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Fourier transform Raman study of glass‐fibre‐reinforced poly(ethylene terephthalate)
Author(s) -
Quintanilla L.,
RodríguezCabello J. C.,
Pastor J. M.
Publication year - 1994
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250250510
Subject(s) - raman spectroscopy , crystallinity , materials science , differential scanning calorimetry , composite number , annealing (glass) , microstructure , fourier transform infrared spectroscopy , ethylene , composite material , glass transition , ethylene glycol , polymer , analytical chemistry (journal) , chemical engineering , chemistry , optics , organic chemistry , thermodynamics , physics , engineering , catalysis
FT‐Raman spectroscopy has been proved as a useful tool to form the quantitative study of conformational changes in glass‐fibre‐reinforced annealed poly(ethylene terephthalate) (PET). Based on composite Raman bands directly related to the ethylene glycol fragment in the trans and gauche conformations, it was observed that glass‐fibre‐reinforced PET exhibits the same two‐phase conformational model as the isolated matrix. In contrast to the matrix, annealing thermal treatment of the composite does not seem to affect the composite microstructure since the isomer contents remain constant with annealing temperature. Thus, the microstructure is mainly determined by the fabrication process and its effect is similar to that observed in an annealed matrix at the highest temperatures. Therefore, the disordered trans isomer content can be considered negligible in the composite. In contrast to the spectroscopic results, the crystallinity values of the composite obtained by differential scanning calorimetry (DSC) only tend to coincide with those of the annealed matrix at temperatures above 150°C, and below this temperature they are always lower. A comparison between the results obtained by FT‐Raman and DSC techniques seems to indicate an improvement in the fibre–matrix interface in which an interfacial structure with a low degree of perfection changes to more perfect crystals.