The effect of high pressure on the main chain motion near the glass transition temperature (Tg) in amorphous chain-deuterated polystyrene is studied using deuteron n.m.r, spin alignment echo and quadrupole echo spectra. Comparison with simulated spectra yields information on the time-scale and the type of motion. In the vicinity of Tg the main chain performs ultra-slow small angle diffusive motion. The temperature dependence of the mean correlation time shows a strongly non-Arrhenius behaviour, typical for the so-called ~-process. The width of the correlation time distribution rapidly increases on approaching T~. The effect of pressure on the motion is found to be much weaker than could be expected from equation-ofstate data.
Посилання на статтю:
2H n.m.r, study of high pressure effects on the molecular dynamics in polystyrene: 1. Main chain motion / A. S. Kulik* and K. O. Prins // Polymer. – 1993. – Vol 34. – P. 4629-4634.