Block copolymer grafted onto a porous polymer substrate

Abstract

There is provided a separation article useful for the separation of composite samples containing materials having different sizes and optionally different ionic groups. The separation article includes a plurality of block copolymers grafted to a solid polymer substrate using a reversible inactivation radical polymerization process. The block copolymers extend from the surface of the solid porous polymer substrate. The blocks include an outer block (i.e., a second polymer block) that effects size exclusion or steric exclusion, and an inner block (i.e., a first polymer block) having an acidic group or a salt thereof, a basic group or a salt thereof, or a combination thereof, which is small enough to bind to a compound having a complementary group and pass through the second polymer block that effects size exclusion or steric exclusion. The separation article can be used, for example, for the separation of biological materials in a sample.

Description

Technical Field

[0001] Provided are methods for separating articles, for making separated articles, and for separating various materials (e.g., biological materials). The separated article includes a block copolymer grafted to a solid, porous polymer substrate. The block copolymer has a second polymer block that effects size exclusion and a first polymer block that can bind to acidic or basic groups on a biological material that are not excluded by the second polymer block.

[0002] In a first aspect, provided is a separated article including (1) a solid, porous polymer substrate and (2) a plurality of block copolymer chains grafted to the solid porous polymer substrate and extending from the surface of the solid porous polymer substrate. The block copolymer chains include (a) a first polymer block covalently bonded to the porous polymer substrate and (b) a second polymer block covalently linked to the first polymer block, wherein the first polymer block is positioned between the second polymer block and the porous polymer substrate. The first polymer block includes first monomer units that are acidic monomer units containing an acidic group or a salt thereof, basic monomer units containing a basic group or a salt thereof, or a combination thereof. The second polymer block includes polyether-containing monomer units.

[0003] In a second aspect, a method of making a separated article is provided. The separated article includes a solid, porous polymer substrate and a plurality of block copolymers grafted to the porous polymer substrate and extending from the surface of the porous polymer substrate. The method includes providing a porous polymer substrate and grafting a plurality of first polymer blocks to the porous polymer substrate using a reversible addition-fragmentation chain transfer (RAFT) polymerization process, wherein the first polymer blocks are covalently attached to the porous polymer substrate. The first polymer blocks are reaction products of a first polymerizable composition comprising 1) an acidic monomer comprising an ethylenically unsaturated group and an acid group or a salt thereof, 2) a basic monomer comprising an ethylenically unsaturated group and a basic group or a salt thereof, or 3) a combination thereof. The method further includes forming a plurality of second polymer blocks using a reversible addition-fragmentation chain transfer (RAFT) polymerization process, wherein the second polymer blocks are covalently attached to the first polymer blocks and the first polymer blocks are positioned between the porous polymer substrate and the second polymer blocks. The second polymer blocks are reaction products of a second polymerizable composition comprising a polyether-containing monomer comprising at least one ethylenically unsaturated group and a polyether group.

[0004] In a third aspect, a method for separating a mixture of materials having different sizes and optionally different ionic charges is provided. The method includes preparing or providing a separation article including a solid porous polymer substrate and a plurality of block copolymers grafted to the porous polymer substrate using a reversible inactivation radical polymerization process, the plurality of block copolymers extending from the surface of the porous polymer substrate. The block copolymer includes (1) a first polymer block covalently bonded to the solid porous polymer substrate and (2) a second polymer block covalently linked to the first polymer block, the first polymer block being positioned between the second polymer block and the porous polymer substrate. The first polymer block includes first monomer units having a bonding group that is an acid group or a salt thereof, a basic group or a salt thereof, or a combination thereof for interacting with a material having complementary groups. The second polymer block includes polyether-containing monomer units. The method further includes passing a mixture of materials through the separation article, wherein the second polymer block separates the mixture of materials based on size exclusion or steric exclusion, allowing only a portion of the materials to contact the acid groups, basic groups, or salts thereof of the first polymer block.

Embodiments for Carrying Out the Invention

[0005] Provided are separation articles useful for the separation of composite samples containing mixtures of materials having different sizes and optionally different ionic charges. The separation articles include a plurality of block copolymers grafted to a solid porous polymer substrate using a reversible inactivation radical polymerization process. The block copolymers extend from the surface of the porous polymer substrate. The block copolymers have an outer polymer block (i.e., the second polymer block) that effects size exclusion or steric exclusion, and an inner polymer block (i.e., the first polymer block) having an acidic group or its salt, a basic group or its salt, or a combination thereof, that is small enough to bind to a material having complementary groups and pass through the second polymer block that effects size exclusion or steric exclusion. The separation articles can be used, for example, for the separation of biological materials in a sample.

[0006] As used herein, the terms "a", "an", "the", and "at least one" are used interchangeably.

[0007] The term "and / or" means either or both. For example, "A and / or B" means A alone, B alone, or both A and B.

[0008] The term "alkyl" refers to a monovalent group that is a radical of an alkane. The alkyl group can have 1 to 32 carbon atoms, 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. The alkyl can be linear, branched, cyclic, or a combination thereof. Linear alkyls have at least 1 carbon atom, while cyclic alkyls have at least 3 carbon atoms, and branched alkyls have at least 2 carbon atoms.

[0009] The term "alkylene" refers to a divalent group that is a radical of an alkane. The alkylene group can have 1 to 32 carbon atoms, 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Alkylene can be linear, branched, cyclic, or a combination thereof. Linear alkylene has at least 1 carbon atom, cyclic alkylene has at least 3 carbon atoms, and branched alkylene has at least 2 carbon atoms.

[0010] The term "alkoxy" refers to a monovalent group of the formula -OR a (wherein R a is alkyl as defined above).

[0011] The term "alkenyl" refers to a monovalent group that is a radical of an alkene, which is a hydrocarbon compound having at least one carbon-carbon double bond. In some embodiments, alkenyl has a single carbon-carbon double bond. In some more specific embodiments, alkenyl has an ethylenically unsaturated group (the carbon-carbon double bond is between the last two carbon atoms in the chain). Alkenyl can be linear, branched, or cyclic. Alkenyl often has at least 2, at least 3, at least 4, or at least 5 carbon atoms and can have up to 32 carbon atoms, up to 24 carbon atoms, up to 20 carbon atoms, up to 12 carbon atoms, up to 10 carbon atoms, or up to 5 carbon atoms.

[0012] The term "alkenyloxy" refers to a monovalent group of the formula -OR b (wherein R b is alkenyl as defined above).

[0013] The term "aryl" refers to a monovalent group that is a radical of an aromatic carbocyclic compound. An aryl group has at least one aromatic carbocyclic ring and can have 1 to 3 optional rings attached to or fused with the aromatic carbocyclic ring. The additional rings can be aromatic, aliphatic, or a combination thereof. An aryl group usually has 5 to 20 carbon atoms or 6 to 10 carbon atoms.

[0014] The term "arylene" refers to a divalent group that is a radical of an aromatic carbocyclic compound. An arylene group has at least one aromatic carbocyclic ring and can have 1 to 3 optional rings attached to or fused with the aromatic carbocyclic ring. The additional rings can be aromatic, aliphatic, or a combination thereof. An arylene group usually has 5 to 20 carbon atoms or 6 to 10 carbon atoms.

[0015] The term "aralkyl" refers to an alkyl group substituted with at least one aryl group. That is, an aralkyl group has the formula -R d -Ar (wherein R d is alkylene and Ar is aryl as defined above). An aralkyl group contains 6 to 40 carbon atoms. An aralkyl group often contains an alkylene group having 1 to 20 carbon atoms or 1 to 10 carbon atoms and an aryl group having 5 to 20 carbon atoms or 6 to 10 carbon atoms.

[0016] The term "aralkylene" refers to an alkylene group substituted with at least one aryl group.

[0017] The term "aralkyloxy" refers to a monovalent group having the formula -O-R d -Ar (wherein R d and Ar are the same as those defined above for aralkyl).

[0018] The term "alkaryl" refers to an aryl group substituted with at least one alkyl group. That is, an alkaryl group has the formula -Ar 1-R a (wherein Ar 1 is arylene and R a is alkyl). The alkaryl group contains 6 to 40 carbon atoms. The alkaryl group often contains an arylene group having 5 to 20 carbon atoms or 6 to 10 carbon atoms and an alkyl group having 1 to 20 carbon atoms or 1 to 10 carbon atoms.

[0019] The terms "boronic acid group" and "boronate" are used interchangeably to refer to a group of the formula -B(OH)2. The boronic acid group can exist in the form of a salt having a cationic counterion.

[0020] The terms "carboxylic acid group" and "carboxy" are used interchangeably to refer to a group of the formula -C(=O)-OH. The carboxylic acid group can exist in the form of a salt having a cationic counterion.

[0021] The term "iniferter" is used to refer to a group that can function as a free radical initiator, a chain transfer agent, or a free radical chain terminator under appropriate conditions. An iniferter activated by UV light can be called a "photoiniferter". The iniferters described herein are typically suitable for use in a reversible addition-fragmentation chain transfer (RAFT) polymerization process and may be called RAFT agents.

[0022] The term "hydrocarbyl" refers to a monovalent radical of a hydrocarbon. The hydrocarbyl can be saturated, partially unsaturated, or unsaturated and can have up to 20 carbon atoms, up to 10 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. It often has at least 1 carbon atom or at least 2 carbon atoms. The hydrocarbyl is often alkyl, aryl, aralkyl, or alkaryl.

[0023] The term "hydrocarbylene" refers to a divalent radical of a hydrocarbon. The hydrocarbylene can be saturated, partially unsaturated, or unsaturated and can have up to 40 carbon atoms, up to 20 carbon atoms, up to 10 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. It often has at least 1 carbon atom or at least 2 carbon atoms. The hydrocarbyl is often alkylene, arylene, aralkylene, or alkarylene.

[0024] The term "catenated atom" refers to an atom within a chain (not an atom of a chain substituent).

[0025] The term "catenated heteroatom" means that one or more carbon atoms in a carbon chain are replaced by heteroatoms. The heteroatoms are typically oxygen, sulfur, or nitrogen.

[0026] The term "fluid" refers to a liquid and / or a gas.

[0027] The term "graft density" refers to millimoles per gram of monomer units grafted onto a substrate. The millimoles are calculated by dividing the mass increase by the molecular weight of the monomer and multiplying by 1000. This value is then normalized by dividing by the original mass (grams) of the substrate. The graft density is expressed as millimoles of grafted monomer units per gram of substrate (mmol / g). For clarity, the material being grafted is typically a polymeric material containing multiple monomer units.

[0028] The term "heteroatom" means an atom other than carbon or hydrogen. The heteroatoms are typically sulfur, nitrogen, or oxygen.

[0029] The term "heterohydrocarbyl" refers to a hydrocarbyl in which at least one chain-linked carbon atom, but not all, is replaced by a heteroatom selected from oxygen (-O-), sulfur (-S-), and nitrogen (e.g., -NH-).

[0030] The term "(hetero)hydrocarbyl" refers to a hydrocarbyl, a heterohydrocarbyl, or both.

[0031] The term "heterohydrocarbylene" refers to a hydrocarbylene in which at least one chain-linked carbon atom, but not all, is replaced by a heteroatom selected from oxygen (-O-), sulfur (-S-), and nitrogen (e.g., -NH-).

[0032] The term "(hetero)hydrocarbylene" refers to a hydrocarbylene, a heterohydrocarbylene, or both.

[0033] The term "heteroarylene" refers to an aralkylene having a heteroatom in the aryl group. In other words, it is an alkylene bonded to a heteroaryl, where the heteroaryl is an aryl in which one of the ring carbon atoms is replaced by a heteroatom selected from oxygen (-O-), sulfur (-S-), and nitrogen (e.g., -NH-).

[0034] The term "hydrogen bond acceptor" refers to a heteroatom selected from oxygen, nitrogen, and sulfur having a lone pair of electrons. The hydrogen bond acceptor is often a carbonyl, a carbonyloxy, or an ether oxygen.

[0035] The term "hydrogen bond donor" refers to a moiety consisting of a hydrogen atom covalently bonded to a heteroatom selected from oxygen, nitrogen, and sulfur. The hydrogen bond donor is often an imino, a thio, or a hydroxy.

[0036] The term "hydrogen bonding moiety" means a moiety containing at least one hydrogen bond donor and at least one hydrogen bond acceptor.

[0037] The term "iminocarbonylimino" refers to the formula -N(R e )-C(=O)-N(R e )- [wherein each R e is independently hydrogen, alkyl (e.g., selected from alkyl groups having 1 to 4 carbon atoms), or aryl], meaning a divalent group or moiety. In many cases, one or both of the R e groups are hydrogen.

[0038] The term "iminothiocarbonylimino" refers to the formula -N(R e )-C(=S)-N(R e )- [wherein each R e is independently hydrogen, alkyl (e.g., selected from alkyl groups having 1 to 4 carbon atoms), or aryl], meaning a divalent group or moiety. In many cases, one or both of the R e groups are hydrogen.

[0039] The term "isocyanato" means a group of the formula -N=C=O.

[0040] The term "modified substrate" refers to a polymeric substrate (e.g., a porous polymeric substrate) having a plurality of thiocarbonylthio-containing groups or semipinacol-containing groups covalently bonded thereto.

[0041] The term "oxycarbonylimino" refers to the formula -O-C(=O)-N(R e )- [wherein R e is hydrogen, alkyl (e.g., selected from alkyl groups having 1 to 4 carbon atoms), or aryl], meaning a divalent group or moiety. In many cases, the R e group is hydrogen.

[0042] The term "oxythiocarbonylimino" refers to the formula -O-C(=S)-N(R e )- [wherein R emeans a divalent group or moiety that is hydrogen, alkyl (e.g., selected from alkyl groups having 1 to 4 carbon atoms), or aryl. In many cases, R e is hydrogen.

[0043] The term "ethylenically unsaturated" means a group of the formula -CY=CH2 where Y is hydrogen or hydrocarbyl (e.g., alkyl or aryl).

[0044] The terms "phosphonic acid group" and "phosphono" refer interchangeably to a group of the formula -PO3H2, which is not bonded to an oxygen atom (it is usually bonded to a carbon atom). The phosphonic acid group can exist as a salt having a cationic counterion.

[0045] The terms "phosphoric acid group" and "phosphato" refer interchangeably to a group of the formula -OPO3H2. The phosphoric acid group can exist as a salt having a cationic counterion.

[0046] The terms "polymer" and "polymer material" are used interchangeably and refer to a material formed by reacting one or more monomers. These terms include homopolymers, copolymers, terpolymers, etc. Similarly, the terms "polymerize" and "polymerizing" refer to the process of making a polymer material that can be a homopolymer, copolymer, terpolymer, etc.

[0047] The term "reversible deactivation radical polymerization" or "RDRP (reversible deactivation radical polymerization)" refers to a polymerization process in which the growing chains are rapidly and reversibly activated and deactivated. A plurality of RDRP techniques are available, and among these, the most common ones are a) stable radical-mediated polymerization (for example, nitroxide-mediated polymerization or NMP (nitroxide mediated polymerization)), b) atom transfer radical polymerization (or ATRP (atom transfer radical polymerization)), and c) reversible addition-fragmentation chain transfer polymerization (or RAFT). For an overview of the industrial use of these processes, see M. Destarac, Polymer Chemistry, 2018, Vol. 9, Issue 40, pp. 4947-4967. As used herein, a process mediated by a semipinacol-containing group is considered to be an RDRP polymerization process.

[0048] The term "semipinacol" refers to a monovalent group covalently bonded to a substrate. The semipinacol group often has two aromatic rings bonded via a carbon atom, which carbon atom is also bonded to the substrate and a hydroxy group. The semipinacol group is often represented by formula (A) or formula (B).

[0049]

Chemical formula

[0050] Each R x and R y is hydrogen, alkyl, for example, alkyl having 1 to 4 carbon atoms, hydroxy, alkoxy, for example, alkoxy having 1 to 4 carbon atoms, halo, sulfo, or sulfalkyleneoxy, for example, sulfalkyleneoxy having 1 to 4 carbon atoms. The group X is a single bond, alkylene having 1 to 3 carbon atoms, or a heteroatom such as -O- or -S-. Asterisk ( *(0) indicates the bonding site of the semipinacol group to the substrate. The semipinacol group is typically formed by UV excitation of a type II photoinitiator that forms a semipinacol radical by abstracting hydrogen from the substrate to form a treated substrate radical. These two radicals then combine, and the semipinacol group bonds covalently to the substrate.

[0051] The terms "sulfonic acid group" and "sulfono" refer interchangeably to a group of the formula -SO3H, which is not bonded to an oxygen atom (it is usually bonded to a carbon atom). The sulfonic acid group can exist as a salt having a cationic counterion.

[0052] The terms "sulfate group" and "sulfato" refer interchangeably to a group of the formula -OSO3H. The sulfate group can exist as a salt having a cationic counterion.

[0053] The term "thiocarbonylimino" refers to a divalent group or moiety of the formula -C(=S)NR e -[wherein R e is hydrogen, alkyl (e.g., selected from alkyl groups having 1 to 4 carbon atoms), or aryl]. The group R e is often hydrogen.

[0054] The term "thiocarbonylthio" refers to the divalent group -S-C(=S)-.

[0055] The term "treated substrate" refers to a polymeric substrate having a plurality of free radicals available for reaction with another compound such as a thiocarbonylthio-containing compound or a semipinacol radical.

[0056] The terms "in a range of" or "in the range of" are used interchangeably to refer to all values within the range and the endpoints of the range.

[0057] The separation article includes a solid porous polymer substrate and a plurality of block copolymers grafted to the porous polymer substrate and extending from the surface of the porous polymer substrate. The block copolymer typically includes a first polymer block covalently bonded to the porous polymer substrate and a second polymer block covalently bonded to the first polymer block, with the first polymer block positioned between the porous polymer substrate and the second polymer block. The first polymer block has a plurality of acidic monomer units or salts thereof, basic monomer units or salts thereof, or combinations thereof, and the second polymer block has a plurality of polyether-containing monomer units that can be optionally crosslinked.

[0058] The separation article can be prepared by grafting a plurality of first polymer blocks to a solid porous polymer substrate using a reversible addition-fragmentation chain transfer (RAFT) polymerization process, where the first polymer blocks are covalently attached to the porous polymer substrate. In most embodiments, the first polymer block is directly bonded to a carbon atom in the backbone of the polymer material of the porous polymer substrate. The first polymer block is the reaction product of a first polymerizable composition comprising 1) an acidic monomer containing an ethylenically unsaturated group and an acid group or salt thereof, 2) a basic monomer containing an ethylenically unsaturated group and a basic group or salt thereof, or 3) a combination thereof. The plurality of second polymer blocks are covalently attached to the first polymer block using a reversible addition-fragmentation chain transfer (RAFT) polymerization process. The second polymer block is the reaction product of a second polymerizable composition comprising a polyether-containing monomer having at least one ethylenically unsaturated group and a polyether group. The first polymer block is positioned between the second polymer block and the solid porous polymer substrate. Additional polymer blocks can be covalently bonded to the second polymer block, but the separation article typically has a plurality of linked diblock copolymers.

[0059] Porous polymer substrate The separated article has a solid, porous polymer substrate. The term "solid" with respect to the porous polymer substrate means that the substrate is not a liquid and is not dissolved in a solution. The pores of the porous polymer substrate can have any desired average size. In some embodiments, the pores are macroporous, mesoporous, microporous, or a mixture thereof. As used herein, the term "macroporous" refers to a polymer substrate having pores with a diameter greater than 50 nanometers, the term "mesoporous" refers to a polymer substrate having pores with a diameter in the range of 2 nanometers to 50 nanometers, and the term "microporous" refers to a material having pores with a diameter less than 2 nanometers.

[0060] The terms "solid porous polymer substrate", "porous polymer substrate", "polymer substrate", "substrate", and similar variations can be used interchangeably herein.

[0061] The porous polymer substrate can have any desired size, shape, and form. For example, the porous polymer substrate can be in the form of particles, fibers, films, nonwoven webs, woven webs, membranes, sponges, or sheets. In some examples, the polymer substrate is a porous membrane or a porous nonwoven web. To prepare large separated articles or many separated articles and to facilitate manufacture, the polymer substrate can be in the form of a roll, such as a roll of film, nonwoven web, woven web, membrane, sponge, or sheet, or can be formed from a roll. This enables the preparation of separated articles using roll-to-roll processing. The porous polymer substrate can include a single layer or multiple layers of the same or different polymer materials.

[0062] The porous polymer substrate is often formed from a thermoplastic material. Suitable thermoplastics include polyolefins, poly(isoprene), poly(butadiene), fluorinated polymers, chlorinated polymers, polyamides, polyimides, polyethers, poly(ether sulfone), poly(sulfone), poly(vinyl acetate) and its copolymers such as poly(ethylene)-co-poly(vinyl acetate), polyesters such as poly(lactic acid), poly(vinyl alcohol) and its copolymers such as poly(ethylene)-co-poly(vinyl alcohol), poly(vinyl ester), poly(vinyl ether), poly(carbonate), polyurethane, poly((meth)acrylate) and its copolymers, and combinations thereof, but are not limited thereto.

[0063] Suitable polyolefins for the porous polymer substrate include poly(ethylene), poly(propylene), poly(1-butene), copolymers of ethylene and propylene, alpha olefin copolymers (e.g., copolymers of ethylene or propylene with 1-butene, 1-hexene, 1-octene, and 1-decene), poly(ethylene-co-1-butene), poly(ethylene-co-1-butene-co-1-hexene), poly(butadiene) and its copolymers, and combinations thereof.

[0064] Suitable fluorinated polymers for the porous polymer substrate include poly(vinyl fluoride), poly(vinylidene fluoride), copolymers of vinylidene fluoride (e.g., poly(vinylidene fluoride-co-hexafluoropropylene)), copolymers of chlorotrifluoroethylene (e.g., poly(ethylene-co-chlorotrifluoroethylene)), and combinations thereof.

[0065] Suitable polyamides for the porous polymer substrate include various nylon compositions, such as poly(iminodiacyliminohexamethylene), poly(iminodiacyliminodecamethylene), polycaprolactam, and combinations thereof. Suitable polyimides include poly(pyromellitimide), and combinations thereof.

[0066] Suitable poly(ether sulfone) for the porous polymer substrate includes poly(diphenyl ether sulfone), poly(diphenyl sulfone-co-diphenylene oxide sulfone), and combinations thereof.

[0067] Suitable copolymers of vinyl acetate for the porous polymer substrate include copolymers of ethylene and vinyl acetate, and terpolymers of vinyl acetate, vinyl alcohol, and ethylene.

[0068] In some embodiments, the porous polymer substrate is a porous membrane having an average pore diameter (average longest pore diameter) often greater than 0.1 micrometer to minimize size exclusion separation, minimize diffusion constraints, and maximize surface area and separation. Generally, the average pore diameter can be in the range of 0.1 to 10 micrometers. For example, the average pore diameter can be at least 0.2 micrometer, at least 0.4 micrometer, at least 0.6 micrometer, or at least 0.8 micrometer, and up to 8 micrometers, up to 6 micrometers, up to 4 micrometers, or up to 2 micrometers.

[0069] The porous polymer substrate can be a macroporous membrane such as a thermally induced phase separation (TIPS) membrane. TIPS membranes are often prepared by forming a solution of a thermoplastic material and a second material that exceeds the melting point of the thermoplastic material. Upon cooling, the thermoplastic material crystallizes and phase separates from the second material. The crystallized material is often stretched. The second material is optionally removed either before or after stretching. Macroporous membranes are further described in U.S. Patent Nos. 4,539,256 (Shipman), 4,726,989 (Mrozinski), 4,867,881 (Kinzer), 5,120,594 (Mrozinski), 5,260,360 (Mrozinski), and 5,962,544 (Waller, Jr.). Some exemplary TIPS membranes include poly(vinylidene fluoride) (PVDF), polyolefins such as poly(ethylene) or poly(propylene), vinyl-containing polymers or copolymers such as ethylene-vinyl alcohol copolymers and butadiene-containing polymers or copolymers, and (meth)acrylate-containing polymers or copolymers. TIPS membranes containing PVDF are further described in U.S. Patent No. 7,338,692 (Smith et al.).

[0070] In some embodiments, the porous polymer substrate can be a nylon macroporous film or sheet (e.g., a macroporous membrane), such as those described in U.S. Patent Nos. 6,056,529 (Meyering et al.), 6,267,916 (Meyering et al.), 6,413,070 (Meyering et al.), 6,776,940 (Meyering et al.), 3,876,738 (Marinaccio et al.), 3,928,517 (Knight et al.), 4,707,265 (Barnes, Jr. et al.), and 5,458,782 (Hou et al.).

[0071] In other embodiments, the porous polymer substrate can be a nonwoven web that can include a nonwoven web produced by any of the generally known methods for making nonwoven webs. As used herein, the term "nonwoven web" refers to a fabric having a structure of individual fibers or filaments randomly and / or alternately arranged in a mat-like manner in one direction.

[0072] For example, fibrous nonwoven webs can be made by wet laying, carding, air laying, spunlace, spunbond, or meltblowing techniques, or combinations thereof. Spunbond fibers are typically small diameter fibers formed by extruding a molten thermoplastic polymer as filaments from a plurality of fine, usually circular capillaries of a spinneret, and the diameter of the extruded fibers rapidly decreases. Meltblown fibers are typically formed by extruding a molten thermoplastic material as a molten thread or filament through a plurality of fine, usually circular die capillaries into a high-speed, usually heated gas (e.g., air) stream, whereby the filaments of the molten thermoplastic material are thinned and the diameter is reduced. The meltblown fibers are then carried by the high-speed gas stream and deposited on a collection surface to form a web of randomly dispersed meltblown fibers. Any of the nonwoven webs can be made from a single type of fiber or from two or more types of fibers having different thermoplastic polymer types and / or thicknesses.

[0073] Further details regarding useful methods for manufacturing nonwoven webs are described in Wente's "Superfine Thermoplastic Fibers," Indus. Eng. Chem., 48, 1342 (1956) and Wente et al.'s "Manufacture of Superfine Organic Fibers," Naval Research Laboratories Report No. 4364 (1954).

[0074] The nonwoven web substrate may optionally further include one or more scrim layers. For example, either or both of the major surfaces of the nonwoven web may each optionally further include a scrim layer. A scrim, which is typically a woven or nonwoven reinforcing layer made from fibers, is included to provide strength to the nonwoven web. Suitable scrim materials include, but are not limited to, nylon, polyester, fiberglass, polyethylene, polypropylene, and the like. The average thickness of the scrim can vary, but is often in the range of about 25 to about 100 micrometers, preferably about 25 to about 50 micrometers. The scrim layer may optionally be bonded to the nonwoven article. A variety of adhesive materials can be used to bond the scrim to the nonwoven. Alternatively, the scrim can be heat-bonded to the nonwoven web.

[0075] The porosity of the nonwoven substrate is typically characterized by properties such as fiber diameter, basis weight, or solidity, rather than pore diameter. The fibers of the nonwoven substrate are typically microfibers having an effective fiber diameter of at least 0.5, 1, 2, or even 4 micrometers, and at most 15, 10, 8, or even 6 micrometers when calculated according to the method described in Davies, C.N., "The Separation of Airborne Dust and Particles," Institution of Mechanical Engineers, London, Proceedings 1B, 1952. The nonwoven substrate preferably has a basis weight of at least 5, 10, 20, or even 50 g / m 2 , and at most 800, 600, 400, 200, or even 100 g / m 2has a basis weight within the range. The minimum tensile strength of the nonwoven web is about 4.0 Newtons. For better fiber bonding and entanglement in the cross-web direction, it is generally recognized that the tensile strength of the nonwoven substrate in the machine direction is lower than that in the cross-web direction. The nonwoven web loft is measured by solidity, a parameter that defines the solid fraction in the volume of the web. Lower solidity values indicate a larger web loft. Solidity (α) is given by α = m f ÷ ρ f × L 不織布 (where m f is the fiber mass per unit sample surface area, ρ f is the fiber density, and L 不織布 is the nonwoven thickness) and is a fraction without units typically represented by. Solidity is used herein to refer to the nonwoven substrate itself and not to the functionalized nonwoven substrate. When the nonwoven substrate contains a mixture of two or more types of fibers, the individual solidities are determined for each type of fiber using the same L 不織布 and these individual solidities are summed together to obtain the solidity α of the web.

[0076] Grafting of the first polymer block onto the porous polymer substrate Multiple block copolymers are grafted onto the surface of the porous polymer substrate using reversible deactivation radical polymerization (RDRP), which may also be referred to as controlled radical polymerization. In this polymerization method, free radical polymerization can be carried out under conditions that mimic living polymerization in the sense that the termination reaction is minimized, as described, for example, in the paper by N. Corrigan et al. in Progress in Polymer Science, 2020, 111, 101311. Using RDRP, the polymer architecture, microstructure, molecular weight, and molecular weight distribution can typically be controlled for solution polymerization reactions.

[0077] The RDRP process can be utilized to covalently modify a porous substrate. The attachment of an RDRP initiator to the substrate enables surface-initiated RDRP (SI-RDRP), or graft polymerization from the surface of the substrate (see the above-mentioned Progress in Polymer Science paper). Attachment of an RDRP initiator to a porous polymer substrate is often very difficult, requires multiple synthetic steps, and can be highly substrate-dependent. The porous polymer substrate typically must have functional groups to which the RDRP initiator can be covalently attached, usually via a condensation reaction. For example, a carboxylic acid-containing RDRP agent can be covalently attached to a cellulose membrane or fiber by esterification to the cellulose hydroxyl group. If suitable functional groups are not available, the substrate must first be chemically modified to introduce functional groups.

[0078] A simple and industrially feasible method for directly attaching an RDRP agent to a solid polymer substrate without the need for chemical modification is described in U.S. Patent Application Publication No. 2021 / 0095088 (Rasmussen et al.). More specifically, multiple thiocarbonylthio-containing groups can be directly covalently linked to a solid porous polymer substrate. The thiocarbonylthio-containing groups typically covalently bond directly to carbon atoms in the main chain of the polymer material in the polymer substrate. These modified substrates having directly attached RDRP agents (e.g., thiocarbonylthio-containing groups) can be used as RDRP initiators or photoinitiators. This approach enables the grafting of various free-radical polymerizable monomers to the substrate, as shown in U.S. Patent Application Publication No. 2020 / 0368694 (Rasmussen et al.). This approach is referred to herein as "Grafting Method 1" and is further described below.

[0079] In another simple and industrially feasible method, the RDRP agent is combined with the monomer in solution. Unlike Grafting Method 1, there is no separate step of forming a modified substrate having a plurality of thiocarbonylthio-containing groups directly covalently bonded, which is performed before the polymerization of the monomer. Rather, the thiocarbonylthio-containing compound and the type II photoinitiator are combined with the monomer in solution. The solution is coated on the substrate, and then the coated substrate is subjected to actinic radiation (e.g., UV irradiation). When using a photoactive substrate, the type II photoinitiator is optional. This method is referred to herein as "Grafting Method 2" and will be further described below.

[0080] In the modification of "Grafting Method 2", the substrate is converted to a substrate treated by e-beam irradiation, and then the treated substrate is combined with a solution containing the monomer and the RDRP agent.

[0081] The thiocarbonylthio-containing compounds and the thiocarbonylthio-containing groups can be any of those known to be useful as RAFT agents, for example, those described in Moad et al., Aust. J. Chem, 2005, 58, 279-410. In this reference, suitable RAFT agents are described as those of the formula R-S-C(=S)-Z (wherein Z is selected to activate or deactivate the thiocarbonyl double bond to adjust the stability of the intermediate radical and R is a free radical leaving group). This reference teaches that the RAFT agent should have a reactive C=S double bond, the S-R bond should cleave easily (i.e., this bond should be weak), it should not cause side reactions, and the released radical (R * ) should efficiently restart the polymerization.

[0082] Any known RAFT agent, including all those described in the above reference by Moad et al., can be used herein, particularly with respect to Grafting Method 2, but the formula -S-C(=S)-R 1It may be advantageous to select a RAFT agent having a thiocarbonylthio group. The group R in this thiocarbonylthio-containing group 1 is typically selected to be alkoxy, aralkyloxy, alkenyloxy or -N(R 4 )2. Each R 4 is alkyl or two adjacent R 4 groups combine with the nitrogen to which they are both attached to form a first heterocyclic ring having 1 to 3 heteroatoms selected from nitrogen, oxygen, and sulfur, which is saturated or unsaturated and optionally fused to one or more second rings which are carbocyclic or heterocyclic. Such thiocarbonylthio-containing compounds can be advantageous when using either grafting method 1 or grafting method 2, but these compounds are particularly advantageous when using grafting method 1. The thiocarbonyl-containing groups selected for use in grafting method 1 are often not typical agents for reversible addition-fragmentation chain transfer (RAFT) polymerization reactions.

[0083] R 1 Suitable alkoxy groups for R typically have at least 1 carbon atom, at least 2 carbon atoms, at least 3 carbon atoms, or at least 4 carbon atoms and can have up to 20 carbon atoms, up to 18 carbon atoms, up to 16 carbon atoms, up to 12 carbon atoms, or up to 10 carbon atoms. Some exemplary alkoxy groups have 1 to 20 carbon atoms, 1 to 10 carbon atoms, 2 to 10 carbon atoms, 1 to 6 carbon atoms, 2 to 6 carbon atoms, or 1 to 4 carbon atoms.

[0084] R 1Alkenyloxy groups suitable for [description] typically have at least 2 carbon atoms, at least 3 carbon atoms, or at least 4 carbon atoms and can have up to 20 carbon atoms, up to 18 carbon atoms, up to 16 carbon atoms, up to 12 carbon atoms, or up to 10 carbon atoms. Some exemplary alkenyloxy groups have 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 6 carbon atoms, or 2 to 4 carbon atoms.

[0085] R 1 Aralkyloxy groups suitable for [description] typically contain an alkylene group having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms and an aryl group having 5 to 12 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms. The aryl group in the aralkyloxy group is often phenyl.

[0086] In some embodiments of the thiocarbonylthio-containing group, R 1 is of the formula -N(R 4 )2 [wherein each R 4 is alkyl or two adjacent R 4 groups combine with the nitrogen to which they are both attached to form a first heterocyclic ring having 1 to 3 heteroatoms selected from nitrogen, oxygen, and sulfur and 2 to 5 carbon atoms, which is saturated or unsaturated (e.g., partially or fully unsaturated) and optionally fused to one or more second rings, which are carbocyclic or heterocyclic].

[0087] Suitable alkyl R 4 groups typically have at least 1 carbon atom, at least 2 carbon atoms, at least 3 carbon atoms, or at least 4 carbon atoms and can have up to 20 carbon atoms, up to 18 carbon atoms, up to 16 carbon atoms, up to 12 carbon atoms, or up to 10 carbon atoms. Some exemplary alkyl groups have 1 to 20 carbon atoms, 1 to 10 carbon atoms, 2 to 10 carbon atoms, 1 to 6 carbon atoms, 2 to 6 carbon atoms, or 1 to 4 carbon atoms.

[0088] When the formula -N(R 4 )2 forms a first heterocyclic ring, the heterocyclic ring typically has 5 to 7 ring members or 5 to 6 ring members and has a first ring structure having 1 to 3 heteroatoms or 1 to 2 heteroatoms in the ring. The ring members that are not heteroatoms are carbon. When there is 1 heteroatom in the first ring structure, the heteroatom is nitrogen. When there are 2 or 3 heteroatoms in the first ring structure, 1 heteroatom is nitrogen, and any further heteroatoms are selected from nitrogen, oxygen, and sulfur. The first ring may optionally be fused to one or more second ring structures that are heterocyclic or carbocyclic and saturated or unsaturated (e.g., partially or completely unsaturated). When the second ring structure is heterocyclic, it typically has 5 to 7 or 5 to 6 ring members and 1, 2, or 3 heteroatoms selected from nitrogen, oxygen, and sulfur. When the second ring structure is carbocyclic, it is often benzene or a saturated ring having 5 or 6 ring members. In many embodiments, the heterocyclic ring has a monocyclic structure having 5 or 6 ring members and 1 or 2 heteroatoms in the ring. Examples of heterocyclic rings include, but are not limited to, morpholino, thiomorpholino, pyrrolidinyl, piperidinyl, homopiperidinyl, indolyl, carbazolyl, imidazolyl, and pyrazolyl.

[0089] Thiocarbonylthio-containing compounds often have the general formula Q-S-C(=S)-R 1 (wherein Q is the remainder of the compound). When the thiocarbonylthio-containing compound contains two or more second groups (or even a third group) of the formula -S-C(=S)-R 1 , the group Q can include such groups. The group R 1 is the same as defined above. These thiocarbonylthio-containing compounds can be referred to interchangeably as RAFT agents or iniferters (e.g., photo-iniferters).

[0090] The general formula Q-S-C(=S)-R 1Some exemplary thiocarbonylthio-containing compounds are symmetric compounds of formula (I). R 1 -C(=S)-S-S-C(=S)-R 1 (I)

[0091] The group R in the thiocarbonylthio-containing group 1 is typically selected to be alkoxy, aralkyloxy, alkenyloxy or -N(R 4 )2. Each R 4 is alkyl or two adjacent R 4 groups combine with the nitrogen to which they are both attached to form a first heterocyclic ring having 1 to 3 heteroatoms selected from nitrogen, oxygen, and sulfur, which is saturated or unsaturated and optionally fused to one or more second rings which are carbocyclic or heterocyclic.

[0092] Examples of the thiocarbonylthio-containing compound of formula (I) include dixanthogen (wherein R 1 is ethoxy) and tetraethylthiuram disulfide (wherein R 1 is represented by the formula -N(R 4 )2 and each R 4 is ethyl), but are not limited thereto.

[0093] Another exemplary thiocarbonylthio-containing compound of the general formula Q-S-C(=S)-R 1 is represented by formula (II).

[0094]

Chemical formula

[0095] In formula (II), each R 1 is alkoxy, aralkyloxy, alkenyloxy, or -N(R 4 )2. Suitable alkoxy, aralkyloxy, alkenyloxy, and -N(R 1 for R 4)The two groups are the same as those described above for the thiocarbonylthio-containing group. Group R 2 is of the formula -(OR 5 ) q -OR 6 or of the formula -C(=O)-X-R 7 . Group R 3 is hydrogen, alkyl, aryl, substituted aryl (i.e., aryl substituted with at least one alkyl, alkoxy, or halo), alkaryl, a group of the formula -C(=O)-OR 8 , or a group of the formula -C(=O)-N(R 9 )2. Group R 5 is alkylene, group R 6 is alkyl, and q is an integer equal to at least 0. Group R 7 is hydrogen, alkyl, aryl, aralkyl, or substituted aryl (i.e., aryl substituted with at least one alkyl, alkoxy, or halo). Groups R 8 and R 9 are each independently alkyl, aryl, aralkyl, or alkaryl. Group X is a single bond, oxy, or -NR 10 . Group R 10 is hydrogen, alkyl, aryl, aralkyl, or alkaryl. The compound of formula (II) can be formed using any suitable method such as the method described in U.S. Patent Application Publication No. 2021 / 0095088 (Rasmussen et al.).

[0096] Examples of the thiocarbonylthio-containing compound of formula (II) include 1,1-bis(10-undecenyloxycarbonothioylsulfanyl)methyl ether, methyl 2,2-bis(isopropoxycarbonothioylsulfanyl)-2-methoxy-acetate, 1,1-bis(isopropoxycarbonothioylsulfanyl)methyl methyl ether, 1,1-bis(isopropoxycarbonothioylsulfanyl)methyl butyl ether, 1,1-bis(ethoxycarbonothioylsulfanyl)methyl butyl ether, 2-ethylhexyl 2,2-bis(isopropoxycarbonothioylsulfanyl)acetate, methyl 2,2-bis(isopropoxycarbonothioylsulfanyl)acetate, tert-butyl 2,2-bis(isopropoxycarbonothioylsulfanyl)acetate, 1,1-bis(isopropoxycarbonothioylsulfanyl)-2-propanone, 2,2-bis(isopropoxycarbonothioylsulfanyl)-1-phenylethanone, and 2,2-bis(isopropoxycarbonothioylsulfanyl)-1-(4-bromophenyl)ethenone, phenyl 2,2-bis(isopropoxycarbonothioylsulfanyl)acetate, N,N-dibutyl-2,2-bis(isopropoxycarbonothioylsulfanyl)acetamide, 1,1-bis(diethylcarbamothioylsulfanyl)methyl butyl ether, 1,1-bis(diethylcarbamothioylsulfanyl)methyl methyl ether, 2-ethylhexyl 2,2-bis(diethylcarbamothioylsulfanyl)acetate, methyl 2,2-bis(diethylcarbamothioylsulfanyl)acetate, and octyl 2,2-bis(diethylcarbamothioylsulfanyl)acetate, but are not limited thereto.

[0097] Another exemplary thiocarbonylthio-containing compound of the general formula Q-S-C(=S)-R 1 is represented by formula (III). R 1 -C(=S)-S-CH2-R 12 (III)

[0098] Group R 1is the same as that defined above for the thiocarbonylthio-containing group. R 12 is the group of the formula -C(=O)-OR 13 (wherein each R 13 is hydrogen, alkyl, aryl, aralkyl or alkaryl), -C(=O)-R 14 (wherein each R 14 is independently alkyl, aryl, aralkyl or alkaryl), the group of the formula -OR 15 (wherein R 15 is alkyl, aryl, aralkyl or alkaryl), or the group of the formula -C(=O)-N(R 16 )2(wherein R 16 are each independently hydrogen or alkyl). When R 13 is hydrogen, the R 12 group may be neutralized to be the group of the formula -C(=O)-O - M + (wherein M+ is an alkali metal ion, a tetraalkylammonium ion, a trialkylammonium ion, or a dialkylammonium ion).

[0099] Specific examples of the thiocarbonylthio-containing compound of formula (III) include, but are not limited to, methyl 2-ethoxycarbonothioylsulfanylacetate, O-ethyl-(2-amino-2-oxo-ethyl)sulfanylmethanethioate, (isopropoxycarbonothioylsulfanyl)methyloctyl ether, 2-ethoxycarbonothioylsulfanylacetate, and the sodium salt. The preparation of these compounds is described in US Patent Application Publication No. 2021 / 0095088 (Rasmussen et al.).

[0100] Using grafting method 1, a thiocarbonylthio-containing group is grafted onto the surface of a porous polymer substrate to form a modified substrate. The polymer substrate itself typically does not contain a thiocarbonylthio-containing group. That is, the polymer substrate does not contain a polymer material having a thiocarbonylthio-containing group (for example, a (meth)acrylate polymer having a pendant thiocarbonylthio-containing group), and / or does not contain a coating layer containing a polymer material having a thiocarbonylthio-containing group. Alternatively, additional thiocarbonyl-containing groups can be grafted onto the polymer substrate or a coating layer containing a thiocarbonylthio-containing group. By grafting, the density of the thiocarbonylthio-containing groups on the surface of the polymer substrate can be substantially increased.

[0101] The modified substrate has a plurality of thiocarbonylthio-containing groups directly covalently bonded to the surface of the porous polymer substrate. The thiocarbonylthio-containing groups typically covalently bond to the carbon atoms of the polymer backbone of the porous polymer substrate. The thiocarbonylthio-containing groups covalently bond by reacting with free radicals on the surface of the porous polymer substrate. Various methods can be used to generate free radicals on this surface. A polymer substrate having free radicals available for further reaction is referred to as a "treated substrate".

[0102] In a first method of forming a treated substrate, an absorption solution is prepared. The absorption solution contains a type II photoinitiator dissolved in a solvent. Examples of the solvent can include water and / or an organic solvent. The absorption solution is applied to the surface of the porous polymer substrate as a coating layer. Then, the coating layer is typically exposed to actinic radiation in the ultraviolet region of the electromagnetic spectrum. When exposed to actinic radiation, the type II photoinitiator extracts hydrogen from the porous polymer substrate, resulting in the generation of free radicals on its surface and the formation of a treated substrate.

[0103] The type-II photoinitiator contained in the absorption solution is typically an aromatic ketone compound. Examples include, but are not limited to, benzophenone, carboxybenzophenone (e.g., 3-carboxybenzophenone), sodium 4-(3-sulfopropyl)benzophenone-3-sulfonate, Michler's ketone, benzil, anthraquinone, 5,12-naphthacenedione, aceanthraquinone, benz[a]anthracene-7,12-dione, 1,4-chrysenedione, 6,13-pentacenedione, 5,7,12,14-pentacenetetrone, 9-fluorenone, anthrone, xanthone, 2-(3-sulfopropylthioxanthen-9-one), acridone, dibenzosuberone, acetophenone, and chromone.

[0104] The absorption solution can contain any suitable amount of the type-II photoinitiator. The concentration is often in the range of 0.1 to 20 weight percent based on the total weight of the type-II photoinitiator and the solvent. For example, the concentration can be at least 0.2 weight percent, at least 0.5 weight percent, at least 1 weight percent, at least 2 weight percent, or at least 5 weight percent, and can be up to 20 weight percent, up to 16 weight percent, up to 12 weight percent, up to 10 weight percent, up to 8 weight percent, up to 6 weight percent, or up to 5 weight percent, depending on the solubility in the solvent.

[0105] Solvents suitable for use in the absorbing solution are typically organic solvents, but may also be water (when the type II photoinitiator is water-soluble) or a mixture of water and an organic solvent. Suitable aprotic polar organic solvents include esters (e.g., ethyl acetate, propyl acetate), alkoxyalkyl acetates (e.g., methoxyethyl acetate, ethoxyethyl acetate, propoxyethyl acetate, and butoxyethyl acetate), trialkyl phosphates, such as triethyl phosphate, ketones (e.g., acetone, methyl ethyl ketone, methyl propyl ketone, and methyl isobutyl ketone), sulfoxides (e.g., dimethyl sulfoxide), and mixtures thereof. Suitable protic polar organic solvents include alcohols (e.g., methanol, ethanol, propanol, isopropanol, n-butanol, and tert-butyl alcohol), glycols (e.g., ethylene glycol and propylene glycol), glycol ethers (e.g., methoxyethanol, ethoxyethanol, propoxyethanol, butoxyethanol, methyl carbitol, and ethyl carbitol), and mixtures thereof. The solvent can be water (e.g., when the type II photoinitiator is soluble in water) or, if desired, an organic solvent mixed with water. Suitable nonpolar organic solvents include alkanes (e.g., pentane, hexane, heptane, isooctane, and decane), aromatic solvents (e.g., benzene, toluene, and xylene), and ethers (e.g., diethyl ether, tetrahydrofuran, dioxane). They may be useful in some cases, but most alcohols and ethers are not preferred as solvents because they tend to interfere with the hydrogen abstraction reaction.

[0106] Any method of applying the absorption solution can be used. In many methods, the absorption solution is applied to the polymer substrate as a coating layer. Prior to exposing the treated substrate to actinic radiation, pressure can optionally be applied to remove air bubbles and excess absorption solution. For example, a cover film that is transparent to actinic radiation can be applied such that the absorption coating layer is positioned between the polymer substrate and the cover film. Pressure can be applied to the surface of the cover film on the opposite side of the absorption coating.

[0107] The actinic radiation source is often an ultraviolet (UV) light source. The UV light can be provided by various light sources such as light emitting diodes (LEDs), black lights, medium pressure mercury lamps, etc., or combinations thereof. The actinic radiation can also be provided using a higher intensity light source such as a light source available from Fusion UV Systems Inc. The ultraviolet light source generally provides from 10 mW / cm 2 over a wavelength range of 280 to 400 nanometers, as measured, for example, using a UVIMAP™ UM365L-S radiometer manufactured by Electronic Instrumentation & Technology, Inc. (Sterling, VA) in accordance with procedures approved by the National Institute of Standards and Technology. Alternatively, a relatively low intensity light source such as a black light that provides generally from 10 mW / cm 2 greater, preferably from 15 to 450 mW / cm 2 intensity can be used, such as a medium pressure mercury lamp. The exposure time can be up to about 30 minutes or more.

[0108] In some embodiments, it is preferred to use light that emits light in a narrow spectrum in the ultraviolet region of the electromagnetic spectrum. These light sources, including LEDs and lasers, can increase the rate of free radical generation or increase the rate of polymerization while maintaining the reactivity of the polymer material in subsequent monomer grafting steps.

[0109] The thiocarbonylthio-containing compound can be present when free radicals are generated on the surface of the solid polymer substrate or can be introduced after the generation of free radicals. When the thiocarbonylthio-containing compound is present during free radical generation, the thiocarbonylthio-containing compound is typically dissolved in the absorption solution together with a type II photoinitiator. When the thiocarbonylthio-containing compound is not present during free radical generation, the intermediate semipinacol radical derived from the type II photoinitiator via hydrogen abstraction typically couples with the radicals on the surface of the substrate to form a semipinacol group. The thiocarbonylthio-containing compound can be applied as a second coating layer to the solid polymer substrate containing the semipinacol group. The coated substrate is again exposed to actinic radiation to regenerate substrate radicals and move the thiocarbonylthio-containing group to the surface of the substrate.

[0110] In another method useful for generating free radicals on the surface of the polymer substrate, the substrate itself is photoactive and a type II photoinitiator is not required. An absorption solution containing the thiocarbonylthio-containing compound dissolved in a solvent is prepared. The absorption solution is applied as a coating layer to the surface of the polymer substrate. The coating layer is then typically exposed to actinic radiation in the ultraviolet region of the electromagnetic spectrum. Upon exposure to actinic radiation, the polymer substrate absorbs sufficient energy to break some of its covalent bonds, resulting in the generation of free radicals on its surface and the formation of the treated substrate. Thereafter, the thiocarbonylthio-containing group migrates to the substrate. Examples of photoactive polymer substrates include polysulfone and poly(ether sulfone). Other photoactive polymer substrates often contain aromatic groups such as, for example, poly(methylphenylsilane) and various homopolymers and block copolymers of polyimides based on benzophenone tetracarboxylic dianhydride.

[0111] In another method for generating free radicals on the surface of a polymer substrate, ionizing radiation is used instead of type II photoinitiators. As used herein, the term "ionizing radiation" refers to radiation of sufficient dose and energy to form free radical reaction sites on and / or in the bulk of the polymer substrate. The radiation has sufficient energy if it is absorbed by the polymer substrate and results in cleavage of chemical bonds and formation of free radicals in the substrate. Ionizing radiation is often beta radiation, gamma radiation, electron beam radiation, X-ray radiation, plasma radiation, or other suitable types of electromagnetic radiation. Preferably, the ionizing radiation is performed in an inert environment to prevent oxygen from reacting with the radicals.

[0112] In many embodiments of this method, the ionizing radiation is electron beam radiation, gamma ray radiation, X-ray radiation, or plasma radiation because suitable generating devices are readily available. Electron beam generating devices are commercially available, for example, the ESI ELECTROCURE EB SYSTEM from Energy Sciences, Inc. (Wilmington, MA, USA) and the BROADBEAM EB PROCESSOR from E-beam Technologies (Davenport, IA, USA). Gamma ray radiation generating devices are commercially available from MDS Nordion, which uses a cobalt 60 high energy source.

[0113] For any given type of ionizing radiation, the delivered dose can be measured according to ISO / ASTM52628-13, "Standard Practice for Dosimetry in Radiation Processing" by ASTM International (West Conshohocken, PA). By varying the extractor grid voltage, beam diameter, exposure time, and distance from the irradiation source, various dose rates can be obtained.

[0114] When ionizing radiation is used, free radicals are typically formed on the surface of the polymeric substrate prior to contacting the thionocarbonylthio-containing compound. That is, there is a first step of generating free radicals on the surface of the solid polymeric substrate to form a treated substrate, and a second step of applying a coating layer of the thionocarbonylthio-containing compound to the treated substrate. The thionocarbonylthio-containing compound reacts with the polymeric substrate having free radicals (i.e., the treated substrate), and the thionocarbonylthio-containing group is covalently bonded to the polymeric substrate to form a modified substrate.

[0115] The thionocarbonylthio-containing group typically binds (e.g., grafts) to the polymeric substrate in the modified substrate. In most cases, the thionocarbonylthio-containing group binds directly to a carbon atom in the main chain of the polymeric material used to form the porous polymeric substrate. Typically, there is no intervening linking group such as an ester bond, an amide bond, a urethane bond, an ether bond, or a siloxane bond between the polymeric substrate and the thionocarbonyl-containing group.

[0116] When Grafting Method 1 is used, the thionocarbonylthio-containing compound reacts with a porous polymeric substrate (PPS) as shown in Reaction Scheme A.

[0117]

Chemical formula

[0118] In Reaction Scheme A, the free radical site is first generated on the porous polymeric substrate (PPS) in Reaction I to form PPS * which represents a porous polymeric substrate having free radicals (i.e., the treated substrate) (1). When the thionocarbonylthio-containing compound (2) contacts the porous polymeric substrate having free radicals (1) in Reaction II, the group -S-C(=S)-R * is formed. 1subsequently releases radical Q * (5) migrates to the porous polymer substrate via the intermediate sulfur-stabilized radical (3) that releases * . This results in radical migration from the surface of the substrate to the group Q of the thiocarbonylthio-containing compound. Reaction (II) has been shown to be reversible, but the reaction is not necessarily reversible when the forward reaction can occur. The modified substrate is PPS-S-C(=S)-R 1 (4). For the sake of simplicity, reaction scheme A shows only one -S-C(=S)-R 1 group bonded to the porous polymer substrate, but there are multiple such bonded groups on the modified substrate.

[0119] The group Q in the thiocarbonylthio-containing compound becomes a free radical during the migration process shown in reaction scheme A. This group can be selected to be weak enough so that the S-Q bond allows for homolytic cleavage without side reactions. In contrast to typical RAFT polymerization reactions, when using grafting method 1, since no monomer is present when the thiocarbonylthio-containing group is covalently bonded to the porous polymer substrate, the released radical (Q * ) does not need to be selected to be able to initiate a free radical polymerization reaction. This allows for the use of thiocarbonylthio-containing compounds that are not normally used in typical RAFT-controlled radical polymerization reactions.

[0120] Therefore, the released radical (Q * ) can be a primary radical, in contrast to the secondary or tertiary radicals used in typical RAFT polymerization. The released radical may cause reversal of the migration reaction (i.e., when the reaction shown in the second step of reaction scheme A is reversible, the covalently bonded group -S-C(=S)-R 1 can combine with the released radical (Q * ) to reform Q-S-C(=S)-R 1 and as a result, radical reformation can occur on the surface of the substrate). Alternatively, the released radical (Q *) can be inactivated, for example, by coupling to form QQ, in a radical termination process well known in the art.

[0121] The amount of thiocarbonylthio-containing groups attached to the polymer substrate typically ranges from 0.1 to 100 micromoles per gram of modified substrate (i.e., micromoles per gram of modified substrate). The amount is often at least 0.2, at least 0.5, at least 1, at least 2, at least 4, at least 5, or at least 10 micromoles per gram, and often up to 100, up to 80, up to 60, up to 40, up to 30, or up to 20 micromoles per gram.

[0122] In grafting method 1, the modified base material PPS-SC(=S)-R 1 is prepared as described above. A compound of the formula -SC(=S)-R is covalently attached to the surface of a polymer substrate. 1 The modified substrate having a plurality of thiocarbonylthio groups is placed in contact with a first polymerizable composition to form a first reaction mixture. When the first reaction mixture is exposed to actinic radiation, such as ultraviolet light, RDRP polymerization of the monomers in the first polymerizable composition can occur, with the thiocarbonylthio-containing groups functioning as RAFT agents (e.g., iniferters or photoiniferters). The polymerization process is shown generally in Reaction Scheme B.

[0123] [ka]

[0124] In Reaction Scheme B, exposure of the first reaction mixture to actinic radiation (e.g., ultraviolet light) results in the formation of radicals (11) and thiocarbonylthio-containing radicals (12) on the porous polymer substrate surface, as shown in Reaction I. The first monomer (for simplicity, CH2=CR x R y(shown as (13)) reacts with the radical (11) on the substrate surface, and as a result, a second radical capable of reacting with another monomer is generated. The polymerization of (n + 1) moles of the first monomer is shown as radical (14) in Reaction II. At any point in this process, the growing radical (14) can recombine with the thiocarbonylthio radical (12) to form a terminal chain as shown as product (15) in Reaction III. Continuing the exposure to actinic radiation, the radicals (14) and the thiocarbonylthio radical (12) can be reformed from the product (15). If more monomers are present, the regenerated radical (14) can undergo further polymerization. Eventually, this radical combines with the thiocarbonylthio radical (12). The polymerization reaction stops when the exposure to actinic radiation is stopped or when no monomers are present anymore. The product contains a plurality of first polymer blocks grafted to the polymer substrate. At least some of the first polymer blocks are terminated with thiocarbonylthio-containing groups. In many cases, the thiocarbonylthio-containing groups are of the formula -S-C(=S)-R 1 as shown in the product (15) of Reaction III. To ensure that most of the first polymer blocks are terminated with thiocarbonylthio-containing groups, even if the substrate has thiocarbonylthio-containing groups attached, the thiocarbonylthio-containing compound is often added to the first reaction mixture.

[0125] When a monomer having a radically polymerizable group such as an ethylenically unsaturated group reacts with a substrate treated using grafting method 1 in the presence of a thiocarbonylthio-containing compound, it does not exist. This tends to increase the likelihood of the thiocarbonylthio group migrating to the treated substrate, and thus, the density of the thiocarbonylthio-containing groups on the surface of the polymeric substrate can be increased. This also enables the preparation and isolation of a modified substrate having covalently bonded thiocarbonylthio-containing groups in the absence of competing polymerization or grafting reactions, and may enable better control over subsequent intended graft (polymerization) reactions. There is no polymeric material formed in solution simultaneously with the formation of the modified substrate.

[0126] The product of reaction scheme B is an intermediate article having a first polymer block covalently bonded thereto. The first polymer block is bonded (e.g., grafted) to the porous polymeric substrate. In most cases, the first polymer block is directly covalently bonded to a carbon atom of the porous polymeric substrate. Typically, there is no intervening linking group such as an ester bond, amide bond, urethane bond, ether bond, siloxane bond, etc. between the polymeric substrate and the first polymer block. At least some of the first polymer blocks are terminated with thiocarbonylthio-containing groups.

[0127] Alternatively, grafting method 2 can be used. Grafting method 2 is different from grafting method 1 in that there is no separate step for forming a modified substrate having thiocarbonylthio-containing groups covalently bonded to the porous polymeric substrate. Rather, the first reaction mixture includes a monomer for forming the first polymer block, a thiocarbonylthio-containing compound, and an optional type II photoinitiator. The type II photoinitiator is not required when the polymeric substrate is photoactive, but is used for polymeric substrates that are not photoactive. The advantage of using grafting method 2 is that there are fewer steps required to graft the first polymer block onto the porous polymeric substrate.

[0128] In grafting method 2, when the first reaction mixture is exposed to actinic radiation (e.g., ultraviolet light), radicals are formed on the surface of the porous polymer substrate (PPS * ). These radicals can react with either a thiocarbonylthio-containing compound Q-S-C(=S)-R 1 or a monomer (CH2=CR x R y ). Since the monomer is typically present at a higher concentration than the thiocarbonylthio-containing compound, the product will often be similar to that of radical (14) shown in reaction scheme B. As in reaction scheme B, radical (14) can continue to grow if additional monomer is present. Eventually, the radical is terminated by combining with radical (12) of the thiocarbonylthio-containing compound to form a polymer product (15). Continued exposure to actinic radiation allows radicals (14) and thiocarbonylthio radicals (12) to reform from the product (15). If more monomer is present, the regenerated radical (14) can undergo further polymerization. Eventually, this radical combines with the thiocarbonylthio radical (12). The polymerization reaction stops when exposure to actinic radiation is stopped or when no more monomer is present. The product contains a plurality of first polymer blocks grafted to the polymer substrate. At least some of the first polymer blocks are terminated with thiocarbonylthio-containing groups as shown for product (15) in reaction III of reaction scheme B.

[0129] The separation article is preferably formed using grafting method 1 or grafting method 2 with a thiocarbonylthio-containing compound such as those of formula (I), (II), or (III), although other methods of forming the separation article may be used. For example, the separation article can be prepared using an alternative reversible deactivation radical polymerization (RDRP) initiator or by using alternative methods to prepare an RDRP initiator.

[0130] In one alternative method that does not involve a thiocarbonylthio-containing compound, an absorption solution containing a type II photoinitiator is coated onto the surface of a porous polymer substrate and then exposed to actinic radiation. Upon exposure to actinic radiation, the type II photoinitiator abstracts hydrogen from the porous polymer substrate, resulting in the generation of free radicals on its surface and the formation of a treated substrate. The intermediate semipinacol radical derived from the type II photoinitiator via hydrogen abstraction typically couples with the radicals on the surface of the substrate to form a semipinacol group. As described, for example, in the paper by H. Ma, et al., Macromolecules, 2000, 33, 331, this substrate with the attached semipinacol group can function as an RDRP initiator. Thus, a substrate with an attached semipinacol group is coated with a first monomer solution and then exposed to actinic radiation to graft-polymerize the first monomer onto the substrate, resulting in covalently grafted polymer chains terminated with semipinacol groups. This method of adding the first monomer solution after forming the semipinacol groups on the substrate surface is referred to as grafting method 3.

[0131] In another alternative method that does not involve a thiocarbonylthio-containing compound, an absorption solution containing a first monomer and a type II photoinitiator is coated on the surface of a porous polymer substrate and then exposed to actinic radiation. Upon exposure to actinic radiation, the type II photoinitiator abstracts hydrogen from the porous polymer substrate, resulting in the generation of free radicals on its surface and the formation of a treated substrate. The treated substrate then interacts with the first monomer to form grafted polymer chains covalently bonded to the substrate. Finally, as described in the paper by Yang and Ranby, Macromolecules, 1996, 29, 3308, the semipinacol radicals derived from the type II photoinitiator via hydrogen abstraction couple with the radicals on the polymer chain ends to form grafted polymer chains having semipinacol chain ends. This grafted substrate can be used to initiate the polymerization of a second block. This method in which the first monomer is present simultaneously with the type II photoinitiator is referred to as grafting method 4.

[0132] In yet another alternative method, a porous polymer substrate having hydroxy groups or amino groups on its surface may react with an RDRP initiator containing a carboxylic acid group or an acid halide group to covalently bond to the RDRP initiator via an ester bond or an amide bond. Such a reaction is shown in the following reaction scheme C for the attachment of an atom transfer radical polymerization (ATRP) initiator.

[0133] [Chemical formula]

[0134] In this reaction scheme, X 3 is -O- or -NH-, and PPS refers to the porous substrate. The treated substrate PPS-X 3-(C=O-C(CH3)2-Br has been used to graft ion-exchange functional groups onto cellulose membranes (Bhut et al., J. Membr. Sci., 325 (2008), 176-183). Similarly, RAFT and NMP initiators are attached to porous polymer substrates. A review (Peng Liu, e-Polymers, 2007, No. 062) describes a variety of methods for attaching RDRP initiators to surfaces. These methods generally involve batch chemical processes for attaching RDRP controllers to substrates, so they are not preferred methods for use in current methods for forming separated articles. However, RDRP-modified substrates can be useful as starting materials for the production of separated articles having the bound block copolymers described herein.

[0135] Regardless of the method of attaching the first block of the block copolymer to the porous polymer substrate, the first polymerizable composition contains at least one first monomer that is an acidic monomer, a basic monomer, or a salt thereof. The first monomer can be in a neutral state, but under some pH conditions, it can be negatively charged (in the case of an acid) or positively charged (in the case of a base). The first monomer can be permanently charged (for example, when the ligand functional group is in the form of a quaternary ammonium salt). The acidic and basic groups are neither polypeptides nor proteins. As used herein, the term "polypeptide" refers to a compound containing more than four amino acid units.

[0136] The first monomer can contain a single ethylenically unsaturated group, or a plurality of ethylenically unsaturated groups (e.g., two or three, or up to a maximum of six) that may be the same or different (preferably the same). The first monomer often has only one ethylenically unsaturated group.

[0137] Suitable acidic groups for the first monomer include those that exhibit at least a certain degree of acidity (which can range from a relatively weak acidity to a relatively strong acidity), and salts thereof. Such acidic groups or salts thereof include those commonly used as ion exchange or metal chelate type ligands. The acid group is often selected from carboxylic acid groups, phosphonic acid groups, phosphoric acid groups, sulfonic acid groups, sulfuric acid groups, boronic acid groups, and salts thereof. When the acidic group is a salt, the counterion is often selected from alkali metals (e.g., sodium or potassium), alkaline earth metals (e.g., magnesium or calcium), ammonium, and tetraalkylammonium, etc., as well as combinations thereof.

[0138] Suitable acidic monomers include, for example, various sulfonic acids such as N - acrylamidomethanesulfonic acid, 2 - acrylamidoethanesulfonic acid, 2 - acrylamido - 2 - methyl - 1 - propanesulfonic acid, 2 - methacrylamido - 2 - methyl - 1 - propanesulfonic acid, vinylsulfonic acid, and 4 - styrenesulfonic acid; (meth)acrylamidophosphonic acids such as (meth)acrylamidoalkylphosphonic acids like 2 - (meth)acrylamidoethylphosphonic acid and 3 - (meth)acrylamidopropylphosphonic acid; (meth)acrylic acid; and carboxyalkyl (meth)acrylates such as 2 - carboxyethyl (meth)acrylate and 3 - carboxypropyl (meth)acrylate. Further suitable acidic monomers include (meth)acryloylamino acids such as those described in U.S. Patent No. 4,157,418 (Heilmann). Exemplary (meth)acryloylamino acids include, but are not limited to, N - acryloylglycine, N - acryloylaspartic acid, N - acryloyl - β - alanine, and 2 - acrylamidoglycolic acid. Salts of any of these acidic monomers can also be used.

[0139] Suitable basic groups for the first monomer include those that exhibit at least a certain degree of basicity (which can range from a relatively weak basicity to a relatively strong basicity), and salts thereof. Such basic groups or salts thereof include those commonly used as ion exchange or metal chelate type ligands. Basic groups are often primary amino groups, secondary amino groups, tertiary amino groups, quaternary amino groups, guanidinium groups, biguanidinium groups, or salts thereof. When the basic group is a salt, the counterion is often selected from halides (e.g., chloride or bromide), carboxylates (e.g., acetate), nitrates, phosphates, bisulfates, methyl sulfates, hydroxide ions, etc., and combinations thereof.

[0140] Suitable basic monomers include, for example, amino acrylates, amino (meth)acrylamides, and various monomers having a quaternary ammonium group. Exemplary amino acrylates include N,N-dialkylaminoalkyl acrylates, such as N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminopropyl acrylate, N,N-dimethylaminopropyl methacrylate, N-tert-butylaminopropyl methacrylate, N-tert-butylaminopropyl acrylate, and the like. Exemplary amino (meth)acrylamides include, for example, N-(3-aminopropyl)methacrylamide, N-(3-aminopropyl)acrylamide, N-[3-(dimethylamino)propyl]methacrylamide, N-(3-imidazolylpropyl)methacrylamide, N-(3-imidazolylpropyl)acrylamide, N-(2-imidazolylethyl)methacrylamide, N-(1,1-dimethyl-3-imidazolylpropyl)methacrylamide, N-(1,1-dimethyl-3-imidazolylpropyl)acrylamide, N-(3-benzimidazolylpropyl)acrylamide, and N-(3-benzimidazolylpropyl)methacrylamide.

[0141] Exemplary monomers having a quaternary ammonium group include (meth)acrylamide alkyltrimethylammonium salts (e.g., 3-methacrylamidopropyltrimethylammonium chloride and 3-acrylamidopropyltrimethylammonium chloride), and (meth)acryloxyalkyltrimethylammonium salts (e.g., 2-acryloxyethyltrimethylammonium chloride, 2-methacryloxyethyltrimethylammonium chloride, 3-methacryloxy-2-hydroxypropyltrimethylammonium chloride, 3-acryloxy-2-hydroxypropyltrimethylammonium chloride, and 2-acryloxyethyltrimethylammonium methyl sulfate), but are not limited thereto.

[0142] In some embodiments, it is advantageous to use acidic or basic monomers having a longer chain length between an ethylenically unsaturated group and either an acidic group or a basic group. The acidic or basic group can be referred to as a "functional group", and the intervening group between the ethylenically unsaturated group and the acidic or basic group can be referred to as a "spacer group". In some embodiments, the number of chain-linked atoms is at least 6, at least 8, at least 10, at least 12, at least 14, at least 16, at least 18, or at least 20, and at most 30, at most 28, at most 26, at most 24, at most 22, at most 20, at most 18, at most 16, at most 14, or at most 12. When the monomer has a (meth)acryloyl group, the carbonyl of this group is counted as part of the spacer group.

[0143] While not wishing to be bound by theory, the spacer length can contribute to the polymer backbone (formed by monomer polymerization) adopting a helical or partial helical structure. When the spacer is relatively short (e.g., less than 6 chain-linking atoms), due to the ionic repulsion between acidic groups or between basic groups, the polymer backbone can be forced into a random coil type structure. As the length of the spacer chain increases, it becomes possible to adopt a helical structure, which can be maximized at a spacer chain length of about 8 to about 14 chain-linking atoms. The helical structure of the polymer grafted to the substrate can facilitate the presentation of acidic groups, basic groups, or salts thereof for interaction with target biomaterials such as viruses and other microorganisms, proteins, cells, endotoxins, acidic carbohydrates, nucleic acids, etc.

[0144] In certain embodiments, the spacer group includes at least one hydrogen bonding moiety as defined above as a moiety containing at least one hydrogen bond donor and at least one hydrogen bond acceptor (both of which contain heteroatoms). Exemplary hydrogen donors are imino, thio, and hydroxy groups. Exemplary hydrogen acceptors are carbonyl, carbonyloxy, or ether oxygen. More preferred spacer groups include at least two hydrogen bonding moieties or at least one hydrogen bonding moiety and at least one hydrogen bond acceptor different from (not part of) the hydrogen bonding moiety.

[0145] In certain embodiments, the hydrogen bonding moiety includes at least two hydrogen bond donors (e.g., donors such as imino, thio, or hydroxy), at least two hydrogen bond acceptors (e.g., acceptors in the form of carbonyl, carbonyloxy, or ether oxygen), or both. For example, an iminocarbonylimino moiety (having two N-H donors and at least two acceptors in the form of two lone pairs on the carbonyl) may optionally be more preferred than a single iminocarbonyl moiety. In certain embodiments, spacer groups include at least one iminocarbonylimino moiety (more preferably in combination with at least one acceptor such as carbonyloxy), at least two iminocarbonyl moieties, or combinations thereof.

[0146] The hydrogen bond donors and hydrogen bond acceptors of the hydrogen bonding moiety may or may not be adjacent (directly bonded) to each other (preferably they are adjacent or separated by a chain of 4 or fewer chain-linking atoms, more preferably they are adjacent). The heteroatoms of the hydrogen bond donors and / or hydrogen bond acceptors can be located within the chain of chain-linking atoms of the spacer group or alternatively within a chain substituent.

[0147] A hydrogen bond donor can also function as a hydrogen bond acceptor (through the lone pair of the heteroatom of the donor), but the hydrogen bonding moiety preferably includes separate donor and acceptor moieties. This promotes intramolecular (inter-monomer) hydrogen bond formation. Without wishing to be bound by theory, such intramolecular hydrogen bonds between adjacent monomers or between proximate repeating units in a polymer molecule can contribute to the hardening of the spacer group to at least some extent. This can facilitate the presentation of acidic groups, basic groups, or salts thereof for interaction with the target biomaterial.

[0148] In certain embodiments, the hydrogen bonding moiety includes carbonylimino, thiocarbonylimino, iminocarbonylimino, iminothiocarbonylimino, oxycarbonylimino, oxythiocarbonylimino, and the like, and combinations thereof. In certain embodiments, the hydrogen bonding moiety includes carbonylimino, iminocarbonylimino, oxycarbonylimino, and combinations thereof (more preferably, carbonylimino, iminocarbonylimino, and combinations thereof). In certain embodiments, the spacer group includes those that are divalent, trivalent, or tetravalent (more preferably divalent or trivalent, even more preferably divalent).

[0149] A useful class of first monomers having a spacer group with at least 6 chain linking atoms is of formula (IV). CH2=CR 21 -C(=O)-X 1 -R 22 -[Z 1 -R 22 n -L (IV)

[0150] In formula (IV), the group R 21 is selected from hydrogen or methyl. Each group R 22 is independently a (hetero)hydrocarbylene. The group X 1 is -O- or -NR 23 -(wherein R 23 is selected from hydrogen or hydrocarbyl). The group Z 1 ​is a hetero hydrocarbylene having at least one hydrogen bond donor, at least one hydrogen bond acceptor, or a combination thereof. The variable n is an integer of 0 or 1. The group L is a ligand functional group which is an acidic group, a basic group or a salt thereof. If desired, different compounds of formula (IV) can be used in combination. The different compounds can both be acidic monomers or salts thereof, both be basic monomers or salts thereof, or be a combination of an acid monomer and a basic monomer or salts thereof. Further, the monomers of formula (IV) can be used in combination with other acidic and / or basic monomers which are not of formula (IV).

[0151] The monomer of formula (IV) has an ethylenically unsaturated group of the formula CH2=CR 21 -(wherein R 21 is hydrogen or methyl).

[0152] Each R 22 is independently a (hetero) hydrocarbylene. Exemplary hydrocarbylenes include alkylene groups, arylene groups, aralkylenes, and alkarylenes. Exemplary hetero hydrocarbylenes include heteroaralkylenes, hydroxy-substituted alkylenes, and hydroxy-substituted aralkylenes. In certain embodiments, each R 22 is independently a hydrocarbylene. For example, each R 22 is independently an alkylene.

[0153] The group X 1 is -O- (oxy) or -NR 23 -. The group R 23 is hydrogen or hydrocarbyl. The hydrocarbyl can be alkyl or aryl. In many instances, R 23 is hydrogen.

[0154] The group Z 1is a hetero hydrocarbylene containing at least one hydrogen bond donor, at least one hydrogen bond acceptor, or a combination thereof. The hydrogen donor is typically a donor such as imino, thio, or hydroxy. The hydrogen acceptor is typically carbonyl, carbonyloxy, or ether oxygen. Thus, group Z 1 is often a hydrogen bonding moiety, such as carbonylimino, thiocarbonylimino, iminocarbonylimino, iminothiocarbonylimino, oxycarbonylimino, oxythiocarbonylimino, etc., and combinations thereof. In certain embodiments, the hydrogen bonding moiety includes carbonylimino, iminocarbonylimino, oxycarbonylimino, and combinations thereof (more preferably, carbonylimino, iminocarbonylimino, and combinations thereof).

[0155] The variable n is often an integer of 1 in the monomer of formula (IV).

[0156] Group L is a ligand functional group containing at least one acidic group selected from carboxy, phosphono, phosphato, sulfono, sulfato, boronate, and combinations thereof (more preferably, selected from carboxy, phosphono, sulfono, and combinations thereof) or a salt thereof. In other embodiments, L is a functional group containing at least one basic group or a salt thereof. The basic group is typically a tertiary amino group, a quaternary amino group, a guanidino group, or a biguanidino group. In some embodiments, L is carboxy, guanidino, or a salt thereof.

[0157] Such monomers can be prepared by known synthetic methods or methods similar to known synthetic methods. For example, an amino group-containing carboxylic acid, an amino group-containing sulfonic acid, or an amino group-containing phosphonic acid can be reacted with an ethylenically unsaturated compound containing at least one group that is reactive with the amino group. Similarly, an acidic group-containing compound that also contains a hydroxy group can be reacted with an ethylenically unsaturated compound containing at least one group that is reactive with the hydroxy group, optionally in the presence of a catalyst.

[0158] Preferred monomers are (meth)acryloyl-containing monomers, which refer to acryloyl-containing monomers and / or methacryloyl-containing monomers. Similarly, the term "(meth)acrylate" refers to acrylate and / or methacrylate monomers. In such monomers, the carbonyl group is part of a spacer group.

[0159] Representative examples of useful monomers of formula (IV) are alkenyl azlactones of formula (V)

[0160]

Chemical formula

[0161] Group R 21 、R 22 、and L are defined as in formula (IV). Group X 2 is oxy or -NR 23 -[wherein R 23 is hydrogen or hydrocarbyl (e.g., alkyl or aryl)]. The resulting compound is represented by formula (IV-1). CH2=CR 21 -C(=O)-NH-R 22 -C(=O)-X 2 -R22 -L (IV-1)

[0162] These compounds are represented by formula (IV) (wherein X 1 is -NH-, the variable n is equal to 1, and Z 1 is -C(=O)-X 2 -).

[0163] Typical examples of useful alkenyl azlactones of formula (V) include 4,4-dimethyl-2-vinyl-4H-oxazole-5-one (vinyldimethylazlactone, VDM), 2-isopropenyl-4H-oxazole-5-one, 4,4-dimethyl-2-isopropenyl-4H-oxazole-5-one, 2-vinyl-4,5-dihydro-[1,3]oxazin-6-one, 4,4-dimethyl-2-vinyl-4,5-dihydro-[1,3]oxazin-6-one, 4,5-dimethyl-2-vinyl-4,5-dihydro-[1,3]oxazin-6-one, etc., and combinations thereof.

[0164] Another typical example of a useful monomer of formula (IV) is the (meth)acryloyl isocyanate monomer of formula (VII) CH2=CR 21 -C(=O)-X 1 -R 22 -N=C=O (VII) which can be prepared by reacting with the compound of formula (VI) (or a salt thereof) described above. The resulting monomer is represented by formula (IV-2). CH2=CR 21 -C(=O)-X 1 -R 22 -NH-C(=O)-X 2 -R 22 -L (IV-2)

[0165] These monomers are represented by formula (IV) (wherein the variable n is equal to 1 and Z 1 is -NH-C(=O)-X 2 -). The group R21 , R 22 , X 1 , X 2 , and L are the same as those defined above.

[0166] Typical examples of the ethylenically unsaturated isocyanate of formula (VII) include 2-isocyanatoethyl (meth)acrylate (IEM or IEA), 3-isocyanatopropyl (meth)acrylate, 4-isocyanatocyclohexyl (meth)acrylate, etc., and combinations thereof.

[0167] Typical examples of useful compounds of formula (VI) that can provide an acidic L group (or a salt thereof) include amino group-containing carboxylic acids, amino group-containing sulfonic acids, amino group-containing boronic acids, and amino group-containing phosphonic acids, and combinations and / or salts thereof. Useful aminocarboxylic acids include α-amino acids (L-, D-, or DL-α-amino acids), for example, glycine, alanine, valine, proline, serine, phenylalanine, histidine, tryptophan, asparagine, glutamine, N-benzylglycine, N-phenylglycine, sarcosine, etc.; β-amino acids, for example, β-alanine, homoleucine, homoglutamine, homophenylalanine, etc.; other α,ω-amino acids, for example, γ-aminobutyric acid, 6-aminohexanoic acid, 11-aminoundecanoic acid, etc.; and combinations thereof. Useful aminosulfonic acids include aminomethanesulfonic acid, 2-aminoethanesulfonic acid (taurine), 3-amino-1-propanesulfonic acid, 6-amino-1-hexanesulfonic acid, etc., and combinations thereof. Useful aminoboronic acids include m-aminophenylboronic acid, p-aminophenylboronic acid, etc., and combinations thereof. Useful aminophosphonic acids include 1-aminomethylphosphonic acid, 2-aminoethylphosphonic acid, 3-aminopropylphosphonic acid, etc., and combinations and / or salts thereof.

[0168] Representative examples of other useful compounds of formula (VI) having an acidic L group (or a salt thereof) include compounds containing a hydroxy group and an acidic group. Specific examples include glycolic acid, lactic acid, 6-hydroxyhexanoic acid, citric acid, 2-hydroxyethylsulfonic acid, 2-hydroxyethylphosphonic acid, etc., as well as combinations and / or salts thereof.

[0169] Still other representative compounds of formula (VI) having an acidic L group (or a salt thereof) are aspartic acid, glutamic acid, α-aminoadipic acid, iminodiacetic acid, N α ,N α -bis(carboxymethyl)lysine, cysteic acid, N-phosphonomethylglycine, etc., and those containing two or more acidic groups including combinations and / or salts thereof.

[0170] Many of the compounds of the above formula (VI) having an acidic L group (or a salt thereof) are commercially available. Still other useful acidic group-containing compounds can be prepared by general synthetic procedures. For example, various diamines or amino alcohols can be reacted with 1 equivalent of a cyclic anhydride to produce an intermediate acidic group-containing compound containing a carboxyl group and an amino group or a hydroxy group.

[0171] Furthermore, useful monomers having an acidic group can be prepared by reacting a hydroxy- or amine-containing (meth)acrylate or (meth)acrylamide monomer with a cyclic anhydride to produce a carboxyl group-containing monomer.

[0172] In certain embodiments, useful monomers of formula (IV) having an L group that is an acidic group (or a salt thereof) may be prepared from the reaction of an alkenyl azlactone with an aminocarboxylic acid, a monomer prepared from the reaction of an alkenyl azlactone with an aminosulfonic acid, a monomer prepared from the reaction of an ethylenically unsaturated isocyanate with an aminocarboxylic acid, a monomer prepared from the reaction of an ethylenically unsaturated isocyanate with an aminosulfonic acid, or combinations thereof.

[0173] Some exemplary monomers having group L in formula (IV) that are acidic groups or salts thereof are further described in U.S. Patent No. 10,352,835 (Rasmussen et al.) and can include the following (many of these are shown as acids, but salts of such acids can also be used): VDM-4-aminomethyl-cyclohexanecarboxylic acid

[0174]

Chem.

[0175]

Chem.

[0176]

Chem.

[0177]

Chem.

[0178]

Chem.

[0179]

Chem.

[0180]

Chem.

[0181]

Chem.

[0182]

Chem.

[0183]

Chem.

[0184]

Chem.

[0185]

Chem.

[0186]

Chem.

[0187]

Chem.

[0188]

Chem.

[0189]

Chem.

[0190]

Chem.

[0191]

Chem.

[0192]

Chem.

[0193]

Chem.

[0194] Typical examples of useful compounds of formula (VI) that can provide a basic L group often contain at least one amino group or hydroxy group and at least one basic group, such as a tertiary or quaternary amino group. Specific examples include 2-(dimethylamino)ethylamine, 3-(diethylamino)propylamine, 6-(dimethylamino)hexylamine, 2-aminoethyltrimethylammonium chloride, 3-aminopropyltrimethylammonium chloride, 2-(dimethylamino)ethanol, 3-(dimethylamino)-1-propanol, 6-(dimethylamino)-1-hexanol, 1-(2-aminoethyl)pyrrolidine, 2-[2-(dimethylamino)ethoxy]ethanol, histamine, 2-aminomethylpyridine, 4-aminomethylpyridine, 4-aminoethylpyridine, etc., and combinations thereof.

[0195] Some exemplary monomers having a group L in formula (IV) that is a basic group such as a tertiary or quaternary amino group are as follows: VDM - 2 - aminoethyltrimethylammonium chloride

[0196] [Chemical formula] IEM - diethylaminoethylamine

[0197] [Chemical formula] IEM - diisopropylaminoethylamine

[0198] [Chemical formula] IEM - 2 - aminoethyltrimethylammonium chloride

[0199] [Chemical formula] VDM adduct of dimethylaminoalkanol

[0200] [Chemical formula]

[0201] Some of the monomers of formula (IV) have an L group that is a guanidino group or a biguanidino group. That is, L is represented by the formula -NR 24 -[C(=NR 24 -NR 24 m R 25 (where m is 1 or 2). When m is equal to 1, the group L is a guanidino group, and when m is equal to 2, the group L is a biguanidino group. The group R 24 is hydrogen or hydrocarbyl, and the group R 25 is hydrogen, hydrocarbyl, or -N(R 24 )2. Suitable hydrocarbyl groups for R 24 and R 25 are often aryl groups or alkyl groups. In many embodiments, R 24 and / or R 25 ​is hydrogen. Such monomers can be prepared as described in PCT International Publication No. WO 2014 / 204763 (Rasmussen et al.) and WO 2013 / 184366 (Bothof et al.).

[0202] Monomers having a guanidino group or a biguanidino group can be prepared, for example, by reacting a (meth)acryloyl halide (e.g., (meth)acryloyl chloride), a (meth)acryloyl isocyanate (such as in formula (VI) above), or an alkenyl azlactone (such as in formula (V) above) with a compound of formula (VIII). HNR 23 -R 22 -NR 24 -[C(=NR 24 -NR 24 m R 25 (VIII)

[0203] The compound of formula (VIII) corresponds to a compound of formula (VI) (wherein X 2 is -NR 23 -, and L is -NR 24 -[C(=NR 24 )-NR 24 m R 25 ). These compounds can be formed, for example, by reacting a diamine with a guanylating agent as described in PCT International Publication No. WO 2014 / 204763 (Rasmussen et al.). The groups R 22 , R 23 , R 24 and R 25 and the variable m are the same as those described above. Some compounds of formula (VIII), for example, 4-aminobutylguanidine (agmatine), are commercially available.

[0204] Reacting a compound of formula (VIII) with an alkenyl azlactone forms a monomer of formula (IV-3). CH2=CR 21 -C(=O)-NH-R​​22 -C(=O)-NR 23 -R 22 -NR 24 -[C(=NR 24 )-NR 24 m R 25 (IV-3)

[0205] This monomer is represented by formula (IV) (where n is equal to 1, Z 1 is -C(=O)-NR 23 -, and X 1 is -NH-). The groups R 21 , R 22 , R 23 , R 24 , and R 25 , as well as the variable m, are the same as those described above.

[0206] Reacting the compound of formula (VIII) with (meth)acryloyl isocyanate forms the monomer of formula (IV-4). CH2=CR 21 -C(=O)-X 1 -R 22 -NH-C(=O)-NR 23 -R 22 -NR 24 -[C(=NR 24 )-NR 24 m R 25 (IV-4)

[0207] This monomer is represented by formula (IV) (where n is equal to 1, Z 1 is -NH-C(=O)-NR 23 -, and L is of the formula -NR 24 -[C(=NR 24 )-NR 24 m R 25 ). The groups R 21 , R 22 , R 23 , R 24 , and R 25 ​​​、and the variable m is the same as described above.

[0208] Some specific examples of the first monomer having a guanidino group as L are shown below. The structure is shown as a neutral compound for simplicity, but it may exist as various salts such as chloride salts or sulfate salts: 2-({[(4-[amino(imino)methyl]aminobutyl)amino]carbonyl}-amino)ethyl methacrylate

[0209] [Chemical formula] N 2 -acryloyl-N 1 -(4-{[amino(imino)methyl]amino}butyl)-2-methylalanine amide

[0210] [Chemical formula] N 2 -acryloyl-N 1 -(6-{[amino(imino)methyl]amino}hexyl)-2-methylalanine amide

[0211] [Chemical formula] 2-({[N-(2-[amino(imino)methyl]aminoethyl)-N-benzylamino]carbonyl}-amino)ethyl methacrylate

[0212] [Chemical formula]

[0213] The above first monomer can be homopolymerized to provide a first polymer block. In other embodiments, various first monomers can be combined and copolymerized. In still other embodiments, other types of monomers can be combined with the first monomer and copolymerized.

[0214] The first polymer block is often a homopolymer of an acidic monomer or a basic monomer in order to prepare a block copolymer having a high binding ability to the material to be captured. That is, the first polymer block can be up to 100 weight percent of acidic monomer units or salts thereof, basic monomer units or salts thereof, or combinations (mixtures) thereof. In some embodiments, other monomers (second monomers) are copolymerized with the first monomer to adjust the binding ability of the first polymer block and / or to achieve other desired properties. Any suitable second monomer can be used.

[0215] The amount of the first monomer having an acidic or basic group can range, for example, from 50 to 100 weight percent acidic or basic monomer units based on the total weight of the monomer units in the first polymer block. The amount can be at least 50, at least 60, at least 70, at least 75, at least 80, at least 85, at least 90, or at least 95, and up to 100, up to 99, up to 98, up to 97, up to 95, up to 90, up to 85, up to 80, or up to 75 weight percent based on the total weight of the monomer units in the first polymer block. The greater the amount of the first monomer, the more likely the binding ability to various target compounds such as biological materials will increase. In many embodiments, the amount of the first monomer that is an acidic group, a basic group, or a salt thereof ranges from 80 to 100, 85 to 100, 90 to 100, or 95 to 100 weight percent based on the total weight of the monomer units.

[0216] The second monomer in the first polymer block can be a hydrophilic monomer, for example, to adjust the degree of hydrophilicity imparted to the substrate. The hydrophilic monomer has an ethylenically unsaturated group and a hydrophilic group, such as a hydroxyl group or an amide group. Suitable hydrophilic monomers include acrylamide, dimethylacrylamide, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ethoxyethyl methacrylate, diethylene glycol methyl ether methacrylate, 2-hydroxyethyl acrylamide, N-vinylpyrrolidone, etc., and combinations thereof.

[0217] Other second monomers in the first polymer block include those having two or more ethylenically unsaturated groups. This type of second monomer is typically used in only relatively small amounts to impart a certain degree of branching and / or relatively mild crosslinking to the resulting copolymer. For example, the amount of these polyfunctional monomers having three or more ethylenically unsaturated groups can be present in an amount in the range of 0.1 to 5 weight percent based on the total weight of the monomers in the first polymerizable composition. The amount can be at least 0.1, at least 0.2, at least 0.5, or at least 1.0 weight percent and up to 5, up to 4, up to 3, up to 2, or up to 1 weight percent. Larger amounts can be used for certain specific applications, but as the amount increases, the binding ability to various biomaterials can decrease.

[0218] The total amount of the second monomer can be up to 50 weight percent of the monomers used to form the first polymer block. Typically, the lower the amount of the second monomer, the more enhanced the binding ability to various target compounds such as biomaterials. When present, the amount is usually equal to 100 minus the weight percent of the first monomer based on the total weight of the monomers in the first polymerizable composition.

[0219] The first polymer block often has a graft density of about 0.02 to about 3 millimoles / gram or even more. The graft density can be at least 0.02, at least 0.05, at least 0.1, at least 0.2, at least 0.5, or at least 1 millimole / gram, and up to 3, up to 2.5, up to 2, up to 1.5, up to 1, up to 0.8, up to 0.7, or up to 0.5 millimole / gram. This corresponds to a weight gain of 1 to 85 percent or more. The weight gain is calculated from the formula [100(weight2 - weight1)÷weight1], where weight1 is the weight of the substrate and weight2 is the weight of the substrate with the grafted polymer attached. The weight gain can be in the range of 1 to 85 weight percent or even more. The amount can be, for example, at least 1, at least 2, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, or at least 50 weight percent, and up to 85, up to 80, up to 75, up to 70, up to 65, up to 60, up to 55, up to 50, up to 45, up to 40, up to 35, or up to 30 weight percent.

[0220] Regardless of whether grafting method 1 or grafting method 2 is used to form the first polymer block, the thiocarbonylthio-containing compound is usually added to the first reaction mixture. This addition is optional, but the presence of the thiocarbonylthio-containing compound can increase the possibility that the end groups of the first polymer block become thiocarbonylthio-containing groups. The presence of this group is necessary to initiate the formation of the second polymer block. The amount of the thiocarbonylthio-containing compound can range from 0 to 20 weight percent in grafting method 1 and from 0.5 to 20 weight percent in grafting method 2. In grafting method 1, the amount is often at least 0, at least 0.1, at least 0.2, at least 0.3, at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5 weight percent, and at most 20, at most 15, at most 10, at most 8, at most 6, at most 5, at most 4, at most 3, or at most 2 weight percent. In grafting method 2, the amount is often at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5 weight percent, and at most 20, at most 15, at most 10, at most 8, at most 6, at most 5, at most 4, at most 3, or at most 2 weight percent. When the thiocarbonyl-thio compound is added in grafting method 1, it may be the same as or different from the thiocarbonylthio-containing compound bound to the surface of the polymer substrate to form the modified substrate.

[0221] The presence of a thiocarbonylthio-containing compound in the reaction mixture may initiate the formation of polymers that are not bound to the substrate. These polymers that are not bound to the substrate are typically removed after the formation of the article, and as a result, the remaining polymers are only the polymers covalently bound to the porous polymer substrate.

[0222] As described above, in some alternative grafting methods, no thiocarbonylthio-containing compound is present, and the covalently bound first polymer block is terminated with a semipinacol group. In these alternative forms, the terminal semipinacol group functions as an RDRP group to initiate the formation of the second polymer block.

[0223] Formation of a second polymer block coupled to the first polymer block A second polymer block is formed that is covalently bonded to the first polymer block, and the first polymer block is located between the second polymer block and the porous polymer substrate. The resulting block copolymer extends from the surface of the porous polymer substrate. Additional polymer blocks can be added, but the grafted block copolymer is typically a diblock polymer.

[0224] Regardless of the method used to form the first polymer block, at least some of the chain ends of that block are terminated with an RDRP agent such as, for example, a thiocarbonylthio-containing group or a semipinacol group. Thus, the chain ends of the first polymer block can function as initiators for the second polymer block. Typically, a substrate comprising a grafted first polymer block is coated with a second polymerizable composition comprising a polyether monomer having at least one ethylenically unsaturated group and a polyether group. The RDRP agent is then activated, for example, by radiation to regenerate free radical chain ends and a radical derived from the RDRP agent. The radical chain ends then initiate the polymerization of the second monomer composition to form the second polymer block. Finally, termination can occur by recombination with a radical derived from the RDRP agent or by any of the other well-known radical termination mechanisms.

[0225] The second polymer block is a reaction product of a second polymerizable composition comprising a polyether monomer having at least one ethylenically unsaturated group and a polyether group. The polyether monomer is typically selected to be hydrophilic or water-swellable. Suitable polyether monomers usually contain a plurality of ethyleneoxy groups, propyleneoxy groups, or mixtures thereof, regardless of the number of ethylenically unsaturated groups. The number of ethylenically unsaturated groups is usually in the range of 1-4, for example, 1-3 or 1-2.

[0226] The second polymer block is formed to provide a porous polymer network that can be used to separate materials in a sample based on size effects or steric effects. That is, the second polymer block can suppress or reduce the number of larger materials that can interact with the acidic and / or basic groups of the first polymer block. In most embodiments, the second polymer block is crosslinked. However, crosslinking may be optional if the polyether groups are long enough and / or intertwined.

[0227] Any suitable approach can be used to crosslink the second polymer block. In some embodiments, crosslinking is performed by using a polyether monomer having a plurality of ethylenically unsaturated groups in the second polymerization composition. Any amount of these polyether monomers can be used to obtain the desired porosity in the second polymer block.

[0228] In some embodiments, all polyether monomers in the second polymerizable composition have at least two ethylenically unsaturated groups. All of these polyether monomers can have the same weight average molecular weight and the same number of ethylenically unsaturated groups, or can be a mixture of different polyether monomers having different weight average molecular weights and / or different numbers of ethylenically unsaturated groups.

[0229] In other embodiments, the second polymerizable composition includes a mixture of a polyether monomer having a single ethylenically unsaturated group and a polyether monomer having a plurality of ethylenically unsaturated groups. The sizes of the polyether monomers in the mixture may be the same or different. The amount of the polyether monomer having a plurality of ethylenically unsaturated groups can be varied to obtain the desired porosity of the polymer network.

[0230] In yet other embodiments, the second polymerizable composition further comprises a crosslinking monomer that is not a polyether monomer. The crosslinking monomer is selected to be water-soluble and can be combined with a polyether monomer having a single ethylenically unsaturated group, a plurality of ethylenically unsaturated groups, or a mixture thereof. The amount of the crosslinking monomer can be varied to obtain the desired porosity of the polymer network.

[0231] The weight average molecular weight of the polyether monomer is often in the range of 250 to 20,000 Daltons. The weight average molecular weight can be at least 300, at least 400, at least 500, at least 700, at least 800, at least 1000, at least 2000, at least 5000, and up to 20,000, up to 10,000, up to 5000, up to 2000, or up to 1000 Daltons.

[0232] Suitable polyether monomers having one or more ethylenically unsaturated groups are commercially available from Aldrich Chemical (Milwaukee, WI, USA), for example, polyethylene glycol diacrylate (PEGDA) having a number average molecular weight of 302, 575, 2000, 6000, and 10,000 Daltons, and poly(ethylene glycol) methyl ether methacrylate (PEGMA) having a number average molecular weight of 200, 400, and 2000 Daltons. Other suitable polyether monomers are commercially available from Sartomer (Exton, PA, USA), for example, those having the trade names SR415 (ethoxylated (20) trimethylolpropane triacrylate), SR610 (polyethylene glycol diacrylate with an average molecular weight of 600 Da), SR9035 (ethoxylated (15) trimethylolpropane triacrylate), and SR9038 (ethoxylated (30) bisphenol A diacrylate).

[0233] When using a crosslinking monomer that is not a polyether monomer, the weight-average molecular weight is often in the range of 100 to 500 Daltons. The weight-average molecular weight can be at least 100, at least 150, or at least 200, and at most 500, at most 450, at most 400, at most 350, or at most 300 Daltons. Examples include, but are not limited to, methylene bisacrylamide, 3-acryloyloxy-2-hydroxypropyl methacrylate, glycerol dimethacrylate, glycerol diacrylate, diacryloyl piperazine, and 1,2-ethylenebisacrylamide.

[0234] The second polymer block often has a graft density in the range of about 0.01 to about 1 millimole / gram or even higher. The graft density can be at least 0.01, at least 0.02, at least 0.05, at least 0.1, at least 0.2, at least 0.3, or at least 0.5 millimole / gram, and at most 1 or even higher, at most 0.8, at most 0.7, at most 0.6, at most 0.5, or at most 0.4 millimole / gram. This corresponds to a weight increase of 0.2 to 90 percent or even higher. The weight increase is calculated from the formula [100(weight3 - weight2)÷weight2] [where weight2 is the weight of the substrate plus the weight of the first polymer block bonded thereto, and weight3 is the weight of the substrate having the bonded block copolymer (both the first polymer block and the second polymer block)]. The weight can be in the range of 0.2 to 90 weight percent or even higher. The amount can be, for example, at least 0.2, at least 0.5, at least 1, at least 2, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, or at least 50 weight percent, and at most 90, at most 85, at most 80, at most 75, at most 70, at most 65, at most 60, at most 55, at most 50, at most 45, at most 40, at most 35, or at most 30 weight percent.

[0235] Method for separating a mixture of materials The separation article can be used to separate various mixtures of materials, such as mixtures of biological materials. As described above, the separation article has a block copolymer grafted to a porous polymer substrate. The block copolymer contains a first polymer block having acidic monomer units, basic monomer units, or combinations thereof that can bind to various biological materials. These monomer units can be in the form of salts depending on the pH. The block copolymer further contains a second polymer block that can separate biological materials based on size or steric parameters. The separation method is to prepare a separation article as described above and then pass a mixture of materials through the separation article, wherein the second polymer block allows only a portion of the materials in the mixture to contact the acid groups or their salts, base groups or their salts, or combinations thereof in the first polymer block, including passing.

[0236] As used herein, the term "portion" refers to the fact that a portion of the components (i.e., materials) of the mixture is restricted from accessing the first block by the presence of the second block. This restriction of access can be observed as a decrease in the binding ability of the components upon addition of the second block. Typically, the larger components of the mixture are the most restricted, and the smaller components can still diffuse through the second block and bind to the first block, thus enabling selective separation of the large and small components. The separation can be 100% selective, for example, the smaller components of the mixture can be completely captured by the first polymer block and removed by the separation device, while the larger components flow through the device (e.g., are excluded by the second polymer block so as not to be captured by the first polymer block) and are recovered with 100 percent purity and yield. Alternatively, the separation can be selective at less than 100 percent and only partially remove components (s) from the mixture. Typical chromatography operations, such as buffer and pH adjustment, flow rate, residence time, etc., can be used to optimize the selectivity of the separation.

[0237] A portion can be any suitable amount. In some embodiments, a portion of the material that reaches the first polymer block through the second polymer block is at least 1 weight percent based on the total weight of the material to be separated. That amount can be at least 2, at least 5, at least 10, at least 20, at least 30, at least 40, at least 60, at least 70, at least 80, or at least 90 weight percent, or even more, based on the total weight of the material to be separated.

[0238] Without wishing to be bound by theory, the ability to achieve selective separation of the separation article is thought to be based on at least one of (a) manipulation of the pore size of the second polymer block, (b) steric exclusion resulting from the presence of polyether chains in the second polymer block, or (c) a combination of both.

[0239] Engberg, et al., Biomed. Mater., 6(2011), 055006 reports that the diffusion coefficient of proteins in crosslinked polyethylene glycol diacrylate (PEGDA) hydrogels is inversely proportional to the concentration of PEGDA when the crosslinking reaction is initiated. Increasing the concentration results in a more densely crosslinked hydrogel, thus reducing the pore size and slowing protein diffusion. Alternatively, increasing the molecular weight of PEGDA increases the distance between crosslinks, thus increasing the pore size of the hydrogel. As a result, in the separation articles described herein, access of the material to the first polymer block can be optimized by manipulation of the molecular weight of the polyether monomer and the concentration during formation of its second polymer block.

[0240] It is well known to bond a hydrophilic polymer, for example, a hydrophilic polymer derived from a polyether-containing monomer, to a surface to make the surface antifouling or protein-repellent. This phenomenon is at least partially due to the preferential hydration of proteins by the presence of polyether groups and steric exclusion that causes mutual repulsion between the two species. This repulsive interaction is known to increase with increasing molecular weight of the polyether monomer (see Bhat, et al., Protein Science, 1 (1992), pp. 1133-1143). The thickness of the hydration shell depends somewhat on the protein, which can affect the effective size of the protein and its ability to penetrate into the hydrogel. Thus, the steric exclusion effect can be regulated by the choice of polyether monomer used in the second polymer block.

[0241] In addition to the choice of polyether monomer and its concentration in the second polymer block, the graft density of the first and second polymer blocks can be varied to optimize the separation selectivity of the separation article. Increasing the graft density of the first polymer block typically increases the binding ability of that block. Increasing the graft density of the second polymer block and thus its thickness typically improves the selectivity of the block copolymer. Finally, controlling the overall graft density can control the flow properties of the separation article.

[0242] As described above, the separation article is advantageously prepared using a thiocarbonylthio-containing compound as the RDRP agent. In some cases, these agents can provide control over selective separation that is better than can be achieved when using other RDRP agents such as, for example, semi-pinacol-containing agents. In other words, it has been found that more fine control over size selectivity can be achieved using a thiocarbonylthio-containing RDRP agent. In some embodiments using a thiocarbonylthio-containing RDRP agent, a separation article can be prepared that captures small biomolecules such as lysozyme, a 14.3 kD protein, while completely or almost completely excluding larger proteins such as IgG, a 150 kD protein. This enables separation of small proteins from large proteins even when both small and large proteins are positively charged at neutral pH. One example where this selectivity can be advantageous is monoclonal antibody purification in a flow-through separation device.

[0243] In other embodiments, for example, by using a semi-pinacol-containing RDRP agent, the selectivity between large and small proteins may not be as good as when using a thiocarbonylthio-containing RDRP agent. However, when separating larger biotherapeutics such as virus-like particles or viral vectors from smaller biological materials such as host cell proteins, the separation article may advantageously be prepared using a somewhat simpler and less expensive semi-pinacol-containing RDRP agent than a thiocarbonylthio-containing RDRP agent. One example where this selectivity is advantageous is when capturing or removing protein impurities from a production stream of viral vectors or virus-like particles in a flow-through separation device.

[0244] The separation article can be used for the separation of various mixtures of materials, such as mixtures of biological materials. Exemplary separations that can be performed on biological materials include, but are not limited to, the following: (1) separation of monoclonal antibodies (mAbs) from host cell protein (HCP) impurities, (2) separation of mAbs from antibody fragments, (3) separation of mAbs from higher molecular weight antibody aggregates, (4) separation of bispecific antibodies (biAbs) from antibody fragments, (5) separation of antibody-drug conjugates (ADCs) from unconjugated drugs, (6) separation of Fc fusion proteins from Fc fusion protein fragments, (7) separation of IVIG antibodies (gamma globulins) from smaller plasma proteins, (8) separation of milk proteins based on size and / or charge, such as lactoferrin, α-lactalbumin, β-lactoglobulin, (9) separation of viral vectors, viruses, or virus-like particles from host cell impurities such as HCP and nucleic acids, and (10) separation of nucleic acids from other nucleic acids or other impurities (e.g., mRNA from its plasmid DNA template, mRNA from DNA fragments, or plasmid DNA from enzymes, DNA fragments, and other impurities).

[0245] As described above, the separation article can be used to separate various materials such as biological materials based on size or three-dimensional parameters. For example, biological materials captured by the first polymer block are generally smaller in size than biological materials excluded by the second polymer block, and thus diffuse through the second polymer block, interact with, and bind to the first polymer block. The biological materials bound to the first polymer block typically have an ionic charge opposite to that of the ionic charge of the first polymer block, and as a result, the binding interaction is an ion-exchange type interaction. The binding interaction, even if exclusively ion-exchange type, may be enhanced by other secondary interaction types such as hydrogen-bonding type, hydrophobic type, or metal-affinity type interactions depending on the structure of the monomers used to form the first polymer block. The bound biological materials may have a net charge similar to or opposite to that of the biological materials separated by the second polymer block. Clearly, the separation method is most advantageous when used to separate materials with similar charge characteristics. The bound biological materials may be impurities that are desired to be removed from the mixture. Alternatively, they may be the subject of purification, whereupon, upon binding, the impurities may be washed away, and then the buffer conditions (pH, conductivity, etc.) may be changed to elute the bound biological materials in a purified form.

Example

[0246]

Table 1

[0247] Test method Method for the protein-binding ability of the functionalized substrate The first grafted substrate and the second grafted substrate prepared as described in the following examples were analyzed for protein binding ability by incubating one disk of the substrate overnight in a solution of the test analyte (protein dissolved in an appropriate binding buffer). The disks were prepared by punching 18 mm diameter disks from sheets of the grafted substrate. Each disk was placed in a 5 mL centrifuge tube with 4.5 mL of the test analyte solution. The tube was capped and tumbled overnight (typically 14 hours) on a rotating mixer (BARNSTEAD / THERMOLYN LABQUAKE Tube Shaker obtained from VWR International (Eagan, MN); Thermo Scientific Tube Revolver Rotator obtained from Thermo Scientific (Waltham, MA)). The supernatant solution was discarded, the tube was filled with binding buffer, and tumbled for 15 - 30 minutes to wash away excess protein solution. The supernatant solution was discarded and the buffer wash was repeated two more times. 4.5 mL of binding buffer containing 1 M NaCl was added and tumbled for 1 hour to elute the bound protein. The eluted supernatant solution was analyzed using a UV-VIS spectrometer (Agilent 8453, Agilent Technologies (Santa Clara, CA)) at 280 nm (applying background correction at 325 nm), or a NANODROP One C Microvolume UV-VIS spectrophotometer (Thermo Scientific (Waltham, MA)). The binding capacity of each substrate was determined from the UV absorbance and protein extinction coefficient provided by the supplier. The results are reported as the average of three replicates in mg / mL (mg of protein bound per 1 mL of substrate volume).

[0248]

Table 2

[0249] Graft density The substrate (film, nonwoven web, or first grafted substrate) was equilibrated in a low-humidity chamber (available from Sanpia Dry Keeper, Sanplatec Corporation, VWR International) with a relative humidity (RH) of 20 - 25 percent (%) for at least 18 hours before grafting. The substrate was removed from the low-humidity chamber, weighed immediately, and then subjected to a free-radical graft reaction (i.e., the grafting procedure) as described below. After the washing and drying process (described below), the substrate was equilibrated again in the low-humidity chamber for at least 18 hours, removed from the chamber, and reweighed immediately to obtain a measure of the mass increase during the graft reaction. Thereafter, the mass increase was utilized to estimate the number of millimoles of monomer units grafted onto the substrate by dividing the mass increase by the molecular weight of the monomer. The graft density was then normalized by dividing by the original mass of the substrate and expressed in millimoles of grafted monomer units per gram of substrate (mmol / g).

[0250] Film coating procedure A coating solution containing the monomer was prepared as described below. For each coating solution, the membrane substrate was placed on a sheet of polyester film, and sufficient coating solution was pipetted onto the upper surface of the substrate to completely wet the membrane substrate. The coating solution for forming the first grafted substrate (i.e., the first polymer block grafted onto the substrate) is described in Procedures A - E below. Each coating solution was allowed to soak into the membrane substrate for about 1 minute, and then a second sheet of polyester film was placed on top of the substrate. A 2.28 kg cylindrical weight was rolled over the resulting three-layer sandwich to squeeze out the excess coating solution. The coating solution for forming the second grafted substrate is described in the individual examples.

[0251] Nonwoven coating procedure A coating solution containing monomers was prepared as described below. For each coating solution, a nonwoven sheet was placed in a plastic bag with a closure, and sufficient coating solution was pipetted onto the upper surface of the nonwoven substrate to completely wet the nonwoven substrate. A cylindrical weight (2.28 kg) was rolled on top of the bag to distribute the fluid throughout the web (i.e., the nonwoven substrate). The plastic bag was purged with nitrogen gas for 10 seconds, and the filled plastic bag was closed to ensure that the coated web was in an oxygen-free environment. The plastic bag was slightly opened, and immediately the cylindrical weight was rolled to exhaust the gas from the bag. The plastic bag was flattened to squeeze out the excess coating solution. The coating solution for forming the first grafted substrate (i.e., the first polymer block grafted onto the substrate) is described in Procedures F - G below. The coating solution for forming the second grafted substrate is described in the individual examples.

[0252] Ultraviolet (UV) Initiated Grafting Procedure Ultraviolet (UV) initiated grafting was performed by irradiating the coated film in a polyester film sandwich or the coated nonwoven in a plastic bag with a closure at the irradiation times shown in Procedures A - G and Examples 1 - 60 using a UV stand (Classic Manufacturing, Inc. (Oakdale, MN)) equipped with 18 bulbs (Sylvania RG2 40W F40 / 350BL / ECO, 10 above and 8 below the substrate, length 1.17 meters (46 inches), center-to-center spacing 5.1 cm (2 inches)). The film or nonwoven sheet was removed and the resulting first grafted substrate was placed in a polyethylene bottle for washing as described below. After washing and drying, the first grafted substrate was tested for graft density and protein binding capacity.

[0253] Unless otherwise described separately below, these same conditions were used to form the second grafted substrate and evaluate its properties.

[0254] Formation of the first grafted substrate (i.e., the first polymer block grafted to the substrate) Procedure A A coating solution with a total volume of 20 mL containing 0.5 M, 0.75 M, 1.0 M, 1.25 M, or 1.5 M AMPS, sodium salt of 3-carboxybenzophenone (Aldrich Chemical (Milwaukee, WI)) (2.0 mL of 0.033 g / mL aqueous solution), and DEX (140 μL) in methanol was prepared. The solution was coated onto a nylon membrane sheet (8 inches × 8 inches) and UV grafted for 15 or 30 minutes by the above UV-initiated grafting procedure to produce a grafted first cation exchange polymer block derived from AMPS and terminated with an ethoxycarbonylthio group. The sheet was washed with 0.9% saline, methanol, 0.9% saline, methanol (two more times) for 30 minutes each, dried, and then the mass increase was measured to determine the graft density (Table 1). Thereafter, sections of each sheet were cut for evaluation or for grafting of the second polymer block.

[0255]

Table 3

[0256] Procedure B The coating solution was prepared by mixing AMPS (10.35 grams), a 1 wt / wt% solution of benzophenone (Aldrich Chemical (Milwaukee, WI)) in methanol (12 mL), DEX (280 μL), methanol (17.65 mL), and deionized water (3 mL). This solution was approximately 1.16 M in AMPS. It was coated onto two nylon membrane sheets (8 inches × 8 inches) and irradiated with UV for 30 minutes by the above UV-initiated grafting procedure to produce a membrane grafted with a first polymer block having monomer units derived from AMPS and terminated with ethoxycarbonylthio groups. After washing and drying as described in Procedure A, membranes B1 and B2 had mass increases of 4.9 and 5.7%, corresponding to graft densities of 0.21 and 0.25 mmol / g, respectively.

[0257] Procedure C The same coating solution as that used for membrane A4 in Table 1 was prepared and used to graft two nylon membrane sheets (8 inches × 8 inches), which were irradiated with UV for 30 minutes by the above UV-initiated grafting procedure to produce a membrane having a grafted first polymer derived from AMPS and terminated with ethoxycarbonylthio groups. The membrane was washed three times with deionized water only and dried to obtain membranes C1 and C2 having mass increases of 9.2 and 8.7%, corresponding to graft densities of 0.40 and 0.38 mmol / g, respectively.

[0258] Procedure D Three coating solutions with a total volume of 20 mL in methanol containing 1.0 M AMPS, DEX (140 μL), and the sodium salt of 3-carboxybenzophenone (an aqueous solution of 0.033 g / mL, 1.0 mL for D1, 0.5 mL for D2, and 0.25 mL for D3 respectively) were prepared. The solutions were coated onto nylon membrane sheets (8 inches × 8 inches) and UV grafted for 15 minutes by the above UV-initiated grafting procedure to produce grafted first cation exchange polymer blocks terminated with ethoxycarbonylthio groups. The sheets were washed with 0.9% saline, methanol, 0.9% saline, and methanol (two more times) for 30 minutes each, dried, and then the mass increase was measured to determine the graft density. The graft densities of D1, D2, and D3 were 0.16 mmol / g, 0.08 mmol / g, and 0.05 mmol / g respectively.

[0259] Procedure E A coating solution containing 1 wt% benzophenone and 2.5 wt% methyl ethyl xanthoyl acetate (MEX) in acetone was prepared by weighing 1.125 grams of MEX and 0.5 grams of benzophenone and diluting the mixture to a total of 45 grams with acetone. The solution was coated onto nylon membrane sheets (8 inches × 8 inches) and irradiated with UV for 30 minutes by the above UV-initiated grafting procedure to produce a membrane functionalized with ethoxycarbonylthio groups. The membrane was washed three times with acetone and then dried for subsequent grafting.

[0260] Procedure F A coating solution with a total volume of 40 mL in methanol containing 0.25 M AMPS, DEX (560 μL), and sodium salt of 3-carboxybenzophenone (4 mL of 0.033 g / mL aqueous solution) was prepared. Approximately 10 mL of the solution was coated onto a nylon bronzed microfiber web (125 grams per square meter, 13.9% solidity, and 5.9 micrometer effective fiber diameter) sheet (3 inches × 4 inches) in a plastic bag with a closure. Two sheets were prepared in separate bags. The coated web was irradiated with UV for 30 minutes by the above UV-initiated grafting procedure to produce a nonwoven fabric grafted with a polymer derived from AMPS and terminated with ethoxythiocarbonylthio groups. The grafted substrate was washed three times with methanol only for 30 minutes each, and after drying the web, the mass increase was measured to determine the graft density. The graft densities of the first grafted substrates F1 and F2 were 0.70 mmol / g and 0.69 mmol / g, respectively.

[0261] Procedure G A coating solution with a total volume of 10 mL in water containing 0.375 M IEM / agmatine, EXA (100 μL of 17.9% aqueous solution), and sodium salt of 3-carboxybenzophenone (0.5 mL of 0.033 g / mL aqueous solution) was prepared. The solution was coated onto a nylon (Nylon6) bronzed microfiber web (125 grams per square meter, 13.9% solidity, and 5.9 micrometer effective fiber diameter) sheet (3 inches × 4 inches) in a plastic bag with a closure. The coated web was irradiated with UV for 30 minutes by the above UV-initiated grafting procedure to produce a nonwoven fabric grafted with a polymer derived from IEM / agmatine and terminated with ethoxythiocarbonylthio groups. The grafted substrate was washed with 0.9% saline (once) and water (twice) for 30 minutes each, and after drying the web, the mass increase was measured to determine the graft density. The graft density of the first grafted substrate G1 was 2.1 mmol / g (85% mass increase).

[0262] Formation of diblock copolymer grafted onto a substrate Examples 1 - 16 The first grafted substrate prepared by the above Procedure A containing a grafted first polymer block was coated with various concentrations of poly(ethylene glycol) diacrylate (PEGDA) in deionized water, and then UV grafted for 15 or 30 minutes by the above UV-initiated grafting procedure to prepare a film having a grafted diblock copolymer (second grafted substrate). The graft density is listed in Table 2. The protein binding ability determined by the above procedure is listed in Table 3, where the control is the corresponding film grafted with only the first polymer block (i.e., the first grafted substrate).

[0263] [Table 4]

[0264] [Table 5] <Below the detection limit of the LOD-NanoDrop device

[0265] Evaluation of Example 16: Dynamic binding experiment using a 25 mm filter housing Using a buffered protein solution, a dynamic binding capacity test was performed on the membrane medium using an acrylic filter housing with a nominal diameter of 25 mm as follows. A 25 mm diameter disk of the functional membrane medium was die-cut from the above dry medium sample A6 and Example 16. For each test medium, five disks of the functional membrane medium were placed at the bottom of the acrylic filter housing. The acrylic housing was then assembled. The acrylic housing was edge-sealed to the periphery of the medium with an O-ring such that the challenge fluid flowed into the housing at the inlet, then through the five layers of the functional membrane medium, and then out of the housing at the outlet, 2.84 square centimeters (cm 2) was configured to define the effective filtration area (EFA). An exhaust valve located near the fluid inlet made it possible to evacuate the air inside the housing before the test.

[0266] The dynamic binding capacity (DBC) was tested using an AKTA Avant 150 system (Cytiva (Marlborough, MA)) according to the manufacturer's instructions. Before each test, the filter housing was first evacuated and flushed with 5 mL of binding buffer, 5 mL of elution buffer, and then 10 mL of binding buffer at a flow rate of 1 mL / min. The binding buffer and elution buffer are shown in Table 4 below. Then, the binding buffer was exchanged for the test analyte solution (protein dissolved in the appropriate binding buffer), and the test was started at a flow rate of 1 mL / min. During the filter test, the UV absorbance at 280 nm of the eluate increased as the protein in the challenge fluid was loaded onto the membrane. The filter was loaded until the absorbance reached 10% of the maximum absorbance of the test analyte solution in the filtrate. After loading, the filter was washed with 10 mL of binding buffer to wash away unbound protein. Two different elution processes were performed to elute the bound protein. In the first elution process, 10 mL of 100% elution buffer was used. In the second elution process, an elution buffer gradient of up to 100% elution buffer over 15 mL was used, together with 5 mL held at the end of the gradient (total elution volume of 20 mL). After elution, 10 mL of binding buffer was passed through the filter.

[0267] Using Cytiva's evaluation software (Unicorn), the peak area of the elution peak was integrated, and the protein concentration was calculated based on the extinction coefficient of the protein eluted from the membrane. The dynamic binding capacity was determined by the amount of protein bound per calculated membrane volume. The filter housing was then washed with 10 mL of binding buffer and 10 mL of elution buffer and re-equilibrated with 10 mL of binding buffer for the next test. Test analyte solutions of 0.28 mg / mL lysozyme and 0.25 mg / mL monoclonal antibody (mAb; IgG1) were prepared in each of the binding buffers. The buffers used are listed in Table 4.

[0268]

Table 6

[0269] The DBC test was performed on membrane A6 and Example 16 in each of the running buffers. The results are listed in Table 5.

[0270]

Table 7

[0271] This example shows that the addition of the PEGDA block in Example 16 did not prevent the binding of lysozyme under flowing conditions, but the binding of mAb decreased and could be regulated by adjusting the buffer conditions. Therefore, it should be possible to remove small proteins from large proteins even if their charges are similar.

[0272] Examples 17 - 21 The first grafted substrate prepared by the above Procedure B was coated with PEG monomers at various concentrations in deionized water and then UV grafted for 15 or 30 minutes by the above UV-initiated grafting procedure to prepare a second grafted substrate which is a film having a grafted diblock copolymer. The graft density is described in Table 6. The protein binding ability determined by the above procedure is described in Table 7, where the control is the first grafted substrate which is a film having a grafted first polymer block.

[0273]

Table 8

[0274]

Table 9

[0275] These examples show that a wide variety of multifunctional PEG monomers provide good protein selectivity.

[0276] Examples 22 - 25 Sections of the first grafted substrate C1 were coated with PEG575 monomer and HEMA monomer (total monomer concentration 0.1 M) in various molar ratios in deionized water and then UV grafted for 30 minutes by the above UV-initiated grafting procedure to prepare a film having a grafted diblock copolymer. The mass increase is described in Table 6. The protein binding ability determined by the above procedure is described in Table 8, where the control is the first grafted substrate.

[0277]

Table 10

[0278] These examples show that the selectivity for proteins can be adjusted by including small comonomers and that a block of 100% small comonomer (CE25) does not provide selectivity.

[0279] Examples 26 - 28 Sections of the first grafted substrate D1 were coated with various concentrations of PEGMA2000, or PEGMA2000 and MBA in deionized water, grafted by 15 - minute UV irradiation, washed three times with deionized water, and dried. The graft density was very low, but the IgG - binding ability determined by the above procedure is listed in Table 9, where the control is the first grafted substrate.

[0280] [Table 11]

[0281] These examples show that monofunctional PEG somewhat reduces the binding ability to large proteins such as IgG, and that the reduction is improved when a cross - linker is included.

[0282] Examples 29 - 31 Sections of the first grafted substrate A2 were UV - grafted for 30 minutes using PEGDA575 or PEGDA575 and additional cross - linkers MBA or AOHPMA. The composition of the coating solution, mass increase, and protein binding are listed in Table 10, where the control is the membrane grafted with only the first polymer block.

[0283] [Table 12]

[0284] These examples show that the addition of short - chain cross - linkers can regulate protein selectivity.

[0285] Examples 32 - 34 Sections of the first grafted substrate C2 were UV - grafted for 30 minutes with various concentrations of high - molecular - weight PEGDA monomer in deionized water. The membranes were washed three times with deionized water and dried. Table 11 lists the monomer, concentration, mass increase, and protein - binding ability.

[0286]

Table 13

[0287] Examples 35 - 36 In Example 35, 2.324 mL of a MAPTAC solution (50 wt / wt% in water) and in Example 36, 2.905 mL of a MAPTAC solution (50 wt / wt% in water) were mixed with 0.5 mL of a 3 - carboxybenzophenone sodium salt solution (0.033 g / mL aqueous solution) and 35 μL of diethyl bisxanthate, and the mixture was diluted to a total of 5 mL with methanol to prepare a coating solution. Thereby, solutions of 1.0 and 1.25 M in MAPTAC were obtained respectively. These solutions were coated on nylon membranes, UV grafted for 30 minutes, washed three times with methanol and dried to produce membranes having a first anion - exchange polymer block terminated with ethoxycarbonylthio groups (first grafted substrates) having graft densities of 0.25 and 0.78 mmol / g respectively. Thereafter, each membrane was grafted with 0.1 M PEGDA575 in deionized water, UV irradiated for 30 minutes, washed and dried to obtain membranes having a second polymer block with mass increases of 10.5 and 10.8% respectively (second grafted substrates).

[0288] These membranes were tested for their binding ability to β - lactoglobulin (a protein with a diameter of 3.5 nm), bovine serum albumin (BSA, a protein with a diameter of 7.1 nm), and phi6 (a bacteriophage with a diameter of 75 - 85 nm). The binding buffer for the proteins was 50 mM HEPES, pH 7 and the binding buffer for phi6 was 25 mM Tris, pH 8. The results are presented in Table 12 as the % decrease in binding of the block copolymer membranes relative to a control of MAPTAC only. The % decrease is calculated as follows: 100 - 100(binding by block copolymer / binding by control).

[0289]

Table 14

[0290] These experiments indicate that while the virus or virus-like particles are purified by perfusion, it should be possible to capture host cell protein impurities present in the clarified cell culture.

[0291] Examples 37 - 39 A 6-inch × 8-inch functionalized membrane prepared by the above procedure E was coated with IEM / agmatine (0.2 M in deionized water) and UV grafted for 30 minutes by the above UV-initiated grafting procedure to produce a membrane having a first anion exchange polymer block terminated with ethoxythiocarbonylthio groups with a ligand density of 0.29 mmol / g. The membrane was cut into four pieces, and three of them were coated with PEGDA575 in deionized water, UV irradiated for 30 minutes, washed, and dried to obtain a membrane having a second polymer block. The membrane was tested for protein binding ability to β-lactoglobulin and BSA. The results are shown in Table 13.

[0292]

Table 15

[0293] These experiments indicate that optimization of the mass increase of the second polymer block can be important. When the amount grafted is too small, no differences are observed; when the amount grafted is too large, smaller proteins begin to be excluded almost to the same extent as larger proteins; when the amount grafted is appropriate, a decrease in the binding of larger proteins is observed and the effect on smaller proteins is minimal.

[0294] Examples 40 - 42 The 6-inch × 8-inch functionalized film prepared by the above procedure E was coated with IEM / GABA (0.5 M in deionized water), and UV grafted for 30 minutes by the above UV-initiated grafting procedure to produce a film having a first cation exchange polymer block terminated with ethoxythiocarbonylthio groups and having a ligand density of 0.33 mmol / g (first grafted substrate). The second polymer block was grafted using various concentrations of PEGDA575 in deionized water with a UV grafting time of 15 minutes in the presence or absence of the addition of water-soluble xanthate, EXA. The results are shown in Table 14.

[0295]

Table 16

[0296] Examples 43 - 45 The 6-inch × 8-inch functionalized film prepared by the above procedure E was coated with IEM / GABA (0.7 M and 0.004 M EXA in deionized water), and UV grafted for 30 minutes by the above UV-initiated grafting procedure to produce a film having a first cation exchange polymer block terminated with ethoxythiocarbonylthio groups and having a ligand density of 0.61 mmol / g (first grafted substrate). The second polymer block was grafted using various concentrations of PEGDA575 in deionized water with a UV grafting time of 30 minutes in the presence or absence of the addition of water-soluble xanthate, EXA. The protein binding ability to lysozyme and IgG was measured. The results are shown in Table 15.

[0297]

Table 17

[0298] These examples show that IgG binding can be reduced by appropriate adjustment of the second polymer block without affecting lysozyme binding.

[0299] Examples 46 - 47 A polyethersulfone membrane substrate (MicroPES 8F, nominal pore size 0.8 μm, obtained from 3M Separation and Purification Sciences (St. Paul, MN)) was grafted with VDM / GABA at monomer concentrations of 0.2 and 0.4 M in deionized water (15 minutes of UV). The grafting solutions also contained 0.004 and 0.008 M EXA, respectively. This yielded a first carboxylate-functional block terminated with a thiocarbonylthio group (the first grafted substrate). After washing and drying, a second polymer block was added to the membrane by grafting with PEG575 at a concentration of 0.2 M in deionized water for a UV irradiation time of 30 minutes to form a second grafted substrate. The first and second grafted substrates were tested for lysozyme and IgG binding ability. The results are presented in Table 16 as the percentage decrease in binding of the block copolymer membrane relative to a VDM / GABA-only control.

[0300]

Table 18

[0301] These examples show that the block copolymer is selective for lysozyme, a smaller protein, over IgG, a larger protein. Optimization of the grafting process was able to improve the selectivity.

[0302] Examples 48 - 50 The 6-inch × 8-inch functionalized film prepared by the above procedure E was coated with IEM / glycine (0.5 M and 0.004 M EXA in deionized water) and UV grafted for 30 minutes by the above UV-initiated grafting procedure to produce a film (first grafted substrate) having a first cation exchange polymer block terminated with ethoxythiocarbonylthio groups and having a ligand density of 0.41 mmol / g. The second polymer block was grafted with various PEG methacrylates, PEGMA200, PEGMA400, and PEGMA2000 in deionized water each using a 30-minute UV grafting time. The protein binding ability to lysozyme and IgG was measured. The results are shown in Table 17.

[0303]

Table 19

[0304] These examples show that IgG binding can be decreased by the second polymer block of PEG methacrylate, presumably by steric exclusion, without any loss of lysozyme binding.

[0305] Example 51 The first grafted substrate F2 prepared by the above procedure F was coated with 0.1 M EGDA (10 mL) in deionized water in a plastic bag with a closure and UV grafted for 30 minutes by the above UV-initiated grafting procedure. The web was washed once with 0.9% saline and twice with deionized water (each for 30 minutes) and then dried. The measured graft density of the second polymer block was F3 - 0.13 mmol / g. The thickness was measured after drying and determined to be 0.79 mm. The protein binding ability determined by the above procedure was measured with the following modifications and described in Table 18 below: 3 mg / mL lysozyme in 50 mM HEPES buffer (pH 7) was used instead of 3.5 mg / mL lysozyme in 10 mM MOPS buffer (pH 7).

[0306]

Table 20

[0307] This example shows that for the block copolymer grafted to the nonwoven substrate, there is no decrease in lysozyme binding, but there is some decrease in the binding of the larger protein IgG.

[0308] Example 52 The first grafted substrate G1 prepared by the above procedure G was cut in half (2 inches × 3 inches), and one piece was coated with 0.15 M PEGDA (5 mL) in deionized water containing EXA (50 μL of 17.9% aqueous solution) in a plastic bag with a closure. The coated nonwoven sheet was UV grafted for 30 minutes by the above UV-initiated grafting procedure. Both nonwoven sheets G1 and G2 were washed once with 0.9% saline and twice with deionized water (30 minutes each), and then dried. The measured graft density of the second polymer block was G2 - 0.42 mmol / g. The thickness was measured after drying and determined to be 0.79 mm.

[0309] Protein binding capacity was determined using a protocol modified compared to the above protocol. Three discs each of G1 and G2 were prepared by punching out 18 mm diameter discs from the substrate sheets. Each disc was placed in a 5 mL centrifuge tube together with 4.5 mL of 5 mg / mL BSA in 25 mM Tris-HCl (pH 7.6) containing 100 mM NaCl. The tube was capped and tumbled overnight. The supernatant solution was discarded, and the tube was filled with 25 mM Tris-HCl, pH 7.6 containing 100 mM NaCl and tumbled for 15 - 30 minutes to wash away the excess protein solution. The supernatant solution was discarded, and the buffer wash was repeated two more times. 3 mL of 25 mM Tris-HCl (pH 7.6) containing 1 M NaCl was added and tumbled for 30 minutes to elute the bound BSA. The protein concentration in the eluate was analyzed using a NANODROP UV-VIS spectrophotometer. The eluate was discarded, and then stripped for 30 minutes with tumbling using another 3 mL of 25 mM Tris-HCl (pH 7.6) containing 1 M NaCl. The strip solution was discarded, and the tube was filled with 25 mM Tris-HCl, pH 7.6 containing 100 mM NaCl and tumbled for 15 - 30 minutes to wash and equilibrate the disc. The supernatant solution was discarded, and the buffer wash was repeated two more times. The excess solution in the disc was gently squeezed out and discarded. 4.5 mL of 5 mg / mL beta-lactoglobulin in 25 mM Tris-HCl (pH 7.6) containing 100 mM NaCl was added to each of the 5 mL tubes containing the washed discs of G1 and G2. The tube was capped and tumbled overnight. The supernatant solution was discarded, and the tube was filled with 25 mM Tris-HCl, pH 7.6 containing 100 mM NaCl and tumbled for 15 - 30 minutes to wash away the excess protein solution. The supernatant solution was discarded, and the buffer wash was repeated two more times. 3 mL of 25 mM Tris-HCl (pH 7.6) containing 1 M NaCl was added and tumbled for 30 minutes to elute the bound beta-lactoglobulin. The protein concentration in the eluate was analyzed using a NANODROP UV-VIS spectrophotometer. The binding capacity of each substrate was determined from the UV absorbance and protein extinction coefficient provided by the supplier.Report the results as the average of three replicates in mg / mL (mg of protein bound per 1 mL of nonwoven volume).

[0310]

Table 21

[0311] This example shows that for the block copolymer grafted to the nonwoven substrate, there is no decrease in β-lactoglobulin binding, but there is a decrease in the larger protein BSA.

[0312] Examples 53 - 54 A coating solution with a total volume of 20 mL containing 1.5 M AMPS and the sodium salt of 3-carboxybenzophenone (Aldrich Chemical (Milwaukee, WI)) (2.0 mL of a 0.033 g / mL aqueous solution) in methanol was prepared. The solution was coated onto a nylon membrane sheet (8 inches × 8 inches) and UV grafted for 15 minutes by the above UV-initiated grafting procedure to produce a grafted first cation exchange polymer block derived from AMPS and terminated with semipinacol-containing groups. The sheet was washed with 0.9% saline, methanol, 0.9% saline, methanol (two more times) for 30 minutes each, dried, and the mass increase was measured to determine that the graft density was 1.25 mmol / g. A portion of this first grafted substrate was coated with poly(ethylene glycol) diacrylate (PEGDA575) at a concentration of 0.1 M (Example 53) or 0.2 M (Example 54) in deionized water and then UV grafted for 15 minutes by the above UV-initiated grafting procedure to prepare membranes of Examples 53 and 54 with grafted diblock copolymers (second grafted substrates). The graft densities of these second grafted substrates were 0.22 and 0.40 mmol / g, respectively. The protein binding ability determined by the above procedure is listed in Table 20, where the control is the corresponding membrane with only the first polymer block grafted (i.e., the first grafted substrate).

[0313]

Table 22

[0314] Examples 55 - 56 A first grafted substrate was prepared by the same procedure as described above for Examples 53 - 54, except that the AMPS concentration was 0.75 M. As a result, a grafted nylon membrane was obtained having a graft density of 0.54 mmol / g and at least some of the graft chains terminated with semipinacol groups. A portion of this first grafted substrate was coated with poly(ethylene glycol) diacrylate (PEGDA575) at a concentration of 0.1 M (Example 55) or 0.2 M (Example 56) in deionized water, and then UV grafted for 15 minutes by the above UV-initiated graft procedure to prepare membranes of Examples 55 and 56 having grafted diblock copolymers (second grafted substrates). The graft densities of these second grafted substrates were 0.17 and 0.39 mmol / g, respectively. The protein binding ability determined by the above procedure is described in Table 21, where the control is the corresponding membrane grafted with only the first polymer block (i.e., the first grafted substrate).

[0315]

Table 23

[0316] Examples 57 - 58 The first grafted substrate was prepared by the same procedure as described above for Examples 53 - 54, except that the AMPS concentration was 0.5 M and the type II photoinitiator was a 1.0 mL solution of sodium carboxybenzophenone initiator, resulting in a grafted nylon membrane with an even lower graft density of 0.30 mmol / g and at least some of the graft chains terminated with semi-pinacol groups. A portion of this first grafted substrate was coated with poly(ethylene glycol) diacrylate (PEGDA575) at a concentration of 0.1 M (Example 57) or 0.2 M (Example 58) in deionized water, and then UV grafted for 15 minutes by the above UV-initiated graft procedure to prepare the membranes of Examples 57 and 58 with grafted diblock copolymers (the second grafted substrates). The graft densities of these second grafted substrates were 0.09 and 0.31 mmol / g, respectively. The protein binding capacity determined by the above procedure is listed in Table 22, where the control is the corresponding membrane with only the first polymer block grafted (i.e., the first grafted substrate).

[0317]

Table 24

[0318] Examples 59 - 60 A coating solution containing 1 wt% benzophenone in acetone was coated onto a nylon membrane sheet (6 inches × 8 inches) and irradiated with UV for 30 minutes by the above UV-initiated graft procedure to produce a membrane functionalized with semi-pinacol-containing groups. The membrane was washed three times with acetone and dried for subsequent grafting.

[0319] This membrane was coated with IEM / GABA (0.4 M in deionized water) and UV grafted for 30 minutes by the above UV-initiated grafting procedure to produce a membrane having a first cation-exchange polymer block terminated with semipinacol groups and having a ligand density of 0.38 mmol / g (the first grafted substrate). A second polymer block was grafted onto a portion of this grafted membrane using various concentrations of PEGDA575 in deionized water and a UV grafting time of 30 minutes. Protein binding ability to lysozyme and IgG was measured. The results are shown in Table 23.

[0320]

Table 25

Claims

1. A porous polymer substrate, which is a solid material, A plurality of block copolymer chains grafted onto the solid porous polymer substrate and extending from the surface of the solid porous polymer substrate, a) A first polymer block covalently bonded to the solid porous polymer substrate, comprising an acidic monomer unit containing an acidic group or a salt thereof, a basic monomer unit containing a basic group or a salt thereof, or a combination thereof, b) A second polymer block covalently bonded to the first polymer block, A separation article comprising a plurality of block copolymer chains, the first polymer block being located between the second polymer block and the solid porous polymer substrate, the second polymer block comprising polyether-containing monomer units, and the second polymer block comprising a plurality of block copolymer chains.

2. The separation article according to claim 1, wherein the first polymer block is directly covalently bonded to the carbon atoms of the solid porous polymer substrate.

3. The acid monomer and / or the basic monomer is of formula (IV) CH ２ =CR ２１ -C(=O)-X １ -R ２２ -[Z-R ２２ ] ｎ -L (IV) [In the formula, R ２１ is hydrogen or methyl, Each R ２２ It is independently a (hetero)hydrocarbylene, X １ is -O- or -NR ２３ -(where R ２３ is hydrogen or hydrocarbyl), and Z is a heterohydrocarbylene comprising at least one hydrogen bond donor, at least one hydrogen bond acceptor, or a combination thereof. n is an integer of 0 or 1, The separation article according to claim 1 or 2, wherein L is an acidic group, a basic group, or a salt thereof, a ligand functional group, or a salt thereof.

4. The separation article according to claim 1 or 2, wherein the porous polymer substrate comprises particles, fibers, films, nonwoven webs, membranes, sponges, or sheets.

5. The separation article according to claim 4, wherein the porous polymer substrate comprises a nonwoven web or a membrane.

6. The separation article according to claim 1 or 2, wherein the second polymer block is hydrophilic or water-swellable.

7. A method for producing a separation article comprising a solid porous polymer substrate and a plurality of block copolymers grafted onto the solid porous polymer substrate and extending from the surface of the solid porous polymer substrate, The preparation of the aforementioned solid porous polymer substrate, Grafting a plurality of first polymer blocks onto the solid porous polymer substrate using a reversible deactivation radical polymerization process, wherein the first polymer blocks are covalently bonded to the solid porous polymer substrate, and the first polymer blocks are 1) Acidic monomers containing an ethylenically unsaturated group and an acidic group or a salt thereof, and / or 2) The reaction product of a first polymerizable composition containing a basic monomer comprising an ethylenically unsaturated group and a basic group or a salt thereof, which is grafted, The method involves forming a plurality of second polymer blocks, wherein the second polymer blocks are covalently bonded to the first polymer block using the reversible deactivation radical polymerization process, the first polymer block is located between the solid porous polymer substrate and the second polymer block, and the second polymer block is 1) A method comprising forming a reaction product of a second polymerizable composition comprising a polyether monomer having at least one ethylenically unsaturated group and a polyether group.

8. The method according to claim 7, wherein the reversible inactivation radical polymerization process is a reversible addition-cleavage chain transfer polymerization process.

9. The method according to claim 7 or 8, wherein the reversible inactivation radical polymerization process includes using a thiocarbonylthio-containing compound as a polymerization control agent.

10. The thiocarbonylthio-containing compound is of the formula -S-C(=S)-R １ It has a thiocarbonylthio-containing group, in the formula, R １ is an alkoxy, aralkyloxy, alkenyloxy or -N(R) ４ ) ２ And, Each R ４ is either alkyl or two adjacent R ４ The method according to claim 7 or 8, wherein the groups are combined with nitrogen to which they are both bonded to form a first heterocycle having 1 to 3 heteroatoms selected from nitrogen, oxygen, and sulfur, which is saturated or unsaturated, and optionally fused to one or more second rings which are carbocyclic or heterocyclic.

11. The method according to claim 7 or 8, wherein the block copolymer is directly covalently bonded to the carbon atoms of the solid porous polymer substrate.

12. The method according to claim 7 or 8, wherein the first polymer block has a terminal thiocarbonylthio-containing group or a semipinacol group before forming the second polymer block.

13. A method for separating a mixture of materials of different sizes and, optionally, different ion contents, A solid porous polymer substrate and a plurality of block copolymers grafted onto the solid porous polymer substrate using a reversible deactivation radical polymerization process, the block copolymers extending from the surface of the solid porous polymer substrate, a) A first polymer block covalently bonded to the porous polymer substrate, comprising a first monomer unit having a bonding group which is an acidic group, a basic group, or a salt thereof for interacting with a material having complementary groups, b) Preparing or providing a separation article comprising a second polymer block covalently bonded to the first polymer block, wherein the first polymer block is located between the second polymer block and the solid porous polymer substrate, and the second polymer block contains polyether-containing monomer units, and a plurality of block copolymers, A method comprising passing a mixture of the materials through the separating article, wherein the second polymer block separates the mixture of materials based on size exclusion or steric exclusion, allowing only a portion of the materials to come into contact with the acidic groups, basic groups, or salts thereof of the first polymer block.

14. The method according to claim 13, wherein the mixture of the materials includes a biomaterial.

Images