THERMO-MECHANICAL CHARACTERIZATION OF ACRYLATE/EPOXY DUAL-CURING RESIN SYSTEMS FOR 3D PRINTING APPLICATIONS
Thermosetting materials have attracted significant interest in advanced manufacturing due to their covalently crosslinked structure, which provides high thermal resistance, chemical stability, and excellent mechanical properties, making them suitable for demanding processes such as high-resolution additive manufacturing. In the liquid state, they can be cured by UV radiation in the presence of photoinitiators, enabling processing through photopolymerization. However, they present limitations such as brittleness, excessive rigidity, high viscosity, and volumetric shrinkage during curing, which affect processability and geometric fidelity of printed parts. This thesis addresses the development and characterization of materials through dual curing, combining acrylic and epoxy networks, exploring molecular architectures and functional modifications to optimize rheology, dimensional stability, and mechanical properties in the liquid, intermediate, and fully cured states.
Chapter 1 provides context on vat photopolymerization (VPP), describing materials, curing mechanisms, and inherent limitations. Chapter 2 details characterization methodologies for resins, evaluating thermal, kinetic, mechanical, and geometric properties in different states. Chapter 3 analyzes the effect of the coupling agent on network interactions, curing kinetics, thermal stability, and mechanical performance, proposing protocols to assess shear strength and bonding of parts. Chapter 4 introduces network modification via PEG and MWCNT‑COOH, controlling crosslinking density, expanding the elastic modulus range (3–2500 MPa), maintaining viscosity <35 mPa·s, and improving adhesion and printing resolution. Chapter 5 develops a dual vitrimeric acrylic/epoxy system with controlled transition from a soft state to a robust network via thermal treatment, evaluating annealing and bonding protocols, demonstrating high mechanical performance and potential for sustainable and recyclable applications.
Overall, the thesis provides a rational approach to designing multifunctional materials for 3D printing via photopolymerization, overcoming current limitations in mechanical properties, processability, and structural functionality, and opening opportunities for high-value, sustainable industrial applications.
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