Computational and Experimental Approaches for Determining Scattering Parameters of OPEFB/PLA Composites to Calculate the Absorption and Attenuation Values at Microwave Frequencies.

Ahmad Fahad Ahmad,Ahmad Mamoun Khamis,Zulkifly Abbas,Sidek Hj Ab Aziz,Daw Mohammad Abdalhadi,Umar Sa’Ad Aliyu

doi:10.3390/polym12091919

Ahmad Fahad Ahmad, Ahmad Mamoun Khamis + Show 4 more

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https://doi.org/10.3390/polym12091919

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Abstract

This article describes attenuation and absorption measurements using the microstrip transmission line technique connected with a microwave vector network analyzer (Agilent 8750B). The magnitudes of the reflection (S11) and transmission (S21) coefficients obtained from the microstrip transmission line were used to determine the attenuation and absorption of oil palm empty fruit bunch/polylactic acid (OPEFB/PLA) composites in a frequency range between 0.20 GHz and 12 GHz at room temperature. The main structure of semi-flexible substrates (OPEFF/PLA) was fabricated using different fiber loading content extracted from oil palm empty fruit bunch (OPEFB) trees hosted in polylactic acid (PLA) using the Brabender blending machine, which ensured mixture homogeneity. The commercial software package, Computer Simulation Technology Microwave Studio (CSTMWS), was used to investigate the microstrip line technique performance by simulating and determine the S11 and S21 for microwave substrate materials. Results showed that the materials’ transmission, reflection, attenuation, and absorption properties could be controlled by changing the percentage of OPEFB filler in the composites. The highest absorption loss was calculated for the highest percentage of filler (70%) OPEFB at 12 GHz to be 0.763 dB, while the lowest absorption loss was calculated for the lowest percentage of filler 30% OPEFB at 12 GHz to be 0.407 dB. Finally, the simulated and measured results were in excellent agreement, but the environmental conditions slightly altered the results. From the results it is observed that the value of the dielectric constant ( and loss factor ( is higher for the OPEFB/PLA composites with a higher content of OPEFB filler. The dielectric constant increased from 2.746 dB to 3.486 dB, while the loss factor increased from 0.090 dB to 0.5941 dB at the highest percentage of 70% OPEFB filler. The dielectric properties obtained from the open-ended coaxial probe were required as input to FEM to calculate the S11 and S21 of the samples.

Highlights

In recent years, the research and development of environment-friendly polymers have attracted more attention due to the concerns related to environmental pollution by non-degradable plastic wastes.Polymers 2020, 12, 1919; doi:10.3390/polym12091919 www.mdpi.com/journal/polymersNatural fiber-reinforced composites using thermoplastic such as polypropylene and polyethylene as a matrix have been widely used in automotive applications, but the composites are partially biodegradable
The findings showed that the material transmission, reflection, and absorption properties can be controlled by changing the percentage of Fe2 O3 filler in the composites
The oil palm empty fruit bunch (OPEFB)/polylactic acid (PLA) composites with 30–70 wt% of OPEFB filler were successfully prepared based on the blending technique using a Brabender Internal Mixer machine

Summary

Introduction

The research and development of environment-friendly polymers have attracted more attention due to the concerns related to environmental pollution by non-degradable plastic wastes.Polymers 2020, 12, 1919; doi:10.3390/polym12091919 www.mdpi.com/journal/polymersNatural fiber-reinforced composites using thermoplastic such as polypropylene and polyethylene as a matrix have been widely used in automotive applications, but the composites are partially biodegradable. The research and development of environment-friendly polymers have attracted more attention due to the concerns related to environmental pollution by non-degradable plastic wastes. Since polylactic acid (PLA) is environment-friendly, it became one of the polymers in the highest demand to be used in applications that are difficult to be recycled. PLA is commonly used to replace commodity synthetic polymers that can cause deterioration of our environment due to solid waste pollution. Many studies on the mechanical properties of natural fiber reinforced with PLA have been developed by other researchers with different types of fiber, including kenaf [2], jute [3], bamboo, [4], ramie [5], banana [6], oil palm [7], and other natural fibers studied as reinforcements to replace synthetic fiber in polymer composites

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