The transesterification reaction among poly(ethylene terephthalate)(PET)

poly(ethylene 2

6- naphthalate)(PEN)

and PET／PEN copolymer were studied with1H-NMR．The rate constant k

the activation energy．and induction period of the transestetifieation reaction for the PET/PEN reactive blend were obtained using a kinetic expression based on a second-order reversible reaction mechanism．The relationship between transesterification and miseibility was discussed on transesterification level and induction period．It was found that miscibility of PET and PEN blends leads to or enhance transesterification

that iS

miscibility is a necessary condition for transesterification in the polyester blends：transesterification accelerates miscibility of PET and PEN blends．Both events are interrelated in the molten state of polyester blends．