NMR-SPECTROSCOPY OF POLY(VINYL CHLORIDE) DEFECTS .2. H-1 AND C-13 NMRANALYSIS OF THE TERMINAL VINYL END GROUP, 1,3-DICHLOROBUTYL END GROUPAND CHLOROMETHYL BRANCH

We have been able to obtain the H-1 NMR subspectra of most of the majo r saturated end groups in PVC. In order to assign the terminal vinyl ( TV) group, CH2=CH-CHCl-, we synthesized and analyzed the symmetrical m odel compound 3,5-dichloro-1,6-heptadiene (4) containing a racemic (r) and a meso (m) isomer. They exhibit distinct NMR signals for the viny l protons, which allowed us to subsequently assign the r diad and the previously unreported m diad terminal vinyl resonances present in very small amounts in commercial PVC. The study of the solvent induced che mical shifts of the vinyl protons in an experimental PVC sample contai ning an unusually high level of this end group allowed us to further a ssign it in terms of the terminal rr, rm, mm and mr triads.