Accurate characterization of relative compositions in multicomponent polymer systems such as statistical copolymers, block copolymers, and polymer blends is critical to understanding and predicting their behavior. Normally, polymer compositional analysis is performed using 1H Nuclear Magnetic Resonance (NMR) Spectroscopy. This analytical technique provides quantitative chemical group concentrations without prior calibration and has enabled 1H NMR spectroscopy to become a routine method for the molecular characterization of polymers. Unfortunately, due to cost constraints, NMR spectroscopy is rarely used for routine materials verification such as quality control in industrial settings that commonly lack on-site advanced instrumentation facilities. Low-field nuclear magnetic resonance spectrometers have recently become commercially available and present an opportunity to replace costlier or destructive methods while utilizing non-deuterated solvents. Many factors play key roles in the ability of low-field nuclear magnetic resonance spectroscopy to accurately analyze polymer systems. Sample characteristics such as polymer concentration, composition, and molecular weight all directly affect the capability of low-field spectrometers to accurately determine polymer microstructures or compositions. In addition to inherent sample properties affecting instrumental accuracy, many choices concerning instrumental parameters (including number of scans, relaxation delay, spectral width and points per scan) must be made that impact the quality of the resulting NMR spectra. Here, we benchmark the capability of a 60 MHz low-field NMR spectrometer for analyzing polymer materials using mixed microstructure polyisoprenes as a model polymer system of interest. Critical sample and instrumental parameters are varied and we report on the ability to quantitatively characterize polyisoprene microstructure to within 1-2% of a higher-field NMR spectrometer (400 MHz). We anticipate our findings to be generally applicable to other low-field spectrometers of similar field strength as well as other polymer systems.

Low-field 1H nuclear magnetic resonance spectroscopy for compositional analysis of multicomponent polymer systems

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.