Details

Autor(en) / Beteiligte

• Fina, L.J.
• Bower, D.I.
• Ward, I.M.

Titel

Raman spectroscopy of stressed samples of oriented poly(ethylene terephthalate)

Ist Teil von

• Polymer (Guilford), 1988-12, Vol.29 (12), p.2146-2151

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

1988

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Measurements of the shift and change of shape of the 1616 cm −1 Raman scattering peak of two moderately oriented samples of poly(ethylene terephthalate) (PET) under tensile loads of up to 0.2 GPa are reported, together with the corresponding strains. To obtain reproducible results load cycling procedures were adopted similar to those established for the study of viscoelastic behaviour. The Raman scattering was observed with polarized incident and scattered light, with the polarization directions either both parallel or both perpendicular to the draw direction in the samples. The results showed that for both samples the Raman shift was linearly related to the applied stress below the yield point. Up to the yield point very little change of line width was observed but above the yield point the width increased significantly. Differences in both widths and shifts were observed for the two polarization directions at the same stress level. The results are discussed in terms of the usual assumptions that the shift of the line gives a measure of the average stress in those chains which predominantly contribute to the peak and that the width and shape of the line give information about the spread of stresses. It is concluded that the technique can give useful information about the molecular stress distribution in thick samples of moderately oriented PET under load, including information about the different stress distributions on chains at different angles to the draw direction.