Influences of SO and O on the ageing of paper investigated by 2 3 in situ diffuse reflectance FTIR and time-resolved trace gas analysis

The interactions of SO2and O3with fresh or aged bleached softwood pulp have been investigated using two techniques. The dry deposition of SO2 g. on paper was studied using on-line gas analysis. Diffuse Reflectance Infrared Fourier Transform DRIFT.spectrometry was applied in situ to characterise the paper surface during exposure to the pollutants. The DRIFT technique is shown to be sensitive enough to measure very small changes on the paper surface. The initial reaction on paper subjected to SO2and O3is shown to be the protonation of carboxylate groups present on the fibre, the hydrogen ions being added through the interaction of SO2 with the moisture present in the paper. Results supportive of the protonation are produced by exposure of the aged paper to NH3 g.. The results show that the combination of these techniques has a potential to show the degradation chemistry of paper under ambient conditions. q2000 Elsevier Science B.V. All rights reserved