A VERY EFFECTIVE METHOD FOR THE CATIONIC MODIFICATION OF CELLULOSE

The interaction between the oppositely charged polymers poly(diallyldi methylammonium chloride) (PDADMAC) and poly(maleic acid-co-alpha-methy lstyrene) (P(MA-MS)) in the presence of cellulose can be used for stro ng surface modification. The dependence of the modification effect on the concentration of polymers and on the method of modification is inv estigated in detail. Different methods are applied to the characteriza tion of the effect, e. g. polyelectrolyte titration, adsorption of an anionic dye, or measurement of zeta potential (streaming potential). A ll of these methods can represent the results very well under certain conditions. Polyelectrolyte titration is correlated to the outer layer of the modified material, whereas dye adsorption is sensitive rather to the inner surface region and is very time-dependent. Another signif icant value is the isoelectric point, which is shifted to higher pH in dependence on the quantity of surface charges. The stability of modif ication, tested with different methods, was shown to be very good for water and good for treatment with hydrochloric acid.