Modelling considerations for the degradation of cellulosic paper

The aim of this research was to design a model for simulating the degradation of paper in various environmental conditions by taking into consideration all the parameters (exogenous and endogenous) that influence the overall process of the acid catalyzed hydrolysis of cellulose. Three kinetic equations (Ekenstam, Calvini, and Ding and Wang) for determining the degradation rate coefficient (k) were compared. For this purpose, previously published and new experimental data on the degradation of pure and unsized cotton linter papers (neutral and acidic) upon ageing were used. The frequency factor parameter (A) in the Arrhenius formula was adjusted with additional input factors in the expression of A proposed by Zou et al. (Cellulose 3:243–267, 1996a). The model takes into account the increase of the acidity and the decrease of the moisture content induced during paper degradation. Besides the temperature and humidity, external gaseous pollutants (NO2, formic and acetic acids) were also taken into account as degradation factors. The model can be used to simulate cellulose depolymerisation of cotton papers exposed to single pollutants, but reached a limit for simulating with confidence the degradation of papers exposed simultaneously to multiple volatile compounds, due to the lack of available data, especially concerning certain volatile compounds counter-degradation effects. Future adjustments can be done when more experimental data becomes available.