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Developing high-performance polymers in a sustainable and simple manner while efficiently converting renewable resources is extremely challenging. In this study, three different diamine (aliphatic, cyclic, and aromatic) derived curing agents with dynamic imine covalent bond were successfully synthesized using vanillin and their chemical structures were validated by FTIR, GCMS and NMR spectroscopy. Further, curing behavior, mechanical and thermal properties of the resulting epoxy thermosets were investigated by DSC, tensile analysis, TGA, and DMA. The curing response of aliphatic amine-derived epoxy polymer shows significantly higher but lower flexural strength (∼37 %), flexural modulus (∼53 %), T g (∼52 %), storage modulus (∼8 %), T d5 % (∼4.5 %), and Char 700 (∼54 %) properties due to the steric-hindrance of aromatic and cyclic rings in the molecular structures. Moreover, these epoxy thermosets can be reprocessed, and repaired several times without losing their mechanical and thermal properties due to incorporate dynamic imine bond into their molecular structures. Notably, the pendant backbone-chain in curing agents significantly influences the dynamic manners of the cured thermosets and aliphatic-chain exhibits the quickest stress relaxation performance. Finally, all cured products showed excellent chemical stability in various solvents. These remarkable findings offer important clues for comprehending the structure-property link of recyclable epoxy thermosets with different amine-derivatives. • Three different diamines (aliphatic, cyclic, and aromatic) derived curing agents with dynamic imine bond were synthesized from biomass resources. • Curing response of aliphatic amine-derived epoxy polymer shows significantly higher, however lower mechanical and thermal properties due to the steric-hindrance of aromatic and cyclic rings in molecular structures. • Developed thermosets can be reprocessed and repaired several times without losing their mechanical and thermal properties.
Rashid et al. (Sat,) studied this question.