Optimization of Nano-Silicon Nitride Content in Acrylonitrile Styrene Acrylate for Material Extrusion 3D Printing: Engineering Response Metrics

Abstract Herein, the motivation was to introduce new nanocomposites for the material extrusion (MEX) 3D printing method with enhanced mechanical properties for the production of more robust parts, increasing the method’s functionality. The efficacy of the silicon nitride (Si ₃ N ₄ ) ceramic was examined, as a nanoparticle form filler in the acrylonitrile styrene acrylate (ASA) polymer. The ASA matrix and Si ₃ N ₄ filler were melt-extruded into filaments, to fabricate 3D-printed specimens in accordance with international standards. These were subjected to various mechanical tests and advanced characterizations including Raman spectroscopy, SEM, TGA, dimensional accuracy analysis, and rheological evaluation. The tensile strength was enhanced, achieving a maximum (43.4 MPa) improvement of 11.6 at 4% Si ₃ N ₄ content, compared to pure ASA. The flexural strength exhibited a similar trend, peaking at 74.8 MPa with 2% filler content. Furthermore, dimensional accuracy was enhanced (238.9 μm at 4% Si ₃ N ₄ ). The porosity also decreased to its lowest value of 0.83% at the same filler concentration, indicating improved structural uniformity. The thermal stability of the ASA polymer was not affected by the introduction of the Si ₃ N ₄ nanoparticles, while the MFR was significantly increased, especially in low nanoparticle content. Furthermore, the Raman lines of ASA pure were differentiated in intensity. Beyond these optimal filler levels, the mechanical performance declined due to filler agglomeration, introducing stress concentration and defects. These findings provide valuable insights into the potential of ASA/Si ₃ N ₄ nanocomposites for 3D printing applications, offering a balanced combination of improved mechanical properties and manufacturing precision. Graphical Abstract