Synthesis and characterization of magnetic nanocomposites of fullerene‐containing polyurethane films for microwave applications

Abstract

Novel nanocomposites of barium hexaferrite-and fullerene-containing polyurethane were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and energy-dispersive X-ray diffraction. The nanoparticles showed good dispersion in the polyurethane matrix. Their thermal, mechanical, and electromagnetic absorbance properties were studied. The complex permeability and permittivity were measured in the frequency range of 8.2-12.4 GHz. The maximum reflection loss of the nanocomposites was found to increase with increasing the ferrite content from 1% to 5%, with maximum value of À7.5 dB at only 5% composition. The incorporation of nanofiller not only imparts mechanical strength to the nanocomposite but also shows good radar-absorbing properties at only 5% filler concentration.

Fullerene containing polyurethane nanocomposites for microwave applications

“…The XRD spectrum in Figure 2(a) shows cubic symmetry with reflection peaks at 2θ values of 22.32, 31.69, 39.05, 45.49, 51.15, 56.39, and 66.01 corresponding to (100), (110), (111), (200), (210), (211), and (220) sets of diffraction planes, respectively and can be indexed to JCPDS#05‐0626 (Joint Committee on Powder Diffraction Standards). The peaks in XRD spectrum of BaF26 are in accord with the magnetoplumbite structure of hexagonal BaF (JCPDS #84‐0757). The average particle size of BaF and BT is estimated from the line broadening of corresponding X‐Ray diffraction peaks using the Scherrer formula 33…”

“…Most of the particles are irregular in the size range of 50–100 nm, with few reaching cubic shape. TEM image of BaF26 also shows a mixture of spherical and hexagonal particles in the same range. The TEM micrograph of B‐PU nanocomposite [Figure 3 (b)] shows that about 80–90% of the particles are ranged from 50 to 100 nm and all shapes, that is, spherical, cubic, and hexagonal are evident suggesting the incorporation of both BT and BaF nanofillers.…”

“…Hence, the synthesis of PU is clearly evidenced by IR. However, as the characteristic bands of BT and BaF are found between 550 and 400 cm −1 26, 32 and these bands are already present in the fullerene‐derived PU, nanofiller incorporation can not be affirmed by IR. Following analytical techniques have been used to prove the nanocomposite formation.…”

“…Table II shows the enhancement in tensile strength with increasing concentration of the filler. The linear PU using butanediol as chain extender in place of fullerenol was also synthesized and found to have a tensile strength of 5 MPa while the fullerene containing PU has tensile strength of 12 MPa 26. Addition of 1–3% of each nanofiller raises its tensile strength upto 29 MPa ± standard deviation.…”

“…A review on polymeric nanocomposites for EM wave absorption by Huo et al22 summarizes the approach to design the ideal absorber and covers a range of polymeric hosts and several dielectric and magnetic materials contributing to EM absorption. Studies on effect of nano‐BT/nano‐BaF incorporation into poly(ether ether ketone)/polyurethane (PU) composites have been performed by our group 23–26…”