Reversible Thixotropic Rheological Properties of Graphene-Incorporated Epoxy Inks for Self-Standing 3D Printing

Area of Science:

• Materials Science
• Additive Manufacturing
• Nanotechnology

Background:

• Three-dimensional (3D) printing requires high-performance materials for load-bearing applications.
• Thixotropic materials offer advantages in 3D printing due to their flow and self-standing properties.
• Graphene nanosheets possess unique properties that can enhance material performance.

Purpose of the Study:

• To develop a thermally curable, graphene-incorporated epoxy ink with thixotropic characteristics.
• To investigate the shear-thinning behavior and upright standing capability of the composite ink.
• To demonstrate the potential of this ink for high-resolution 3D printing of defect-free structures.

Main Methods:

• Formulation of a graphene-incorporated epoxy ink system.
• Characterization of rheological properties, including static yield stress and viscoelasticity.
• Evaluation of the ink's performance in continuous filament 3D printing.
• Post-printing thermal curing and structural integrity analysis.

Main Results:

• The developed ink exhibits significant shear-thinning behavior and high static yield stress (~1,680 Pa).
• A reversible liquid-to-solid phase transition was observed, enabling upright standing capability.
• Continuous filament printing of 10 stacked layers was achieved without filament spreading.
• The 3D-printed structures showed robust integrity, free from weld lines and voids after thermal curing.

Conclusions:

• The graphene-incorporated epoxy ink demonstrates excellent thixotropic properties suitable for advanced 3D printing.
• The material's characteristics facilitate the creation of complex, defect-free layered structures.
• This ink system holds significant potential for diverse applications requiring high-performance 3D printed components.