Electrical conductivity and microwave absorbing properties of nickel-coated multiwalled carbon nanotubes/poly(phthalazinone ether sulfone ketone)s composites

Nickel-coated multiwalled carbon nanotubes (NiMWNT) were prepared by electroless deposition with ultrasonic vibrations. The morphologies and components were characterized by scanning electron microscope and energy dispersive spectroscopy. Two types of fillers, multiwalled carbon nanotubes (MWNT) and Ni-MWNT, were blended with poly(phthalazinone ether sulfone ketone)s (PPESK) by the solution-mixing method, respectively. The electrical conductivity and microwave absorbing properties of the composites were investigated. The results show that Ni-MWNT/PPESK composites have relatively lower electrical resistivity values than MWNT/PPESK, and in both cases the decrease in electrical resistivity indicates a similar percolation transition behavior in the same MWNT content region. Moreover, as MWNT loading is 5 parts per hundred parts of resin (phr), Ni-MWNT/PPESK composite has the wider frequency region (9.5-13.5 GHz) of the reflection loss (RL) less than -10 dB and the lower minimum value of RL (-27.5 dB) compared with MWNT/PPESK. The better microwave absorption properties can be attributed to the improved dielectric and magnetic properties of the fillers. A good correlation between electrical conductivity and microwave absorption was found for MWNT/PPESK composites. In addition, tensile test and thermogravimetric analysis indicate that introducing Ni-MWNT into PPESK is favorable for the improvement of the mechanical properties and high temperature stability of the composites.