NUCLEAR-MAGNETIC-RESONANCE STUDY OF SPATIAL RELATIONSHIPS BETWEEN CHEMICAL-COMPONENTS IN WOOD CELL-WALLS

CP/MAS NMR was used to monitor proton spin diffusion between components of wood.The results were consistent with a model in which microfibrils of cellulose about 14 nm thick were encrusted with a mixture of hemicelluloses and lignin. Spin relaxation experiments provided evidence for relatively intimate mixing of crystalline cellulose with disordered cellulose and of acetylated hemicelluloses with lignin. Moistening wood enhanced proton spin-lattice relaxation and improved discrimination between rotating-frame spin relaxation rates for cellulose and lignin.