Patent ID: 7160980

Claim:
A method of purifying a polymeric material which includes: (A) phenyl moieties; (B) ketone and/or sulphone moieties; and (C) ether and/or thioether moieties; wherein said polymeric material has a moiety of formula: and/or a moiety of formula and/or a moiety of formula wherein “a” represents the mole % of units of formula I in said polymeric material, “b” represents the mole % of units of formula II in said polymeric material and “c” represents the mole % of units of formula III in said polymeric material, wherein the sum of a, b and c is at least 90; wherein the phenyl moieties in units I, II, and III are independently optionally substituted and optionally cross-linked; and wherein m, r, s, t, v, w and z independently represent zero or a positive integer, E and E′ independently represent an oxygen or a sulphur atom or a direct link, G represents an oxygen or sulphur atom, a direct link or a —O—Ph—O— moiety where Ph represents a phenyl group and Ar is selected from one of the following moieties (i)*, (i)**, (i) to (x) which is bonded via one or more of its phenyl moieties to adjacent moieties the method including contacting the polymeric material which is in solid form and which includes less than 1 wt % of polycondensation solvent with a solvent formulation which is at a temperature of greater than 100° C. and a pressure above ambient pressure thereby to charge the solvent formulation with impurities derived from said polymeric material, and separating the charged solvent from the polymeric material.