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Rheo‐optical FT‐Raman study of uniaxially stretched poly(vinylidene fluoride)
Author(s) -
RodríguezCabello José Carlos,
Merino Juan Carlos,
Pastor José María,
Hoffmann Uwe,
Okretic Stephano,
Siesler Heinz Wilhelm
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021960311
Subject(s) - raman spectroscopy , absorption band , materials science , deformation (meteorology) , phase transition , absorption (acoustics) , fluoride , blueshift , phase (matter) , composite material , polymer chemistry , molecular physics , chemistry , optics , condensed matter physics , optoelectronics , photoluminescence , organic chemistry , inorganic chemistry , physics
A Fourier‐transform Raman‐sepectroscopy‐based rheo‐optical system was used to study the process of uniaxial stretching of poly(vinylidene fluoride) (PVF 2 ). This rheo‐optical system made possible to reduce the rate of stretching and favoured the acquisition of a higher number of spectra in different mechanical stages during the stretching process. Those can be the eleastic zone or the formation of the neck. Thus, it has been possible to establish that the stretching‐induced phase transition in PVF 2 takes place in the beginning of the neck formation. Shortly after the neck development that transition has reached its maximum extent. The performance of the transition was highly temperature dependent. As the temperature of stretching increases, the extent of the transition decreases. Along with this permanent modification of the sample structure, other transient modifications were found. High resolution spectra of the phase β of loaded PVF 2 showed a wavenumber shift of specific absorption bands. These band shift have been interpreted as a deformation of the geometry of the bonds reflected by the absorption band. This bands with high contribution of skeletal CC bonds suffered the highest band shift, suggesting that these bonds were most sensible to the applied load. This band shift and, consequently, bond deformation immediately vanished after removal of the load.