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Molecular changes of PET yarns during stretching measured with rheo‐optical infrared spectroscopy and other techniques
Author(s) -
Van Den Heuvel C. J. M.,
Heuvel H. M.,
Fassen W. A.,
Veurink J.,
Lucas L. J.
Publication year - 1993
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1993.070490518
Subject(s) - amorphous solid , materials science , molecule , composite material , deformation (meteorology) , infrared , infrared spectroscopy , modulus , ultimate tensile strength , stress (linguistics) , spectroscopy , size exclusion chromatography , polymer chemistry , crystallography , optics , nuclear magnetic resonance , chemistry , physics , linguistics , philosophy , organic chemistry , quantum mechanics , enzyme
A method has been developed for measuring infrared spectra during the mechanical deformation of yarns. This rheooptical technique was applied to study the molecular processes that take place along the stress‐strain curve of PET yarns. The results were combined with data obtained from size exclusion chromatography (SEC) and tensile measurements at elevated temperatures. The results indicate that the first modulus maximum marks the breakdown of the amorphous entanglement network and the start of molecular uncolling by gauche → trans transitions. In addition, stress develops on the crystals and particularly on tie molecules with a short contour length in the amorphous domains. Ultimately, molecular fracture of taut‐tie molecules causes the modulus to pass through a second maximum. The chain ends of broken molecules recoil by trans → gauche transitions. Local stress accumulation will lead eventually to yarn rupture. © 1993 John Wiley & Sons, Inc.