Atomic force microscopy characterization of the ageing of pure cellulose paper

Atomic force microscopy was used to characterize the effects of chemical reactions induced by accelerated ageing in a climatic chamber (80 degrees C, R.H. 65%) on Whatman no. 1 chromatography paper surface, in order to study ageing consequences on sub-micron structures in cellulose. Evaluation was carried out by means of a comparison of topographic data with chemical characterization, in addition to spectrophotometric measurement in the UV-vis-NIR range. Imaging of samples at several treatment stages showed a non-homogeneous decomposition of the fibre surface into fibril bunches. Over paper sheet surfaces, occurrence of this phenomenon increases with ageing. Spectrophotometry measurements showed a strong variation of contributions in the UV-vis bands, both in the yellow chromophores region and in the carbonyl formation region, which was consistent with the hypothesis that a predominant oxidation mechanism is involved. (c) 2005 Elsevier Ltd. All rights reserved.