Novel family of broadband nanocomposite microwave absorbers with carbon nanotubes in solid polymer films

Nanocomposites absorbers with carbon nanotubes (CNTs) in solid polymer films are proposed for high EMI absorption performances. These conductive films exhibit a low permittivity at microwaves, which means a low reflection, with a high absorption capacity. Compared with usual solution based on foamed conductive composites, we indeed show that solid polymer films with two phases matrix and carbon nanotubes charges can be a great alternative to these foams. The two phases considered are polypropylene (PP) and poly[styrene-b-(ethylenealt-propylene)-b-styrene] (SEPS) copolymer. The electrical conductivity, the permittivity and EMI absorption are correlated with the quality of the dispersion. As a result of the low and constant permittivity of the obtained composite, the absorption performances are not limited by reflection mechanisms but fully controlled by the level of conductivity, fixed by the dispersion and weight content in CNTs.