Influence of oxygen concentration on the kinetics of cellulose wadding degradation

The kinetics of thermal decomposition of cellulose wadding was investigated from TG–MS experiments. Different oxygen concentrations in the atmosphere and several heating rates were used to study the influence of oxygen concentration on the mass loss of the sample and on the emission of gases. A shift and an amplitude variation of the DTG curves as well as an increase of the emission of gases such as CO and CO2 were observed. Then, a kinetic model was proposed to predict the mass loss of the cellulose wadding. Three stages were considered: the cellulose pyrolysis, the char oxidation and the decomposition of calcium carbonate. For the pyrolysis, the kinetic parameters were expressed according to the partial pressure of oxygen. For the char oxidation, a power law was used to account for the influence of oxygen whereas the other kinetic parameters were considered constant regardless of oxygen concentration. The decomposition of calcium carbonate was modelled by a first order influenced by the pressure of CO2.