Pulp fiber nanostructure

The fiber wall is a heterogeneous nanocomposite comprised of cellulose fibrils in a matrix of lignin and hemicellulose. When wood is subjected to chemical treatments, the reactions take place within this nanocomposite. How process conditions affect the structure of the composite is not known, as we lack methods to characterize the fiber wall on a nanoscale. The nanostructure of the fiber wall is important as it in many cases determines the properties such as the fiber strength or accessibility of chemicals. If the pulping processes are studied by using x-ray scattering techniques, it will be possible to modify the parameters in unit processes in such a way that pulp fibers with a more accessible fiber wall are obtained, improving for example the bleachability or the dissolution of cellulose. A deeper understanding of how processes affect the fiber wall also opens up the possibility to tailor-make pulps for entirely new applications.

Tomas Larsson has developed a method to measure the nanostructure of the fiber wall using small angle x-ray scattering, SAXS. Combining that with the well-established NMR technique for cellulose characterization enables us to get a better understanding of the fiber wall nanostructure.

PhD student Cláudia Esteves