Development of Epoxy-OPEFB composites for shielding applications
Microwave absorbers are widely used in applications to eliminate unwanted or stray radiated electro-magnetic signals which might interfere with a system’s operation. These absorbers are basically made up of a polymer matrix reinforced with a filler material which might be one element or more. Fer...
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2019
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/83620/1/FS%202019%203%20-%20ir.pdf |
| _version_ | 1796981258597695488 |
|---|---|
| author | Khamis, Ahmad |
| author_facet | Khamis, Ahmad |
| author_sort | Khamis, Ahmad |
| collection | UPM |
| description | Microwave absorbers are widely used in applications to eliminate unwanted or
stray radiated electro-magnetic signals which might interfere with a system’s
operation. These absorbers are basically made up of a polymer matrix reinforced
with a filler material which might be one element or more. Ferrite composites are
widely used in the development of microwave absorbers. However, ferrites are
expensive, corrosive, heavy, and non-biodegradable.
This research focuses on using oil palm empty fruit bunch (OPEFB) fibres as a
filler for microwave absorber with epoxy resin as the host matrix. OPEFB fibres
have several advantages including biodegradability, low density, low cost, and
better thermal properties. Also epoxy resin has various advantages such as
good dimensional stability, high mechanical properties, ease of processing and
curing, and moisture resistance. Epoxy-OPEFB composites were fabricated by
varying the OPEFB percentages (0%, 5%, 10%, 15%, 20%, 25%, 30%, and
40%). OPEFB fillers of 300 μm size, epoxy resin and hardener were mixed and
stirred to produce Epoxy-OPEFB composites using mini vortex mixer at 3000
rpm for 30 minutes at room temperature (25 °C). ). The total mass of each mixture
was 12 g which then poured into two different flanges in order to use two different
techniques of complex permittivity characterizations. The dielectric constant and
loss factor are main parameters related to dielectric characteristics of a particular
material, and directly associated to the absorbing characteristics. . The complex
permittivity, transmission coefficient |S21|, reflection coefficient |S11|, power
loss, reflection loss, and total shielding effectiveness (SE) were studied in the
frequency range (8-12) GHz. Dielectric constant, loss factor, reflection
and transmission coefficients of the composites were measured using
rectangular waveguide (RWG) connected to vector network analyser (VNA) in
the frequency range (8-12) GHz. Also an open ended coaxial probe (OECP) connected to a vector network analyser was utilized to measure the dielectric
constant and loss factor of all composites at room temperature (25 °C). X-Ray
diffraction was utilized to analyse the microstructure of the composites. The
results show that the dielectric properties increased but |S11| and |S21| decreased
by increasing OPEFB percentage in the composites. The complex permittivity
was dependable on the OPEFB percentage of the composites, increasing
OPEFB content in the composites caused an increment in the complex
permittivity of Epoxy-OPEFB composites. Epoxy-OPEFB composites were
found to have a very close dielectric constant and loss factor to ferrite-polymer
composites. At 10 GHz, the dielectric constant and loss factor of the Epoxy-
OPEFB composites were be between 2.8 to 3.35 and 0.14 to 0.29, respectively.
In addition, results of |S11| and |S21| were used to determine the power loss,
reflection loss and total shielding effectiveness of Epoxy-OPEFB composites.
OPEFB had a strong influence on the shielding effectiveness, power loss and
reflection loss which increased by increasing OPEFB percentage in the
composites. The total shielding effectiveness values were found to be between
15.4 dB and 18.9 dB at 10 GHz. The calculations of the S-Parameters
coefficients of the samples were carried out using Finite Element Method (FEM)
technique by COMSOL software. The measured and calculated results of |S11|
and |S21| were also investigated.
The simulated and measured results of |S11| and |S21|were in a good agreement.
Finally, the electric field distribution was visualized using Comsol software, it was
found that the amplitude of electric field was strongly reduced after passing
through Epoxy-OPEFB composites. |
| first_indexed | 2024-03-06T10:34:59Z |
| format | Thesis |
| id | upm.eprints-83620 |
| institution | Universiti Putra Malaysia |
| language | English |
| last_indexed | 2024-03-06T10:34:59Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | upm.eprints-836202022-01-06T02:18:28Z http://psasir.upm.edu.my/id/eprint/83620/ Development of Epoxy-OPEFB composites for shielding applications Khamis, Ahmad Microwave absorbers are widely used in applications to eliminate unwanted or stray radiated electro-magnetic signals which might interfere with a system’s operation. These absorbers are basically made up of a polymer matrix reinforced with a filler material which might be one element or more. Ferrite composites are widely used in the development of microwave absorbers. However, ferrites are expensive, corrosive, heavy, and non-biodegradable. This research focuses on using oil palm empty fruit bunch (OPEFB) fibres as a filler for microwave absorber with epoxy resin as the host matrix. OPEFB fibres have several advantages including biodegradability, low density, low cost, and better thermal properties. Also epoxy resin has various advantages such as good dimensional stability, high mechanical properties, ease of processing and curing, and moisture resistance. Epoxy-OPEFB composites were fabricated by varying the OPEFB percentages (0%, 5%, 10%, 15%, 20%, 25%, 30%, and 40%). OPEFB fillers of 300 μm size, epoxy resin and hardener were mixed and stirred to produce Epoxy-OPEFB composites using mini vortex mixer at 3000 rpm for 30 minutes at room temperature (25 °C). ). The total mass of each mixture was 12 g which then poured into two different flanges in order to use two different techniques of complex permittivity characterizations. The dielectric constant and loss factor are main parameters related to dielectric characteristics of a particular material, and directly associated to the absorbing characteristics. . The complex permittivity, transmission coefficient |S21|, reflection coefficient |S11|, power loss, reflection loss, and total shielding effectiveness (SE) were studied in the frequency range (8-12) GHz. Dielectric constant, loss factor, reflection and transmission coefficients of the composites were measured using rectangular waveguide (RWG) connected to vector network analyser (VNA) in the frequency range (8-12) GHz. Also an open ended coaxial probe (OECP) connected to a vector network analyser was utilized to measure the dielectric constant and loss factor of all composites at room temperature (25 °C). X-Ray diffraction was utilized to analyse the microstructure of the composites. The results show that the dielectric properties increased but |S11| and |S21| decreased by increasing OPEFB percentage in the composites. The complex permittivity was dependable on the OPEFB percentage of the composites, increasing OPEFB content in the composites caused an increment in the complex permittivity of Epoxy-OPEFB composites. Epoxy-OPEFB composites were found to have a very close dielectric constant and loss factor to ferrite-polymer composites. At 10 GHz, the dielectric constant and loss factor of the Epoxy- OPEFB composites were be between 2.8 to 3.35 and 0.14 to 0.29, respectively. In addition, results of |S11| and |S21| were used to determine the power loss, reflection loss and total shielding effectiveness of Epoxy-OPEFB composites. OPEFB had a strong influence on the shielding effectiveness, power loss and reflection loss which increased by increasing OPEFB percentage in the composites. The total shielding effectiveness values were found to be between 15.4 dB and 18.9 dB at 10 GHz. The calculations of the S-Parameters coefficients of the samples were carried out using Finite Element Method (FEM) technique by COMSOL software. The measured and calculated results of |S11| and |S21| were also investigated. The simulated and measured results of |S11| and |S21|were in a good agreement. Finally, the electric field distribution was visualized using Comsol software, it was found that the amplitude of electric field was strongly reduced after passing through Epoxy-OPEFB composites. 2019-03 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/83620/1/FS%202019%203%20-%20ir.pdf Khamis, Ahmad (2019) Development of Epoxy-OPEFB composites for shielding applications. Masters thesis, Universiti Putra Malaysia. Oil palm - Case studies Shielding (Electricity) Magnetic shielding |
| spellingShingle | Oil palm - Case studies Shielding (Electricity) Magnetic shielding Khamis, Ahmad Development of Epoxy-OPEFB composites for shielding applications |
| title | Development of Epoxy-OPEFB composites for shielding applications |
| title_full | Development of Epoxy-OPEFB composites for shielding applications |
| title_fullStr | Development of Epoxy-OPEFB composites for shielding applications |
| title_full_unstemmed | Development of Epoxy-OPEFB composites for shielding applications |
| title_short | Development of Epoxy-OPEFB composites for shielding applications |
| title_sort | development of epoxy opefb composites for shielding applications |
| topic | Oil palm - Case studies Shielding (Electricity) Magnetic shielding |
| url | http://psasir.upm.edu.my/id/eprint/83620/1/FS%202019%203%20-%20ir.pdf |
| work_keys_str_mv | AT khamisahmad developmentofepoxyopefbcompositesforshieldingapplications |