Pressure‐induced freezing of conformational states of poly(vinyl chloride)

Abstract

The pressure‐induced freezing of high‐energy conformations (trans‐gauche) of poly(vinyl chloride) has been measured by FTIR absorbance spectroscopy. The conformational change predicted from the increase in Tg with pressure and the change in population (absorbance) with temperature is larger than the observed change in population (absorbance). This difference is of the right order of magnitude as that predicted from the volume difference between conformers which favors the trans isomer at high pressure. Samples prepared at high pressure recover to their equilibrium population at the normal zero‐pressure glass temperature when heated with no applied pressure.

FTIR studies of conformational energies of poly(acrylic acid) in cast films

“…Substitution of these relations into the van't Hoff times controlling a structural relaxation. 11,12,14,15 Then the equilibrium constant, K is defined by relation yields Figure 3. Difference spectra of PAA obtained at 10ЊC intervals from 50 to 110ЊC.…”

“…A similar apture stability of better than {0.1ЊC. Calculation of the spectra was performed by Grams/386 (Gaproach was followed to study conformational changes of poly(vinyl chloride), 11,12 poly(methyl lactic Industries Co.) methacrylate) (PMMA), 13,14 and of deuterated PMMA 15 of various tacticity, and the conformational energies acquired were confronted with the…”

Subglass-transition-temperature annealing of poly(ethylene terephthalate) studied by FTIR

“…The long-range chain conformational of the process, 7,8 but more work would be desirable structure and interchain aggregation of an amorto examine the changes of the polymer molecules in phous polymer will depend on the way the solid was the physical aging process. 9 In this article we prepared and on the thermal and mechanical history examine the conformational aspects of the state of of the sample. The phenomenon of physical aging is quenched samples and that of slowly cooled samassociated with the approach of an equilibrium state ples using FTIR spectroscopy, and the conformafrom a nonequilibrium state of the glassy polymer.…”