Experimental study demonstrates closed-loop chemical recycling in high-performance 1,3,5-triazine epoxy thermosets, highlighting a viable pathway toward sustainable industrial polymers.
Key Points
Develop a high-performance, chemically recyclable epoxy thermoset utilizing nucleophilic aromatic substitution without sacrificing thermal and mechanical robustness.
Synthesized a cross-linked thermoset under bulk conditions using the trifunctional epoxy monomer TOMTA and secondary aromatic diamine hardener MBMA.
Conducted network depolymerization using an optimized binary K2CO3/TBD catalyst system in ethanol, followed by liquid-liquid extraction.
Characterized thermomechanical properties, evaluated recyclability across multiple closed-loop cycles, and demonstrated application as a debondable glass coating.
The synthesized thermoset exhibited a glass transition temperature (Tg) of 105°C, thermal degradation temperature (Td5%) of 256°C, Young's modulus of 3.0 GPa, and tensile strength of 96 MPa.
Catalyzed depolymerization recovered building blocks TETA and tetraol BDHPPM in 70% and 65% yields, respectively.
Re-crosslinking the recovered monomers fully regenerated the thermoset network with nearly identical mechanical properties across repeated recycling cycles.