3D printed PLA based bionanocomposites with improved mechanical and dynamic mechanical properties: effect of varying CNC reinforcements

The 3D printing technique for the fabrication of composite components appears to be an emerging and revolutionary method in the manufacturing sector. The present work is dedicated to analyse the effect of varying weight percentages of crystalline nanocellulose (i.e., 0, 1, 3, and 5) on the morphology, crystallinity, and mechanical and dynamical mechanical properties of 3D-printed PLA-based bionanocomposites. The crystalline behaviour and mechanical and dynamical mechanical properties of the bionanocomposites were seen to be significantly improved by the incorporation of cellulose nanocrystals (CNCs). The highest tensile strength and modulus were achieved at 1 wt% CNC reinforcement showing increases of 22.3% and 64.17%, respectively over neat PLA. Similarly, the maximum flexural strength and modulus were also observed at 1 wt% CNC reinforcement. The impact strength of the bionanocomposites was consistently increased with CNC reinforcement and its maximum value (16.92 kJ/m2) was seen for bionanocomposite with 5 wt% CNC reinforcement, which was 53.95% higher than that of neat PLA. A statistical analysis was also performed to analyse significant differences in the mechanical properties among the 3D printed bionanocomposites. DMA analysis revealed significant changes in storage and loss modulus and their highest values were observed at 5 wt% of CNC reinforcement, which was more than the neat PLA by 34.50% and 53.95%, respectively. However, the glass transition temperature of the bionanocomposites remained largely unaffected by the addition of CNCs.