Effect of different forms of SiO2 nanoparticles on the performance of 3D-printed Poly(lactic acid) composites

Poly(lactic acid) (PLA)-based composites incorporated with silicon dioxide (SiO₂) nanoparticles are widely used in medical, aviation, automotive and other fields due to their excellent mechanical, antibacterial and biocompatibility properties. However, current research has primarily focused on the influence of a single type of SiO₂ nanoparticle at varying concentrations, and there is limited research on how the size and shape of hydrophobic SiO₂ nanoparticles affect the properties of PLA matrix. Here, this study prepares PLA/SiO₂ nanoparticle composites using hydrophobically modified SiO₂ nanoparticles of different sizes and shapes and investigates the effect of nanoparticle size and shape on composites. Mechanical and thermodynamic tests results show that the addition of SiO₂ nanoparticles can significantly improve the mechanical properties and thermal stability of PLA composites, which can be explained by the contribution of nanoparticle dispersion, interfacial interaction and particle morphology. Scanning electron microscopy images of the tensile fracture surfaces further verify the effect of different forms of SiO₂ nanoparticles on PLA matrix, offering valuable guidance for the design and optimization of composites in practical applications.