High‐Performance, Reprocessable Epoxy Resin From Bio‐Based Precursors for Sustainable Material Applications

ABSTRACT Thermoset polymers are widely used due to their stability, mechanical strength, and chemical resistance; however, their reliance on petroleum sources and limited recyclability resulted in sustainability‐related issues. Bio‐based degradable epoxy esters present an eco‐friendly alternative to traditional thermosets like epoxy resins. Herein, we developed a bio‐derived epoxy resin from the bio‐based units: gallic acid, ethylene glycol, and succinic anhydride. The synthesis of the gallic acid epoxy monomer was optimized, and it was then cured with ethylene glycol bis(succinic acid), which was synthesized via a green approach. The monomers were obtained in moderate to high yields and characterized using spectroscopic techniques. The influence of the epoxy‐to‐curing agent and zinc catalyst ratios on the polymer thermal properties was evaluated. The zinc‐catalyzed epoxy resin demonstrated good thermal stability and re‐processability, exhibited a high gel content, a tensile strength of 18.5 MPa, a crosslink density of 3.41 × 10 −4 mol/cm 3 , and shape memory behavior. The material showed complete degradability within 24 h in a 5% NaOH solution, attributed to the hydrophilic nature of the curing agent and high ester group content. Reprocessing the polymer retained its shape memory properties, although it resulted in a slight decrease in glass transition temperature.