The effect of cellulose nanowhiskers on the flexural properties of self-reinforced polylactic acid composites

Self-reinforced polylactic acid (SR PLA) composites incorporating cellulose nanowhiskers (CNWs) were produced by coating orientated PLA fibres with a polyvinyl acetate (PVAc)-CNW mixture as a binder prior to hot compaction at 95 degrees C. PLA fibres were produced with an average diameter of 11 (+/- 0.9) mu m via a melt-drawing process at 180 degrees C. Scanning electron microscopy (SEM) images revealed that the CNWs imparted roughness to the PLA fibre surface. Cross-sectional examination of the SR PLA composites after hot-pressing confirmed that the PLA fibres had maintained their morphology. Incorporation of 8 wt% CNWs within the SR-PLA composites revealed an increase in their flexural strength (48%) and modulus (39%) compared to the control composite (flexural strength similar to 82 MPa and modulus similar to 3.9 GPa). In addition, whilst the control SR-PLA composite revealed quite brittle characteristics, the addition of CNWs and PVAc gave the self-reinforced composite a more ductile behaviour. (C) 2014 Elsevier B.V. All rights reserved.