QUALITATIVE METHODS FOR THE STUDY OF LIGNIN DISTRIBUTION IN WOOD AND SURFACE-LAYERS OF UNBLEACHED PULP FIBERS AND PAPER

Some techniques for the staining of lignin components in the wood and pulp fibres for SEM analyses, backscattered electron imaging (BEI) mod e, are presented ana assessed. Potassium permanganate and bromine trea tments are considered convenient. The water-free bromine gas is especi ally suited for analyses of fibres in paper, as the paper structure is not affected. Sample preparation and scientific applications are desc ribed. The methods are not suited for accurate quantitative assessment s of lignin contents.