THE INFLUENCE OF STRUCTURAL PARAMETERS ON THE GLASS TEMPERATURE AND COMPATIBILITY OF POLY(PHENYLENE ETHER KETONE)S

It is shown that the glass temperature of poly(phenylene ether ketone) s (PEKs) decreases with increasing number of intercalated phenylene th ioether units in the main chain. The decrease is similar for the diffe rent classes of poly(phenylene ether ketone)s, i.e. poly(phenylene eth er ether ketone)s, poly(phenylene thioether ether ketone)s, and poly(p henylene ether sulphone ketone)s. At the same time, the compatibility of such PEK families with poly(phenylene ether sulphone) decreases. Th e compatibility changes are explained by the disturbing effect of the intercalated phenylene thioether units on the matching of the rigid pa irs of phenylene units stiffened by the intercalated sulphone or keton e units, respectively. Although the glass temperatures roughly obey th e mass/'flexible' bond rule of Schneider-Di Marzio, for a more exact p rediction additional volume effects of the flexible groups have to be considered.