Polyaryletherketones

Claim 2

A polyaryletherketone characterised by comprising repeating units of structures I and II:­ wherein Ph is 1,4-phenylene and Ar is 4,4′-biphenylene or 4,4˝ terphenylene, alone or in conjunction with other repeating units, the repeating units being connected by ether linkages.

Claim 3

A polyaryletherketone according to claim 1, which comprises repating units of structure III:- Ph CO Ph CO Ph      III

Claim 4

A polyaryletherketone according to claim 1 or claim 2, which comprises a minor proportion of repeating units selected from 2,6-­naphthylene, 4,4′-diphenylsulphone, 4,4′-diphenylketone, 1,4-bis(4-­phenylsulphonyl) benzene, 4,4′-bis(4-benzoyl)biphenyl and 4,4′-bis(4-­phenylsulphonyl) biphenyl.

Claim 5

A polyaryletherketone according to anyone of the preceding claims, which Ar is Ph₂.

Claim 6

A polyaryletherketone according to any one of the preceding claims, which exhibits a degree of crystallinity of at least 30%.

Claim 7

A film, fibre or solvent resistant article, or composite material comprising a polyaryletherketone according to any one of the preceding claims.

Claim 8

A process for making a polyaryletherketone according to claim 1 is characterised by comprising polycondensing under substantially anhydrous conditions in the presence of a base at least one compound of structure IV with at least one compound of structure V Y₃ Ar Y₄      V wherein Ar and Ph are as hereinbefore defined, Y₁, Y₂, Y₃ and Y₄ are each independently halogen or OH, and, when Y₃ and/or Y₄ is halogen, the group Ar is such that the halogen is activated by an inert electron - withdrawing group in at least one of the positions ortho- or para- to the halogen, and the proportions of IV and V and the nature of Y₁, Y₁, Y₃ and Y₄ are chosen so that the halogen and the groups -OH are in substantially equimolar amounts.