STEREOCHEMICAL STRUCTURE OF POLYMER SYSTEMS BEARING A VITAMIN-E SUBSTITUENT STUDIED BY C-13 NMR-SPECTROSCOPY

The microstructural analysis of poly(alpha-tocopherylmethacrylate) (PM VE) was carried out by one-dimensional C-13 n.m.r. spectroscopy. The s ensitivity of both aromatic and methyl (those attached to the aromatic ring) carbon signals to the stereosequences depends mainly on the pro ximity of these carbons to the maximum shielding zone of the neighbour ing conjugated blocks formed by the aromatic ring and the pyran cycle. The sensitivity of the ester carbonyl signal to the chain microstruct ure is influenced mainly by the gamma-gauche shielding effect. For PMV E prepared by radical polymerization Bernoullian statistics account sa tisfactorily for the observed relative intensities at the tried and pe ntad level. (C) 1998 Elsevier Science Ltd. All rights reserved.