Dassan, Emayaruba G Barathi
(2021)
X-Band Frequency Electromagnetic Interference Shielding And Mechanical Properties Of Dual Functionalization Multi-Walled Carbon Nanotube (Mwcnt) Epoxy Polymer Nanocomposites.
Masters thesis, Universiti Sains Malaysia.
Abstract
The wide development of gigahertz electronic systems and telecommunication devices in civilian and military sectors have brought severe electromagnetic pollution, which may affect the operation of the electronic device and pose a health issue to the public. The effective electromagnetic interference (EMI) shielding material solutions in a wide range of applications are active quest. This research experimentally investigated the EMI shielding performance, and mechanical properties of the carbon nanotubes (CNTs) epoxy reinforced composites. The CNTs were synthesized using dual catalyst consist of nickel and ferrocene via chemical vapor deposition (CVD) at a temperature ranging between 600 to 900oC. The composites were manufactured via solution processing and casting reinforced with CNT that were functionalized via surfactant (DF-CNT) functionalization, which then compared with pristine CNT (PRS-CNT). As synthesized CNT had the size between 19 – 24 nm and 48.36 wt% of carbon according to field emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HRTEM), and energy dispersive x-ray (EDX), while x-ray diffraction (XRD) revealed the existence of carbon phase. CNT synthesized at 800°C displayed the best quality of carbon deposited, which attributed to the restructuring into high crystalline graphene sheets with the smallest CNT diameter after functionalization. DF-CNT had the size between 15.1 to 23.4 nm and 90.6 – 94.5 wt% with average size reduction of 21.55% and displayed highest purity and crystallinity with ID/IG ranging 1.06 - 1.25 suggesting surfactant functionalization had produced the best quality of CNT with minimal defects and impurities. Epoxy reinforced with DF-CNT (EP/DF-CNT) composite showed higher EMI, thermal, electrical, hardness, dielectric and mechanical properties than PRS-CNT reinforced epoxy. This increment is associated with the less minimal CNT wall damage and agglomeration with highly oxygenated functional groups which enable homogeneous dispersion of CNT-epoxy. It was demonstrated that the DF-CNT filled epoxy composites are capable of increasing tensile strength and modulus by up to 19% and 69%, flexural strength and modulus of 57% and 62%, compressive strength and modulus of 56% and 41%, EMI shielding effectiveness (EMI SE) of 42.3%, thermal conductivity of 27%, hardness of 53% and electrical conductivity of 27% when compared to a PRS-CNT. This research provides a feasible functionalization way to produce multifunctional CNT reinforced epoxy composite with excellent EMI shielding performance that is possible to be applied in the electronics and aerospace industries.
Keywords-component; carbon nanotube (CNT); surfactant-functionalised CNT (DF- CNT); polymer nanocomposites; Electromagnetic (EM) wave radiation; Electromagnetic interference (EMI); EMI shielding; Mechanical properties
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