Crystallization and melting behaviour of poly(butylene naphthalene-2,6-dicarboxylate)

Isothermal crystallization of poly(butylene naphthalene-2,6-dicarboxylate) (PBN), from the melt, at various crystallization temperatures ranging from 213 up to 225°C was studied. During isothermal crystallization, relatively high crystallinity was found to develop. Isothermal crystallization kinetics was studied using the Avrami equation. For non-isothermal studies, PBN was crystallized by cooling rates ranging from 0.5 to 20°C/min. Only semicrystalline PBN was produced, not depending on the cooling process. The Ozawa and modified-Avrami approaches were used to describe the non-isothermal crystallization kinetics of PBN. Recrystallization phenomena and multiple melting peaks were observed during heating of isothermally and non-isothermally crystallized samples. Annealing at temperatures very close to the original melting point increased the latter from 248 to 264°C.