Crystallization kinetics, melting behavior, and RAP of novel etheroatom containing naphthyl polyesters

The changes in crystalline phase of poly (butylene naphthalate) (PBN), poly(diethylene naphthalate) (PDEN) and poly(thiodiethylene naphthalate) (PTDEN) upon thermal treatments were evaluated by X-ray diffraction technique. The melting behavior and the crystallization kinetics of the polymers under investigation were investigated by means of differential scanning calorimetry. Multiple endotherms were evidenced in PBN and PTDEN, due to melting and recrystallization processes. By applying the Hoffman–Weeks’ method, the Tm of PBN, PDEN, and PTDEN was derived: the introduction of ethero-atoms along PBN polymer chain causes a decrement of Tm value. The isothermal crystallization kinetics was analyzed according to the Avrami’s treatment: the presence of etheroxygen or sulphur atoms in the chain deeply reduces the PBN ability of crystallizing. Finally, no interphase was evidenced both in PDEN and PTDEN.