The effect of high pressure up to 2500 bar on the chain motion in amorphous chain-deuterated polyethylene is studied in a wide range of temperature (203-393 K) using the deuteron nuclear magnetic resonance (2H n.m.r.) quadrupole echo and spin alignment echo technique. Quadrupole echo spectra simulated on the basis of Flory's rotational isomeric state model appear to reproduce the experimental spectra quite well. The comparison yields information on the time-scale of the motion. The temperature dependence of the mean correlation time shows an Arrhenius behaviour in the temperature range from 223 to 383 K. The activation energy at ambient pressure is 11.3 kJ mol- 1, which is slightly lower than the value of the barrier between the trans and gauche conformations (13.2 kJ mol- 1). The effect of increasing the pressure by 1 kbar corresponds roughly to lowering the temperature by 15 K.
Посилання на статтю:
Deuteron nuclear magnetic resonance study of high-pressure effects on the molecular dynamics in amorphous polyethylene / A. S. Kulik and K. O. Prins // Polymer. – 1994. – Vol 35. – P. 2307-2314.