Impact of Limonene Dioxide Incorporation Into DGEBA Epoxy Resins: Effect on Thermal, Rheological, Mechanical, and Dynamic Mechanical Properties

ABSTRACT This study investigates the incorporation of limonene dioxide (LDO), a bio‐based epoxide, into bisphenol A diglycidyl ether (DGEBA) epoxy resins and its effect on the thermal, rheological, mechanical, and dynamic mechanical properties of the resulting resin. Six formulations with increasing LDO content (0–100 wt%) were prepared and cured using methyltetrahydrophthalic anhydride. Differential scanning calorimetry revealed a decrease in the glass transition temperature ( T g ) from 106°C (neat DGEBA) to 86°C (neat LDO), while dynamic mechanical analysis showed a slight increase in T g from 107°C to 115°C. Viscosity decreased significantly with LDO addition, from 1515 to 71 mPa s, and gel time increased from 11 to 40 min. Mechanical properties such as shore D hardness and elastic modulus also decreased for higher LDO content, along with crosslinking density and gel content. Thermogravimetric analysis indicated lower thermal stability for LDO‐rich systems. Despite that, blends containing up to 40–60 wt% LDO maintained favorable performance while improving processability and renewable carbon content. These findings demonstrate the potential of LDO as a sustainable modifier for designing epoxy systems with tunable properties and lower environmental impact.