Relaxation dynamics and cold crystallization of poly(pentamethylene terephthalate) as revealed by dielectric spectroscopy
journal contributionposted on 27.09.2017, 10:49 by M. Soccio, Aurora Nogales, Ignacio Martin-Fabiani, N. Lotti, A. Munari, Tiberio A. Ezquerra
The relaxation dynamics of poly(pentamethylene terephthalate) has been investigated by means of dielectric spectroscopy. The sub-glass dynamics is characterized by the existence of a bimodal β process whose faster and slower components have been assigned to the relaxation of the bond between the ester oxygen and the aliphatic carbon and to the link between the aromatic ring carbon and the ester carbon, respectively. By comparison with other closely related aromatic polyesters it is shown that the faster component strongly depends on the amount of methylene groups while the slower one is not considerably affected by the nature of the glycol subunit. The changes in the α process associated to the segmental relaxation during cold crystallization reveal the formation of a rigid amorphous phase fraction. Combination of dielectric experiments with X-ray scattering ones suggests that during cold crystallization PPT crystal lamellae tend to fill the space homogeneously.
Financial support by MAT2008-03232, MAT2011-23455, and MAT2012-33517 from MINECO is gratefully acknowledged. M.S. thanks CSIC and the Fondo Social Europeo (FSE) for cofinancing the JAE-Doc contract.
- Aeronautical, Automotive, Chemical and Materials Engineering