Besides of the ability of improving dielectric thermal conductivity

implantation of inorganic fillers with high thermal conductivity into composite dielectric material also brings some influences on polymer insulating behavior and dielectric relaxation.This study emphasizes the high-temperature dielectric properties of epoxy resin filled with carbon nanotubes and micron-sized glass fibres.Under 20 to 180℃and 0.01 Hz to 1 MHz

AC breakdown field

dielectric permittivity

conductivity and glass transition temperature of modified epoxy resin composite were measured.Experimental results show that

within 100 and 180℃

short-time AC breakdown field of epoxy resin can be improved by 37.7%to 49.2%.Moreover

relative permittivity and dielectric loss factor of composite also can be decreased by 2.2 to 3.4 and 27.4%to 69.7%

respectively.The glass transition temperature of epoxy resin can be increased from 109 to 141℃.It is considered that synergistic effect of carbon nanotubes and micron-sized glass fibres in polymer composite is responsible for the inhibition of electron avalanche development

ion migration and structural creep

which obviously improved the insulating behavior of polymer composite.