Abstract: The invention pertains to a method for emulsion polymerization of at least one fluoromonomer, said method comprising: (i) providing at least one aqueous emulsion comprising at least one surfactant and a monomer mixture [mixture (M)] comprising at least one fluoromonomer [monomer (F)] and optionally at least one additional monomer, and at least one RAFT/MADIX agent; (ii) initiating the polymerization of said monomer mixture in said aqueous emulsion adding at least one radical initiator; (iii) continuing the polymerization by adding additional amounts of said mixture (M) and said RAFT/MADIX agent, until converting the targeted amount of said mixture (M), and (iv) terminating the polymerization and recovering a latex of fluoropolymer [polymer (F)]; wherein the amount of RAFT/MADIX agent is comprised between 0.1 and 0.

Abstract: A (per)fluoroelastomer composition having improved plasma resistance comprising at least one (per)fluoroelastomer [fluoroelastomer (A)] and from 0.1 to 50 weight parts per 100 parts by weight of said fluoroelastomer (A) of alkaline-earth metal carbonate particles [particles (P)]. Each particle comprises a core consisting essentially of at least one alkaline-earth metal carbonate and a shell consisting essentially of at least one Group IV transition metal compound.

Abstract: The invention pertains to a (per)fluoroelastomer composition comprising at least one (per)fluoroelastomer [(per)fluoroelastomer (A)] matrix comprising particles of at least one perfluoropolymer [polymer (F)] having a melt flow index (MFI), measured at 372° C. under a 5 Kg load according to ASTM D1238 standard, of less than 10 g/10 min, said particles having an average size of less than 100 nm.

Abstract: The invention pertains to a process for manufacturing a fluoroelastomer [fluoroelastomer (A)] having a heat of fusion of less than 5 J/g as measured by ASTM D-3418-08, said method comprising emulsion polymerizing vinylidene fluoride (VDF) in the presence of at least one additional fluorinated monomer, in an aqueous polymerization medium, said method comprising polymerizing VDF and said additional fluorinated monomer(s) in the presence of a redox radical initiator system comprising: —at least one organic oxidizing agent [agent (O)]; —at least one organic reducing agent [agent (R)]; wherein agent (O) is fed to said polymerization medium separately from agent (R), so that agent (O) comes in contact with agent (R) exclusively in said polymerization medium comprising VDF and optional additional monomer(s), to fluoroelastomers having low amount of chain defects and low amount of polar end groups, notably obtainable from said process, and to curable compositions therefrom.

Abstract: The invention pertains to a hyperbranched (per)fluoroelastomer [fluoroelastomer (B)] comprising recurring units derived from a bis-olefin [bis-olefin (OF)] having general formula (I): wherein R1, R2, R3, R4, R5 and R6, equal or different from each other, are H or C1-C5 alkyl; Z is a linear or branched C1-C18 alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical, said fluoroelastomer (B) having a slope in G? curve such that the ratio: G?100/G?0.01 is of less than 10, when determined at 260° C. according to ASTM D4440 standard, wherein G?100 is the storage modulus at a shear rate of 100 rad/sec and G?0.01 is the storage modulus at a shear rate of 0.01 rad/sec, to compositions comprising the same, and to a process for their manufacture.

Abstract: The invention pertains to a method for emulsion polymerization of at least one fluoromonomer, said method comprising: (i) providing at least one aqueous emulsion comprising at least one surfactant and a monomer mixture [mixture (M)] comprising at least one fluoromonomer [monomer (F)] and optionally at least one additional monomer, and at least one RAFT/MADIX agent; (ii) initiating the polymerization of said monomer mixture in said aqueous emulsion adding at least one radical initiator; (iii) continuing the polymerization by adding additional amounts of said mixture (M) and said RAFT/MADIX agent, until converting the targeted amount of said mixture (M), and (iv) terminating the polymerization and recovering a latex of fluoropolymer [polymer (F)]; wherein the amount of RAFT/MADIX agent is comprised between 0.1 and 0.

Abstract: The invention pertains to a fluoroelastomer comprising recurring units derived from vinylidene fluoride (VDF), hexa fluoropropylene (HFP); and from 0.1 to 10% by moles of recurring units derived from hexafluoroisobutene (HFIB), wherein the mole percentages are based on the total moles of recurring units.

Abstract: The invention pertains to a process for cryogenic milling mixtures of (per)fluoroelastomers and semicrystalline thermoplastic VDF polymers, and to free-flowing micronized pellets obtainable therefrom, said micronized pellets advantageously yielding, after extrusion and compounding, excellent mechanical properties, even improved over those of base fluoroelastomer matrix.

Abstract: The invention pertains to a low viscosity curable (per)fluoroelastomer [fluoroelastomer (A)] having a number-averaged molecular weight of 3 000 to 45 000, said (per)fluoroelastomer comprising at least 1% moles, with respect to the total moles of recurring units, of recurring units derived from at least one (per)fluoromethoxyalkylvinylether of formula (I): CFX??CX?OCF2ORf??formula (I) wherein X? and X?, equal to or different from each other, are independently H or F; and Rf is selected from the group consisting of C1-C6 (per)fluoroalkyls, linear or branched; C5-C6 cyclic (per)fluoroalkyls; and C2-C6 (per)fluorooxyalkyls, linear or branched, comprising from 1 to 3 catenary ethereal oxygen atoms [monomer (M)].

Abstract: The invention pertains to a fluoroelastomer composition comprising: —at least one fluoroelastomer [fluoroelastomer (A)]; —from 0.1 to 15 weight parts, per 100 parts by weight of said fluoroelastomer (A), of meta-divinylbenzene; —from 0.1 to 10 weight parts, per 100 parts by weight of said fluoroelastomer (A), of at least one peroxide.

Abstract: The invention pertains to a process for cryogenic milling mixtures of (per)fluoroelastomers and semicrystalline thermoplastic VDF polymers, and to free-flowing micronized pellets obtainable therefrom, said micronized pellets advantageously yielding, after extrusion and compounding, excellent mechanical properties, even improved over those of base fluoroelastomer matrix.

Abstract: The invention pertains to a hyperbranched (per)fluoroelastomer [fluoroelastomer (B)] comprising recurring units derived from a bis-olefin [bis-olefin (OF)] having general formula (I): wherein R1, R2, R3, R4, R5 and R6, equal or different from each other, are H or C1-C5 alkyl; Z is a linear or branched C1-C18 alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical, said fluoroelastomer (B) having a slope in G? curve such that the ratio: G?100/G?0.01 is of less than 10, when determined at 260° C. according to ASTM D4440 standard, wherein G?100 is the storage modulus at a shear rate of 100 rad/sec and G?0.01 is the storage modulus at a shear rate of 0.01 rad/sec, to compositions comprising the same, and to a process for their manufacture.

Abstract: The invention pertains to a process for manufacturing a fluoroelastomer [fluoroelastomer (A)] having a heat of fusion of less than 5 J/g as measured by ASTM D-3418-08, said method comprising emulsion polymerizing vinylidene fluoride (VDF) in the presence of at least one additional fluorinated monomer, in an aqueous polymerization medium, said method comprising polymerizing VDF and said additional fluorinated monomer(s) in the presence of a redox radical initiator system comprising: —at least one organic oxidizing agent [agent (O)]; —at least one organic reducing agent [agent (R)]; wherein agent (O) is fed to said polymerization medium separately from agent (R), so that agent (O) comes in contact with agent (R) exclusively in said polymerization medium comprising VDF and optional additional monomer(s), to fluoroelastomers having low amount of chain defects and low amount of polar end groups, notably obtainable from said process, and to curable compositions therefrom.

Abstract: The invention pertains to a low viscosity curable (per)fluoroelastomer [fluoroelastomer (A)] having a number-averaged molecular weight of 3 000 to 45 000, said (per)fluoroelastomer comprising at least 1% moles, with respect to the total moles of recurring units, of recurring units derived from at least one (per)fluoromethoxyalkylvinylether of formula (I): CFX??CX?OCF2ORf??formula (I) wherein X? and X?, equal to or different from each other, are independently H or F; and Rf is selected from the group consisting of C1-C6 (per)fluoroalkyls, linear or branched; C5-C6 cyclic (per)fluoroalkyls; and C2-C6 (per)fluorooxyalkyls, linear or branched, comprising from 1 to 3 catenary ethereal oxygen atoms [monomer (M)].

Abstract: A (per)fluoroelastomeric composition curable by peroxidic way comprising for 100 phr of (per)fluoroelastomer: as filler, from 2 to 70 phr of carbon black having a surface area between 25 and 35 m2/g; as crosslinking agent, from 0.5 to 10 phr of a bis-olefin having general formula: wherein: R1, R2, R3, R4, R5, R6, equal to or different from each other, are H or C1-C5 alkyls; Z is selected between a linear or branched C1-C18 alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical.

Abstract: A (per)fluoroelastomer composition having improved plasma resistance comprising at least one (per)fluoroelastomer [fluoroelastomer (A)] and from 0.1 to 50 weight parts per 100 parts by weight of said fluoroelastomer (A) of alkaline-earth metal carbonate particles [particles (P)]. Each particle comprises a core consisting essentially of at least one alkaline-earth metal carbonate and a shell consisting essentially of at least one Group IV transition metal compound.

Abstract: This invention pertains to sealing articles of vulcanized (per)fluoroelastomer compositions incorporating particles of a vinylidene fluoride (VDF) polymers having a Shore A hardness of at least 85 when determined according to ASTM D 2240 Type A Durometer method, and a compression set of less than 30%, when determined according to ASTM D395 at 200° C. for 70 h on O-ring according to ASTM D1414, and to a process for their manufacture by vulcanizing-molding and thermal post-treating at a temperature above the melting point of the VDF polymer.

Abstract: Extrudable (per)fluoroelastomer compositions comprising crosslinkable (per)fluoroelastomers having: at least two glass transition temperatures Tg on DSC analysis, at least one melting peak on DSC analysis with a ?H of second melting of between 0.3 and 5.5 J/g, and a bimodal molecular weight distribution such that the ratio Mn1/Mn2 is between 10 and 30, wherein Mn1 represents the number-average molecular weight of the distribution of the high molecular weight fluoroelastomer and Mn2 represents the number-average molecular weight of the distribution of the low molecular weight fluoroelastomer.

Abstract: A fluoroelastomer composition comprising: at least one fluoroelastomer [fluoroelastomer (A)]; from 0.1 to 25 phr (with respect to fluoroelastomer (A)) of at least one melt-processable per(halo)fluoropolymer having a melting point of at most 250° C. [polymer (F)]; and optionally at least one (per)fluoropolyether [(per)fluoropolyether (E)]. The incorporation of the polymer (F) in the fluoroelastomer composition as described above enables easier processing of the fluoroelastomer composition, both in injection molding and extrusion molding technologies, yielding improved behavior in mold release, mold fouling, and aspect surface of the molded parts.

Abstract: Vulcanizable fluoroelastomer compositions comprising: A) a fluoroelastomer matrix based on vinylidene fluoride (VDF) with a Mooney viscosity (1+10) at 121° C. of less than 35 MU (Mooney Units) measured according to ASTM standard D 1646; and B) a semi-crystalline fluoropolymer, in an amount of from 20% to 70% by weight relative to the total weight of A)+B), the semi-crystalline fluoropolymer being constituted of tetrafluoroethylene (TFE) homopolymers and copolymers of TFE with one or more monomers containing at least one unsaturation of ethylenic type, in an amount of from 0.01 to 10 mol %, said semi-crystalline fluoropolymer having a mean particle size between 10 and 400 nm.