This communication reports
on the preparation of novel nanocomposites foams that
are efficient broadband microwave absorbers.7 Multiwalled
carbon nanotubes (MWNT) are first successfully
dispersed into polymer matrix by melt-blending as
confirmed by TEM microscopy and rheology. Then
foaming of these nanocomposites8 occurs under
supercritical CO2 conditions by a two-step process.9
This physical foaming constitutes a green alternative to
classical foaming agents.10 Well-defined microcellular
foams11 were obtained with cell size around 10-50 μm
and cellular density around 108 cells per cm3, the
morphology of the foam was determined by SEM
microscopy. The impact of several criteria on the
morphology of the foam will be discussed. The EMI
shielding efficiency of these materials are then
evaluated and compared to the non-foamed
nanocomposites. Finally, we will discuss about the
design of the foam that is essential to optimize the
performances of the EMI absorber
