Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

Abstract

Herein are presented the 188.6 MHz 13C NMR spectra (corresponding to 750 MHz 1H resonance frequency) of a series of copolymers from ethylene and 1-octene monomers. These spectra permit the resolution of unique 13C resonances from hexyl chain branches. The 750 MHz high-temperature pulsed field gradient (PFG), heteronuclear multiple quantum correlation (HMQC), and heteronuclear multiple-bond correlation (HMBC) two-dimensional (2D) NMR spectra of ethylene/1-octene copolymers are also presented. Data are presented from a new probe capable of performing high-temperature PFG coherence selection experiments at temperatures typical of those used in many polymer analyses. The performance of this probe is illustrated with PFG−HMQC and PFG−HMBC spectra of copolymers from ethylene/1-octene at 120 °C. Detailed unequivocal proof of the resonance assignments for poly(ethylene-co-1-octene) is reported. The 2D NMR spectra were used to confirm 1H and 13C chemical shift assignments previously determined by empirical methods. Quantitative analyses of the ethylene/1-octene copolymers were also performed.

Partitioning of Main and Side-Chain Units between Different Phases: A Solid-State 13C NMR Inversion-Recovery Cross-Polarization Study on a Homogeneous, Metallocene-Based, Ethylene-1-Octene Copolymer

“…3. The resonances of side-chain carbons are resolved from those of the main chain, as can be seen from Table 1, which shows the spectrum assignment [38]. Crystallization causes significant line broadening, which is the largest for methine and methylene carbon atoms of the main chain (see Fig.…”

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

“…Such differences could be enhanced by an order of magnitude through adjusting temperature and sample concentration. [27] This work allowed resolution of characteristic 13 C resonances for long-chain branches up to 10 carbons in length. [26] More recently, Qiao's group [28] reported an improved solution 13 C NMR method using AVANCEIII-400 MHz spectrometer, based on the chemical shift difference ( δ ∆ ) between CH(B 4 ) and CH(B n ), i.e.,…”

“…The log G′ versus log G″ curve is independent of MW for polymer melts with high MW and low PDI and it is only loosely dependent on temperature. For linear PEs with narrow MWDs, G′ and G″ obtained at various temperatures and MWs can be described by a single master curve as Equation (27) [78,121] G G 0.00541…”

Characterization of n -butyl acrylate centered triads in poly( n -butyl acrylate- co -carbon monoxide- co -ethylene) by isotopic labeling and two dimensional NMR

“…Employing PFG at high field (750 MHz) permitted resolution of 13 C resonances from minor structural components; unique 13 C spectral assignments were reported in branches up to ten carbons long [9]. These NMR techniques have just recently been applied to a series of ethylene/1-octene [10] copolymers and ethylene/1-butene [11], affording assignments of new 13 C resonances and confirmation of assignments previously made by empirical means.…”