Radiation shielding, mechanical and structural properties of TiO₂-Doped photopolymer composites fabricated via DLP 3D...

This study investigated the structural, physical, and radiation shielding properties of TiO₂-doped photopolymer composites fabricated via Digital Light Processing (DLP) 3D printing. Leveraging the high resolution and design flexibility of DLP, TiO₂, a high-Z and non-toxic ceramic, was incorporated into a polyurethane acrylate resin at concentrations of 0 %, 0.020 %, 0.062 %, and 0.180 %. The composites were characterized by SEM, FTIR, XRD, TG-DTG, mechanical testing, contact angle and chemical resistance analyses. Results showed that TiO₂ enhanced compressive strength at higher concentrations, though tensile ductility decreased due to the rigidifying effect of the additive. Contact angle studies confirmed superhydrophobic behavior (contact angles >170°) for all composites, with the highest hydrophobicity at the maximum TiO₂ content. Furthermore, chemical resistance evaluations revealed excellent stability against acidic, basic, and aromatic medium. Gamma shielding performance was systematically assessed using NaI(Tl) detectors and multiple gamma sources. As a result of the measurements, Linear Attenuation Coefficient (LAC), which is the amount of absorption per unit thickness, Mass Attenuation Coefficient (MAC), Half and Tenth Value Layers (HVL)(TVL), and Mean Free Path (MFP) parameters were calculated. According to the MAC results, the MAC value increased to 0.0605 cm²/g for the pure resin at 81 keV gamma energy and to 0.0748 cm²/g when the TiO₂ content was increased by 0.180 %. As can be seen from these results, the increase in TiO₂ positively impacted radiation shielding properties. Overall, this study demonstrates the applicability of DLP 3D printing to design advanced polymer-based composites with structural, surface, and shielding properties specifically designed for next-generation protective systems.