We have developed a process for producing single sheet functionalized graphene by the oxidation and thermal exfoliation of graphite. The oxidation is accomplished by treatment of graphite with a mixture of sulfuric acid, nitric acid and potassium chlorate for 96 hours. The resulting graphite oxide (GO) has an increased layer spacing from the 0.34 nm found in natural graphite to between 0.65 and 0.75 nm. This increase in spacing is found to be critical for the successful exfoliation of the graphite to individual graphene sheets. Rapid heating results in the sheets being forced apart by an abrupt evolution of gas. The thermal treatment also reduces the GO sheets, changing the ratio of carbon to oxygen atoms from 2 to 1 in the graphite oxide to 12 to 1 in the exfoliated graphene sheets (FGS). The high aspect ratio of the produced sheets makes this an exciting nanofiller. In addition, the functionalized surface of the sheets allows for the dispersion of the filler into polymer matrixes. We will present results of our investigation into the production of FGS as well as investigations into the use of FGS as a nanofiller in polymer composites.