Innovative Castor Oil Derivative Synthesized through a Sustainable Approach Generating Reactive Cross-Linker from...

Additive manufacturing utilizes various reactive precursors to fabricate diverse products, including prototypes, functional components, and designer objects. This work presents a synthesis approach toward a novel biobased printable compound, 2-hydroxypropyl ricinoleate dimethacrylate (2-HPRDM). Our proposed strategy involves the castor oil transesterification process, producing 2-hydroxypropyl ricinoleate (2-HPR). We used high-performance liquid chromatography (HPLC) analysis to investigate the reaction progress at equimolar and excess reactant concentrations. This fatty acid ester was modified with methacrylic anhydride to form 2-HPRDM, releasing the secondary reaction product methacrylic acid (MA). This compound was used for the synthesis of propylene glycol dimethacrylate (PGDMA), which valorized all potential wastes generated during the 2-HPRDM production. This article presents the innovative vacuum-distillation esterification approach that generates PGDMA. All synthesized compounds were structurally characterized via NMR, ESI-MS, and FTIR analyses. The formed curable compounds were fabricated into testing specimens and a detailed prototype by an mSLA three-dimensional (3D) printer to confirm their usability. The 3D-printed object was used for the mechanical and thermomechanical characterization of the formulated curable resins via dynamic mechanical analysis (DMA), tensile, and flexural tests. The best-performing 2-HPRDM-based system contained 45 wt % of PGDMA and recorded a storage modulus of 750 MPa, a glass-transition temperature of 85.6 °C, a cross-linking density of 18.9 kmol/m³, a tensile strength of 16.1 ± 2.4 MPa, and a flexural strength of 14.3 ± 1.0 MPa.