Etude par ¹H NMR des groupements chlorométhyles du poly(chlorure de vinyle), 2. Etude par écho de spin et comparaison avec des modèles moléculaires

Abstract

In order to assign all -CH,CI resonances observed by ' H NMR in poly(viny1 chloride), (PVC), a preliminary study of the diastereoisomers of molecular models for the groups CH2Cl-CHCI- [11] and ClCH,-CH< [IV] is used, in conjunction with spin echo experiments. The complex region [3,5 -4,O ppm] which corresponds to saturated -CH,CI chloromethyl protons is completely assigned. A separate evaluation of -CHCI-CH,CI[II], -CH,-CH,CI[III] and >CH-CH,CI [IV] is proposed and tested on raw PVC samples. The main interest of this ' H NMR determination is the fact that raw PVC can be used and that it gives the ratio [II]/[III] which is not accessible by I3C NMR on reduced samples.