Properties of poly(lactic acid)/walnut shell/hydroxyapatite composites prepared with fused deposition modeling

In this work, fused deposition modeling (FDM) technology was used to prepare poly(lactic acid)/walnut shell/hydroxyapatite (PLA/WS/HA) composite filaments. HA was treated with silane and characterized by Fourier transform infrared spectroscopy (FTIR). The composites were investigated by using simultaneous thermal analyzer, scanning electron microscopy (SEM) and a universal mechanical testing machine. The results showed that incorporating either HA or WS improved the thermal stability and water absorption of PLA, but lowered the tensile and compression strength. Fillers toughened the PLA matrix, resulting in higher tensile elongation and compressive strain. The tensile and compressive strengths of samples significantly dropped after water-immersion for 6 weeks. Finally, scaffolds were manufactured by using FDM. The compression modulus and structural feature of scaffolds indicated that the PLA/WS/HA composites have the potential to be applied in structural parts, such as bone implants.