偶联剂协同低温等离子体的复合材料氧化铝填料表面改性

环氧树脂广泛应用在电机绝缘领域,向树脂中添加微米氧化铝可以减缓绝缘老化的侵蚀,为了进一步提升氧化铝/环氧树脂复合材料电气性能,本文引入偶联剂协同低温等离子体复合改性方法对氧化铝填料进行表面处理。将偶联剂包覆改性后的微米氧化铝置于重复脉冲低温等离子体中分别进行0~9min表面改性处理,其次将氧化铝掺杂进环氧树脂中制备复合材料。观测氧化铝填料外表的形貌、官能团及结构变化,对复合材料局部放电起始电压进行测试分析。结果表明,偶联剂和低温等离子体复合改性能有效提升氧化铝填料表面活性官能团的含量,为氧化铝与树脂基体的紧密键合提供了基础,进而提升了氧化铝/环氧树脂复合材料的电气性能。在复合改性中等离子体处理时间为3min时,氧化铝填料表面含氧基团的含量相对于单一偶联剂改性增长了3.32%,表面偶联剂的接枝率提升了24.5%,复合材料的电气性能提升了7.9%。

Surface Modification of Al2O3 Filler to Compound Material on Coupling Agent and Low Temperature Plasma

Epoxy resin is widely used in electric insulation. Adding micron Al2O3 to the resin could slow down the erosion of insulation aging. In order to further improve the electrical properties of Al2O3/epoxy resin, the coupling agent and low temperature plasma were used to modify the surface of Al2O3 filler. Placing the micro-Al2O3 which was treated by the coupling agent in the low-temperature plasma to modify the Al2O3 suiface for 0～9 minutes, then the Al2O3 was filled into the epoxy resin to prepare the composite material. The morphology, functional group and structure of Al2O3 filler were observed, the partial discharge voltage of composite material was measured and analyzed. The results show that the low-temperature plasma and coupling agent modification can effectively enhance the surface functional content of the Al2O3 filler. It provides the basis for the tight bonding of Al2O3 and resin matrix, thus improves the electrical properties of Al2O3/epoxy resin. Compared with the coupling agent modification technology, the content of Al2O3 filler surface active functional groups is increased by 3.32％, the surface grafting rate of the coupling agent is increased by 24.5％ and the electrical properties of the composite is improved by 7.9％when the micro-Al2O3 is treated in 3min.