Whilst the nanocellulose acted as a nucleation agent for PLA crystal growth, the effect of the filler on composite behaviour is masked by the effect of strain-induced chain orientation
during melt-spinning. Strain induced chain orientation due to melt spinning resulted in PLLA fibres with enhanced modulus and strength, the incorporation of 2 wt.% C6-BC into PLA resulted in moderate strength improvement. Filling the PLA above the percolating network threshold of CNC by extrusion followed by meltspinning resulted in even lower draw ratios, whilst these fibres had lower mechanical properties, their strain to failure significantly
increased over fibres filled with 2 wt.% BC and neat PLA fibres. Furthermore we reported a route to produce UD PLLA/CNC fibre reinforced PDLLA, with or without CNCs at percolating thresholds (7 wt.% CNC) via controlled layer-by-layer filament winding and subsequent consolidation. Consolidation was conducted at temperatures sufficient to allow the PDLLA/CNC matrix to flow, wetting the PLLA/CNC composite fibres. We observed improvements in viscoelastic properties of up to 175% in terms of storage modulus in bending. Furthermore strains to failure for PLLA fibre
reinforced PDLLA were recorded to be as high as 17%. This processing route is adaptable for other thermoplastic polymers, and is extendible to stereo-complex PLA reinforced semi-crystalline matrices, with applications at higher temperatures than amorphous PLA.