The role of mild TEMPO–NaBr–NaClO oxidation on the wet adhesion of regenerated cellulose membranes with polyvinylamine

X-ray Photoelectron Spectroscopy (XPS) was used to characterize the functional groups present on regenerated cellulose films after mild oxidation with TEMPO–NaBr–NaClO and the results were correlated with the adhesion forces holding together two wet cellulose films laminated with a thin (i.e. less than 10 mg/m2) layer of polyvinylamine (PVAm). There was no correlation between adhesion and carboxyl content, whereas wet adhesion was proportional to the total content of aldehyde and hemiacetal groups on the cellulose. It is proposed that aldehyde groups react with neighboring cellulose chains to form hemiacetals which serve as crosslinks strengthening the cellulose surface. The hemiacetals can also be attacked by primary amines to give imine and aminal covalent linkages to the PVAm adhesive layer.