“…The absorption peaks at 2900–2800 cm −1 are characteristic of stretching vibrations of aliphatic C–H groups and the peak at 1435 cm −1 and 1371 cm −1 corresponds to the vibration of CH 2 bond in a PVB molecule. 30,31 Figure 1.Structural analysis of composites for (a) XRD and (b) FT-IR analysis. XRD: X-ray diffraction; FT-IR: Fourier transform-infrared spectroscopy.…”
Barium titanate (BaTiO3)-polyvinyl butyral (PVB) composites at various weight concentrations were prepared via ultrasonic probe sonicator. The sonication was carried out at 20 kHz and 70% amplitude for about 2 h and BaTiO3 nanoparticles were dispersed well in the mixture of PVB/ethanol under probe sonication. As a microwave absorbent, the microwave absorbing properties of the BaTiO3 nanoparticle-PVB composites with different mixture ratios of 5 wt.% (RAM1), 10 wt.% (RAM2) and 15 wt.% (RAM3) BaTiO3 were investigated based on transmission line theory in the frequency range from 1 GHz to 14 GHz. The minimum reflection loss (RL) of the RAM1 reaches −3.47 dB at 5.57 GHz with a matching thickness of only 7.0 mm. For RAM2 with 4 mm and 4.2 mm thickness ( tm), the RL values are less than −10 dB obtained in the frequency 10.3–13.4 GHz. The RAM3 composite with 15 wt.% BaTiO3 mixture ratio shows a minimum reflection loss of −43.8 dB at 11.01 GHz with a −15 dB bandwidth over the extended frequency range of 10.2–13.2 GHz for a thickness of 2.8 mm and −44.2 dB at 4.77 GHz for a thickness of 6.5 mm.
“…The absorption peaks at 2900–2800 cm −1 are characteristic of stretching vibrations of aliphatic C–H groups and the peak at 1435 cm −1 and 1371 cm −1 corresponds to the vibration of CH 2 bond in a PVB molecule. 30,31 Figure 1.Structural analysis of composites for (a) XRD and (b) FT-IR analysis. XRD: X-ray diffraction; FT-IR: Fourier transform-infrared spectroscopy.…”
Barium titanate (BaTiO3)-polyvinyl butyral (PVB) composites at various weight concentrations were prepared via ultrasonic probe sonicator. The sonication was carried out at 20 kHz and 70% amplitude for about 2 h and BaTiO3 nanoparticles were dispersed well in the mixture of PVB/ethanol under probe sonication. As a microwave absorbent, the microwave absorbing properties of the BaTiO3 nanoparticle-PVB composites with different mixture ratios of 5 wt.% (RAM1), 10 wt.% (RAM2) and 15 wt.% (RAM3) BaTiO3 were investigated based on transmission line theory in the frequency range from 1 GHz to 14 GHz. The minimum reflection loss (RL) of the RAM1 reaches −3.47 dB at 5.57 GHz with a matching thickness of only 7.0 mm. For RAM2 with 4 mm and 4.2 mm thickness ( tm), the RL values are less than −10 dB obtained in the frequency 10.3–13.4 GHz. The RAM3 composite with 15 wt.% BaTiO3 mixture ratio shows a minimum reflection loss of −43.8 dB at 11.01 GHz with a −15 dB bandwidth over the extended frequency range of 10.2–13.2 GHz for a thickness of 2.8 mm and −44.2 dB at 4.77 GHz for a thickness of 6.5 mm.
“…The spectrum for neat PVB was almost identical to that reported in the literature, specifically the existence of peaks at 2,950 cm −1 and 2,870 cm −1 , characterizing the valence vibrations of CH 2 groups of the polymer backbone, as well as corresponding deformation modes at around 1,420 cm −1 and 1,380 cm −1 . [32] No sharp peak was discerned relating to C O stretching vibrations of the acetate group, typically appearing at around 1,730 cm −1 , most probably due to very low content (1-4%) of vinyl acetate groups in the commercial PVB. [33] However, no significant differences in the spectra were visible, indicating that chemical interactions had not occurred between the MNPs and PVB during preparation of the solution in methanol.…”
Section: Morphological and Structural Characterization Of The Membrmentioning
Removing iron ions from groundwater to purify, it is a challenge faced by countries across the globe, which is why developing polymeric microfiltration membranes has garnered much attention. The authors of this study set out to develop nanofibrous membranes by embedding magnetic Fe2O3 nanoparticles (MNPs) into polyvinylbutyral (PVB) nanofibers via the electrospinning process. Investigation was made into the effects of the concentration of the PVB and MNPs on the morphology of the nanofibers, their magnetic properties, and capacity for filtration to remove iron ions. The fabrication and presence of well‐incorporated MNPs in the PVB nanofibers were confirmed by scanning electron microscopy and transmission electron microscopy. Depending on the concentration of the MNPs, the membranes exhibited magnetization to the extent of 45.5 emu g−1; hence, they exceeded the performance of related nanofibrous membranes in the literature. The magnetic membranes possessed significantly higher efficiency for filtration compared to their nonmagnetic analogues, revealing their potential for groundwater treatment applications.
“…In general, the MAMs include ferrites, metallic oxides, carbon materials and conducting polymer etc. At present stage, ferromagnetic metals (Fe, Co, Ni) and their oxides have been widely investigated for the advantages of strong absorption ability, high efficiency, low cost and so on, e. g. Wu et al .…”
Section: Introductionmentioning
confidence: 99%
“…Therefore, as a kind of functional material, the microwave absorption materials (MAMs) which can dis-sipate the electromagnetic (EM) by converting the EM radiation energy to heat or other energy have drawn more and more attentions. [1][2][3][4] In general, the MAMs include ferrites, [5][6][7] metallic oxides, [8][9][10] carbon materials [11,12] and conducting polymer [13,14] etc. At present stage, ferromagnetic metals (Fe, Co, Ni) and their oxides have been widely investigated for the advantages of strong absorption ability, high efficiency, low cost and so on, e. g. Wu et al [15] prepped porous CoÀ Co 3 O 4 hybrid hollow spheres via hydrogen reduction.…”
In this paper, the Co3O4/MWCNTs/Graphene ternary composite was synthesized by a facile one‐pot hydrothermal method. The crystal structure, microstructure and elementary composition, electromagnetic parameters and microwave absorption property were systemically investigated by the XRD, SEM, TEM and VNA respectively. The results showed that the as‐prepared ternary composite exhibits enhanced absorption property in the frequency range of 0.1–3.0 GHz, which is mainly attributed to the synergistic effects of the dielectric loss and magnetic loss. The enhanced dielectric loss mainly generates from the strong dipole and interfacial polarization of the adherent MWCNTs and embedded graphene fragments, and the enhanced magnetic loss derives from eddy current loss and nature resonance together. The maximum reflection loss of this composite can reach −42.56 dB at 0.39 GHz with a thickness of 5 mm, while the maximum effective absorption bandwidth covers from 0.77 GHz to 1.99 GHz with a relatively thinner thickness of 2 mm. This study provides a facile method to synthesize Co3O4/MWCNTs/Graphene composite with excellent properties that is a potential candidate for microwave absorption in low frequency band.
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