Preparation of Graphene and Its Effect on Conductivity Epoxy Resin

Abstract

High quality graphene and its epoxy composites were prepared by exfoliation of first stage FeCl3-GICs with sodium borohydride (NaBH4) aqueous solution, followed by compounding with epoxy resin. First stage FeCl3-GICs were prepared by compounding anhydrous FeCl3 and graphite at 330℃. XRD analysis and scanning electron microscopy data show that the interlayer spacing of graphite intercalation compounds is increased from 0.335nm to 0.930nm,indicates first stage FeCl3-GIC is obtained. Transmission electron microscopy shows single layer grapheme is made. Raman spectroscopy and XPS data show that the graphene's ID/IG=0.09,C/O=40.80, comparing that of flake graphite's ID/IG=0.17 and FTIR spectra, suggesting that NaBH4 exfoliation can simultaneously repair the structural defects of flake graphite. Characteristic peaks of C=O(1735cm-1),C-O(1228cm-1)are found in FTIR spectra of flake graphite, while no functional groups characteristic peaks of graphene shows up in the corresponding locations, indicating that hydrogen produced by sodium borohydride successfully reduces oxygen from graphite makes the graphite more complete structure. The conductivity of composites gradually increases with the increase of graphene content, and the volume resistivity decreases from the pure epoxy resin of 1.95×1013Ω·cm to 3.41×105Ω·cm when the volume fraction is 3.70%. The conductivity of the composites increases by 8 orders of magnitude.SEM images of fracture morphology shows some incompatibility exists between graphene and epoxy resin.

Keywords

• graphene
• super conjugated structure
• graphite intercalation compound
• epoxy resin
• volume resistivity