Three-dimensional printing of cellulose nanofibers reinforced PHB/PCL/Fe3O4 magneto-responsive shape memory polymer composites with excellent mechanical properties

The combination of shape memory polymer composites and 3D printing technology provides novel opportunities for customized manufacturing and intelligentization of products. Here, we developed magneto-responsive shape memory polymer composites with well-balanced strengths and toughness by adding Fe3O4 and cellulose nanofibers (CNFs) to a poly-hydroxybutyrate/poly(epsilon-caprolactone) blend as functional particles and reinforcing component. The influences of Fe3O4 and CNFs on the properties including micromorphology, and rheological, melting-crystallizational, thermomechanical, static mechanical, and magneto-responsive shape-memory behaviors were investigated. The results displayed that the PHB/PCL (80:20) composites with 10 wt% Fe3O4 and 0.5 wt % CNFs had the optimal comprehensive mechanical and magneto-responsive shape-memory properties. Moreover, 3D printing tests found that the addition of CNFs and printing parameters were crucial for the mechanical and magneto-responsive shape-memory properties of the resulting products. Finally, the fabrication of a scaffold with excellent load-carrying performance and a magneto-responsive self-recovery snowflake demonstrated the application feasibility of our work.