Enhancing Electrical, Thermal, and Mechanical Properties of HV Cross-Linked Polyethylene Insulation Using Silica Nanofillers

Cross-linked polyethylene (XLPE) is commonly used as insulation in power cables. In the last decades, extensive researches were initiated to enhance its electrical, chemical, and mechanical properties. This paper aimed to enhance the electrical, thermal, and mechanical properties of the commercial XLPE power cables main insulation using nonfunctionalized and chemically functionalized silicon dioxide (SiO₂) nanoparticles. XLPE/SiO₂ samples were synthesized using the melt blending method. The functionalization process for SiO₂ nanoparticles was carried out to decrease the agglomeration of nanoparticles and distribute it homogeneously inside the polymer matrix of XLPE. The samples were prepared by melt blending of nonfunctionalized inorganic SiO₂ nanoparticles denoted as “nonfunctionalized XLPE nanocomposites,” and the samples were prepared by melt blending of SiO₂ functionalized inorganic nanoparticles denoted as “functionalized XLPE nanocomposites.” Firstly, the surface of SiO₂ nanoparticles was activated using methane sulfonic acid; then, the surface modification was performed using amino silane coupling agent. XLPE/SiO₂ nanocomposites were fabricated with different ratios of nanoparticles (0.5, 2, 3.5, and 5 wt.%). The relative permittivity (ɛ_r) and loss tangent (tan δ) were measured in a frequency range from 1 Hz to 1 MHz. Thermal stability and mechanical properties for a nanocomposite were measured and discussed. It was found that the functionalized nanocomposites have better dielectric, thermal, and mechanical properties compared with the nonfunctionalized SiO₂ and XLPE.