The reliance on foreign imports for the production materials of semi-conductive shielding materials (SCSM) used in domestic 110 kV and above high-voltage cables has long been a significant barrier to the development of domestic high-voltage cable industry. There is an urgent need to conduct research on the domestication of SCSM for high-voltage cables. To address this issue
the domestically produced ethylene vinyl acetate copolymer (EVA) was selected as the matrix resin
and the low-density polyethylene (LDPE) was incorporated to enhance the thermal stability of EVA-based composite materials through blending modification techniques. Moreover
the key properties between EBA and EVA/LDPE composites were comprehensively compared
and the influences of LDPE incorporation on thermal stability
mechanical performance and electrical properties
and the underlying mechanisms were also elucidated. Additionally
the electrical and mechanical properties of SCSM prepared with ethylene-butyl acrylate (EBA) and EVA/LDPE composites as matrix resins were compared. The selective distribution of conductive carbon black in the EVA/LDPE shielding material was analyzed. Experimental results demonstrate that
due to the good interfacial compatibility between EVA and LDPE
the introduction of LDPE can restrict the thermal mobility of molecular chains in the ester side chains of EVA
thereby effectively improving the thermal stability and processability of the EVA/LDPE composites while ensuring their excellent mechanical properties. The selective distribution of conductive carbon black endows the EVA/LDPE SCSM with superior temperature stability of volume resistivity
and its elongation at break is significantly improved compared to EBA-based SCSM. This study provides valuable insights into the application of domestic matrix resins in the field of SCSM used in high voltage cables.