Effects of Chemical Grafting on the Dielectric Properties of Aramid Fiber Reinforced Composites

In this paper, polyethyleneimine (PEI) with abundant
$-\text{NH}_{2}$
groups is grafted onto the surface of aramid fibers after surface activation by plasma pretreatment, and aramid fiber reinforced epoxy composite (AFRC) samples are prepared to research their dielectric properties. The results indicate that PEI is successfully grafted onto the aramid fiber surface. The interfacial shear strength increased from 29.5 MPa to 63.7 MPa, demonstrate ng an enhancement in interfacial bonding strength. The dielectric properties of the composite material, including DC conductivity, dielectric constant, and breakdown strength, are improved, attributed to the reduced interface polarization and increased interface bonding strength. This research provides a scientific basis for improving the performance of AFRC for insulation rods used in gas insulated switchgear (GIS).