Preparation And Properties Of Al₂O₃-FG/Polymer Composites For Thermal Conductivity With Electrical Insulating

Insulating thermal conductive polymer composites have important applications in electronic packaging and other fields.The research of materials with high thermal conductivity and excellent electrical insulation is the basic premise for the good development of electronic and electrical fields.In this paper,high thermal conductivity carbon based material flake graphite?FG?and inorganic thermal conductive filler alumina?Al₂O₃?were blended to prepare polymer composites with excellent thermal conductivity by torque rheometer.However,due to the conductive network formed by graphite flakes in the polymer matrix,the insulation properties decreased.In this project,alumina?Al₂O₃?and stone were prepared by controlling the selective distribution of thermal conductive fillers The insulating polymer matrix thermal conductive composites filled with flake graphite?FG?were prepared by low-temperature processing method.The relationship between the distribution of thermal conductive fillers and thermal conductivity,electrical conductivity and mechanical properties was studiedIt was found that the thermal diffusivity and thermal conductivity of FG/PC/Al₂O₃/PP composites were 4.5 and 5.6 times higher than that of pure PP,and the volume resistivity was 10¹⁵?�cm when the content of FG was 15 wt%and alumina was 35wt%The order of magnitude.However,the composites prepared by conventional high temperature melt blending?processing temperature higher than PC processing temperature?can also achieve good thermal diffusivity and thermal conductivity,but the volume resistivity is only 10⁸?�cm and the insulation is poor.The SEM results show that in the thermal conductive and insulating composites prepared by low temperature processing,FG filler is forced to be selectively distributed in PC phase,and Al₂O₃ is dispersed in PP phase and wrapped outside FG/PC phase to form an insulating layer,thus improving the insulation properties of the composite.Because the addition of thermal conductive filler increases the viscosity of the system,resulting in the decrease of mechanical properties of the composite,which will greatly reduce the use value of the composite.On the basis of the experiment of Al₂O₃-FG/PP/PC composites,the thermal conductivity and mechanical properties of the composites are improved by preparing Al₂O₃-FG/PA6/PC composites.The results show that the thermal diffusivity is 0.49 m²/s,the thermal conductivity is 1.26 W/m�K,and the volume resistivity is 10¹⁶?�cm when the content of FG is 15 wt%and alumina is 20wt%.It was found that the mechanical properties of Al₂O₃-FG/PA6/PC composites prepared by low-temperature processing and blending were good,and the tensile strength and bending strength were significantly improved.