Impact of UV Exposure on Dielectric and Mechanical Properties of a Flame Retardant LLDPE-Based Composite

Abstract

Polyethylene-based composites are increasingly dominant in the modern cable industry, where incorporating mineral flame retardants is a standard approach to improve fire safety. However, adding these fillers into a non-polar polymer matrix can significantly compromise critical dielectric and mechanical properties, especially under long-term environmental stress. This study investigates the impact of ultraviolet (UV) radiation on the stability of linear low-density polyethylene (LLDPE) composites filled with an eco-friendly, ternary hybrid flame-retardant system consisting of aluminium hydroxide, magnesium hydroxide, and halloysite nanotubes. Specimens with a total filler content of 5 wt.% at an equal weight ratio (1:1:1) were subjected to accelerated UV ageing, using neat LLDPE as a reference. The degradation effects were systematically evaluated through broadband dielectric spectroscopy, focusing on the dissipation factor, and mechanical tensile testing. The study aims to quantify the photo-oxidative degradation rates and evaluate the practical serviceability and suitability of this specific hybrid filler system for cable insulation and protective sheathing applications.