Microstructure determination of ethylene-styrene-1-hexene terpolymers with fast 2D NMR by nonuniform sampling. (15th April 2019)

• Record Type: Journal Article
• Authors: Long, Ying-Yun; Wang, Yong-Xia; Li, Bai-Xiang; Li, Yan-Guo; Li, Yue-Sheng
• Is Part Of: Polymer. Volume 169(2019)
• Page Start: 185
• Page End: 194
• Publication Date: 2019-04-15
• Subjects: Nonuniform sampling -- Fast 2D NMR -- Olefin terpolymer; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2019.02.043
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: A series of poly(ethylene-styrene-hexene) samples with relatively low glass-transition temperatures ( T g = −38 ‒28 °C) were synthesized using Me2 Si(Me4 Cp)(N-t-Bu)TiCl2/MMAO system. For the first time, nonuniform sampling with 2D- 1 H/ 13 C 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. Graphical abstract: A series of ethylene-styrene-hexene terpolymers with varying monomer compositions and low glass-transition temperatures ( T g = −38 ‒28 °C) were synthesized. For the first time, 2D- 1 H/ 13 C HSQC and HMBC experiments with nonuniform sampling were employed to determine the microstructure of these terpolymers. New signals, hidden peaks in overlaps and new triads were clearly identified qualitatively and quantitatively with 50% experiment times and improved sensitivity.Image 1 Highlights: A series of poly(ethylene- co -styrene- co -1-hexene) samples with low glass-transition temperatures ( T g = −38 ‒ 28 °C) were synthesized. For the first time, nonuniform sampling (NUS) together with 2D- 1 H/ 13 C HSQC and HMBC spectra were employed to determine the microstructure of these terpolymers, exhibiting the same results as conventional 2D NMR with less experiment time. 2D NMR with NUS was superior in terms of sensitivity and periment time.