Morphology of dry lignins and size and shape of dissolved kraft lignin particles by X-ray scattering.

Lignin is a highly branched polymer consisting of phenylpropane units, and it is one of the ingredients of the supporting matrix in plant cell walls. The morphology of several lignins extracted from plant cell walls using different methods was studied by small-angle and ultra-small-angle X-ray scattering. A power-law type intensity was observed for the dry lignins, but on the basis of the power-law exponent the fractal approach often applied to lignins is not fully justified.

Analysis of technical lignins by two- and three-dimensional NMR spectroscopy.

Modern multidimensional NMR spectroscopic methods were applied to investigate the effects of kraft pulping and oxygen delignification on lignin side-chain structures. In addition to the two-dimensional HSQC measurements, the three-dimensional HSQC-TOCSY technique was utilized to elucidate the (1)H-(1)H and (1)H-(13)C correlations of individual spin systems and thus indicate a certain lignin side-chain structure. Unlike earlier, nonlabeled samples were used for 3D measurements.