Thermal crosslinking behavior of poly (aryl ether ketone) copolymers containing naphthalene moieties

A series of poly[ (ether ether ketone)-co-(ether naphthalene ether ketone) ] (P (EEK-co-ENEK)) copolymers were heated under a variety of conditions. The thermal crosslinking behavior was monitored by differential scanning calorimetry (DSC), electron spin resonance (ESR) and wide-angle X-ray diffraction (WAXD). The results indicate that under a non-oxidative environment such as nitrogen P(EEK-co-ENEK) is more stable, while under oxidative conditions a crosslinking reaction takes place that causes a reduction in the crystallizability of the copolymers, and an increase in the concentration of free radicals on the copolymer. ESR results suggest that the crosslinking reaction proceeds via free radicals. Subsequently two kinds of free radicals were characterized: one is an RO. type free radical and the other is a naphthalene ring free radical. (C) 2004 Society of Chemical Industry.