The present invention relates to a process for preparing a fluoropolymer in a liquid reaction medium, comprising the following steps: provide a reactor containing a liquid reaction medium comprising water introduce in said reactor ethylene monomers and fluorinated monomers, said fluorinated monomers being selected from tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or mixtures thereof, pressurize the reactor, initiate polymerization feeding into said reactor a redox initiator comprising an oxidising agent and a reducing agent, wherein said reducing agent in said redox couple initiator is free from sulphur atoms having an oxidation number of 4 or below, wherein the reaction medium is free of fluorinated surfactants.

The present invention relates to a process for preparing a fluoropolymer in a liquid reaction medium, comprising the following steps: provide a reactor containing a liquid reaction medium comprising water introduce in said reactor ethylene monomers and fluorinated monomers, said fluorinated monomers being selected from tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or mixtures thereof, pressurize the reactor, initiate polymerization feeding into said reactor a redox initiator comprising an oxidising agent and a reducing agent, wherein said reducing agent in said redox couple initiator is free from sulphur atoms having an oxidation number of 4 or below, wherein the reaction medium is free of fluorinated surfactants.

A polymer including VDF-based units having an electrocaloric effect under the effect of a variable electric field. The polymer includes 0.1 to 10.0 mol % double bonds, which are substantially non-conjugated. Also, a corresponding composition including the polymer, a corresponding film including the polymer, and to various uses of the polymer.

A polymer including VDF-based units having an electrocaloric effect under the effect of a variable electric field. The polymer includes 0.1 to 10.0 mol % double bonds, which are substantially non-conjugated. Also, a corresponding composition including the polymer, a corresponding film including the polymer, and to various uses of the polymer.

A copolymer including fluorinated units of formula (I):

—CX.sub.1X.sub.2—CX.sub.3X.sub.4—  (I)

in which each of the X.sub.1, X.sub.2, X.sub.3 and X.sub.4 is independently chosen from H, F and alkyl groups including from 1 to 3 carbon atoms which are optionally partially or totally fluorinated; and fluorinated units of formula (II):

—CX.sub.5X.sub.6—CX.sub.7Z—  (II)

in which each of the X.sub.5, X.sub.6 and X.sub.7 is independently chosen from H, F and alkyl groups including from 1 to 3 carbon atoms which are optionally partially or totally fluorinated, and in which Z is a photoactive group of formula —Y—Ar—R, Y representing an oxygen atom or an NH group or a sulfur atom, Ar representing an aryl group, and R being a monodentate or bidentate group including from 1 to 30 carbon atoms. Also, a process for preparing this copolymer, a composition including this copolymer, and a film obtained from this copolymer.

A copolymer including fluorinated units of formula (I):

—CX.sub.1X.sub.2—CX.sub.3X.sub.4—  (I)

in which each of the X.sub.1, X.sub.2, X.sub.3 and X.sub.4 is independently chosen from H, F and alkyl groups including from 1 to 3 carbon atoms which are optionally partially or totally fluorinated; and fluorinated units of formula (II):

—CX.sub.5X.sub.6—CX.sub.7Z—  (II)

in which each of the X.sub.5, X.sub.6 and X.sub.7 is independently chosen from H, F and alkyl groups including from 1 to 3 carbon atoms which are optionally partially or totally fluorinated, and in which Z is a photoactive group of formula —Y—Ar—R, Y representing an oxygen atom or an NH group or a sulfur atom, Ar representing an aryl group, and R being a monodentate or bidentate group including from 1 to 30 carbon atoms. Also, a process for preparing this copolymer, a composition including this copolymer, and a film obtained from this copolymer.

Provided is a composition including a polyvinylidene fluoride (A); and a vinylidene fluoride polymer (B) excluding the polyvinylidene fluoride (A), wherein the polyvinylidene fluoride (A) comprises vinylidene fluoride unit and a pentenoic acid unit represented by formula (1): CH.sub.2═CH—(CH).sub.2—COOY wherein Y represents at least one selected from the group consisting of an inorganic cation and an organic cation, a content of vinylidene fluoride unit of the polyvinylidene fluoride (A) is 95.0 to 99.99 mol % based on all monomer units of the polyvinylidene fluoride (A), and a content of the pentenoic acid unit of the polyvinylidene fluoride (A) is 0.01 to 5.0 mol % based on all monomer units of the polyvinylidene fluoride (A).

Provided is a composition including a polyvinylidene fluoride (A); and a vinylidene fluoride polymer (B) excluding the polyvinylidene fluoride (A), wherein the polyvinylidene fluoride (A) comprises vinylidene fluoride unit and a pentenoic acid unit represented by formula (1): CH.sub.2═CH—(CH).sub.2—COOY wherein Y represents at least one selected from the group consisting of an inorganic cation and an organic cation, a content of vinylidene fluoride unit of the polyvinylidene fluoride (A) is 95.0 to 99.99 mol % based on all monomer units of the polyvinylidene fluoride (A), and a content of the pentenoic acid unit of the polyvinylidene fluoride (A) is 0.01 to 5.0 mol % based on all monomer units of the polyvinylidene fluoride (A).

A polymer for an electrode protective layer including a polymer (A) including a fluorine-based polymer in which a monomer unit including poly(alkylene oxide) and a monomer unit including a curable functional group (e.g., a thermocurable functional group or a photocurable functional group) are grafted on the fluorine-based polymer, and when preparing an electrode by coating an electrode active material layer using the polymer and curing (e.g., thermally curing or photocuring) the result, excellent lithium ion conductivity is obtained since lithium ion flow is not inhibited, chemical resistance for an electrolyte liquid is high, and voltage stability of a secondary battery may be enhanced by suppressing side reactions with the electrolyte liquid occurring on an electrode active material surface due to properties of a uniform and flexible protective layer.

A polymer for an electrode protective layer including a polymer (A) including a fluorine-based polymer in which a monomer unit including poly(alkylene oxide) and a monomer unit including a curable functional group (e.g., a thermocurable functional group or a photocurable functional group) are grafted on the fluorine-based polymer, and when preparing an electrode by coating an electrode active material layer using the polymer and curing (e.g., thermally curing or photocuring) the result, excellent lithium ion conductivity is obtained since lithium ion flow is not inhibited, chemical resistance for an electrolyte liquid is high, and voltage stability of a secondary battery may be enhanced by suppressing side reactions with the electrolyte liquid occurring on an electrode active material surface due to properties of a uniform and flexible protective layer.