高导热钛酸锶/环氧树脂纳米复合材料的绝缘特性

Dielectric Properties of SrTiO_3/Epoxy Nanocomposites with High Thermal Conductivity

为研究复合材料的形貌、导热特性及电气性能,通过熔融共混法制备了填充体积分数(质量分数)分别为1.72%(7%),3.95%(15%),7.2%(25%),13.44%(40%)的钛酸锶/环氧树脂纳米复合材料。微观形貌分析表明纳米颗粒分散均匀,没有孔洞和裂痕。纳米复合材料的导热系数随着填充量的增加而增加,40%质量比复合材料的导热系数达到了0.52 W/(m·K),与纯环氧树脂相比提升了160%。复合材料的介电常数随着填充质量比的增加而增大,随着频率的增加而减小。复合材料击穿场强的Weibull分布图显示复合材料的本征击穿场强比纯环氧树脂高,增幅在25%以内。脉冲电压下沿面放电试验发现纳米复合材料沿面放电前的最高温度值低于纯环氧树脂。沿面放电电压随纳米颗粒填充量增加而显著升高,填充质量分数为40%时,沿面放电电压与纯环氧树脂相比升高了47.4%,并且具有更快的散热速率,表明填充SrTiO_3纳米颗粒可以改善环氧树脂的沿面放电特性。综上所述,填充SrTiO_3纳米颗粒的环氧树脂具有优良的导热性能和绝缘特性,为开发新型高导热绝缘材料提供了参考。

To investigated the morphology of the nanocomposites,thermal conduction characteristic and electrical properties of the composites,SrTiO3/epoxy nanocomposites have been prepared via facile solution-processing technique by incorporating SrTiO3 nanoparticles into the epoxy resin matrix with different loading amounts such as 1.72 vol%(7 wt%),3.95 vol%(15 wt%),7.2 vol%(25 wt%),and 13.44 vol%(40 wt%),respectively.The uniformity of dispersion in the absence of pinholes or cracks was verified in the cross-section SEM images of nanocomposites.It was found that thermal conductivity increased with SrTiO3 weight fraction,thermal conductivity of the SrTiO3/epoxy composite with 40%weight fraction rose up to 0.52 W/(m·K).The dielectric constant increased with the weight fraction and decreased with frequency.The Weibull distribution showed that breakdown strength of nanocomposites increased by about 25%after SrTiO3 incorporation.Moreover,the highest temperature on the surface of samples of nanocomposites was lower than that of pure epoxy when the surface breakdown happened under impulse voltage imposition.The creeping discharge inception voltage of SrTiO3/epoxy nanocompositeswith 40%weight fraction,compared with pure epoxy,increases by 47.4%,showing faster heat dissipation ability.Thus,adding SrTiO3 nanoparticles can improve the creeping discharge properties of epoxy resin dielectric materials.To sum up,adding SrTiO3/epoxy nanocomposites is beneficial to improving the thermal and dielectric properties,offering a basic reference for new insulation material development.