An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

Polycyclocarbonate compounds and upgraded molecular weight polymers made from such compounds are provided. The polymers have particular utility in coating compositions, especially for use on food and beverage contact substrates that are formed into or will be formed into containers or container components.

Polycyclocarbonate compounds and upgraded molecular weight polymers made from such compounds are provided. The polymers have particular utility in coating compositions, especially for use on food and beverage contact substrates that are formed into or will be formed into containers or container components.

A compound represented by the following formula (1).

##STR00001##

(In the formula (1), A is a group containing a heteroatom; R.sup.1 is a 2n-valent group having 1 to 30 carbon atoms and optionally having a substituent; R.sup.2 to R.sup.5 are each independently a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms and optionally having a substituent, an aryl group having 6 to 30 carbon atoms and optionally having a substituent, an alkenyl group having 2 to 30 carbon atoms and optionally having a substituent, an alkynyl group having 2 to 30 carbon atoms and optionally having a substituent, an alkoxy group having 1 to 30 carbon atoms and optionally having a substituent, a halogen atom, a nitro group, an amino group, a carboxylic acid group, a crosslinkable group, a dissociation group, a thiol group or a hydroxy group, wherein the alkyl group, the aryl group, the alkenyl group and the alkoxy group each optionally contain an ether bond, a ketone bond or an ester bond and at least one R.sup.4 and/or at least one R.sup.5 is a hydroxy group and/or a thiol group; m.sup.2 and m.sup.3 are each independently an integer of 0 to 8; m.sup.4 and m.sup.5 are each independently an integer of 0 to 9; n is an integer of 1 to 4; and p.sup.2 to p.sup.5 are each independently an integer of 0 to 2.)

A compound represented by the following formula (1).

##STR00001##

(In the formula (1), A is a group containing a heteroatom; R.sup.1 is a 2n-valent group having 1 to 30 carbon atoms and optionally having a substituent; R.sup.2 to R.sup.5 are each independently a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms and optionally having a substituent, an aryl group having 6 to 30 carbon atoms and optionally having a substituent, an alkenyl group having 2 to 30 carbon atoms and optionally having a substituent, an alkynyl group having 2 to 30 carbon atoms and optionally having a substituent, an alkoxy group having 1 to 30 carbon atoms and optionally having a substituent, a halogen atom, a nitro group, an amino group, a carboxylic acid group, a crosslinkable group, a dissociation group, a thiol group or a hydroxy group, wherein the alkyl group, the aryl group, the alkenyl group and the alkoxy group each optionally contain an ether bond, a ketone bond or an ester bond and at least one R.sup.4 and/or at least one R.sup.5 is a hydroxy group and/or a thiol group; m.sup.2 and m.sup.3 are each independently an integer of 0 to 8; m.sup.4 and m.sup.5 are each independently an integer of 0 to 9; n is an integer of 1 to 4; and p.sup.2 to p.sup.5 are each independently an integer of 0 to 2.)

A polymer electrolyte membrane of the present disclosure comprises a perfluorosulfonic acid resin (A), wherein the polymer electrolyte membrane has a phase-separation structure having a phase where fluorine atoms are detected in majority and a phase where carbon atoms are detected in majority, in an image of a membrane surface observed under an SEM-EDX, and the polymer electrolyte membrane has a phase having an average aspect ratio of 1.5 or more and 10 or less in an image of a membrane cross-section observed under an SEM.

A method to purify a polymer is disclosed. The method is part of a manufacturing process wherein a virgin polymer is produced from a polymerization process employing at least a monomer or a comonomer as a feedstock. The monomer or the comonomer is selected from the group consisting of organic polar monomers, inorganic monomers, vinyl aromatic monomers, conjugated dienes, and mixtures thereof. In the method, the polymer in solid, liquid or molten state is brought into contact with a fluid solvent or an extraction fluid in a supercritical state or near supercritical state. The contact is at controlled temperature and pressure, allowing the fluid solvent to diffuse into the polymer and extract the impurities intended to remove. The method can be used to remove at least 10%, or at least 20%, or at least 50% of the target impurity from the polymer.

A method to purify a polymer is disclosed. The method is part of a manufacturing process wherein a virgin polymer is produced from a polymerization process employing at least a monomer or a comonomer as a feedstock. The monomer or the comonomer is selected from the group consisting of organic polar monomers, inorganic monomers, vinyl aromatic monomers, conjugated dienes, and mixtures thereof. In the method, the polymer in solid, liquid or molten state is brought into contact with a fluid solvent or an extraction fluid in a supercritical state or near supercritical state. The contact is at controlled temperature and pressure, allowing the fluid solvent to diffuse into the polymer and extract the impurities intended to remove. The method can be used to remove at least 10%, or at least 20%, or at least 50% of the target impurity from the polymer.

Purification of a poly(phenylene ether) includes contacting a liquid feed solution with a hydrated acidic clay adsorbent under conditions effective to provide a liquid effluent solution. The liquid feed solution includes a poly(phenylene ether), an organic acid impurity, and an amine impurity. The weight average molecular weight of the poly(phenylene ether) of the liquid effluent solution is within 1 percent of the weight average molecular weight of the poly(phenylene ether) of the feed solution, and the concentration of the amine impurity and the organic acid impurity of the liquid effluent solution is reduced by at least 40 percent relative to the concentration of the each impurity in the feed solution. Compositions and articles comprising a purified poly(phenylene ether) are also described.