Polarized resonance Raman and FTIR reflectance spectroscopic investigationof the molecular orientation in industrial poly(vinyl chloride) specimens

The molecular orientation of uniaxially drawn commercial poly(vinyl chlorid e), PVC, specimens has been investigated by polarized Fourier transform inf rared (FTIR) in the specular reflectance mode and by resonance Raman scatte ring in various combinations of sample orientation, scattering configuratio n and polarization geometry. The orientation was examined as a function of the specimen draw ratio. The Kramers-Kronig transformation has been used to obtain infrared absorption spectra from the FTIR reflectance data; the ori entation was determined by the dichroic ratio of the C-Cl stretching and CH 2 rocking modes of PVC. The resonance Raman spectra of polyene segments tha t result from partial thermal degradation/dehydrochlorination of PVC during processing have been utilized in order to determine the parameters of the orientation distribution function. The all-trans conjugated polyene sequenc es formed during degradation are considered as rodlike segments in the poly mer backbone and are used as indicators of orientation within the amorphous -like polymer phase. As far as the trends are concerned, data analysis show ed good agreement between FTIR and Raman results regarding the induced mole cular orientation in industrial PVC specimens.