Abstract: A process for producing a perfluoropolymer, the process including extruding a polymer obtained by polymerizing a perfluoromonomer to prepare strands, and bringing a gas comprising from 3 to 50 volume % of fluorine gas into contact with the strands; the process being conducted on an apparatus that includes an extruder for melting and extruding the polymer obtained by polymerizing a perfluoromonomer, a die having a plurality of pores for preparing the strands from the molten polymer extruded, and a fluorination tank for bringing the gas comprising from 3 to 50 volume % of fluorine gas into contact with the strands.

Abstract: Improved expanded PTFE materials and improved gasket materials made therefrom, the gaskets being capable of forming a seal with greater bolt load retention than is possible with existing PTFE gaskets. The expanded PTFE membranes of the invention can be tailored to exhibit a matrix tensile strength in at least one direction of at least 25,000 psi, a matrix tensile strength ratio in two orthogonal directions of between 0.25 and 4, an orientation index of 50° or less, and a density of 2.0 g/cc or less. The improved gaskets exhibit improved mechanical properties such as high bolt load retention, low creep, high tensile strength, low stress to seal and high crystallinity index.

Abstract: Disclosed herein is a method to produce a semi-crystalline fluoro-polymer film. A semi-crystalline fluoro-polymer material is used. The material is compressed to produce the film. During compression, the material is maintained at a temperature below the melting point of the material. The compression step can be cycled to allow cooling of the material between compression stages. Alternative methods are provided for compressing the material with a co-extrusion substrate, extruding the material and utilizing mandrel expansion for the material.

Abstract: A polyvinylidene difluoride copolymer with a fluoroolefin selected from 2,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene, 2-chloro-pentafluoropropene, hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoro-2-trifluoromethylpropene and a mixture thereof, wherein the stoichiometry of the co-monomers defines the barrier properties of the copolymer. Such polymers include moisture barrier copolymers and oxygen barrier copolymer. Processes for preparing such moisture barrier copolymers and oxygen barrier copolymers are also provided.

Abstract: Disclosed herein are novel fluoroolefins of formula Rf—O—(CF2CF2)n(CH2CF2)m—CH?CH2, wherein n is 1 or 2, m is 0 or 1 and Rf is a C1-C8 fluoroalkyl or fluoroalkoxy group. The fluoroolefins may be oxidized to manufacture fluorinated carboxylic acids. Also disclosed are fluoropolymers comprising copolymerized units of the fluoroolefins of the invention and at least one other fluoromonomer.

Abstract: A fluorine-containing elastomer composition assuring a low compression set and comprising a perfluoroelastomer (A) comprising (a) 18 to 33% by mole of a perfluoro(alkyl vinyl ether) unit, (b) 0.3 to 0.6% by mole of a monomer unit having at least one selected from the group consisting of a nitrile group, a carboxyl group and an alkoxycarbonyl group and (c) a tetrafluoroethylene unit.

Abstract: The invention provides surfactant-containing cosmetic, dermatological, and pharmaceutical agents comprising at least one water-soluble or water-swellable copolymer obtainable by free-radical copolymerization of A) acryloyldimethyltaurine and/or acryloyldimethyltaurates, B) if desired, one or more further olefinically unsaturated, noncationic comonomers, C) if desired, one or more olefinically unsaturated, cationic comonomers, D) if desired, a silicon-containing component(s), E) if desired, a fluorine-containing component(s), F) if desired, one or more macromonomers, G) the copolymerization taking place if desired in the presence of at least one polymeric additive, H) with the proviso that component A) is copolymerized with at least one component selected from one of the groups D) to G).

Abstract: A process for forming a multilayer film includes coating a polymeric substrate film with a liquid fluoropolymer coating. The liquid fluoropolymer coating includes a fluoropolymer, solvent, a compatible cross-linkable adhesive polymer, and a cross-linking agent. The process further includes cross-linking the compatible cross-linkable adhesive polymer to form a cross-linked polymer network in the fluoropolymer coating, removing the solvent from the fluoropolymer coating, and adhering the fluoropolymer coating to the polymeric substrate film. A liquid fluoropolymer coating composition includes a fluoropolymer selected from homopolymers and copolymers of vinyl fluoride and homopolymers and copolymers of vinylidene fluoride, solvent, a compatible cross-linkable adhesive polymer, and a cross-linking agent. A fluoropolymer coated film includes a polymeric substrate film and a fluoropolymer coating on the polymeric substrate film.

Abstract: A mixture of polyfluoroalkadienes represented by the general formulae: CF3(CF2)nCF?CH(CF2)m+1CH?CH2 [Ia] and CF3(CF2)n+1CH?CF(CF2)mCH?CH2 [Ib], wherein n is an integer of 0 to 5, and m is an integer of 0 to 6, is obtained as a mixture fraction of products [Ia] and [Ib] by reacting a polyfluoroalkyl iodide represented by the general formula: CF3(CF2)n+1CH2(CF2)m+1(CH2CH2)I [II], with an organic basic compound. The polyfluoroalkadiene mixture is compounds having a perfluoroalkyl group in which the number of successive CF2 groups is 5 or less, and is effectively used as a copolymerizable monomer in the production of resinous or elastomeric fluorine-containing copolymers, which are used as active ingredients of surface-treating agents, such as water- and oil-repellents and mold-release agents.

Abstract: A polyvinylidene difluoride copolymer with a fluoroolefin selected from 2,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene, 2-chloro-pentafluoropropene, hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoro-2-trifluoromethylpropene and a mixture thereof, wherein the stoichiometry of the co-monomers defines the barrier properties of the copolymer. Such polymers include moisture barrier copolymers and oxygen barrier copolymer. Processes for preparing such moisture barrier copolymers and oxygen barrier copolymers are also provided.

Abstract: Improved expanded PTFE materials and improved gasket materials made therefrom, the gaskets being capable of forming a seal with greater bolt load retention than is possible with existing PTFE gaskets. The expanded PTFE membranes of the invention can be tailored to exhibit a matrix tensile strength in at least one direction of at least 25,000 psi, a matrix tensile strength ratio in two orthogonal directions of between 0.25 and 4, an orientation index of 50° or less, and a density of 2.0 g/cc or less. The improved gaskets exhibit improved mechanical properties such as high bolt load retention, low creep, high tensile strength, low stress to seal and high crystallinity index.

Abstract: A composite ionomeric membrane comprising a layer or film of a porous inert material on which a (per) fluorinated sulphonic ionomer is deposited wherein the sulphonic groups are at the end of short side chains (SSC), said ionomer having: equivalent weight comprised between 280 and 1,700 g/eq; side chains of formula: —O—CF2—CF2—SO3—M+, wherein M is hydrogen or an alkaline metal; said membrane having in each of the two orthogonal directions xy of the plane, after dipping in demineralized water at 100° C. for 30 minutes and preliminary drying at 105° C. under vacuum for one hour, the following size variations: in one direction, size variation lower than 25%; in the other direction, size variation lower than 20%.

Abstract: The present invention relates to a method for the polymerization of fluoromonomers using non-fluorinated alkyl phosphonate surfactants, and to the fluoropolymers formed thereby. Specifically, the method of the polymerization uses one or more alkyl phosphonic acids or salts thereof.

Abstract: The invention provides a fluoropolymer coated film comprising: a polymeric substrate film; and a fluoropolymer coating on the polymeric substrate film, the fluoropolymer coating comprising a vinyl fluoride copolymer comprised of about 40 to about 90 mole % of repeat units derived from vinyl fluoride and about 10 to about 60 mole % of repeat units derived from monomer selected from the group consisting of (a) and (b) below and mixtures thereof, with the proviso that about 0.

Abstract: A process comprising polymerizing tetrafluoroethylene in an aqueous emulsion in the presence of a non-telogenic surfactant having an anionic portion with the general formula (I): Rf—O-L-CO2—??(I) wherein Rf is selected from a partially fluorinated alkyl group, a perfluorinated alkyl group, a partially fluorinated alkyl group interrupted by one or more oxygen atoms, and a perfluorinated alkyl group interrupted by one or more oxygen atoms, wherein Rf has from 1 to 10 carbon atoms; and L is an alkylene group having the general formula (CX2)n wherein each X is independently selected from Rf, fluorine, and hydrogen and n is selected from 1 to 5, with the proviso that the surfactant contains at least one unit selected from a —CH2— unit and a —CHF— unit. Also provided are aqueous dispersions comprising these surfactants and methods of coating substrates with the aqueous dispersions.

Abstract: A composition and its use as a mold release composition are disclosed. The composition comprises a fluorotelomer, which comprises repeat units derived from a fluoroalkene, and optionally a comonomer, and has an endgroup derived from an alcohol, an alcohol derivative, or a combination thereof, and said fluorotelomer has or comprises a structure depicted as H(CX2)pBqDr or a mixture of structures depicted as H(CX2)pBq and H(CX2)pDr, wherein each X is independently H or F, provided at least one X is F, p is a number from about 16 to about 1500, B represents a unit derived from a hydrofluorocarbon, q is a number from 0.02 to 0.4, D represents an endgroup derived from said alcohol, alcohol derivative, or combination thereof, and r is a number 0.2 to 1.0.

Abstract: A novel aqueous polymerization process for making fluoropolymer dispersions is disclosed in which non-ionic non-fluorinated emulsifier is used to produce fluoropolymer emulsions. The emulsifiers contain blocks of polyethylene glycol, polypropylene glycol and/or polytetramethylene glycol. The process and fluoropolymer produced contain no fluorinated surfactant. The fluoropolymers have excellent resistance to discoloration.

Abstract: Cured perfluoroelastomer articles are disclosed which have improved surface characteristics. The articles are coated with a thin durable film comprising a fluorocarbon telomer which reduces surface stickiness, while maintaining the sealing properties of the article.

Abstract: The invention provides surfactant-free cosmetic, pharmaceutical, and dermatological compositions comprising at least one copolymer obtainable by free-radical copolymerization of A) acryloyldimethyltaurine and/or acryloyldimethyltaurates, B) if desired, one or more further olefinically unsaturated, noncationic comonomers, C) if desired, one or more olefinically unsaturated, cationic comonomers, D) if desired, one or more silicon-containing components, E) if desired, one or more fluorine-containing components, F) if desired, one or more macromonomers, G) the copolymerization taking place if desired in the presence of at least one polymeric additive, H) with the proviso that component A) is copolymerized with at least one component selected from one of the groups.

Abstract: A membrane humidifier assembly includes a first flow field plate adapted to facilitate flow of a first gas thereto and a second flow field plate adapted to facilitate flow of a second gas thereto. A polymeric membrane is disposed between the first and second flow fields and adapted to permit transfer of water from the first flow field plate to the second flow field plate. The polymeric membrane includes a polymer having perfluorocyclobutyl groups.

Abstract: A polymer useful as an ion conductor in fuel cells includes a perfluorocyclobutyl moiety and pendant PFSA side groups. The polymer is made by a variation of the Ullmann reaction. Ion conducting membranes incorporating the polymer are provided.

Abstract: An ion exchange membrane is prepared from a block copolymer comprising a hydrophobic polymer segment and a polar polymer segment. The ion exchange membrane is formed by placing a film layer in steam, water or an electric field at a temperature greater than about 40° C. for sufficient amount of time to develop a bicontinuous morphology. The ion exchange membrane is also formed from a film layer comprising a block copolymer and a solvent. The film layer is placed in an electric field at an elevated temperature and dried therein. The film layer is thereby converted into an ion exchange membrane with bicontinuous morphology. The ion exchange membrane prepared according to these processes exhibits improved mechanical and electrochemical properties.

Abstract: A polymer useful as an ion conducting membrane for fuel cell applications includes both main chain and side chain protogenic groups. Methods for preparing the polymer include addition of the side chains both before and after addition of the protogenic groups.

Abstract: A blend composition comprises a fluorine-containing polymer electrolyte and a fluoro-rubber. An electrolyte membrane may be prepared from the blend composition. The electrolyte membrane may be used in electrochemical cells such as electrolyzers, batteries and fuel cells.

Abstract: The invention relates to the field of chemistry and relates to radically coupled PTFE polymer powders that can be used, for example, as tribomaterials, and a method for the production thereof. There is disclosed radically coupled PTFE polymer powders which, when incorporated into a matrix as PTFE polymer compound, exhibit improved wear resistance, and furthermore a simple and efficient method for the production thereof. There is provided radically coupled PTFE polymer powders comprising radiation-chemically and/or plasma-chemically modified PTFE powders, onto the particle surface of which homopolymers, copolymers or terpolymers are radically coupled via a reaction in dispersion or in solid.

Abstract: To provide a process for efficiently producing a perfluoropolymer having unstable terminal groups reduced. A process for producing a fluorination-treated perfluoropolymer, which comprises melting a thermoplastic perfluoropolymer to form strands and contacting the polymer strands with a fluorine gas. For fluorination-treatment of the perfluoropolymer, an apparatus 10 is used, which comprises a melt extruder 11 for melting and extruding the perfluoropolymer, a die 12 for forming the melt extruded polymer into continuous strands 1 and a fluorination tank 13 for contacting the continuous strands 1 with a fluorine gas.

Abstract: A composition of tetrafluoroethylene/perfluoro(ethyl vinyl ether) copolymer particles and metal powder is disclosed that enables the composition to be used for adhering a lining to an interior surface of a hollow article.

Abstract: A composite membrane for fuel cell applications includes a support substrate with a predefined void volume. The void volume is at least partially filled with an ion conducting polymer composition. Characteristically, the ion conducting polymer composition includes a first polymer with a cyclobutyl moiety and a second polymer that is different than the first polymer.

Abstract: An ion conducting polymeric structure suitable for fuel cell applications is provided. The polymeric structure comprises a non-homogenous polymeric layer. The non-homogeneous layer is a blend of a first polymer comprising cyclobutyl moiety; and a second polymer having a non-ionic polymer segment. The weight ratio of the first polymer to the second polymer varies as a function of position within the non-homogenous layer. The blend composition may be cast into an electrolyte membrane that can be used to prepare electrochemical cells such as batteries and fuel cells.

Abstract: An emulsion polymerization process for the production of non-elastomeric fluoropolymers is disclosed wherein at least one fluorosurfactant is employed as dispersant, said fluorosurfactant being a fluoroalkylphosphoric acid ester of the formula X-Rf-(CH2)n—O—P(O)(OM)2, wherein n is 1 or 2, X?H or F, M=a univalent cation, and Rf is a C4-C6 fluoroalkyl or fluoroalkoxy group. Optionally, a second dispersing agent may be employed in the polymerization, said second agent being a perfluoropolyether having at least one endgroup selected from the group consisting of carboxylic acid, a salt thereof, sulfonic acid and a salt thereof, phosphoric acid and a salt thereof.

Abstract: A method of forming an ionomeric membrane includes a step of reacting a first polymer in chlorosulfonic acid to form a first precipitate. The first precipitate comprising a polymer including a polymer unit having at least one —SO2Cl moiety attached thereto and includes a step of dissolving the first precipitate in a polar aprotic solvent to form the first solution. A polymeric membrane is then formed from the first solution such that the membrane includes the polymer unit having at least one —SO2Cl. The polymer including a polymer unit a polymer unit having at least one —SO2Cl is then reacted with a nucleophilic compound to form the polymeric membrane.

Abstract: A polymer blend useful as an ion conductor in fuel cells includes a first polymer having a cyclobutyl moiety and a second polymer include a sulfonic acid group.

Abstract: A membrane humidifier assembly includes a first flow field plate adapted to facilitate flow of a first gas thereto and a second flow field plate adapted to facilitate flow of a second gas thereto. A polymeric membrane is disposed between the first and second flow fields and adapted to permit transfer of water from the first flow field plate to the second flow field plate. The polymeric membrane includes a polymer having perfluorocyclobutyl groups and a pendant side chain having a protogenic group.

Abstract: A repellent agent composition including an aqueous continuous phase and a graft copolymer dispersed in the aqueous continuous phase. The graft copolymer has a water soluble polymer trunk having hydroxyl groups and branches having fluorinated groups bonded to the polymer trunk at a carbon atom substituted with a hydroxyl group. Also disclosed is a method of making the graft copolymer and a substrate treated with the repellent composition.

Abstract: Copolymers prepared by copolymerization of at least one fluorinated vinyl ether are provided. In one embodiment, the at least one fluorinated vinyl ether comprises ethylene directly substituted at an olefinic carbon atom with a moiety —OR* and optionally substituted with one, two, or three additional nonhydrogen substituents, wherein R* comprises a fluorinated alkyl moiety substituted with a protected or unprotected hydroxyl group, and further wherein an atom within R* may be (i) taken together with one of the additional nonhydrogen substituents, if present, or (ii) directly bound to an olefinic carbon atom, to form a ring. The polymers are useful, for example, in lithographic photoresist compositions, particularly chemical amplification resists. In a preferred embodiment, the polymers are substantially transparent to deep ultraviolet (DUV) radiation, and are thus useful in DUV lithographic photoresist compositions.

Abstract: The present invention provides a fluorinated polymer excellent in the crosslinking reactivity, crosslinked rubber physical properties and chemical resistance, and its crosslinked rubber. A fluorinated polymer comprising repeating units (a) based on at least one monomer selected from the group consisting of ethylenic unsaturated compounds each having a hydroxyphenyl group, repeating units (b) based on at least one fluoromonomer selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, 3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, 1,1,2-trifluoroethylene, vinyl fluoride, 1,2-difluoroethylene and CF2?CF—O—Rf (wherein Rf is a C1-8 saturated perfluoroalkyl group or a perfluoro(alkoxyalkyl) group) and, if necessary, repeating units (c) based on at least one hydrocarbon monomer selected from the group consisting of ethylene, propylene and CH2?CH—O—R1.

Abstract: A cell dispersion method, a cell dispersing agent and a cell measurement method, each of which can disperse a cell mass while reducing damage to a cell are provided. Upon dispersing a cell mass, a fluororesin particle is used. A cell mass composed of an aggregated of multiple cells is mixed with a fluororesin particle in a liquid medium, thereby separating the cell mass into individual cells to disperse the cells. In addition, the dispersed cells are measured by flow cytometry, thereby carrying out cell measurement.

Abstract: An FEP pellet having a volatile content of 0.2% by weight or less. The FEP pellet satisfies the following requirements (i) and (ii) when used to form a insulating material coating a core wire by extrusion coating at a coating speed of 2,800 ft/min.: (i) an adhesive strength between the insulating material and said core wire of 0.8 kg or more; and (ii) an average number of cone-breaks in the insulating material of one or less per 50,000 feet of the coated core wire.

Abstract: The present invention has for its object to provide a fluorocopolymer which is available at low cost, has fluidity at room temperature, and is curable, a method of producing the same copolymer and a curable composition having good processability and in situ moldability. The present invention is directed to a fluorocopolymer which is fluid at room temperature and curable, and which is obtainable from a trifluorovinyl group-containing monomer with an ethylenically unsaturated double bond moiety being a trifluorovinyl group.

Abstract: A proton conductive graft polymer comprises at least a structure unit of a sulfonated polymer side chain covalently attached to a hydrophobic perfluorocyclobutane polymer main chain. The sulfonated condensation polymer side chain has a high local ion exchange capacity while the main polymer chain is substantially free of sulfonic acid group. A membrane made from the graft polymer can provide good mechanical properties and high proton conductivity at wide range of humidity and temperatures.

Abstract: In one embodiment, a copolymer comprises a sulfonatable segment covalently linked to an un-sulfonatable segment through an organic linking group. The sulfonatable group segment may be sulfonated through direction sulfonation or sulfonation through a spacer molecule. In another embodiment, a copolymer comprises a sulfonated segment and an unsulfonated segment. A membrane electrode assembly and a fuel cell may be produced using the copolymer.

Abstract: A sulfonated aromatic perfluorocyclobutane block copolymer comprises a hydrophobic perfluorocyclobutane ether chain segment and a hydrophilic sulfonated perfluorocyclobutane ether chain segment. The sulfonated perfluorocyclobutane copolymer may be used to make proton conductive membranes and membrane electrode assemblies in fuel cells. Processes of making the block copolymer through thermal coupling reactions are also disclosed.

Abstract: A polymer for ion conductor applications includes a polymer segment having a perfluorocyclobutyl moiety and a polymer segment not having such a moiety. One of these polymer segments is sulfonated to improve ionic conductivity. Fuel cells incorporating the ion conducting polymers are provided.

Abstract: An elastic fluorocopolymer comprises repeating units (l) based on a fluoromonomer such as tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride or CF2?CF—O—Rf (wherein Rf is a C1-8 saturated perfluoroalkyl group or a perfluoro(alkoxyalkyl) group) and repeating units (m) based on the formula CR1R2?CR3COOCH?CH2 (wherein each of R1 and R2 is a hydrogen atom, a C1-10 alkyl group or a C1-10 alkoxyalkyl group containing an etheric oxygen atom, and R3 is a hydrogen atom, a fluorine atom or a methyl group) in a molar ratio of (m)/((l)+(n))=0.0001 to 0.1. Further, an elastic fluorocopolymer composition comprises (A) the above elastic fluorocopolymer, (B) an unsaturated multifunctional compound and (C) a bivalent metal oxide and/or hydroxide. The elastic fluorocopolymer and the elastic fluorocopolymer composition are excellent in the crosslinkability and can provide a crosslinked rubber thereof excellent in crosslinked rubber properties.

Abstract: Powders or hydrophilic manufactured articles of E/CTFE and/or E/TFE thermoprocessable polymers, or of CTFE copolymers, wherein, on the surface of the powder or the manufactured article, one or more of the following hydrophilic units are present: —C(COOH)H—CH2—; —C(COOM)H—CH2—; —C(OCOOH)H—CH2—; —C(OCOOM)H—CH2—; with M=alkaline ion.

Abstract: The subject invention concerns the use of staple length nano polytetrafluoroethylene (PTFE) crystallites obtained by liquid shearing PTFE dispersion particles that are wet by a liquid with a surface tension below 30 dynes/cm this liquid will spread on PTFE resin surfaces and has a contact angle of zero (0) degrees with a PTFE surface. Staple length PTFE resin micro-fibers will form rapidly under high liquid shearing force at 125° C. when diluted 1 part PTFE resin to 20 parts liquid. The subject invention also includes the application of products that are multi-directional planar oriented and isotropic as sheet, membranes and structures useful for high performance filtering, fuel and solar cells and related energy applications. It also concerns products made from formulations as coatings and product for forming, shaping and molding sheet and structures of the subject invention and methods of adhering, bond and laminating components of these structures without adhesives.

Abstract: To provide a method for producing a melt-processable fluororesin, which is capable of increasing the molecular weight of the fluororesin and preventing coloration of the fluororesin, by using a specific fluorinated emulsifier other than ammonium perfluorooctanoate. A method for producing a melt-processable fluororesin which is characterized in that a fluorinated monomer is emulsion-polymerized in an aqueous medium containing a fluorinated emulsifier of a formula (I) XCF2CF2(O)mCF2CF2OCF2COOA wherein X is a hydrogen atom or a fluorine atom, A is a hydrogen atom, an alkali metal or NH4, and m is an integer of 0 or 1.

Abstract: The present invention provides a vinyl fluoride copolymer comprising: about 40 to about 90 mole % of repeat units derived from vinyl fluoride; and about 10 to about 60 mole % of repeat units derived from monomer selected from the group consisting of (a) and (b) below and mixtures thereof, with the proviso that about 0.1 mole % to 50 mole % of repeat units in the copolymer are derived from monomer selected from (b): (a) monomer selected from the group consisting of, tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene and mixtures thereof; and (b) vinyl monomer containing at least one functional group selected from the group consisting of hydroxyls, thiols, carbonyls, carboxylic acids, carboxylic esters, acid anhydrides, sulfonyls, sulfonic acids, sulfonic esters, phosphoric acids, phosphoric esters, boric acids, boric esters, epoxies, isocyanates, thiocyanates, amines, amides, nitriles and halogen selected from bromide and iodide.

Abstract: VDF-based curable fluorelastomers, having a glass transition temperature from ?10° C. to ?35° C., comprising: B) monomer of formula: CF2?CFOCF2OCF3 (a), C) one or more comonomers selected from: tetrafluoroethylene (TFE), per-fluoromethylvinylether (PMVE), perfluoropropene (HFP), and an amount of —COF end groups in the polymer lower than the sensitivity limit of the method which uses the FT-IR spectroscopy described in the present application.

Abstract: Improved expanded PTFE materials and improved gasket materials made therefrom, the gaskets being capable of forming a seal with greater bolt load retention than is possible with existing PTFE gaskets. The expanded PTFE membranes of the invention can be tailored to exhibit a matrix tensile strength in at least one direction of at least 25,000 psi, a matrix tensile strength ratio in two orthogonal directions of between 0.25 and 4, an orientation index of 50° or less, and a density of 2.0 g/cc or less. The improved gaskets exhibit improved mechanical properties such as high bolt load retention, low creep, high tensile strength, low stress to seal and high crystallinity index.