Solid State NMR a Powerful Technique for Investigating Sustainable/Renewable Cellulose-Based Materials

Abstract

Solid state nuclear magnetic resonance (ssNMR) is a powerful and attractive characterization method for obtaining insights into the chemical structure and dynamics of a wide range of materials. Current interest in cellulose-based materials, as sustainable and renewable natural polymer products, requires deep investigation and analysis of the chemical structure, molecular packing, end chain motion, functional modification, and solvent–matrix interactions, which strongly dictate the final product properties and tailor their end applications. In comparison to other spectroscopic techniques, on an atomic level, ssNMR is considered more advanced, especially in the structural analysis of cellulose-based materials; however, due to a dearth in the availability of a broad range of pulse sequences, and time consuming experiments, its capabilities are underestimated. This critical review article presents the comprehensive and up-to-date work done using ssNMR, including the most advanced NMR strategies used to overcome and resolve the structural difficulties present in different types of cellulose-based materials.

Physicochemical Characterization of Nanobiocomposites

“…order to get accurate measures using this technique, the following factors should be considered: signal-to-noise ratio, saturation effects, peak shape, resolution, isotopic satellite, spinning sidebands, baseline slant, and curvature [33,34]. The advancement of NMR to include computer-assisted methods enabled more information on molecular modeling and conformational analysis of many natural polymers [33].…”

“…NMR can be used to characterize liquid NBCs samples like gels, dispersion, melt, and solutions with increased spectral specificity compared to solid samples [31,32]. Consequently, dilution, dispersion, increased temperature, etc., can give more information related to polymeric microstructure, its dynamics, and interactions with other ingredients within an NBC [33]. Liquid state NMR can be classified into onedenominational and multi-dimensional (2D and 3D) techniques.…”

“…Highpower dipolar decoupling, cross-polarization, and magic angle spinning to produce high-resolution 13 C NMR spectra avoid long instrument running time. Likewise, the combined rotation and multi-pulse (CRAMPS) experiment can permit H spectra with narrower line widths to be obtained [31,33,35].…”

“…Examples of published literature about using 1 H NMR include: include N-carboxyethyl chitosan and glycol chitosan [36], 2,3epoxypropyltrimethylammonium chloride grafted starch [37], heteroaryl pyrazole chitosan derivatives [38], sulfonated chitosans [5], Cellulose Nanocrystals with 2-Isocyanatoethyl Methacrylate [24] and many others. 1H NMR has also been used to predict the rigidity of polymers and different phases of a polymer like cellulose [33].…”

Solid-State NMR Spectroscopy: Towards Structural Insights into Starch-Based Materials in the Food Industry

“…ssNMR is a powerful technique, well known for its use in studying the structure and dynamics of carbohydrate polymers [ 48 , 49 ]. This includes, but is not limited to, starch [ 18 , 50 ], cellulose [ 51 ] and alginate [ 49 ]. While limited in terms of resolution and sensitivity, ssNMR enjoys several advantages over different analytical techniques.…”