Phase Transition and Melt-Recrystallization Behavior of Poly(Butylene Adipate) Investigated by Simultaneous Measurements of Wide-Angle X-Ray Diffraction (WAXD) and Differential Scanning Calorimetry (DSC).

ABSTRACT: Simultaneous measurements of wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) were carried out to investigate the phase transition and melting behaviors of poly(butylene adipate) (PBA). Thermal expansion changes along the a and b axes of the ? form unit cell are different from each other during the heating process. At the beginning of the ? to ?H (high-temperature ? phase) phase transition, the ? phase melts very fast, while the recrystallization of the ?H phase is delayed and slowed. With the further increment of the temperature, the melting rate of the ? phase slows down, while the recrystallization of the ?H phase accelerates. The diffraction peak intensity ratios of the ?(020):?(110) and ?H(020):?H(110) diffraction peaks during the first heating process have similar value. However, the above value is different from the value of ?(020):?(110) during the following melt-crystallization process. This difference comes from the different orientations of the crystal lattices of the ? and ?H(?) crystals to the substrate plane, which indicates that the ?H phase inherits the orientation of the ? phase during phase transition and the orientation of ?H form crystals is different from the ? form crystals that crystallized from the melt.

SUBMITTER: Wang M 

PROVIDER: S-EPMC7023612 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature