Polymeric composite materials for radiation shielding: a review

Abstract

The rising use of radioactive elements is increasing radioactive pollution and calling for advanced materials to protect individuals. For instance, polymers are promising due to their mechanical, electrical, thermal, and multifunctional properties. Moreover, composites made of polymers and high atomic number fillers should allow to obtain material with low-weight, good flexibility, and good processability. Here we review the synthesis of polymer materials for radiation protection, with focus on the role of the nanofillers. We discuss the effectivness of polymeric materials for the absorption of fast neutrons. We also present the recycling of polymers into composites.

Keywords: Gamma radiation; Ionizing radiation; Polymer composite materials; Polymer recycling and radiation shielding.

Fig. 1

Polymers are categorized as thermosets and thermoplastics under changing temperature which can be divided into semicrystalline and amorphous

Fig. 2

Narrow beam good geometry setup including a radioactive point source which is set based on a specific measurements, the sample, the detector, a high-voltage source (HV), an amplifier (Amp), and a multichannel analyser (MCA) which are all connected to a dedicated computer software (Alsayed et al. 2020)

Fig. 3

In situ synthesis for polymer nanocomposites where nanoparticles are added to polymer matrix to form polymer nanocomposite

Fig. 4

Melt intercalation method steps: preparing the polymer matrix which is followed by annealing at high temperature and then adding the nanofiller, and all the mixture is blended to form a uniformly distributed polymer composite

Fig. 5

Sol-gel synthesis of where a compound which contains a highly reactive component is solidified via sol-gel or solution which is followed by annealing and heat treatment

Fig. 6

Ultrasound cavitation technique in which a solution containing a nanopolymer composite is prepared after mixing two solutions A and B, and then a sonicator probe is immersed, and using a pulse controller, ultrasound is applied

Fig. 7

Melt processing extrusion technique that involves direct mixing the host nanofillers with a polymer powder by a twin-screw extruder or blender, pressing the mixture into a pellet, and heating at the appropriate temperature

Fig. 8

Ball milling technique involving the use of agate balls in a ball mill jar where the nanoparticles are milled with the polymer to produce a polymer nanocomposite

Fig. 9

Many forms of nanoplates, nanoparticles, fibers, tubes, and whiskers can be added to polymer matrix to synthesize polymer composites which can be used as radiation shielding materials in radiation facilities, nuclear power plants, and also nuclear cleaning of environment

Fig. 10

Use of polymer composite materials after recycling in various applications such as protective shielding materials in radiation facilities, aerospace engineering, industry, electromagnetic, and nuclear shielding

Fig. 11

Mass attenuation coefficient of polymer nanocomposites: 20% hematite/polystyrene, 50% lead oxide/polystyrene, 50% lead oxide/high-density polyethylene, and 40% zinc oxide/high-density polyethylene compared to concrete

Fig. 12

Half-value layer (HVL) measured in cm of polymer nanocomposites:50% hematite/polystyrene, 50% lead oxide/high-density polyethylene, 20% zinc oxide /polyacrylamide (PAM), and 40% zinc oxide/high-density polyethylene compared to concrete. The characteristics of the radiation shield are used to determine their performance against gamma radiation. The incorporation of fillers into the polymer matrices improves the properties of these polymers and compensates for the drawbacks such as mechanical failure and cracks. The filler interacts with the polymer matrix by facilitating the interlocking mechanism of polymeric chains and thus increases the hardness of the composite (Rajendran et al. 2011). Also, the type, concentration, and size of filler are important parameters to be considered when synthesizing a polymer composite. The nanoparticles with their large surface-to-volume ratio are reactive fillers that can be dispersed easily within the matrix and form an interphase region between the surface of the particle and the matrix itself (Puglia and Kenny 2018)