DETERMINATION OF IONIC GROUPS IN CATIONIC PULPS - COLORIMETRIC ANALYSIS AND POLYELECTROLYTE TITRATION

For cationically modified pulp, which finds more and more interest as a potential paper auxiliary, a new colorimetric method of analysis has been developed permitting the quantitative determination of cationic groups, both on the fibre surface and inside. This technique is based on the known colorimetric method for the determination of carboxylic g roups. As cationic pulps always contain additional negatively charged functions, a model was suggested describing the amphoteric character o f such fibres. Therefore oxidised Linters were cationically modified. By analysing those amphoteric pulps by colorimetric and polyelectrolyt e titration, as well as by their nitrogen content according to Kjeldah l, it was found, that ion - pair salts were formed depending on the ch arge densities. These ion pairs have a considerable influence on the c harge related properties of the fibres.