KH-SiO2/PES/BMI-F51复合材料的介电性能

采用3-缩水甘油醚氧基丙基三甲氧基硅烷(KH-560)修饰纳米二氧化硅(nano-SiO2)获得改性纳米二氧化硅(KH-SiO2)。以酚醛环氧树脂(F51)和双马来酰亚胺(BMI)作为基体,添加4%(质量分数,下同)聚醚砜(PES)和不同含量(0.5%~2.5%)的KH-SiO2,制备KH-SiO2/PES/BMI-F51多相复合材料。红外光谱(FT-IR)、扫描电镜(SEM)和透射电镜结果表明:纳米SiO2表面修饰效果良好,纳米粒子团聚倾向减弱,粒径减小,比表面积增大。介电性能测试结果表明:随着KH-SiO2掺杂量的增加,材料的介电常数先降低后升高,介电损耗没有明显变化,体积电阻率和击穿强度先升高后降低。当KH-SiO2掺杂量为1.5%时,10Hz下介电常数和介电损耗角正切分别为4.55和0.0029,体积电阻率和击穿强度分别为1.74×10^14Ω·m和29.11kV/mm,比树脂基体提高了68.9%和35.9%。

Dielectric properties of KH-SiO2/PES/BMI-F51 composites

KH-SiO 2 was obtained by using 3-glycid-oxypropyl-trimethoxy-silane (KH-560) to modify nano-silica (nano-SiO 2). KH-SiO 2/PES/BMI-F51 multi-phase composite was prepared, the phenolic epoxy resin (F51) and bismaleimide (BMI) as the matrix, 4%(mass fraction, the same below) polyethe-rsulfone (PES) as toughening agent and different contents (0.5%-2.5%) of KH-SiO 2 as modifier. The results of Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscope (TEM) show that the surface modification of nano-SiO 2 is favourable, the agglomeration tendency of nanoparticles is weakened, the size is decreased and the specific surface area is increased. Dielectric properties test displays that the dielectric constant of the material is decreased first and then increased with the increase of doping amount of KH-SiO2. There is no significant change in dielectric loss tangent, and the volume resistivity and breakdown strength are increased first and then decreased. The dielectric constant and dielectric loss tangent of composite reach 4.55 and 0.0029 at 10Hz, respectively, when the doping amount of KH-SiO 2 is 1.5%. The volume resistivity and breakdown strength are 1.74×10^14 Ω·m and 29.11kV/mm, respectively, which are 68.9% and 35.9% higher than that of resin matrix.