Study on the structure and γ‐ray shielding performance of polypropylene/PbO composites with heterogeneous networks.

Polymer‐based radiation shielding materials are receiving more and more interests due to their desirable advantages in lightweight and maneuverability. Herein, we employ polypropylene (PP) as the matrix to construct γ‐ray shielding composites through the embedment of PbO particles with a wet reaction melt blending method. From the changes in dynamic rheological behaviors and fracture surface of PP/PbO composite, it can be found that the gradient addition of PbO particles facilitates the formation of heterogeneous network structure with, and high PbO content may make the composites undergo a “liquid–solid” transition. Rheological temperature and time scanning show that both PbO content and heterogeneous network structure greatly contribute to the storage modulus (G') and thermal stability. The γ‐ray (137Cs) shielding tests manifest that BPP/PbO‐4 has the best shielding performance, whose thicknesses of half value layer (HVL) and tenth value layer (TVL) are 0.32 and 1.05 cm, respectively, obviously smaller than those shielding materials ever reported. The analyses on effective atomic number (Zeff) and effective electron density (NE) reveal that the good shielding performance of BPP/PbO‐4 benefits from its proper content and dispersion of PbO particles. [ABSTRACT FROM AUTHOR]