Synthesis of a bio-based and intrinsically anti-flammable epoxy thermoset and the application of its carbonized foam as an efficient CO2 capture adsorbent

The production of multifunctional carbon foams from biomass has attracted great interest due to the increasing awareness of green and sustainable development. Here, we report a bio-based epoxy thermoset prepared by curing a furan-derived di-functional epoxy monomer (5-hydroxymethyl-2-furaldehyde (HMF)-3, 5-diamino-1,2,4-triazole (GU)-EP) with a furan-derived curing agent, 5,5′-methylenedifurfurylamine (DFA). For comparison, the cured commercial diglycidyl ether of bisphenol-A was used as a thermoset epoxy resin. Due to its unique structure rich in aromatic and nitrogenous structures, the cured HMF-GU-EP/DFA thermoset possessed exceptional charring ability. This fully bio-based epoxy thermoset had a very high char yield (55.8 wt%) at 800 °C under nitrogen, while the cured diglycidyl ether of bisphenol-A/4, 4′-diaminodiphenylmethane was only 13.6 wt%. Due to this excellent carbonization ability, the cured HMF-GU-EP/DFA was carbonized at 700 °C to obtain a carbon foam as a CO2 absorbent. The Brunauer–Emmett–Teller surface area and total pore volume were measured to be 472 m2/g and 0.22 cm3/g, respectively. The amounts of CO2 adsorbed with this carbon foam were 4.72 and 2.15 mmol/g at 273 and 298 K, respectively. In conclusion, this study provides a bio-based, strong and rigid, inherently flammable, and highly carbonizable epoxy thermoset and the potential application of its carbonized foam as an efficient adsorbent for CO2 capture.