Dielectric strength of glass fibre fabric reinforced epoxy by nano-Al2O3

Filling epoxy resin in glass fibre fabric with surface modified nano-Al
2
O
3
as a means of increasing the dielectric strength is investigated in this work. The 50 Hz breakdown strength with 3 wt% nano-Al
2
O
3
is shown to be 10% higher than the neat epoxy/glass fibre material and 4% higher than the neat epoxy. An improved interface bonding between the glass fibre and the epoxy is evidenced by SEM characterization. Based on a multilayer dielectric model, it is found that introducing nano-Al
2
O
3
to the epoxy resin can efficiently alleviate the dielectric constant mismatch between the epoxy and the epoxy-integrated glass fibre layer, which results in an improvement in the dielectric strength.