Fig. 1
MAS NMR of amorphous PET powder at 30 °C and 70 °C. a 13C spectra in the range of 40–80 ppm showing the characteristic spectra for the EG carbons. The trans and gauche contents were quantified by fitting a Voigt function to the experimental spectra (red). The sum of the Voigt fits (shaded in purple and green, respectively, for trans and gauche conformers) is shown as dotted curve. The inset shows the EG fragment in the trans and gauche conformations. MAS sidebands are denoted by asterisks. b 1H–13C DIPSHIFT curves for phenylene and EG carbons acquired at a MAS rate of 8 kHz. The solid lines are the best-fit simulations and dashed lines represent the rigid limit. Experimental error bars were determined from the noise level. Order parameters S from the measured dipolar couplings are given.
