Fully biobased epoxy resin systems composed of a vanillin-derived epoxy resin and renewable phenolic hardeners

Abstract A new bio-based epoxy resin (DGEDVCP) was synthesized by the glycidylation of 2,5-bis(4-hydroxy-3-methoxybenzylidene)cyclopentanone (DVCP) prepared by the crossed-aldol condensation of vanillin and cyclopentanone. The thermal and mechanical properties of DGEDVCP resins cured with renewable quercetin (QC) and guaiacol novolac (GCN) in addition to a petroleum-based phenol novolac (PN) were compared with those of bisphenol A diglycidyl ether (DGEBA) resins cured with QC, GCN and PN. Regarding the hardeners used for curing, the higher order of loss modulus (E″) peak temperature of cured products was QC > PN > GCN. The E″ peak temperatures of DGEDVCP/GCN and DGEDVCP/PN cured products were higher than and comparable to those of DGEBA/GCN and DGEBA/PN cured products, respectively. Thermal degradation temperatures of DGEDVCP-based products were slightly lower than those of DGEBA-based products. Char yields at 500 °C for DGEDVCP-based products were much higher than those of DGEBA-based products. The flexural strengths and moduli of the DGEDVCP/QC and DGEDVCP/GCN cured products were comparable to those of DGEBA/QC and DGEBA/GCN cured products, respectively.