Chemical modification of biomass plays a crucial role in enhancing material properties for various applications. These modifications are industrially often carried in multiphase systems, where solid e.g. cellulose interacts with reactants in mixed solid-liquid-gas phase system. Ideally, reagents distribute uniformly within the cellulose matrix, producing a homogeneous product. However, batch-to-batch variations persist, even when the overall degree of modification remains constant, leading to product inconsistencies in mechanical strength, durability, and performance.
To better understand how chemical modifications are distributed within cellulose, we use solid-state NMR spectroscopy enhanced with Dynamic Nuclear Polarization (DNP-NMR). This technique boosts NMR signal by several orders of magnitude , allowing for the detection of subtle differences in modification patterns. By utilizing spin diffusion and DNP enhancement, we can probe the heterogeneity of modifications at the nanometer to micrometer level. The insights gained from this approach aim to optimizing modification processes and improving the reproducibility of chemically modified cellulose materials.