STUDY OF STRESS-INDUCED CHANGES IN POLY(ETHYLENE-TEREPHTHALATE) THROUGH FOURIER-TRANSFORM INFRARED SPECTROSCOPY

The molecular level changes resulting from an external stress applied onto a highly uniaxially oriented poly(ethylene terephthalate) film has been studied. For this purpose, a new technique - Fourier Transform Infrared Spectroscopy - has been employed. Stress-induced differences are visible in a number of bands within the IR spectra of stressed PETP films. From the assignments of these IR bands, it is inferred how external stresses applied on the polymer films are actually transmitted to the molecular level. The intermicrofibrillar chains are the first to be stressed followed by stress transmission on the crystalline regions. These stresses are also responsible for stretching the backbone bonds, for transforming gauche conformations (predominantly present in the amorphous regions) of the ethylene glycol linkages to the trans, and for modifying the interchain interactions. © 1979 Dr. Dietrich Steinkopff Verlag.