THz spectra of drawn and undrawn fibers measured on fiber shape samples

Abstract

This paper describes how to measure THz spectrum of a filament shape sample without freeze-crushing chemical fiber. The filament yarn was installed in parallel on a stainless-steel O-ring. The fiber axis direction of this O-ring was installed in parallel to THz polarization direction. THz spectrum measured by this pre-treatment method was measured at a high S/N ratio than THz spectrum of the freeze-crushing sample. Next, THz spectra of drawn and undrawn fibers, which were confirmed to have different internal structure of the fibers by wide-angle X-ray images, were measured. THz spectra of these samples were measured with different yarn spacings and at different angles (at regular angle intervals of 30°) between the polarization direction of THz light and the fiber axis direction. When the fiber molecules were oriented along the axis by the drawing process, THz spectrum shape changed with the polarization angle, but it did not when the fiber orientations were random. This pre-treatment method avoids freeze-crushing, so the raw molecular structure inside the fiber was not altered thermally or mechanically and could be measured directly.

Keywords:

• THz spectroscopy
• fiber shape sample
• pre-treatment method
• drawn and undrawn fiber
• polarization angle

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to express appreciation for the support by Grants-in-Aid for Scientific Research (KAKENHI) [Project Number = JSPS KAKENHI Grant Numbers JP17K00785].