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 °C. PLA fibres were produced with an average diameter of 11 (±0.9) μm via a melt-drawing process at 180 °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 ∼82 MPa and modulus ∼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.

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