Microscopic Investigations on Woody Biomass as Treated with Ionic Liquids

Woody biomass is one of the most promising renewable alternatives to fossil resources. However, some physical and chemical treatment is required to convert their chemical components into biofuels and valuable chemicals because of their low degradative properties. Recently, there has been considerable interest in ionic liquid treatment for biorefinery, and many fundamental studies on the reactivity of wood with ionic liquids have been performed from a chemical and morphological point of view. This chapter highlights the findings regarding morphological and topochemical features of wood cell walls in the degradation process as a result of ionic liquid treatment. Bright-field microscopy and scanning electron microscopy have revealed the swelling behavior of cell walls and the detailed ultrastructural features of wood tissues treated with ionic liquid. Polarized light microscopy and confocal Raman microscopy have clarified the changes in cellulose crystallinity and distribution of chemical compositions such as polysaccharides and lignin during ionic liquid treatment at the cellular level

Application of Confocal Raman Microscopy for the Analysis of the Distribution of Wood Preservative Coatings

The distribution of wood preservative coatings in wood surface layer was assessed at the cellular level using confocal Raman microscopy. Raman images were created based on the fingerprint Raman bands of the different wood polymers and coating components (resin and pigment). The wood cell walls and the distribution of the resin and pigment were clearly visualized at the same time. It was concluded that confocal Raman microscopy is suitable for the evaluation of the microdistribution of wood coatings, providing valuable information for the improvement of wood coating technology