A fluoropolyether group-containing silane compound of the formula (1a) or the formula (1b), the symbols of which are as defined herein:
R.sup.F1X.sup.AR.sup.Si(1a)
R.sup.SiX.sup.AR.sup.F2X.sup.AR.sup.Si(1b).

A method for sulfonation of poly(phenylene ether) can comprise: dissolving a poly(phenylene ether) comprising 2,6-dimethyl-1,4-phenylene ether units, 2,3,6-trimethyl-1,4-phenylene ether units, 3,3,5,5-tetramethyl-4,4-dihydroxybiphenyl ether units, or a combination thereof in a mixture of 1,2-dichloroethane and a cosolvent to form a solvent mixture in a mixing vessel, wherein the cosolvent comprises at least one of methyl ethyl ketone, diethyl ether, methyl ethyl sulfone, ethyl acetate, or tetramethylene sulfone; combining a sulfonating agent with the solvent mixture, wherein the sulfonating agent reacts with the poly(phenylene ether) to form sulfonated poly(phenylene ether); precipitating the sulfonated poly(phenylene ether); and filtering the precipitated sulfonated poly(phenylene ether) to form a sulfonated poly(phenylene ether) precipitate and a filtrate; wherein the sulfonated poly(phenylene ether) has a sulfonation level of 20 to 50%.

A polymer composition contains a polyether polymer having a thiol group, in which the polyether polymer having a thiol group has a polyether moiety represented by Formula (1) in a main chain and a structural unit represented by Formula (2) at a terminal, a thiol group content in the polyether polymer containing a thiol group is 8 wt/mass % or more, and the polymer composition further contains a cationic surfactant

##STR00001## where R.sup.1 is a residue obtained by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol having 10 or less carbon atoms, R.sup.2 is an alkylene group having 2 to 6 carbon atoms, n is 1 to 200, and m is 2 to 8.

##STR00002##

A polymer composition contains a polyether polymer having a thiol group, in which the polyether polymer having a thiol group has a polyether moiety represented by Formula (1) in a main chain and a structural unit represented by Formula (2) at a terminal, a thiol group content in the polyether polymer containing a thiol group is 8 wt/mass % or more, and the polymer composition further contains a cationic surfactant

##STR00001## where R.sup.1 is a residue obtained by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol having 10 or less carbon atoms, R.sup.2 is an alkylene group having 2 to 6 carbon atoms, n is 1 to 200, and m is 2 to 8.

##STR00002##

A thiol group-containing polyether polymer is provided which has a lower viscosity than that of an epoxy adhesive in which a conventional polymercaptan curing agent is used and which is excellent in workability and can maintain the low viscosity of an epoxy adhesive even when the amount of the additive is increased. The thiol group-containing polyether polymer includes a polyether moiety represented by general formula (1) below and a structural unit represented by general formula (2) below in a main chain; and a structural unit represented by general formula (3) below at a terminal, where R.sup.1, R.sup.2, n and m of formula (1); x and I of formula (2); and I of formula (3) are as defined.

##STR00001##

A thiol group-containing polyether polymer is provided which has a lower viscosity than that of an epoxy adhesive in which a conventional polymercaptan curing agent is used and which is excellent in workability and can maintain the low viscosity of an epoxy adhesive even when the amount of the additive is increased. The thiol group-containing polyether polymer includes a polyether moiety represented by general formula (1) below and a structural unit represented by general formula (2) below in a main chain; and a structural unit represented by general formula (3) below at a terminal, where R.sup.1, R.sup.2, n and m of formula (1); x and I of formula (2); and I of formula (3) are as defined.

##STR00001##