A T spin lattice relaxation study of the molecular motions of a semicrystalline polyimide matrix

Abstract The kHz molecular motion of a semicrystalline polyimide was studied through ¹³ C solid state NMR spectroscopy. Variable temperature T experiments were performed on a Bruker msl‐300 spectrometer for various B ₁ applied radio frequency fields. Similar activation energies of motion for different carbon atoms in the flexible spacer gave evidence of a group motion of this molecular segment. It was also found that aromatic activation energies were higher than those of aliphatic carbons.