Cellulose fibrils in wood cell walls and their potential for technical applications

Hamburg

2007

S. 137-151

10 Abb., zahlr. Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200151619

Electron and atomic force microscopy were used to investigate the arrangement of cellulose fibril agglomerates in fractured (partly chemically pre-treated), embedded and microtomed or polished Norway spruce blocks. The ultrastructural appearance changes considerably depending on the applied sample processing and microscopy method. Even slight changes in cell wall constitution markedly influence the interactions of the cell wall components and thus fracture mechanics and ultrastructural appearance of wood cell wall cross sections. The capability of the nano-scaled cellulose fibril agglomerates for reinforcing polymers was studied in a second, more applied part of the study. For this purpose, fibrils with diameters below 100 nanometers and lengths of several tens of micrometers were isolated from a commercial softwood sulphite pulp. Homogeneous, translucent fibril films and polymer composites with hydroxypropyl cellulose were prepared. For mechanical characterisation tensile tests were carried out. The addition of fibrils led to an up to threefold higher Modulus of Elasticity (MOE) and an up to fivefold higher tensile strength of the polymers. From the results, cellulose fibrils could have great potential in many applications including coatings, adhesives, medicine, packaging and transportation.