Analyzing Morphology and Thermal History of Polybutylene Terephthalate by THz Time-domain Spectroscopy

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 32; no. 7; pp. 952 - 959
• Main Authors: Wietzke, Steffen, Reuter, Marco, Nestle, Nikolaus, Klimov, Evgueni, Zadok, Uri, Fischer, Bernd M., Koch, Martin
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.07.2011; Springer Nature B.V
• Subjects: Band spectra; Banded structure; Chemical industry; Classical Electrodynamics; Crystal structure; Crystallinity; Degree of crystallinity; Dielectrics; Electrical Engineering; Electronics and Microelectronics; Engineering; Infrared; Instrumentation; Morphology; Polybutylene terephthalates; Polyethylene terephthalate; Refractivity; Spectroscopy; Semi-crystalline polymer; PBT; Terahertz time-domain spectroscopy; Refractive index; Absorption coefficient; Polybutylene terephthalate; Degree of crystallinity; Amorphous domains; Macromolecule; Thermal history; Morphology; Analysis; Non-destructive; Structure; Index of refraction
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-011-9810-9

We have measured the frequency-dependent dielectric function of semi-crystalline polybutylene terephthalate (PBT) in the terahertz region between 100 GHz and approximately 2.8 THz. A characteristic band is observed around 2.38 THz. The intensity of this band is a good indicator of the degree of crystallinity of the different samples. A potential assignment of this band is proposed, based on the comparison with spectroscopic data of the structurally very similar polyethylene terephtalate (PET). Furthermore, the frequency-dependent index of refraction of PBT reveals more insight about the morphology and different thermal history of the samples under investigation.