrafluoroethylene, and expanded polyethylene.

10. providing a first porous polymer having a plurality of pores; providing a solid sorbent; combining the sorbent with the first porous polymer such that at least a portion of the sorbent is disposed within pores of the first porous polymer, the pore size of the pores being defined by a plurality of contractible fibrils; and immobilizing the solid sorbent within the pores of the first porous polymer by shrinking the plurality of fibrils; A method of combining a solid sorbent with a first porous polymer, comprising the steps of:

11. The method of claim 10 , wherein combining the sorbent and the porous polymer comprises delivering a slurry including the sorbent to the first porous polymer.

12. The method of claim 11 , wherein the slurry further comprises a liquid carrier.

13. The method of claim 10 , wherein combining the sorbent with the first porous polymer comprises applying the sorbent in dry particulate form to the first porous polymer under a forced air stream.

14. The step of immobilizing the solid sorbent comprises: applying a solvent to the combination of the first porous polymer and the sorbent; and evaporating the solvent; The method of claim 10 further comprising the steps of:

15. The method of claim 14 , wherein the evaporating step shrinks the pore size of the plurality of pores in the first porous polymer.

16. The method of claim 10 , wherein the immobilizing step comprises applying heat to the first porous polymer and the sorbent.

17. 17. The method of claim 16, wherein applying heat to the first porous polymer and the sorbent shrinks the pore size of the plurality of pores in the first porous polymer.

18. The method of any one of claims 10 to 17, wherein the immobilizing step further comprises attaching a second region to the first porous polymer having a sorbent material.

19. 20. The method of claim 18, wherein the attaching process comprises laminating the second region to the first porous polymer having the sorbent material.

20. a first porous polymer including a plurality of nodes, a plurality of fibrils that are contractible and connect adjacent nodes, and a plurality of pores defined by the nodes and the fibrils; and a plurality of solid particles held within said pores in a first state and immobilized within said pores in a second state by contraction of said plurality of fibrils; Including, The first porous polymer is the first state in which the fibrils are straight; and a second state in which the fibrils are wavy or tortuous and the pores are smaller in size than in the first state; 1. An entrained polymer composite article comprising:

21. The plurality of solid particles are Career, and a sorptive material coating the carrier; 21. The entrained polymer composite article of claim 20, comprising:

22. The entrained polymer composite article of claim 20, wherein the solid particles have an average particle size of from 0.1 μm to 100 μm.

23. a second porous polymer region; a third porous polymeric region; and an end seal region extending between the second porous polymer region and the third porous polymer region; further comprising the first porous polymer is sandwiched between the second porous polymer region and the third porous polymer region; The entrained polymer composite article of any one of claims 20-22, wherein the second porous polymer region, the third porous polymer region, and the edge seal region cooperate to protect the solid particles within the first porous polymer region.

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