One-pot interpenetrating epoxy thermosets from renewable dual biomass to high performance

The 5-hydroxymethylfurfural, honokiol, and magnolol are converted into sustainable epoxy monomers, i.e., 5,5′-(((3′,5-diallyl-[1,1′-biphenyl]-2,4′-diyl)bis(oxy))bis- (methyl-ene))bis(2-((oxiran-2-ylmethoxy)methyl)furan) (MGHF) and 5,5′-(((5,5′-diallyl-[1,1′-biphenyl]-2,2′-diyl)bis(oxy))bis(methylene))bis(2-((oxiran-2-ylmethoxy)- methyl)furan) (MGMF), and they are finally cured by 3,3′-diamino diphenylsulfone (33DDS) and 4,4′-diamino diphenylsulfone (44DDS), thus affording novel interpenetrating polymer networks (IPN). Interestingly, 33DDS induces a twist-stacked structure, whereas 44DDS provides a planar weave matrix. As to the twist-stacked layout MGMF/33DDS, it behaves a superhigh storage modulus (∼5.04 GPa), a high phase transition temperature (T_g, 222.7 °C), and an elevated onset temperature (T_d5, 362.8 °C). For planar weave arrays, MGHF/44DDS shows the highest values in T_g (224.9 °C), lap shear strength (∼20.4 MPa), hardness (∼508 MPa), and reduced Young's modulus (∼6.06 GPa). Furthermore, MGMF/44DDS shows an excellent dielectric property (11.15, 0.02) (∼1 kHz, 25 °C) and a moderate thermal conductivity (0.355 W (m·K)⁻¹) alonging with increased flame retardancy. Besides, those biobased epoxy resin wastes are reclaimable through aerobic or anaerobic pyrolysis. Anaerobic pyrolysis of planar weave networks selectively yields more doped graphene, whereas similar event readily happens to the aerobic pyrolysis of the twist-stacked polymers. In view of these reported advantages, this novel strategy opens new avenues for multifunctional epoxy resins.