NORMAN AND JENKINS HOLOCELLULOSE PREPARATION REEXAMINED BY MEANS OF THE CATION-EXCHANGE TECHNIQUE

Holocellulose composition, characterized by polyose fraction of wood a nd containing almost the whole of carboxyl groups, enables the use of cation exchange technique to follow its preparation and to give a qual ity appraisal. Progress in the formation of Norman and Jenkins holocel lulose from hardwood (Populus euroamericana 'I 214') and softwood (Pin us pinea) shows that the most of lignin seems to be solubilized in the initial stages while hemicelluloses to be attacked at the final ones. Taking into account several hardwood and softwood holocelluloses, it can be seen that the first ones withstand better the chemicals and mai ntain more than 85% of the initial cation exchange capacity (c.e.c.), while the second ones attain only 56% of their original c.e.c. If a sp ecific hemicellulose loss occurs, this is tentatively attributed to th e mannans, and a research on sugar variation is in progress.