Adaptable Phosphate Networks towards Robust, Reprocessable, Weldable, and Alertable-Yet-Extinguishable Epoxy Vitrimer

Area of Science:

• Polymer Science
• Materials Science
• Chemical Engineering

Background:

• Covalent adaptable networks (CANs) offer a blend of thermoplastic reprocessability and thermoset covalent crosslinking.
• Achieving simultaneous reversibility and mechanical robustness in CANs remains a significant challenge.

Purpose of the Study:

• To develop novel epoxy vitrimers (EVs) with adaptable phosphate networks (APNs).
• To investigate the mechanical properties, reprocessability, and fire safety of these new EVs.

Main Methods:

• Synthesis of epoxy vitrimers incorporating adaptable phosphate networks.
• Characterization of mechanical properties (tensile strength, modulus) under ambient conditions.
• Evaluation of thermal behavior, shape memory performance, self-healing, reprocessing, welding, and flame retardancy at elevated temperatures.

Main Results:

• The developed EVs exhibit promising mechanical properties (tensile strength: 62.5–87.8 MPa; modulus: 1360.1–2975.3 MPa).
• Phosphate transesterification enables topology rearrangement for shape memory, self-healing, reprocessing, and welding.
• Incorporation of APNs enhances anti-ignition, reducing heat release and smoke generation for improved fire safety.
• Reprocessed EVs retain thermal, mechanical, and flame-retardant properties comparable to original materials.

Conclusions:

• Novel epoxy vitrimers with adaptable phosphate networks demonstrate a unique combination of mechanical robustness and reprocessability.
• These materials possess intrinsic fire safety, making them suitable for demanding applications.
• The developed EVs are successfully manufactured into flame-triggered switches, showcasing their potential in fire alarm systems.