Electrical Tree Properties and Mechanism of Modified Aramid/Epoxy Composites

The introduction of micro and nanoparticles is an important means to improve the electrical tree properties of epoxy (EP) resin composites. Aiming at the problem that the waste aramid powder generated during the production process of aramid fiber products is difficult to be effectively utilized. The article adopts both dopamine modification and co-modification with dopamine and 2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane in the treatment of micrometer-sized aramid fiber powders. The untreated aramid powder (AP), dopamine-modified powder (DAP), and co-modified powder (SDAP) are prepared into composite specimens with EP, and the trap properties, electrical trees initiation, and growth characteristics of the three specimens with different doping concentrations are investigated for the first time. Tests and analyses show that the powder inside AP/EP is mostly agglomerated and entangled, the shallow phenomenon of deep traps is serious, and electrical tree properties have declined. With the increase of doping concentration, the energy level and density of deep traps of DAP/EP and SDAP/EP specimens increased, which helps to improve the initiation and growth characteristics of the electrical trees. The results of the study expand the application forms of aramid products and provide new ideas and choices for the search for high-quality fillers to improve the electrical tree properties of EP resins.