Microstructure determination of ethylene-styrene-1-hexene terpolymers with fast 2D NMR by nonuniform sampling

A series of poly(ethylene-styrene-hexene) samples with relatively low glass-transition temperatures (T-g = -38-28 degrees C) were synthesized using Me2Si(Me4Cp)(N-t-Bu) TiCl2/MMAO system. For the first time, nonuniform sampling with 2D-H-1/C-13 HSQC and HMBC experimentsis employed to determine the microstructure of these complicated terpolymers. The signals hiddenin the specta overlaps are clearly discriminated, and the assignments of new peaksfrom novel sequences are successfully achieved with about 50% of conventional experiment time. The distributionsof 11 triads are quantatively presented. The results demonstrate that 2D NMR with nonuniform sampling is superior to the traditional uniform sampling approaches in terms of resolution, experiment time, signal-to-noise ratio and structural information gathered, and this approach represents a fast way for microstructure determination of complicated synthetic polymers.