Sub-glass-temperature dynamic processes in amorphous solids: a deuterium and carbon-13 NMR study of poly(phenylene sulfide)

Deuterium NMR spectroscopy shows that the aromatic rings in deuterated amorphous poly(phenylene sulfide) (PPS) undergo rapid 180 o flips at room temperature. Detailed analysis shows that any subsidiary motion that accompanies ring flipping involves ring reorientation of no more than 20 o . There is a distribution in the natural logarithm of the flipping rates of 6.8 at 205 K and 3.9 at 350 K. The signals in the 13 C NMR spectrum of amorphous PPS are exceptionally broad, reflecting a wide range of local conformations for the polymer chains that are imposed by the local packing of the chains