Mechanical behavior of recycled fibers.

By nowadays, the environmental policy is important: the deforestation or the stress on the wood market contribute to the increased interest to improve the recovered rate in papers. Particularly, high value papers constitute a specific target due to their high amount of virgin fibers.

The aim of this work was to characterize the modifications of morphological and physical properties occurring during drying and rewetting cycles. To reach this aim, experimental techniques have been revisited or developed like the inverse size exclusion chromatography, the atomic force microscopy, the environmental scanning electron microscopy and the micro-tomography.This experimental study showed that the main morphological changes occur during the first cycle.

Furthermore, delamination and densification of cell wall fibres were highlighted. Evolutions of the mechanical behavior of handsheets and their 3D structures were analyzed in function of the proportion and quality (number of cycles) of fibers.

Microtomographs of handsheets produced from never dried (left)and ten times recycled (right) pulps

Researcher

Dr Imtiaz