Cold Crystallization of Poly(trimethylene terephthalate) As Revealed by Simultaneous WAXS, SAXS, and Dielectric Spectroscopy

This work presents an experimental study on the interplay between structure and dynamics during isothermal and nonisothermal cold crystallization of poly(trimethylene terephthalate). Simultaneous X-ray scattering and dielectric spectroscopy measurements revealed that, during cold crystallization, crystalline lamellae tend to be homogeneously distributed along the sample. A significant amount of rigid amorphous phase is formed during cold crystallization, and its location is assigned to the crystal−amorphous interface. The formation of the rigid amorphous phase during cold crystallization is less effective for poly(trimethylene terephthalate) than for other similar aromatic polyesters like poly(ethylene terephthalate). The mobile amorphous phase, giving rise to the dielectric α relaxation, is mainly located between consecutive crystalline lamellae. The segmental dynamics of the amorphous phase is restricted by the growing crystals during both primary and secondary crystallization.