Effects of Recycled Fe2O3 Nanofiller on the Structural, Thermal, Mechanical, Dielectric, and Magnetic Properties of PTFE Matrix

Abstract

The purpose of this study was to improve the dielectric, magnetic, and thermal properties of polytetrafluoroethylene (PTFE) composites using recycled Fe2O3 (rFe2O3) nanofiller. Hematite (Fe2O3) was recycled from mill scale waste and the particle size was reduced to 11.3 nm after 6 h of high-energy ball milling. Different compositions (5–25 wt %) of rFe2O3 nanoparticles were incorporated as a filler in the PTFE matrix through a hydraulic pressing and sintering method in order to fabricate rFe2O3–PTFE nanocomposites. The microstructure properties of rFe2O3 nanoparticles and the nanocomposites were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). The thermal expansion coefficients (CTEs) of the PTFE matrix and nanocomposites were determined using a dilatometer apparatus. The complex permittivity and permeability were measured using rectangular waveguide connected to vector network analyzer (VNA) in the frequency range 8.2–12.4 GHz. The CTE of PTFE matrix decreased from 65.28×10−6/°C to 39.84×10−6/°C when the filler loading increased to 25 wt %. The real (ε′) and imaginary (ε″) parts of permittivity increased with the rFe2O3 loading and reached maximum values of 3.1 and 0.23 at 8 GHz when the filler loading was increased from 5 to 25 wt %. A maximum complex permeability of 1.1−j0.07 was also achieved by 25 wt % nanocomposite at 10 GHz.

Fabrication and characterization of Fe2O3‐OPEFB‐PTFE nanocomposites for microwave shielding applications

“…The complex permittivity (ε 0 -jε 00 ), complex permeability (μ 0 -jμ 00 The measurement procedures were also reported in our previous study. [41] 3 | RESULTS AND DISCUSSION indicate the cellulose crystallinity in the OPEFB fiber, in agreement with previous studies. [42,43] The XRD spectra of Fe 2 O 3 -OPEFB-PTFE nanocomposites did not show the OPEFB broad peaks which could be attributed to the crystalline structure of PTFE and Fe 2 O 3 which made it hard for OPEFB broad peaks to be observed.…”

“…This made it harder for the magnetic field to pass through the samples, hence, increasing the values of μ 0 and μ 00 . The results of μ 0 and μ 00 of Fe 2 O 3 -OPEFB-PTFE samples showed almost the same results as Fe 2 O 3 -PTFE ones reported previously [41] because OPEFB fiber is a non-magnetic material. The non-steady pattern of μ 00 with frequency is ascribed to the magnetic loss while the peaks shown in μ 00 results are associated with the natural ferromagnetic resonance.…”

“…Therefore, the spectra of Fe 2 O 3 ‐OPEFB‐PTFE nanocomposites are similar to the spectra of Fe 2 O 3 ‐PTFE nanocomposites which reported in our previous work. [ 41 ] Consequently, the peaks of the nanocomposites composed of the raw materials used in their fabrication as there were no new peaks observed in the profiles. The absence of any new peaks suggests that there was no chemical interaction in the Fe 2 O 3 ‐OPEFB‐PTFE nanocomposites and that the mixture was physical in nature.…”

“…This indicates a good dispersal and total embedment of the recycled Fe 2 O 3 and OPEFB fiber in the PTFE matrix thereby providing the interfacial bonding required to improve the complex permittivity ( ε ′– jε ″) and permeability ( μ ′– jμ ″) of the nanocomposites. [ 41 ]…”

Optimization of α-Fe2O3 Nanopillars Diameters for Photoelectrochemical Enhancement of α-Fe2O3-TiO2 Heterojunction

“…α-Fe 2 O 3 is the most stable iron oxide compound material and is widely used in photoelectrodes, gas sensing, catalysts, magnetic recording, and medical fields. Hematite (α- Fe 2 O 3 ) is one of the most attractive materials for obtaining hydrogen from solar energy due to its properties [ 21 , 22 ]. Hematite has a band gap of 2.1 eV, which allows absorbing visible light up to 600 nm in the solar spectrum, and it has good chemical stability in aqueous alkaline environments.…”