Structure and properties of a pulp fibre-reinforced composite with regenerated cellulose matrix

Fully bio-based cellulose-cellulose composites were produced by partly dissolving beech pulp fibres in lithium chloride/dimethylacetamide (LiCl/DMAc) and subsequent regeneration of matrix cellulose in the presence of undissolved fibres. Compared to cellulose-epoxy composites produced from the same fibres, a two-fold increase in tensile strength and elastic modulus was observed for cellulose-cellulose composites. From scanning electron microscopy and nanoindentation it is concluded that changes in the fibre cell wall during LiCl/DMAc treatment, improved matrix properties of regenerated cellulose compared to epoxy, and improved fibre-matrix adhesion are responsible for the superior properties of cellulose-cellulose composites.