Liquid Deposition Modeling of Biobased Epoxy Composites: Natural Fillers as Rheology Modifiers and Reinforcements

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Developing sustainable composite pastes for 3D printing is crucial for advanced manufacturing.
• Cardanol-based epoxy resins offer a renewable alternative for composite development.
• Tuning rheological properties is essential for successful liquid deposition modeling (LDM) 3D printing.

Purpose of the Study:

• To investigate the rheological properties of cardanol-based epoxy composites for LDM 3D printing.
• To evaluate the effects of microcrystalline cellulose (MCC), microfibrillated cellulose (MFC), and nanoclay (MMT) as fillers.
• To optimize composite formulations for enhanced printability and mechanical performance.

Main Methods:

• Incorporation of MCC, MFC, and MMT into a cardanol-based epoxy resin.
• Rheological characterization using the Herschel-Bulkley model to determine key parameters (yield stress, consistency index, flow behavior index).
• Analysis of thermal cross-linking via ATR-FTIR and DSC; mechanical testing (tensile modulus and strength).

Main Results:

• Fillers induced shear-thinning behavior and solid-like to liquid-like transitions, crucial for LDM.
• MFC enhanced rheology and mechanics but caused shrinkage; partial substitution with MCC improved viscosity and shear thinning.
• An optimized formulation (22 vol% MCC, 1 vol% MFC) demonstrated excellent printability and post-curing mechanical properties (tensile modulus 5.34 MPa, strength 1.31 MPa).

Conclusions:

• Biomass-based fillers effectively tune the rheology of cardanol-based epoxy composites for LDM 3D printing.
• Partial substitution of MCC with MFC is a promising strategy for balancing printability and mechanical reinforcement.
• The optimized composite formulation shows significant potential for sustainable additive manufacturing applications.