Novel Amine Hardeners Derived from Eugenol for Biobased Epoxy Resins: Synthesis and Multiscale Characterization

Abstract

Fully sustainable biobased thermosets were synthesized using renewable resorcinol diglycidylether (RDGE) as the epoxy precursor, cured with a novel amine hardener. A tetra-amine wassuccessfully synthesized from eugenol by using an oxidative coupling reaction to obtain dieugenol(DE) followed by a thiol-ene reaction. New RDGE/TMDE thermosets were furtherobtained by an epoxy-amine curing process and compared to petro- and bio-based resins developedpreviously by our group. The thermomechanical behavior was investigated by DifferentialScanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and mechanical testing.The glass transition temperature 𝑇 𝑔and the flexural modulus 𝐸 𝐹of the novel resins werecomparable to the benchmark materials, with an attractive fracture toughness 𝐾 𝐼𝐶offer anoutstanding compromise between high stiffness and high fracture toughness properties. 1 𝐻Double Quantum (DQ) and MSE NMR were successfully considered to relate such macroscopicproperties to the inner network morphology and chain mobility at the molecular scale.

Keywords: Eugenol, Biobased phenol, Biobased hardener, Biobased epoxy resin, 1𝐻 DQ NMR, MSE NMR