Characterization, crystallization kinetics, and melting behavior of poly(ethylene succinate) copolyester containing 7 mol % butylene succinate

Abstract

AbstractThe copolyester was synthesized and characterized as having 92.7 mol % ethylene succinate units and 7.3 mol % butylene succinate (BS) units in a random sequence, as determined by the use of nuclear magnetic resonance. Isothermal crystallization kinetics of this copolyester was examined in the temperature range (Tc) from 30 to 80°C with the use of differential scanning calorimetry (DSC). The melting behavior after isothermal crystallization was studied with DSC by varying the Tc, the heating rate, and the crystallization time. The complex melting behavior involves both mechanisms of various lamellar crystals and melting–recrystallization–remelting. As the Tc increases, the contribution of recrystallization gradually decreases and finally disappears. The Hoffman–Weeks linear plot yielded an equilibrium melting temperature of 111.1°C, which is 1.6°C less than that of poly(ethylene succinate) (PES). The kinetic analysis of the spherulitic growth rates (G) indicated that a regime II→III transition occurred at ∼59°C (TII→III), which is ∼ 11°C less than that of PES. The overall crystallization rate, TII→III and G indicate that the random incorporation of only 7.3 mol % BS units into PES significantly inhibits the crystallization rate of PES. Finally, the morphology of melt‐crystallized samples was examined using polarized light microscopy and scanning electron microscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009