Terahertz spectroscopic estimation of crystallinity of poly(phenylene sulfide)

Abstract

As a crystalline polymer, various properties of poly(phenylene sulfide) (PPS) depend on its crystallinity. Evaluation of crystallinity of PPS is examined by terahertz (THz) absorption spectroscopy in this research. For sheets of PPS thermally annealed differently, sharp absorption peaks appearing at 3.2 and 4.2 THz are well proportional to the crystallinity estimated by X‐ray diffraction, differential scanning calorimetry, and Fourier transform infrared (FTIR) absorption spectroscopy. Therefore, THz absorption spectroscopy can be a good tool for estimating the crystallinity of PPS. Especially, it is useful for thick PPS sheets, for which FTIR spectroscopy in transmission mode is difficult to apply due to the saturation of absorbance. Since THz spectroscopy and FTIR spectroscopy are complementary in the vibrations that the two methods can detect, using the two methods should be effective to improve the accuracy of estimation of crystallinity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46427.

Broadband FIR absorption spectra of low‐density polyethylene sheets containing six different antioxidants and estimation of their contents by chemometric analysis

“…The TAS7500TS spectrometer can measure the time‐resolved changes in the intensity and phase of electric fields, transmitted through or reflected from a sample, in a frequency range from 0.5 to 5.0 THz (16.7–167 cm −1 ). The method to obtain frequency‐domain absorption spectra from time‐domain spectra is basically the Fourier transform, of which the details are found elsewhere [13]. On the other hand, the VIR‐F spectrometer directly measures absorption spectra from 100 to 600 cm −1 .…”

“…Absorption spectra of these sheets were measured in a broadband FIR range from 0.5 to 18.0 THz (16.7-600 cm −1 ) in a transmission mode using a THz time-domain spectrometer (THz-TDS, TAS7500TS, Advantest) and an FT-FIR absorption spectrometer (VIR-F, JASCO). The TAS7500TS spectrometer can measure the time-resolved changes in the intensity and phase of electric fields, transmitted through or reflected from a sample, in a frequency range from 0.5 to 5.0 THz (16.7-167 cm −1 found elsewhere [13]. On the other hand, the VIR-F spectrometer directly measures absorption spectra from 100 to 600 cm −1 .…”

“…Since the generation and detection of THz waves has recently become much easier with the advent of related technologies, various applications of THz waves, for example, THz absorption spectroscopy have become industrially possible. Various pieces of valuable information on macroscopic molecular structures in inorganic and organic substances, such as lattice vibrations, intermolecular interactions, and skeletal oscillations, can be obtained by analysing THz absorption spectra [12][13][14][15][16][17][18][19][20][21][22][23].…”

Evaluation of crystallinity in carbon fiber‐reinforced poly(ether ether ketone) by using infrared low frequency Raman spectroscopy

“…In some polymer material, bands at the low wavenumber region have been reported and assigned to inter molecular interactions. [10][11][12][13][14][15][16][17][18] Therefore we might presumed that these bands could also be related to the inter molecular mode, but their origin is unknown and will not be discussed in this study. Although the origin of these bands should be supported by theoretical calculations and so on, in this study, the behavior of the peak depending on the crystallinity was experimentally investigated.…”

“…On the other hand, the peaks in the low wavenumber region are attributed to inter molecular interactions. [10][11][12][13][14][15][16][17][18] The distribution of crystallinity of a poly(ε-caprolactone) films has been reported using terahertz imaging in which the intensity ratio of the two spectral peaks at 1.42 and 2.03 THz are used to decide the crystallinity. 16 The relationship between intramolecular vibration modes and crystallinity is indirect, whereas intermolecular vibration has a more direct relationship.…”