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Properties of arylpolyesters with reference to water content
Author(s) -
Rueda D. R.,
Viksne A.,
Kajaks J.,
BaltaCalleja F. J.,
Zachmann H. G.
Publication year - 1995
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19950940123
Subject(s) - absorbance , molar absorptivity , overtone , analytical chemistry (journal) , fourier transform infrared spectroscopy , materials science , infrared spectroscopy , amorphous solid , bound water , water content , infrared , spectroscopy , spectral line , molecule , polymer chemistry , chemistry , optics , crystallography , organic chemistry , chromatography , physics , geotechnical engineering , quantum mechanics , astronomy , engineering
The 4000–2000 cm −1 infrared spectral region from transmission FTIR spectra of films (≈ 220 μm thick) of amorphous poly (ethylene terephthalate) (PET) and poly(ethylene 2, 6‐naphthalenedicarboxylate) (PEN) was analyzed. In addition to the strong bands for the stretching vibration modes of H‐C bonds, the ester‐overtone band at about 3430 cm −1 and a doublet (3630, 3550 cm −1 ) band, related to absorbed water, appear. The spectra for these materials show significant differences in absorptivity and frequency for the ester overtone band. Real time water sorption/desorption in these films was investigated simultaneously by FTIR spectroscopy and by measurement of weight changes. A linear correlation between the integrated absorbance of the water bands and the relative weight variation of the films was found for these two polymers. Results show that the infrared absorptivity of these bands is identical in both materials and that water molecules are weakly bound to ester groups throughout the films. However, it turns out that the water content is higher in the case of PEN which has a larger specific volume.