3D printing with biobased epoxidized formulations based on vegetable oils with dynamic polymer network properties

Abstract

In this work, we developed and characterized bio-based formulations derived from functionalized vegetable oils, aiming to create sustainable resins suitable for 3D printing with dynamic polymer network (DPN) properties. Epoxidized castor oil (ECO), known for its inherent DPN behaviour due to the presence of hydroxyl groups enabling transesterification, was used as the primary component. However, its high viscosity at room temperature limits its printability. To address this, epoxidized soybean oil (ESO), a less viscous and equally bio-based alternative, was blended with ECO in varying weight ratios: 100% ECO, 100% ESO, ECO–ESO 70–30, and ECO–ESO 50–50. UV-curing characterization of the prepared formulations was performed through FTIR and photo-DSC. Their thermal and mechanical properties were investigated through DMTA and tensile tests, while rheological analyses were conducted to assess their printability. DPN behaviour was evaluated via stress relaxation tests in the presence of a bio-based transesterification catalyst, eugenol-based phosphate ester (EUGP). Among the blends, the ECO–ESO 70–30 formulation retained good DPN dynamics, while in the 50–50 blend, this feature decreased due to the lack of hydroxyl groups in ESO. The DPN systems demonstrated successful 3D printability and were proven to be thermally reprocessable. This work highlights the potential of renewable, plant-oil-based materials in advancing circular and sustainable additive manufacturing technologies.