Adsorption studies of phenolformaldehyde resin onto cellulose fibres

Adsorption of phenolformaldehyde reson (PFR) onto microcrystalline cellulose was investigated as a function of pH, ionic strength, temperature and shear. The effect of adsorption was also studied by measuring the electrophoretic mobility of the cellulose particles. Adsorption was found to occur above a critical ionic strength. Suppression of the electrical double layer and reduce solubility of PFR appear to be necessary to promote adsorption. Increasing the intensity and duration of shear was found to increase the amount of PFR adsorbed. In the presence of high molecular weight poly(ethylene oxide) (PEO), complex formation between PEO and PFR also competes with the interaction between PFR and the cellulose particles. The mobility data indicate that the PFR directly affects the cellulose surface rather than the PEO.