Measuring of physical characteristics of above-molecular structure of native wood celluloses is a complicated methodical problem. The problem difficulty is connected with structural features of the investigated objects, diffraction patterns of which contain the limited number of the small contrast reflections stipulated by high diffuse background. Thus preparation of objects and roentgenography conditions will play a decisive role in the solving of this problem.
Usually we investigate the butt-end and radial-stem cuts to obtain the structural parameters of native wood celluloses. Using of these two sorts of cuts allows us to register the number of reflections sufficient for the structure studying. However, this technique has some demerits: the scattering patterns from early and late wood celluloses may impose each other as volumes from different woods take part in the X-ray diffraction.
We have suggested different methods of the diffractograms obtaining to avoid drawbacks given above. The investigations are carried out on tangential cuts prepared for early and late wood separately. The sample thickness is determined by the year ring width. The radiated square of the cut depends on roentgenography conditions. Diffractograms are registered in two positions of the sample: in the first case fibres are parallel to the goniometer axis and in the another one they are perpendicular to it. Experiments have showed that the X-% ray scattering patterns of native wood contain 12-15 reflections which may be used for obtaining of the structure characteristics of early and late wood celluloses.
The lattice constants of native wood cellulose of fir-tree and pine-tree were calculated using this method. These results confirm the idea that native wood celluloses are crystallized by the same way but they have individual differences.