Crosslinking of poly(arylene ether ketone)s 1. Rheological behavior of the melt and mechanical properties of cured resin

Elemental sulfur has been used to crosslink poly(arylene ether ketone)s. Evidence for crosslinking is presented in terms of rheological data of the melt. The effects of crosslinking on mechanical properties have been examined using tensile creep, stress–relaxation, and dynamic‐mechanical properties in torsion. The crosslinking elevates the glass transition temperature (Tg), as measured by the maximum in the loss tangent, and reduces creep strain at temperatures above Tg. A new technique for monitoring cure is also presented. One of the advantages of this method for crosslinking poly(arylene ether ketone)s is that the crosslinking can be carried out both in the solid state and in the melt, the rate being dependent on the temperature (above Tg) of annealing.