ABSTRACT
Irradiated low-density polyethylene (LDPE)-filled sepiolite was studied to obtain a halogen-free flame-retardant compound for electrical cable and wire applications. This study aimed to investigate the effect of different sepiolite loadings (0, 2, 4, 6, 8 and 10 part per hundred [phr]) on the mechanical, thermal, morphology and flammability properties of unirradiated and irradiated LDPE/sepiolite nanocomposite. The LDPE/sepiolite nanocomposite was prepared using a twin-screw extruder with a screw speed of 50 rpm at a temperature profile of 160°C to 180°C from the feed to the die zone. The compounds underwent injection molding to produce test specimens and were exposed to electron beam (EB) radiation at a range of 0–200 kiloGray (kGy) using a 3-MeV EB accelerator. The sepiolite characteristic peak disappears in X-ray diffraction (XRD), indicating that the sepiolite has exfoliated into the LDPE matrix. After exposure to the irradiation dose, the gel contents of the samples were increased along with the sepiolite content due to the formation of radiation-induced cross-linking. In addition, the tensile properties were marginally increased with increasing irradiation doses. The thermogravimetric analysis (TGA) result revealed no significant variation at the 4 or 8 phr sepiolite loading. The differential scanning calorimetry (DSC) results of Tm, Xc and ΔHm gradually decreased at both 4 and 8 phr sepiolite loadings. The lower burning rate indicates lower flammability, and the sepiolite particles were well dispersed after undergoing the irradiation process.
