The invention provides for a process for removing thiocarbonylthio groups from polymer prepared by RAFT polymerization, the process comprising: introducing into a flow reactor a solution comprising the RAFT polymer in solvent; and promoting a reaction within the flow reactor that removes the thiocarbonylthio groups so as to form a solution that flows out of the reactor comprising the RAFT polymer absent the thiocarbonylthio groups.

The invention provides for a process for removing thiocarbonylthio groups from polymer prepared by RAFT polymerization, the process comprising: introducing into a flow reactor a solution comprising the RAFT polymer in solvent; and promoting a reaction within the flow reactor that removes the thiocarbonylthio groups so as to form a solution that flows out of the reactor comprising the RAFT polymer absent the thiocarbonylthio groups.

To provide a fluorinated copolymer which is capable of providing an ion exchange membrane having little adverse effect due to impurities in an alkali chloride aqueous solution on electrolysis of the alkali chloride aqueous solution. To use a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, wherein the proportion of components having a common logarithm (log M) of a molecular weight M being from 2.0 to 3.5 is at most 10 mass % per 100 mass % of components having a common logarithm (log M) of a molecular weight M being at least 2.0, contained in a CClF.sub.2CF.sub.2CClFH soluble content.

To provide a fluorinated copolymer which is capable of providing an ion exchange membrane having little adverse effect due to impurities in an alkali chloride aqueous solution on electrolysis of the alkali chloride aqueous solution. To use a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, wherein the proportion of components having a common logarithm (log M) of a molecular weight M being from 2.0 to 3.5 is at most 10 mass % per 100 mass % of components having a common logarithm (log M) of a molecular weight M being at least 2.0, contained in a CClF.sub.2CF.sub.2CClFH soluble content.

A method for producing a modified polymer or a hydrogenated product thereof, includes polymerizing a monomer in a polymerization solvent which includes a hydrocarbon-based solvent, using a polymerization initiator to obtain a reaction solution. A functional group is introduced into the modified polymer or the hydrogenated product thereof, using a compound having the functional group protected with a silyl group. The reaction solution is separated into a solvent fraction including the hydrocarbon-based solvent, and a solid fraction including the modified polymer or the hydrogenated product thereof. The solvent fraction separated from the reaction solution is distilled to obtain a low-boiling fraction including the hydrocarbon-based solvent and a silanol compound. At least part of the silanol compound is removed from the low-boiling fraction by liquid-liquid extraction. At least part of a raffinate of the low-boiling fraction is recycled as a polymerization solvent.

A method for producing a modified polymer or a hydrogenated product thereof, includes polymerizing a monomer in a polymerization solvent which includes a hydrocarbon-based solvent, using a polymerization initiator to obtain a reaction solution. A functional group is introduced into the modified polymer or the hydrogenated product thereof, using a compound having the functional group protected with a silyl group. The reaction solution is separated into a solvent fraction including the hydrocarbon-based solvent, and a solid fraction including the modified polymer or the hydrogenated product thereof. The solvent fraction separated from the reaction solution is distilled to obtain a low-boiling fraction including the hydrocarbon-based solvent and a silanol compound. At least part of the silanol compound is removed from the low-boiling fraction by liquid-liquid extraction. At least part of a raffinate of the low-boiling fraction is recycled as a polymerization solvent.

A method for producing a modified polymer or a hydrogenated product thereof, includes polymerizing a monomer in a polymerization solvent which includes a hydrocarbon-based solvent, using a polymerization initiator to obtain a reaction solution. A functional group is introduced into the modified polymer or the hydrogenated product thereof, using a compound having the functional group protected with a silyl group. The reaction solution is separated into a solvent fraction including the hydrocarbon-based solvent, and a solid fraction including the modified polymer or the hydrogenated product thereof. The solvent fraction separated from the reaction solution is distilled to obtain a low-boiling fraction including the hydrocarbon-based solvent and a silanol compound. At least part of the silanol compound is removed from the low-boiling fraction by liquid-liquid extraction. At least part of a raffinate of the low-boiling fraction is recycled as a polymerization solvent.

A composition containing polytetrafluoroethylene and substantially free from a compound represented by Formula (3):
(H(CF.sub.2).sub.8SO.sub.3).sub.qM.sup.2
wherein M.sup.2 is H, a metal atom, NR.sup.5.sub.4 (where R.sup.5s may be the same as or different from each other and are each H or an organic group having 1 to 10 carbon atoms), an imidazolium optionally having a substituent, a pyridinium optionally having a substituent, or a phosphonium optionally having a substituent, and q is 1 or 2. Also disclosed is a molded boy including the composition.

A composition containing polytetrafluoroethylene and substantially free from a compound represented by Formula (3):
(H(CF.sub.2).sub.8SO.sub.3).sub.qM.sup.2
wherein M.sup.2 is H, a metal atom, NR.sup.5.sub.4 (where R.sup.5s may be the same as or different from each other and are each H or an organic group having 1 to 10 carbon atoms), an imidazolium optionally having a substituent, a pyridinium optionally having a substituent, or a phosphonium optionally having a substituent, and q is 1 or 2. Also disclosed is a molded boy including the composition.