C-13 NMR CHARACTERIZATION OF ETHYLENE 1-BUTENE COPOLYMERS

The C-13 NMR assignments in ethylene/1-butene copolymers are reviewed with samples of different composition and with NMR spectral editing experiments and reaction probability models. Corrections of previous assignments have been made. The use of the computerized analytical approach indicates that many of the copolymers exhibit compositional heterogeneity. The NMR data for batch copolymers can be fitted, in most cases, with a two-state statistical model, indicating that the copolymer can be considered approximately to contain at least two components with different preferences for ethylene and 1-butene. The assignment scheme given herein is also applicable to hydrogenated polybutadiene and linear low-density polyethylene.