EFFECTS OF PROCESSING ON MECHANICAL, MORPHOLOGICAL, AND NEUTRON-SHIELDING PROPERTIES OF B2O3/UHMWPE COMPOSITES
Keywords:
UHMWPE, boron oxide, mechanical properties, extrusion, compression, morphologyAbstract
Sufficient and high-quality neutron-shielding materials are necessary for safety of radiation-related workers from the risk of excessive neutron exposure. As a result, This work investigated effects of two different processes, namely a combination of extrusion and compression molding (two-step method) and a compression molding (one-step method), used to produce neutron-shielding sheets from Ultra High Molecular Weight Polyethylene (UHMWPE) with the addition of 50 wt% boron oxide (B2O3) on mechanical, morphological, and neutron-shielding properties. The results indicated that, for a pristine UHMWPE, the neutron-shielding properties from both processes were not noticeably different. However, with the addition of 50 wt% B2O3, neutron-shielding properties were significantly enhanced, with the values obtained from the two-step method considerably higher than the ones from the one-step method. The improvement in the neutron-shielding properties in samples processed with the two-step method, which was also the case in overall mechanical properties, were mostly due to better dispersion of the B2O3 particles from the additional extrusion step. Furthermore, morphological images obtained using SEM revealed that less agglomeration of B2O3 particles was found in the UHWMPE composites processed using the two-step method. This contributed in part to better phase continuity of the UHMWPE matrix and, consequently, higher mechanical and neutron-shielding properties.
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