Improving flame resistance and shielding properties for cross-linked polyethylene (XLPE) using nanoclay filler

Abstract

Polymers play an essential role in both industry and medical fields due to their diverse and adaptable properties. In this work, prepared crosslinking polyethylene (XLPE) samples with hydrophilic bentonite nanoclay fillers (H₂Al₂O₆Si) at concentrations of 0, 1, 2.5, 4, and 5 wt% enhance their flame-retardant and radiation shielding efficiency. The research investigated flame retardancy and thermal stability parameters. The XLPE/H₂Al₂O₆Si nanocomposite polymer sheets were exposed to a collimated beam of fast neutrons using an Am/Be neutron source (5 Ci) and to gamma radiation using a ¹³⁷Cs point source (5 μCi) to assess their radiation shielding properties. The study found that uniform dispersion of nanoclay particles enhanced the thermal properties of the composite, forming a char layer that acted as a barrier, slowing thermal decomposition and reducing the heat release rate. Limiting oxygen index (LOI) increased from 28% to 34%, and burning rate improved with higher nanoclay concentrations. Additionally, absorption and optical band gap calculations decreased with increasing filler concentrations. Radiation attenuation capabilities increased by approximately 40% for neutrons and 30% for gamma radiation compared to pure XLPE. The study concluded that incorporating nanoclay fillers into XLPE enhances its shielding capabilities and improves flame resistance properties, making the prepared samples suitable for various industrial applications.