Structure-Property Relationship of Stereolithography Resins Containing Polysiloxane Core-Shell Nanoparticles

Stereolithography (SL) is an additive manufacturing technique for fabricating bulk and delicate objects layer by layer using UV-curable resin. However, epoxy-based photocurable resins used in SL printers are commonly brittle due to the high cross-linking density, thus restricting the widespread adoption of SL. In an effort to overcome this drawback, this paper details an approach of toughening the resulting workpieces by incorporating polysiloxane core-shell nanoparticles (SCSP) into an epoxy-based, photocurable formulation. This approach attempted to attain both thermal stabilities and transparency qualities comparable to that of resin without SCSP. This work systematically analyzed how the shell thickness of the SCSP impacted the final properties of the printed product. Introducing 5% w/w SCSP with a diameter of approximately 132 nm into the resin improved strain at break measured by tensile and flexural tests by 745.5 and 248.6%, respectively, and increased the fracture toughness by 166.3%. Owing to the advantages of toughness, thermal stabilities, transparency, and high accuracy of epoxy-based photocurable resin with SCSP, the 3D printing nanocomposite developed here is capable of preparing a poly(methyl methacrylate) (PMMA)-like workpiece with a commercial SL 3D printer. These results may expand the scope of the application of 3D printing in a wide variety of industries.