苯乙烯接枝改性纳米氧化铝环氧树脂复合材料的制备和性能研究

Preparation and Properties of Polystyrene-Grafted Al2O3/Epoxy Nanocomposites

为了改善传统电工环氧树脂复合材料的综合电气、热学性能,通过对纳米Al_(2)O_(3)表面接枝改性提高其在环氧树脂基体中的分散性和界面强度,进而提高其对纳米环氧树脂复合物电气和热学性能的影响。以双酚A型环氧树脂为基体,通过将纳米Al_(2)O_(3)粒子包覆硅烷偶联剂和长链苯乙烯(PS)进行接枝改性,利用机械分散法制备了不同质量分数的纳米Al_(2)O_(3)环氧树脂复合材料,研究了不同含量的苯乙烯接枝改性纳米Al_(2)O_(3)对环氧树脂复合材料热稳定性、玻璃化转变温度、击穿场强及介电特性的影响。结果表明:接枝改性后的纳米Al_(2)O_(3)粒子在环氧树脂基体中分散均匀;随着掺杂量的增加,接枝改性纳米Al_(2)O_(3)环氧树脂复合材料的击穿场强与介电常数均有升高,相对于纯环氧树脂,质量分数3%的苯乙烯接枝改性纳米Al_(2)O_(3)环氧树脂复合材料的击穿场强提高了5.67%,质量分数5%的苯乙烯接枝改性纳米Al_(2)O_(3)环氧树脂复合材料的介电常数提高了8.59%。分析认为:利用苯乙烯对纳米Al_(2)O_(3)表面进行接枝改性,可极大改善纳米粒子与聚合物基体的相容性,增强分散性,进而提高击穿强度,为电气领域环氧树脂纳米复合材料的研制和推广提供了依据。

In order to improve the comprehensive electrical and thermal properties of traditional electrical epoxy composites,surface graft modification of nano-Al_(2)O_(3) is applied to achieve better dispersion and interface strength in epoxy matrix,so as to improve its influence on the electrical and thermal properties of epoxy nano-composites.Bisphenol-A epoxy resin is taken as the matrix material,and the nano-Al_(2)O_(3) particles coated with silane coupling agent and long-chain polystyrene(PS)are grafted and modified.The epoxy nano-composites with different mass fractions of surface-modified nano-Al_(2)O_(3) are prepared by mechanical dispersion method.The effects of different contents of PS-grafted nano-Al_(2)O_(3) on thermal stability,glass transition temperature,breakdown field strength and dielectric properties of the epoxy composites are studied.The results show that the grafted and modified nano-Al_(2)O_(3) particles disperse evenly in the epoxy matrix.With the increase of doping amount,both the breakdown strength and electric constant of the grafted and modified nano-Al_(2)O_(3) epoxy composite increase.Compared with neat epoxy,the grafted and modified nano-Al_(2)O_(3)/epoxy composite with 3%mass fraction shows the highest dielectric breakdown strength and the strength increases by about 5.67%.The dielectric constant of the nano-Al_(2)O_(3)/epoxy composite grafted with 5%styrene increases by 8.59%.It is concluded that grafting styrene to the surface of nano-Al_(2)O_(3) can greatly improve the compatibility between the nano-particles and the polymer matrix,enhance the dispersibility and further improve the breakdown strength,which may provide a basis for the development and promotion of epoxy nanocomposites in the electrical field.