Development of Exfoliated Graphite using Innovative Chemical Technique for Aerospace Applications 2022-01-0051

Several conventional methods on preparation of exfoliated graphite are in practice. However, their major limitations are poor quality of exfoliated graphite, lower yield, more expensive with higher processing time. To address these issues, a unique method for development of exfoliation of graphite using tri-solvents namely Water, Ethanol and Acetic acid is attempted in the present work. Ethanol acts as a supporting group for the long term stable dispersions of ex-graphite nanosheets. Glacial acetic acid, which readily dissolves in water, penetrates through the layers of graphite sheets and breaks the -C=C bond force between layers with the help of stirring and sonication resulting in exfoliation of graphite layers. Exfoliated graphite nanosheets were produced by using optimized mixtures of water, acetic acid and ethanol.

XRD, SEM and FTIR studies have been carried out on the developed exfoliated graphite. Nanosheets of exfoliated graphite with size ranging from 100 nm to 150 nm were obtained while using an optimal mixture of water, ethanol and glacial acetic acid of 75 ml, 40 ml and 200 ml respectively with a stirring time of 6 hrs and sonication time 16 hrs. FTIR studies have confirmed the presence of -C=C at wavenumber of 1652 cm^-1 and demonstrates the formation of graphene.

It was observed that the quality of exfoliated graphite and yield were improved from the present method of processing of graphene nanosheets. Further, the process time is less when compared with existing conventional methods. As the exfoliated graphite nanosheets possess lower value of coefficient of thermal expansion, excellent chemical resistance & stability coupled with higher flame retardancy, they can be potential candidate novel nano materials for aerospace applications as coatings against the harsh climate of the space.