DNP-Enhanced Solid-State NMR for Radial Profiling of Chemically Modified Cellulose Fibers.

Interest in biomass-derived materials, particularly cellulose-based materials, has been growing lately as alternatives to fossil fuel–based products. However, the inherent properties of native cellulose are often insufficient to meet the demands of industrial applications. Chemical modification provides an effective strategy to tailor the properties of cellulose fibers, especially their thermoprocessability, which is essential for industrial manufacturing and processing. Since these modifications are primarily carried out in the solid state, the functional groups distribute in the fiber walls to varying depths, thereby influencing the final material properties differently. This depth profile of these modifications remains so far poorly understood.

Hence, this work aims to improve the understanding of structure–property relationships in chemically modified cellulose materials by investigating the radial distribution of functional groups within cellulose fibers. Solid-state NMR spectroscopy, enhanced with dynamic nuclear polarization (DNP-NMR), is used as the main tool to characterize and explore the depth profile of the modifications. The findings are expected to provide new insights into how the spatial distribution of chemical functionalities influences material performance, thereby supporting the development of more sustainable and high-performance cellulose-based materials.