Two-stage oxidation of polyarylene sulfides

Abstract

Polyarylene thioethers having recurring units of the formula [--(S--E--).sub.a --(--SO--E--).sub.b --(SO.sub.2 --E).sub.c --](I) in which E are, independently of one another, phenylene, naphthylene or biphenylene, a and c have, independently of one another, values from 0 to less than 1 and b has values from greater than zero to less than 1, with the proviso that the sum of a+b+c is equal to 1 and at least two of the indices are greater than zero, are obtained by oxidation of polyarylene sulfides in two stages, wherein in the first stage a polymer in solid form in a suspension medium is oxidized with ozone and the reaction product obtained is in the second stage reacted in acetic acid with hydrogen peroxide in the presence of catalytic amounts of concentrated sulfuric acid and/or with addition of equilibrium per-acids. The polyarylene thioethers are suitable for the production of molded parts having high temperature resistance and high resistance to chemicals.

Dependencies are inferred from the claim text.