Enhancement of Mechanical, Thermal and Dielectric Properties of Hybrid Carbon Nanotubes and Alumina in Epoxy Nanocomposites

Penambahan nanotiub karbon (CNT) dalam nanokomposit polimer telah memberikan cabaran kepada penyelidik disebabkan oleh taburannya dalam matriks polimer. Kajian ini memberikan fokus terhadap sebatian hibrid CNT-alumina yang dihasilkan melalui pemendapan wap kimia (CVD) yang digunakan untuk mempertingkatkan taburan dan menambah baik sifat-sifat mekanik, terma dan dielektrik bagi nanokomposit epoksi. Sebatian hibrid CNT-alumina telah berjaya disintesis melalui kaedah CVD dengan menggunakan pemangkin nikel di bawah atmosfera metana pada suhu 800 °C. Bagi tujuan perbandingan, campuran CNT-alumina secara fizikal juga disediakan dengan menggunakan kaedah pengisaran bebola bagi tujuan perbandingan. Nanokomposit epoksi terisi sebatian hibrid CNT-alumina dan CNT-alumina yang dicampurkan secara fizikal telah dicirikan berdasarkan muatan pengisi (iaitu 1% - 5%). Sebatian hibrid CNT-alumina masing-masing mempunyai saiz antara 10 – 30 nm dan 12 % berat karbon berdasarkan analisis medan pancaran mikroskop imbasan electron pancaran medan (FESEM), mikroskop pemancaran elektron resolusi tinggi (HRTEM) dan serakan tenaga sinar-x (EDX), manakala analisis pembelauan sinar-x (XRD) mendedahkan kewujudan fasa karbon antara beberapa fasa alumina. Penilaian bagi sebatian hibrid CNT-alumina terisi nanokomposit epoksi menunjukkan sifat-sifat mekanik, terma dan dielektrik yang lebih tinggi berbanding CNT-alumina yang dicampurkan secara fizikal serta terisi nanokomposit epoksi. Peningkatan ini berkaitan dengan taburan seragam sebatian hibrid CNT-alumina seperti yang diperhatikan daripada FESEM dan HRTEM. Penggunaan sebatian hibrid CNT-alumina terisi nanokomposit epoksi telah dibuktikan mampu untuk meningkatkan kekuatan tegangan sehingga 30%, modulus tegangan sebanyak 39%, kekuatan lenturan sebanyak 30%, modulus lenturan sebanyak 35%, kekerasan sebanyak 17%, konduktiviti terma sebanyak 20%, nilai suhu peralihan kaca sebanyak 25% dan pemalar dielektrik sebanyak 20% apabila dibandingkan dengan epoksi yang tulen. _________________________________________________________________________________________________________________________ The incorporation of carbon nanotube (CNT) in polymer nanocomposites has become challenges for researchers due to its dispersion in polymer matrix. This work focuses on CNT-alumina hybrid compound prepared via chemical vapor deposition (CVD) which is used to improve dispersion and enhance the mechanical, thermal and dielectric properties of epoxy nanocomposites. The CNT-alumina hybrid compound was successfully synthesized via CVD by using nickel catalyst under methane atmosphere at 800 °C. The physically mixed CNT-alumina was also prepared by ball milling method for comparison. The CNT-alumina hybrid compound and physically mixed CNT-alumina filled epoxy nanocomposites were characterized according to their filler loadings (i.e. 1% - 5%). The CNT-alumina hybrid compound had the size between 10 – 30 nm and 12 Wt % of carbon according to field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM) and energy dispersive x-ray (EDX) analysis respectively, while x-ray diffraction (XRD) revealed the existence of carbon phase among several phases of alumina. The CNT-alumina hybrid compound filled epoxy nanocomposites assessments showed higher mechanical, thermal and dielectric properties than the physically mixed CNT-alumina filled epoxy nanocomposites. This increase is associated with the homogeneous dispersion of CNT-alumina hybrid compound as observed from FESEM and HRTEM. It was demonstrated that the CNT-alumina hybrid compound filled epoxy nanocomposites are capable of increasing tensile strength by up to 30%, giving tensile modulus of 39%, flexural strength of 30%, flexural modulus of 35%, hardness of 17%, thermal conductivity of 20%, glass transition temperature value of 25% and dielectric constant of 20% when compared to a neat epoxy

Woven Carbon Fiber Epoxy Composite Laminates Reinforced With Carbon Nanotube Interlayer Using Electrospray Deposition Method

The hybridization of woven carbon fiber-carbon nanotube (CF-CNT) received enormous attention from research communities in the field of epoxy laminates composites. In this study, electrospray deposition (ESD) method was used to deposit carbon nanotube (CNT) on the woven carbon fiber (CF) surface. The deposition of the CNT on the woven CF surface is intended to improve the surface roughness of the woven CF as well as to provide a mechanical interlocking between the woven CF and the epoxy matrix. For ESD method, the stability of the CNT in the solvent is very crucial during the ESD process and N-Methyl-2-Pyrrolidone is proven suitable for dispersing CNT due to high stability. The effect of voltage and spray time of ESD on the morphologies of the woven hybrid CF-CNT has been studied. The optimum voltage and spray time to achieve homogeneous and even CNT coating on the woven CF surface is 15 kV and 15 min, respectively. From single fiber test, the ESD method is found to be safe without any significant degradation on the tensile strength of the woven CF-CNT. The epoxy composite laminates with optimized woven hybrid CF-CNT and woven CF without deposited CNT were then prepared and compared in terms of mechanical, thermal and dielectric properties. The evaluation showed that woven hybrid CF-CNT epoxy composite laminates have greater mechanical, thermal and dielectric properties than woven CF epoxy composite laminates. The results demonstrate that the woven hybrid CF-CNT epoxy composite laminates are capable of improving tensile strength, tensile modulus, flexural strength, flexural modulus,interlaminar shear strength, thermal conductivity and dielectric constant about 21 %, 37 %, 19 %, 27 %, 25%, 35 % and 22 %, respectively, compared to the woven CF epoxy composite laminates

Dielectric performance of Hybrid Carbon Nanotube-Alumina Filled Epoxy Nanocomposites / Muhammad Razlan Zakaria...[et al.]

The multi-scale hybridisation of alumina (Al2O3) and carbon nanotubes (CNTs) was synthesised with the use of chemical vapour deposition (CVD). The CNTs were grown directly on the Al2O3 particle by utilising a nickel catalyst while being under an atmosphere of methane. When incorporated into the epoxy matrix, the CNT-Al2O3 hybrid filler provided new opportunity for the development of high performance multifunctional composites. The goal of hybridizing CNTs and Al2O3 particles is to avoid CNT agglomeration as a result of van der Waals attractions. The particles of Al2O3 serve as “vehicles” for CNTs so that they can homogenously disperse in the epoxy matrix. As a comparative study, preparation of CNT-Al2O3 was also done through a physical mixing method. The result revealed that compared to the CNT–Al2O3 filler that was physically mixed, the CNT–Al2O3 hybrid filler exhibited a more homogeneous dispersion within the epoxy matrix and it had a higher dielectric constant. Furthermore, compared to the neat epoxy, the dielectric constant of the CNT–Al2O3 hybrid epoxy nanocomposites was enhanced by up to 22%

Improvement of Fracture Toughness in Epoxy Nanocomposites through Chemical Hybridization of Carbon Nanotubes and Alumina

The current study investigated the effect of adding a carbon nanotube–alumina (CNT–Al2O3) hybrid on the fracture toughness of epoxy nanocomposites. The CNT–Al2O3 hybrid was synthesised by growing CNTs on Al2O3 particles via the chemical vapour deposition method. The CNTs were strongly attached onto the Al2O3 particles, which served to transport and disperse the CNTs homogenously, and to prevent agglomeration in the CNTs. The experimental results demonstrated that the CNT–Al2O3 hybrid-filled epoxy nanocomposites showed improvement in terms of the fracture toughness, as indicated by an increase of up to 26% in the critical stress intensity factor, K1C, compared to neat epoxy

Enhancement of Tensile Properties of Glass Fibre Epoxy Laminated Composites Reinforced with Carbon Nanotubes interlayer using Electrospray Deposition

The introduction of carbon nanotubes (CNTs) onto glass fibre (GF) to create a hierarchical structure of epoxy laminated composites has attracted considerable interest due to their merits in improving performance and multifunctionality. Field emission scanning electron microscopy (FESEM) was used to analyze the woven hybrid GF-CNT. The results demonstrated that CNT was successfully deposited on the woven GF surface. Woven hybrid GF-CNT epoxy laminated composites were then prepared and compared with woven GF epoxy laminated composites in terms of their tensile properties. The results indicated that the tensile strength and tensile modulus of the woven hybrid GF-CNT epoxy laminated composites were improved by up to 9% and 8%, respectively compared to the woven hybrid GF epoxy laminated composites

Structure property investigation of glass-carbon prepreg waste-polymer hybrid composites degradation in water condition

The limited shelf life of carbon prepreg waste (CPW) from component manufacturing restricts its use as a composite reinforcement fibre on its own. However, CPW can be recycled with glass fibre (GF) reinforcement to develop a unique remediate material. Therefore, this study fabricated (1) a glass fibre-carbon prepreg waste reinforced polymer hybrid composite (GF-CPW-PP), (2) a polypropylene composite (PP), (3) a carbon prepreg waste reinforced composite (CPW-PP), and (4) a glass fibre reinforced composite (GF-PP) and reported their degradation and residual tension properties after immersion in water. The polymer hybrid composites were fabricated via extrusion technique with minimum reinforce glass-carbon prepreg waste content of 10 wt%. The immersion test was conducted at room temperature using distilled water. Moisture content and diffusion coefficient (DC) were determined based on water adsorption values recorded at 24-h intervals over a one-week period. The results indicated that GF-PP reinforced composites retained the most moisture post-168 h of immersion. However, hardness and tensile strength were found to decrease with increased water adsorption. Tensile strength was found to be compromised since pores produced during hydrolysis reduced interfacial bonding between glass fibre and prepreg carbon reinforcements and the PP matrix

Improving flexural and dielectric properties of carbon fiber epoxy composite laminates reinforced with carbon nanotubes interlayer using electrospray deposition

The electrospray deposition method was used to deposit carbon nanotubes (CNT) onto the surfaces of woven carbon fiber (CF) to produce woven hybrid carbon fiber–carbon nanotubes (CF–CNT). Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the woven hybrid CF–CNT. The results demonstrated that CNT was successfully and homogenously distributed on the woven CF surface. Woven hybrid CF–CNT epoxy composite laminates were then prepared and compared with woven CF epoxy composite laminates in terms of their flexural and dielectric properties. The results indicated that the flexural strength, flexural modulus and dielectric constant of the woven hybrid CF–CNT epoxy composite laminates were improved up to 19, 27 and 25%, respectively, compared with the woven CF epoxy composite laminates

Hierarchical Carbon Fiber-Carbon Nanotubes by Using Electrospray Deposition Method with Preserved Tensile Properties

In this study, the electrospray deposition (ESD) method was used to deposit carbon nanotubes (CNT) onto the surfaces of carbon fibers (CF) in order to produce hybrid carbon fiber-carbon nanotubes (CF-CNT) which is rarely reported in the past. Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), high-resolution transmission electron microscopy (HRTEM) and x-ray photoelectron spectroscopy (XPS) were used to analyse the hybrid carbon fiber-carbon nanotube (CF-CNT). The results demonstrated that CNT was successfully and homogenously distributed on the CF surface. Hybrid CF-CNT was then prepared and compared with CF without CNT deposition in terms of their tensile properties. Statistically, the tensile strength and the tensile modulus of the hybrid CF-CNT were increased by up to 3% and 25%, respectively, as compared to the CF without CNT deposition. The results indicated that the ESD method did not cause any reduction of tensile properties of hybrid CF-CNT. Based on this finding, it can be prominently identified some new and significant information of interest to researchers and industrialists working on CF based products

Mechanical and Dielectric Properties of Hybrid Carbon Nanotubes-Woven Glass Fibre Reinforced Epoxy Laminated Composites via the Electrospray Deposition Method

Herein, the effects of multi-walled carbon nanotubes (CNTs) on the mechanical and dielectric performance of hybrid carbon nanotube-woven glass fiber (GF) reinforced epoxy laminated composited are investigated. CNTs are deposited on woven GF surface using an electrospray deposition method which is rarely reported in the past. The woven GF deposited with CNT and without deposited with CNT are used to produce epoxy laminated composites using a vacuum assisted resin transfer moulding. The tensile, flexural, dielectric constant and dielectric loss properties of the epoxy laminated composites were then characterized. The results confirm that the mechanical and dielectric properties of the woven glass fiber reinforced epoxy laminated composited increases with the addition of CNTs. Field emission scanning electron microscope is used to examine the post damage analysis for all tested specimens. Based on this finding, it can be prominently identified some new and significant information of interest to researchers and industrialists working on GF based products