Enhancing the mechanical properties of biodegradable PLLA/PBAT blends for 3D filament via one-pot synthesized CNCs-PVAc powder

The combination of polymer blends and nanofillers is an effective strategy for creating high-performance polymer alloys with a hierarchical structure. Herein, a one-pot synthesized polyvinyl acetate-modified cellulose nanocrystal (CNCs-PVAc) powder was used, without removing the ungrafted homopolymer, to enhance the properties of a poly (L-lactic acid) (PLLA)/poly (butylene adipate-co-terephthalate) (PBAT) blend for 3D filament via a simple melt-extrusion process. Compared with neat PVAc-grafted CNCs (CNCs-g-PVAc), it was found that the presence of ungrafted PVAc homopolymer is helpful for promoting the dispersion of CNCs in the PLLA/PBAT blend, leading to an improvement in both strength and toughness, as well as a decrease in the domain size of the PBAT disperse phase. Notably, the synergism of CNCs-PVAc and strong shear action in fused deposition modeling (FDM) resulted in the formation of highly oriented PBAT nanofibers in PLLA/PBAT/CNCs-PVAc nanocomposites, thereby contributing to the strength-toughness balance of 3D print objects. The tensile breaking energy and notch impact strength (90 degrees infilled) of the prepared 3D print objects were enhanced by 896% and 969%, respectively, compared with pure PLLA. Additionally, the designed nanocomposites exhibit outstanding biodegradability, biocompatibility, and shape-memory properties, making them suitable for medical vascular clips and strongtoughness load-bearing frames.

Automated summary

The combination of polymer blends and nanofillers is an effective strategy for creating high-performance polymer alloys. In this study, a one-pot synthesized polyvinyl acetate-modified cellulose nanocrystal (CNCs-PVAc) powder was used to enhance the properties of a PLLA/PBAT blend for 3D filament. The presence of ungrafted PVAc homopolymer improved the dispersion of CNCs in the blend and resulted in an improvement in strength and toughness. Additionally, the nanocomposites showed excellent biodegradability, biocompatibility, and shape-memory properties.