EEK has been synthesize by polycondensation of excess 4

4'-diflu oro benzo phen o ne (DFBP) with hydroqulnone in diphenyl sulfo ne. B yusing UV

MI

TGA and DSC techniques

the effects of phenoxide groups andits relative concentration on the structure and propenies of PEEK during Synthsisand processing have been studied. The results showed that the phenoxide groupscould lead to branching and cross--linking

and this increased with its relativeconcentration. We can control the molecular weight of product by synthesizing PEEK with excess DFBP

it also helps to preventing side reactions such as branching and crosslinking

and inproving the flow and thermal properties of PEEK. We also discuss in this paper the mechanism of the branching reaction and the mechanism of the thermal degradation of branched PEEK cahin.