Most flake graphite exfoliation is affected by subjecting the intercalated product to heat energy. Heating of the intercallant results in a phase change which provides the inter-laminar pressure needed to force layer planes to get separated.

The maximum expansion potential of a specific grade of intercalated graphite sheet can only be realized if the heating rate used to affect exfoliation is rapid. Slow heated or heating in ramping stages will produce low expansion and will even result in no expansion. Since the expansion process depends on harnessing the force developed by an expanding gas, it is important to develop maximum force by causing a sudden, rapid gas expansion. To slow heating and thus slow expansion will result in less than the threshold gas pressure required to affect expansion.

A good way to view the above concept is to model the graphite gasket exfoliation process as the expansion of a gas in a cylinder with a loose fitting piston. Assume that the bottom of the piston and the bottom of the cylinder represent two adjacent graphene layers and that the clearance between the cylinder walls and piston represent the prismatic edges that define each graphene layer. Ultimately gas will escape through these edges. The blue spheres trapped between the piston and cylinder bottom represent the intercalate substance assumed to be bisulfate in this case.

The second, and equally important, material parameter that affects the expansion ratio is the particle size of the intercalated flake graphite. Generally particle size is directly proportional to expansion ratio. Large flakes typically have higher expansion ratios than smaller flakes.

As the particles get smaller, intercallant gases have a more efficient escape pathway. Rapid gas escape prevents development of the pressure required to push adjacent graphene layers apart. The result is then the low expansion ratio.

In addition to the pressure effect modeled above, the thickness of the expandable graphite flakes also has a significant effect on expansion ratio. Since the interlayer spacing is the same in spite of the flake thickness, thicker flake will expand proportionally more than thinner flakes. When grinding, screening, or reducing the particle size of flake graphite, cleavage parallel to the basal plane occurs. The result is the creation of thinner flakes with subsequent reduction of the expansion potential of those flakes.