NUCLEAR MAGNETIC-RELAXATION OF MODIFIED POLY(P-PHENYLENE SULFIDE)

The influence of controlled purification and thermal treatment on the nuclear magnetic relaxation of poly(p-phenylene sulfide) (PPS) has been studied. The temperature dependence of spin-lattice relaxation times at 30 and 90 MHz in modified samples has been measured. High temperature annealing leads to an increase in the number of paramagnetic centres, which are most probably radical cations, and to the observed increase in molecular weight of PPS. Sustained purification and degassing of PPS causes the removal of low molecular weight oligomers and paramagnetic oxygen. This effect leads to non-exponential magnetization recovery.