This paper established a new kind of polyimide/C-MXene
composite
films with a microcellular structure for electromagnetic interference
shielding through solution mixing and liquid phase separation methods.
Polyimide was used as the resin material, Ti3C2Tx MXene was used as the electromagnetic
wave-shielding medium, l-citrulline was used as the surface
modification agent, ferric trichloride (especially the ferric ion)
was used as the cross-linking agent between the polyimide and modified
C-MXene, and a microcell was used as the shielding structure. By adjusting
the content of ferric ions, the foam structure, mechanical properties,
thermal conductivity, and electromagnetic interference shielding efficiency
of the polyimide/C-MXene microcellular composite film could be controlled.
The higher the ferric ion content, the smaller the foam size and the
higher the electromagnetic interference shielding efficiency. With
increasing ferric ion content, the tensile strength and Young’s
modulus appeared to first increase and then decrease; when the ferric
ion content was 0.8 wt %, the tensile strength and Young’s
modulus reached their maximum values, which were 10.06 and 325.29
MPa, respectively. In addition, with increasing ferric ion content,
the thermal insulation showed first decreasing and then increasing
tendency; the lowest thermal conductivity was 0.17 W/(m·K) when
the ferric ion content was 0.8 wt %