Study On Preparation And Performance Of Thermal Conductive Insulating Cable Material

With the rapid development of society,the demand for wires and cables is increasing.However,the heat generated during the use of wires and cables not only increases the cost of electricity transportation,but also reduces the safety of the wires and cables during use.Therefore,the preparation of thermally conductive insulating cable material is of great significance to increase the safety of wire and cable use and reduce the cost of electricity transportation.Low-density polyethylene?LDPE?can be used to prepare cable insulation due to its good electrical insulation,dielectric properties and mechanical properties;Silicone rubber can be used to prepare cable sheath because of its good radiation resistance,cold resistance,acid-alkali resistance,corrosion resistance and good heat resistance.In this paper,a heat-conducting insulating low-density polyethylene composite material for cable insulation layer is prepared with silicon powder as thermal conductive filler,and a heat-conducting insulating silicone rubber composite material for cable sheath is prepared with spherical alumina and hexagonal boron nitride as thermal conductive filler.And its performance is characterized,mainly composed of the following two parts.1)Silicon powder was used as the thermal conductive filler and modified by silane coupling agent?-aminopropyltriethoxysilane?KH550?.And then heat-conducting insulating low-density polyethylene composite material for cable insulation layer was prepared by melt extrusion method when polyethylene-glycidyl methacrylate?PE-g-GMA?used as compatibilizer,N,N'-Hexamethylenebis?3,5-di-tert-butyl-4-hydroxyhydrocinnamamide??1098?as antioxidant,and LDPE as matrix.The effects of the amount of silicon powder,KH550 and PE-g-GMA on the microscopic morphology,mechanical property,thermal conductivity,and insulation property of composite material were studied.The results show that when the filling amount of silicon powder is 35vol%,the amount of silane coupling agent used is0.6wt%of silicon powder,and the amount of compatibilizer PE-g-GMA is 3wt%of composite material,the composite material has the best comprehensive performance with the thermal conductivity of 0.72W·m^-1·K^-1,the tensile strength of 15.2MPa,the elongation at break of 43.82%,the volume resistivity of 3.63×10¹⁵?·cm and the breakdown voltage of 35.1 KV/mm.2)A spherical alumina-coated hexagonal boron nitride composite filler was prepared by electrostatic self-assembly.And then a heat-conducting insulating silicone rubber composite material for cable sheathing layer was prepared by a two-roller mixing and plate forming method when the as-prepared composite filler used as thermal conductive filler and 2,5-dimethyl-2,5bis?t-butyl peroxide?as vulcanizing agent.Finally,the effects of the amount of composite filler,alkali treatment time,and mass ratio of hexagonal boron nitride to spherical alumina on the micro-morphology,mechanical property,thermal conductivity,and insulation property of the silicone rubber composite were studied.The results show that when the amount of composite filler is 47 vol%,the alkali treatment time is 12h,and the mass ratio of hexagonal boron nitride to spherical alumina is 1:1,the the silicone rubber composite has the best comprehensive performance with the thermal conductivity of 1.614 W·m^-1·K^-1,the tensile strength of 2.79MPa,the elongation at break of 258.61%,the volume resistivity of 8.05×10¹⁵?·cm and the breakdown voltage of 32.3KV/mm.