Project leader: Tommy Iversen
Ph.D student: Eva-Lena Hult
STFI
Tel.: +46 8 676 70 00
Fax: +46 8 411 55 18

Fibre chemistry - structure of cellulose and hemicellulose

CONCLUDED

Aim: The aim of the project is to elucidate important relations between structural characteristics of wood cellulose and hemicelluioses and the reactivates and properties of fibre substrates.

Background: Although cellulose is a simple homopolysaccharide. natural celluloses have a solid state architecture with a high degree of individuality, depending on their biological origin and the isolation procedure used. The solid state structure is expected to greatly influence the reactivity and physical properties of cellulosic materials.

Project description: The work is focused on the influence of supramolecular and surface structure of cellulose fibrils and the association to hemicelluloses on pulp and paper properties and accessibility/ reactivity in enzyme-assisted fibre modification strategies.
1 3 C - CP/MAS - NMR - spectroscopy (high resolution solid state NMR) and quantification of the individual cellulose forms by line fitting is a method well suited for investigation of different solid state structures in cellulose substrates. A cluster with a distribution between 86 and 92 ppm contains fairly sharp signals corresponding to C-4 carbons situated in crystalline cellulose l (X and l 0 domains together with paracrystalline cellulose. The C-4 carbons of more disordered regions are distributed in a broad band ranging from 80 to 86 ppm. In the disordered region a pair of signals resolved at 84.0 ppm and 84.9 ppm assigned to surfaces of cellulose fibrils are also visible. This methology allows analyses of the bulk composition of different celluloses and also supplies information about fibril dimensions, e.g. core versus surface structures.

Project group:
Tommy Iversen, STFI
Eva-Lena Hult, STFI
Ants Teder, KTH
Göran Gellerstedt, KTH
Karl Hult, KTH (activity 2)
Mikael Lindström
, STFI (activity 3).
Thomas Nilsson, SLU
Geoffrey Daniel, SLU

Industrial mentors:
Ulla Johansson, Södra
Monika Ek, StoraEnso
Torsten Nilsson, Korsnäs