Fluorine-19 NMR investigation of poly(trifluoroethylene)

An NMR investigation of poly(trifluoroethylene) is reported. Using known as signments of the fluorine solution-state spectrum, the defect level has bee n determined as well as a high degree of atacticity confirmed. The solid-st ate (FNMR)-F-19 study concentrated on the detection of heterogeneities in t he polymer. Transient oscillations in H-1 --> C-13 CP curves have been used in order to determine effective bond distances and, consequently, to detec t motion of the polymer chain. The onset of motion has been confirmed by co mparing the measured axially symmetric fluorine shielding tensor with the a symmetric tensor obtained from ab initio calculations carried out on the ri gid molecule. (C) 2000 Elsevier Science Ltd. All rights reserved.