Solid-state NMR is a nondestructive and noninvasive technique used to study the chemical structure and dynamics of starch-based materials and to bridge the gap between structure-function relationships and industrial applications. The study of crystallinity, chemical modification, product blending, molecular packing, amylose-amylopectin ratio, end chain motion, and solvent-matrix interactions is essential for tailoring starch product properties to various applications. This article aims to provide a comprehensive and critical review of research characterizing starch-based materials using solid-state NMR, and to briefly introduce the most advanced and promising NMR strategies and hardware designs used to overcome the sensitivity and resolution issues involved in structure-function relationships.
View Article and Find Full Text PDFSolid 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.
View Article and Find Full Text PDFThe role of water as highly effective hydrogen-bond donor (HBD) for promoting the coupling reaction of CO with a variety of epoxides was demonstrated under very mild conditions (25-60 °C, 2-10 bar CO ). Water led to a dramatic increase in the cyclic carbonate yield when employed in combination with tetrabutylammonium iodide (Bu NI) whereas it had a detrimental effect with the corresponding bromide and chloride salts. The efficiency of water in promoting the activity of the organic halide was compared with three state-of-the-art hydrogen bond donors, that is, phenol, gallic acid and ascorbic acid.
View Article and Find Full Text PDF