Attenuation performance of polymer composites incorporating NZF filler for electromagnetic interference shielding at microwave frequencies

Polymer composites have been thoroughly explored for future electromagnetic interference (EMI) applications owing to their unique combination of electrical, mechanical, and optical properties. The composition, morphology, and surface characteristics of the filler material play critical roles in regulating the composite activity. We studied the formation, synthesis and EM attenuation properties of nickel zinc ferrite (NZF) + Polycaprolactone (PCL) microcomposites that were prepared via the conventional mixed oxide (CMO) technique. Compared with other preparation routes, CMO may provide the advantages of a simple process and the ability for mass production and controlled product formation. A rectangular waveguide connected to a vector network analyser coaxial cable was employed to measure the scattering parameters [S] for use in determining the attenuation values of NZF+PCL substrates for a variety of NZF% values. Measurement tests showed a simultaneous increment in the attenuation value with the filler percentage. NZF+PCL samples of 1-mm thickness were able to attenuate microwave frequencies by up to ~3.33 dB, where the highest attenuation magnitude of 8.599 dB over a large area was attributed to the 12.5% NZF filler content at 12 GHz. Thus, a low transmission of waves resulted from the high shielding effectiveness (SE) values that showed a maximum 6.86 dB EM interference. Scanning electron microscopy (SEM) was utilized to analyse the average particle size (1.45 μm) of the filler powder

Dielectric behavior of OPEFB reinforced polycaprolactone composites at X-band frequency

Short fibres are often used as reinforcing materials with thermoplastic polymers to improve the dielectric properties of the composites. In this work, the effects of oil palm empty fruit bunch (OPEFB)-fibre loading on polycaprolactone (PCL) polymer were extensively studied. The synthesis of OPEFBPCL composites were prepared via melt blend method. Theoretical and experimental analysis of electromagnetic (EMI) propagation, absorption and shielding effectiveness (SE) properties of the composite were also studied. The magnitudes of S-parameters for OPEFB fiber-reinforced PCL composites with different percentages of filler were measured by a rectangular waveguide connected with a microwave vector network analyzer (VNA) at (8-12) GHz frequency. Whilst the dielectric properties were studied using an open ended coaxial probe. The morphological characterization of the OPEFBPCL composite was carried out using X-ray diffraction and scanning electron microscopy (SEM). This work showed that XRD profile patterns slightly changed duo to the filler loading increment which result a reduction in both dielectric constant and loss factor. However, the relative permittivity of pure oil palm fibre and PCL was measured as (1.8-j*0.08) and (2.929-j*0.3242) respectively. In addition, the composition of 12.5 wt% filler gave the highest dielectric constant and loss factor values. However, the reflection loss increases to filler content increments at the maximum frequency of 12 GHz- The excellent behavior of these polymer composites makes them superior nominees for microwave low absorption materials