Insulating Properties of Low Density Polyethylene/Alumina Nanocomposites

High-Voltage Direct Current (HVDC) cable has become an important factor in the development of HVDC transmission. However, there are still difficulties such as space charge distribution in the development of HVDC cables. In this study, Low Density Polyethylene (LDPE) nanocomposites filled with nano alumina (nano-Al₂O₃) particles with or without modification were prepared by employing melting blend method. The results show that the modified nano-Al₂O₃ particles with vinyl silane coupling can be homogeneously dispersed in LDPE matrix. Space charge of the LDPE nanocomposites was tested by Pulsed Electro-Acoustic (PEA) method. The PEA spectrum indicated that decay charge effect of the LDPE/Al₂O₃ nanocomposites is better than that of neat LDPE. The space charge accumulated in the nanocomposites can be effectively decayed. The J-V curves show the nano-Al₂O₃ decrease the carrier mobility. The excellent insulation properties of the LDPE nanocomposites were attributed to the better interfacial adhesion between the surface-treated nano-Al₂O₃ particles and the matrix.