Multi‐Scale Investigation of Bio‐Based Epoxy–Polyether Networks: From Monomer Synthesis to Resin Structure–Property Relationships

In this present investigation, epoxy polyether resins with tunable properties have been obtained. These epoxy polyether molecules were synthesized using resorcinol ( R ), a phenolic building block, as well as biobased polyols such as glycerol ( G ) and hexanediol ( H ). The obtained functional monomers were then cured with hexamethylenediamine ( HMDA ) to yield fully crosslinked epoxy polyether resins. The structures of such functional monomers were investigated by liquid‐state NMR 1 H, 13 C, and HSQC in order to better understand the structure. The epoxy equivalent weight (EEW) was also determined for resin formulation while the thermomechanical properties for cured resins were determined using different analytical methods such as dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), three‐point bending, and tenacity. Finally, Time Domain 1 H Double Quantum (DQ) NMR was used to yield a better insight into the network morphology of the epoxy polyether resins. It was found that these resins possess comparable thermomechanical properties with their industrial counterparts with flexural modulus reaching up to 3.5 GPa and flexural strength up to 134 MPa. The glass transition temperatures T g of these resins range from 40 to 70 °C, and it was found that the polyols work as “’spacers”’ rendering the material more flexible and therefore decreasing its T g when compared to industrial epoxy resins.