  High-performance sealing materials that can guard key components against high
pressure gases and liquid chemicals while withstanding mechanical deformation
are of utmost importance in a number of industries. In this present work,
graphene nanoplatelets (GNPs) were introduced into a fluoroelastomer (FKM)
matrix to improve its mechanical and barrier properties and test its
suitability for sealing applications. Nanocomposites filled with different
loadings of GNPs were prepared and compared with their counterparts loaded with
carbon black (CB). GNPs were dispersed homogeneously with a high degree of
in-plane alignment. The tensile and barrier properties of the FKM were improved
significantly by the addition of GNPs. Micromechanical modelling based on the
shear-lag/rule-of-mixtures theory was used to analyse the reinforcing
efficiency of the GNPs. Upon the addition of the GNPs, the elastomer was able
to swell anisotropically in liquids, a fact that can be used to tune the
swelling properties for sealing applications. In terms of gas permeability, a
modification of the well-established Nielsen's theory was introduced to analyse
the CO2 permeability for the bulk composite samples. The significantly improved
mechanical, thermal and barrier properties at relatively low filler loadings,
reveal that the FKM/GNP nanocomposites produced are very promising for use in
advanced sealing applications.
