Electrical property improvement of phenolic formaldehyde resin with graphene and ionic liquid

The ionic liquid 3-decyl-bis(1-vinyl-1H-imidazole-3-ium-bromide) (C₁₀[VImBr]₂) was synthesized and its chemical structure characterized by Fourier-transform infrared spectroscopy and ¹H nuclear magnetic resonance spectroscopy. To improve the electrical conductivity of the phenolic formaldehyde (PF) resin, PF/graphene and PF/graphene/C₁₀[VImBr]₂ composites were prepared via a melt blending and compression-curing process. The impact strength of the composites was shown to increase with the addition of increasing proportion of graphene, and with increasing proportion of C₁₀[VImBr]₂, of up to 5 wt%. In detail, the electrical conductivity of the PF/graphene composites increased significantly from 2.3×10⁻¹² to 4×10⁻⁴S/cm as the graphene content increased from 0 to 20 wt%. Moreover, the electrical conductivity of the PF/graphene/C₁₀[VImBr]₂ composites containing 15 wt% graphene was shown to increase from 5.6×10⁻⁵ to 9.2×10⁻⁴ S/cm as the content of C₁₀[VImBr]₂ increased from 0 to 5 wt%.