Modification of 3D Printable Polymer Filaments for Radiation Shielding Applications

Abstract

There is a growing need to develop lead-free shielding materials that are safe, low weight, durable, environmentally friendly, chemically and mechanically stable and customizable for specific applications. Fused deposition modeling (FDM), an additive manufacturing technique based on the extrusion of a thermoplastic filament into a 3D printed object one layer at a time, could be employed well in applications involving ionizing radiation due to its relatively low cost, design flexibility and high manufacturing precision. This study aimed at developing 3D printing composites that contain Titanium dioxide as a filler agent for shielding in a medical radiation environment. First, the effect of low-dose ionizing radiation (up to 15 Gy) on the mechanical properties of common 3D printing polymers, ABS, ULTRAT, PLA, NYLON, ASA and PETG, was investigated. Since ABS experienced the lowest variation in its ultimate tensile strength (±5%) and Young’s modulus (−5%/+11%), it was chosen as a matrix for a new extruded 3D filament containing TiO2 at 1 wt.%, 3 wt.%, and 5 wt.%. With the incorporation of TiO2 at different filler contents, the UTS of the ABS composites varied between 24.1 MPa and 28.4 MPa, with the highest value recorded for 3 wt.% TiO2. Young’s modulus values were dependent on both the TiO2 concentration and on the irradiation dose. In addition, the ABS/TiO2 composites with a higher filler content (3 wt.% and 5 wt.%) maintained their attenuation ability even after exposure to a radiation dose of 100 Gy as opposed to pure ABS, which exhibited a ~2.5% reduction in its mass attenuation coefficient after exposure to the same dose of radiation. The pilot investigation performed demonstrated that the newly developed ABS/TiO2 composite containing 5 wt.% of filler can be successfully employed to shield electronic devices operating in a radiotherapy room.

Fatigue Behavior of Rotary Friction Welding of Acrylonitrile Butadiene Styrene and Polycarbonate Dissimilar Materials

“…The fatigue test specimen was also a cylindrical rod with a diameter of 15 mm and a length of 150 mm. The specimens were printed using a three-dimensional printing apparatus called fused deposition modeling (FDM) (Teklink smart solution Inc., New Taipei City, Taiwan) with two different kinds of thermoplastic filaments, i.e., ABS (Thunder 3D Inc., New Taipei City, Taiwan) and PC (Thunder 3D Inc., New Taipei City, Taiwan) [ 25 , 26 , 27 ]. The printing parameters for the ABS specimens involved a printing bed temperature of 100 °C, a printing speed of 80 mm/s, a printing temperature of 230 °C, and a layer thickness of 0.4 mm [ 28 ].…”