NMR-Untersuchungen über molekulare Bewegungsprozesse in Phenylensulfiden

Abstract

Abstract Internal motion in poly (p-phenylene sulfides) and in some low-molecular phenylene sulfides has been studied using NMR relaxation and broad line techniques. The relaxation rates T1 -1 in the laboratory frame at 30 or 15 MHz, and T1e -1 in the rotating frame at 45 kHz, and the second moments (or local fields or linewidths) have been measured over an extended range of temperatures for five different materials. For the polymers, the most important process has an activation energy of approximately 40 kJ/mole; it is ascribed to reorientational random oscillations of the phenylene groups, and it depends upon the detailed polymer structure. The origin of further processes of motion observed with activation energies of 20 and 11 kcal/mole is discussed. The rather narrow lines which occur in the NMR spectra at temperatures well above the glass transition are explained by the mobile fraction of chains of the non-crystalline regions.