Quelques aspects du comportement hygromécanique du papier

Some aspects of the hygromechanical behaviour of paper. Paper is mainly made up of cellulosic fibrous materials. On one hand, the nature of the fibres (softwood or hardwood) and on the other hand, their mechanical treatments severely affect the obtained porous structure. The porosity can vary from 1% to 95% according to the aimed end-use properties. Consequently, the mechanical behaviour strongly varies. Indeed, the mechanical resistance is related on the quality of fibres and the bonds between these fibres. Moreover, the mechanical behaviour of the final products is influenced by both the orientation of fibres and moisture. Consequently, it is important to better understand the moisture-induced changes of dimensions and mechanical properties of papers. Experiments were undertaken to this end. Moreover, in order to observe the fibrous microstructure of paper, experiments based on synchrotron microtomography were carried out with the help of the "European Synchrotron Radiation Facility" (ESRF).