Ethene/4-Methyl-1-pentene Copolymers by Metallocene-Based Catalysts: Exhaustive Microstructural Characterization by 13C NMR Spectroscopy

The availability of a series of ethene/4-methyl-1-pentene copolymers spreading over a very broad range of chemical compositions, from about 1% up to 90% as 4-methyl-1-pentene molar content, paralleled by the heteronuclear 1H−13C gradient-assisted 2D NMR techniques, has allowed for an improved peak assignment of their 13C NMR spectra. In particular, sequences richer in comonomer could be assigned, and the previous ambiguous assignment of Sαγ methylene carbon of the main chain was corrected. Starting from whole set of the previous and newly proposed assignments, a comprehensive check of consistency of the 13C NMR assignment can be completely fulfilled. From now on, the correct evaluation of the copolymer microstructure at tetrad level and of the copolymerization parameters of this interesting family of copolymers will be accessible.