A lightweight polymer composite developed at North Carolina State University could replace lead and other The gamma shielding experimental setup. Source: Da Cao et al.heavy, potentially toxic and more costly metals used as ionizing radiation shielding materials in medical, military and other applications.

Bismuth trioxide particles were embedded into poly(methyl methacrylate) (PMMA) and then cured with UV light. This curing approach is considerably less time-, cost- and energy- intensive than conventionally used high-temperature techniques and lends itself to faster manufacturing. The process was used to synthesize polymer compound samples with as much as 44% bismuth trioxide by weight at room temperature in a matter of minutes.

The material was tested in 30 minute radiation shielding experiments with cesium 137, barium 133, cadmium 109, cobalt 57 and cobalt 60 as gamma radiation sources. The composites showed a gamma shielding ability superior to that of pure PMMA for gamma energy up to 1,000 keV. Knoop hardness test measurements confirm that high loading of bismuth trioxide particles in PMMA improves material micro-hardness to nearly seven times that of pure PMMA.

The research reported in Nuclear Engineering and Technology demonstrates great potential for the UV curing method in rapid manufacturing of effective radiation shielding materials.