Synthesis and analysis of iron-dopped CNT/PU composites for microwave applications

Polyurethane (PU) matrix reinforced with carbon nanofillers forms a nanocomposite, which in addition helps to attain unique material properties by the use of the extreme high aspect ratio and nanoscopic dimensions of the nanofillers. Multi-walled carbon nanotubes (MWCNTs) are used as the nanofillers with weight percentage (wt%) ranging from 1% to 10%. The electromagnetic properties of the nanocomposites are then extracted and these show that the novel nanocomposite is a potential candidate for various microwave applications. MWCNT functionalized with Iron (Fe
₃
O
₄
) is used to prepare CNT/PU nanocomposites in three distinct concentrations, with lower weight percentage of 5% Fe
₃
O
₄
and higher weight percentage of 20 % Fe
₃
O
₄
. The effect of Fe
₃
O
₄
on the electrical conductivity is then analyzed and the results show the undesirable oxidization effect of Fe
₃
O
₄
, which significantly reduced the electrical conductivity of the composites. The oxidization effect is verified by comparing the performance of CNT-Fe
₃
O
₄
/PU composites with Fe
₃
O
₄
powder/PU composites.