Speedy quantitative microstructure determination of Poly(ethylene-co-1-hexene) at triads by 1H–13C two-dimensional NMR. (16th August 2021)

• Record Type: Journal Article
• Authors: Long, Ying-Yun; Lv, Juan; Li, Bai-Xiang; Liu, Yong-Gang
• Is Part Of: Polymer. Volume 229(2021)
• Publication Date: 2021-08-16
• Subjects: Polyolefins -- 2D HSQC -- Non-uniform sampling -- Quantitative determination; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.123993
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: One of the most commonly utilized techniques for microstructure determination of polyolefins is quantitative 13 C NMR, but it generally requires long experiment times and large amounts of samples to achieve reliable quantification for its low sensitivity. In this context, we report the use of two-dimensional (2D) 1 H– 13 C heteronuclear single-quantum correlation (HSQC) spectroscopy to rapidly determine the microstructure of a typical linear low density polyethylene (LLDPE), poly(ethylene- co -1-hexene) at triads. Moreover, the 2D HSQC with non-uniform sampling (NUS) enable the reduction of experiment time from more than 23 h to several minutes with composition accuracy higher than 99.5%. The methodology is robust, and it can find wide-spread applications in areas where a quantitative analysis of polymers is necessary. Graphical abstract: For the first time, 2D 1 H– 13 C HSQC with Non-uniform sampling (NUS) was used for the quantitative microstructure determination of polyolefins, which not only enabled the reduction of experiment time from more than 23 h to less than 1 h, but also achieved accuracy higher than 99.5% regarding to the composition and triads content of the poly(ethylene-co-1-hexene). Image 1 Highlights: 2D HSQC is used for rapid quantitative microstructure determination of the typical LLDPE. High accuracy can be achieved within several minutes. This is the first example of the use of 2D NMR/NUS for determination of poly(ethylene-co-1-hexene).