Geant4 Simulation of the Effect of Different Composites on Polyimide Photon and Neutron Shielding Properties

Abstract

Polymers are widely used materials that have many medical and industrial applications. Some polymers have even been introduced as radiation-shielding materials; therefore, many studies are focusing on new polymers and their interactions with photons and neutrons. Research has recently focused on the theoretical estimation of the shielding effectiveness of Polyimide doped with different composites. It is well known that theoretical studies on the shielding properties of different materials through modeling and simulation have many benefits, as they help scientists to choose the right shielding material for a specific application, and they are also much more cost-effective and take much less time compared to experimental studies. In this study, Polyimide (C35H28N2O7) was investigated. It is a high-performance polymer, well known for its outstanding chemical and thermal stability, as well as for its high mechanical resistance. Because of its exceptional properties, it is used in high-end applications. The performance of Polyimide and Polyimide doped with different weight fractions of composites (5, 10, 15, 20 and 25 wt.%) as a shielding material against photons and neutrons were investigated using a Monte Carlo-based simulation toolkit Geant4 within a wide range of energies of both photons and neutrons from 10 to 2000 KeVs. Polyimide can be considered a good neutron shielding material, and its photon shielding abilities could be further enhanced when adding different high atomic number composites to it. The results showed that Au and Ag gave the best results in terms of the photon shielding properties, while ZnO and TiO2 had the least negative effect on the neutron shielding properties. The results also indicate that Geant4 is a very reliable tool when it comes to evaluating the shielding properties against photons and neutrons of any material.

Tribological Properties of Polyimide Composites Modified with Diamondoid Metal–Organic Frameworks

“…Polyimide (PI) is a high-performance polymer matrix that has been developed since 1950s, and it has excellent low-temperature resistance [ 1 ], high-temperature resistance [ 2 ], radiation resistance [ 3 ], and excellent self-lubricating properties [ 4 ]; as a result, it is widely used in the aerospace industry [ 5 ], triboelectric nanogenerators [ 6 ], and radiation-shielding materials [ 7 ]. However, the coefficient of friction and wear rate of pure PI are relatively high, which limits its application in extreme environments [ 8 ].…”

Characterization of Radiation Shielding Capabilities of High Concentration PLA-W Composite for 3D Printing of Radiation Therapy Collimators

“…However, the development of metal oxide PLA composites has allowed for a greater advantage in this area [ 17 , 18 ]. Computer simulation work using the Geant4 Monte Carlo code has evaluated the potential capacity that PLA compounds doped with oxides of Mg, Fe, Zn, and Ti [ 17 ] and polyimide compounds doped with Zn, Ti, Ag, and Au [ 19 ] would have for photon and neutrons shielding in a wide energy range (10–2000 keV). Additionally, polymers doped with Ag nanoparticles have also been experimentally analyzed for their effectiveness in shielding against 662 keV gamma rays [ 20 ].…”

“…Modern radiotherapy uses electron linear accelerators (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18), which produce photons with MeV energies, with the capacity to penetrate matter significantly more than the keV energies assessed thus far [24]. For a medium such as PLA or Polyethylene, the linear attenuation coefficient for the 20-100 keV range is 0.7773-0.1996 cm −1 [19,24] whereas for the same materials at energies in the 1-6 MeV range the linear attenuation coefficients are in average 8.4 times lower (0.0838-0.0324 cm −1 ) [19,24], which will result in an attenuation 3-4 orders of magnitude lower for 1-6 MeV photons. This suggests that the production of any type of radiotherapy accessory by MEX would require polymeric compounds doped with high Z and high-density metals (such as W or Pb with linear attenuation coefficients of 1.2740-0.8104 cm −1 and 0.8054-0.4979 cm −1 respectively for 1-6 MeV [24]) in concentrations exceeding 90% to achieve attenuation of the radiation beam to 1/7 of its value in reasonable thickness dimensions.…”