A versatile filler in polyhydroxyalcanoates filaments for FDM: A diverse panorama for pullulan application

Abstract Continuous advances in 3D printing technology, associated with the development of sustainable materials, have driven the manufacture of new biofilaments compatible with numerous applications, such as automotive, robotics, food, and biomedical. In this work, sustainable filaments of PHB and PHBV filled with 5 wt% of pullulan were prepared, and its chemical, thermal, and morphological properties, crystallinity, 3D printing capability, and cytotoxicity were evaluated. Two PHBV samples were compared with different valerate concentrations: 6 and 8 wt%. Raman and FTIR results indicated that pullulan altered the polymeric chain organization, impacting the polymer crystallinity as corroborated by DSC analysis. The composites showed higher heat resistance in the range of 5–30% of mass loss, and all samples showed adequate thermal stability for fused deposition modeling (FDM) processing. pullulan increased the PHB and PHBVs crystallinity due to the nucleation effect and shifted melting temperatures to lower temperatures due to the dispersed phase/matrix interface. While PHB composites showed an irregular surface with large agglomerates, PHBVs composites showed good dispersion and filler/matrix interaction, which slightly impacted the filaments diameters, but classified these materials as a potential for 3D filaments printing. PHBV filaments were printed into biomedical scaffolds, and the results indicated the influence of valerate and filler dispersion, in which 8 wt% valerate is the adequate concentration for 3D printing. The printed scaffolds represent a novel biocomposite to the tissue regeneration field, confirmed by the cell viability values above 80%, being appropriate for biomedical and other 3D printing applications.