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 ( 137 Cs) 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 ( Z eff ) and effective electron density ( N E ) reveal that the good shielding performance of BPP/PbO-4 benefits from its proper content and dispersion of PbO particles.