Patent ID: 8394910

Claim:
A method of making a polymeric material which includes moieties of formula and moieties of formula wherein the sum of the mole % of moieties IX and X in said polymeric material is at least 90 mole %, the method comprising contacting a compound of formula with a compound of formula In the presence of a solvent of formula where W is a direct link, an oxygen atom or two hydrogen atoms, one being attached to each benzene ring, and Z and Z′, which may be the same or different, are hydrogen atoms or phenyl groups; wherein each X in the compound of formula I is selected from a group comprising a chlorine and a fluorine atom, n represents 1, 2 or 3 and each Y 1 is selected from a group comprising an alkali metal and a hydrogen atom; wherein the ratio of the number of moles of compound(s) of formula I to the number of moles of compound(s) of formula II contacted in the method is in the range 1 to 1.1, the ratio of the number of moles of solvent to the number of moles of compounds of formula I used in the method is at least 5, and the melt viscosity (MV) of said polymeric material is at least 0.085 kNsm −2 , when measured using capillary rheometry operating at 40° C. at a shear rate of 1000 s − using a tungsten carbide die, 0.5×3.175 mm.