Controlled surface modification of cellulose fibers by amino derivatives using N,N′-carbonyldiimidazole as activator

Surface grafting of different amino derivatives was carried on under mild condition using N,N′-carbonyldiimidazole (CDI) as an activator. The action of a diamine or a triamine on previously activated cellulose fibres proceeds by the reaction of one amine function giving rise to a carbamate derivative. The other terminal amino groups remained available for further reaction. In particular, their activation with CDI generates a reactive carboxamide able to condense with an aliphatic amine through a urea linkage. Evidence for the occurrence of the reaction at each modification step was confirmed by Fourier Transform Infrared Spectroscopy (FTIRS) and X-ray photoelectron spectroscopy (XPS). The contact angle measurement, using water as a probe, was used to explore the evolution of the surface wettability for the different modification sequences. It was shown that the contact angle value is determined by the ratio between polar and methylene groups and by the spatial arrangement of the molecule on the surface.