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Hybrid fillers can be produced via various methods, such as physical mixing and chemical modification. However, there is a limited number of studies on the effect of hybridisation on the mechanical performance of hybrid filler-reinforced polymer composites, especially in the context of wear performance. This study investigated the wear resistance of carbon nanotubes (CNTs)/alumina hybrid-filled phenolic composite, where two hybrid methods were used to produce the CNTs/alumina hybrid filler. The CNTs/alumina (CVD hybrid) was synthesised using the chemical vapour deposition (CVD) method, whereas the CNTs-/alumina (physically hybrid) was prepared using the ball milling method. The CNTs/alumina hybrid filler was then used as a filler in the phenolic composites. The composites were prepared using a hot mounting press and then subjected to a dry sliding wear test using a pin-on-disc (POD) tester. The results show that the composite filled with the CVD hybrid filler (HYB composite) had better wear resistance than the composite filled with physically hybrid filler (PHY composite) and pure phenolic. At 5 wt%, the HYB composite showed a 74.68% reduction in wear, while the PHY composite showed a 56.44% reduction in wear compared to pure phenolic. The HYB composite exhibited the lowest average coefficient of friction (COF) compared to the PHY composite and pure phenolic. The average COF decreased with increasing sliding speeds and applied loads. The phenolic composites’ wear and average COF are in the order HYB composite < PHY composite < pure phenolic under all sliding speeds and applied loads.

The effect of the polymeric cross-link density on the thermal conductivity of an oxidized graphene (OG)-filled epoxy nanocomposite was investigated by two different fabrication methods, namely a conventional OG mixing (OGconventional) and a diamine–colloidized OG (OGcolloidized) method. Epoxy composites with 3 wt% OG were prepared via the diamine–OG fabrication method to produce an epoxy nanocomposite with a higher cross-link density than that of an epoxy composite with also 3 wt% of OG prepared via the conventional fabrication method. The cross-link densities of the epoxy nanocomposites were calculated by means of a solvent swelling test. The epoxy/OGcolloidized nanocomposite showed a higher cross-link density and higher thermal conductivity than the epoxy/OGconventional nanocomposite with the same filler concentration. It was observed that for the epoxy/OGcolloidized nanocomposite, where an amide network was relatively formed between the carboxylic and amine groups, a high cross-link density enhanced the thermal conductivity by means of the transport of phonons. Furthermore, high dispersion of OG gives high dielectric constant to epoxy/OGcolloidized even having the same amount of graphene loading.

A different sequence of epoxy composite preparation was performed by mixing oxidized graphene platelets (oGNP) with a curing agent prior to mixing it with epoxy resin. When oGNP was mixed with trimethylhexamethylene diamine (TMD), the condensation reaction between the hydroxyl and amine groups resulted in the formation of a TMD/oGNP colloid. The TMD/oGNP colloid was used to cure epoxy resin. The colloidization eventually improved the dispersion and prevented re-agglomeration in the epoxy resin. A thermogravimetric analysis showed that the thermal stability of the epoxy/oGNP system had improved, while the presence of the oGNP gave more stability to the solvent in terms of an increase in the crosslink density. These results showed that the TMD/oGNP colloid sequence was better able to enhance the properties of the epoxy composite compared to the conventional method of obtaining epoxy/graphene by mixing the graphene with the epoxy resin prior to adding in the curing agent.

Nano-sized carbons, such as graphene nanoparticle (GNP) and multiwall carbon nanotube (MWCNT), have attracted a great deal of attention due to their extraordinary intrinsic properties. Extensive research has been done on each carbon material for epoxy nanocomposites but only a few have ventured into a comparison study. In this paper, the effect of GNP and MWCNT, at various filler loadings, on the mechanical, thermal and dielectric properties of epoxy nanocomposites have been investigated. The experimental results demonstrate that GNP filled epoxy nanocomposites showed higher thermal and dielectric properties, but slightly lower mechanical properties compared to the MWCNT filled epoxy nanocomposites. The tensile strength, flexural strength, thermal conductivity and dielectric constant of GNP filled epoxy nanocomposites improved up to 11%, 17%, 126%, and 171% respectively, and MWCNT filled epoxy nanocomposites improved up to 26%, 29%, 60%, and 73% respectively.

The multi-scale hybridisation of carbon nanotube (CNT) and alumina (Al 2 O 3 ) was synthesised by using chemical vapour deposition. The idea of hybridisation between the CNT and Al 2 O 3 particles is to prevent the agglomeration of the CNT due to van der Waals attractions. The Al 2 O 3 particles work as “vehicles” for the CNTs to disperse homogenously in the epoxy matrix and improve the particle/matrix interface. Epoxy composites with the CNT–Al 2 O 3 hybrid compound were observed to exhibit an enhancement of 117% and 148% in compressive strength and compressive modulus, respectively. Similarly, thermal stability improvement has also been observed for the CNT–Al 2 O 3 hybrid compound epoxy composite system.

This paper presents a multi-scale hybridization of carbon nanotube (CNT) with clay in polymers, which offers improvement in the mechanical properties of the composites. In this study, hybrid filler, comprised of CNT grown directly on muscovite particles by chemical vapour deposition using methane as the carbon precursor, is prepared. This CNT–Muscovite Hybrid compound is incorporated into the epoxy matrix at various filler loadings (1–5 wt.%) and compared with physically mixed CNT–Muscovite. The tensile strength, tensile modulus, and micro-hardness of Epoxy/CNT–MUS HYB nanocomposites are determine to exhibit an improvement of up to 86.58%, 134.59% and 14%, respectively, compared to neat epoxy. These improvements are mainly attributed to by the good dispersion of CNT–Muscovite Hybrid in the epoxy composites. Keywords: Polymer composites, Nanocomposites, Multiwalled carbon nanotubes, Chemical vapour deposition

Hybridization of multi wall carbon nanotubes (MWCNTs) with other filler in polymer matrix composites (PMC) is one of the techniques for combining different properties of fillers for making more unique composites. In this work, the hybrid filler (CNTs–dolomite) are prepared via chemical vapour deposition (CVD hybrid) and the milling method (physically hybrid). The effect of different hybrid method on properties of multi wall carbon nanotubes/dolomite hybrid filled phenolic composites were studied. Phenolic/CVD hybrid composites and phenolic/physically hybrid composites with different filler loadings were prepared using hot mounting press. The prepared samples were characterized for their thermal conductivity and hardness. The thermal conductivity was measured using the Transient Plane Source (TPS) method, using a Hot-DiskTM Thermal Constant Analyzer and the hardness was measured using Rockwell micro-hardness. The results showed that at 5% filler loading, the phenolic/CVD hybrid composites were capable of increasing the thermal conductivity and micro-hardness up to 7.22% and 101.6% respectively compared to pure phenolic.

In this study, the authors attempted to enhance the flexural and dielectric properties of epoxy resin using advanced carbon nanotube–alumina (CNT–Al 2 O 3 ) hybrid filler system that was chemically synthesised via chemical vapor deposition (CVD). The hybrid CNT–Al 2 O 3 filled epoxy composite was compared to the physically mixed CNT–Al 2 O 3 filled epoxy composites. The assessment showed that the CNT–Al 2 O 3 hybrid filler produced more homogeneous dispersion in the epoxy matrix with higher flexural and dielectric properties as compared to the physically mixed CNT–Al 2 O 3 filler. The flexural strength, flexural modulus and dielectric constant of CNT–Al 2 O 3 hybrid epoxy composites improved significantly up to 30%, 35% and 20%, respectively, compared to the neat epoxy.

A novel hybrid carbon nanotube-muscovite (CNT-muscovite) compound was synthesized via chemical vapour deposition (CVD) by directly grown CNT on muscovite particles. The synthesis of CNT using nickel catalyst and muscovite as a substrate material is rarely found. Morphological analysis using scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) showed that the CNT was successfully grown on muscovite flaky particles. The CNT-muscovite compound can be potentially used as a new class of filler in polymer composites technology.

This paper presents the multi-scale hybridization of carbon nanotube (CNT) with microparticles in polymers which offers new opportunity to develop high performance multifunctional composites. The hybrid carbon nanotube-alumina (CNT-Al2O3) compound was synthesized via chemical vapour deposition (CVD) by direct growth of CNT on alumina particles. This hybrid CNT-Al2O3 compound was incorporated into the epoxy matrix at various filler loadings (i.e., 1–5%) and compared to physically mixed CNT-Al2O3. The CNT-Al2O3 hybrid epoxy composites showed higher hardness compared to the CNT-Al2O3 physically mixed epoxy composites. This enhancement was associated with the homogenous dispersion of CNT-Al2O3 hybrid compound in the epoxy matrix.

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.

This paper presents the properties of epoxy nanocomposites, prepared using a synthesized hybrid carbon nanotube–alumina (CNT–Al 2 O 3 ) filler, via chemical vapour deposition and a physically mixed CNT–Al 2 O 3 filler, at various filler loadings (i.e., 1–5%). The tensile and thermal properties of both nanocomposites were investigated at different weight percentages of filler loading. The CNT–Al 2 O 3 hybrid epoxy composites showed higher tensile and thermal properties than the CNT–Al 2 O 3 physically mixed epoxy composites. This increase was associated with the homogenous dispersion of CNT–Al 2 O 3 particle filler; as observed under a field emission scanning electron microscope. It was demonstrated that the CNT–Al 2 O 3 hybrid epoxy composites are capable of increasing tensile strength by up to 30%, giving a tensile modulus of 39%, thermal conductivity of 20%, and a glass transition temperature value of 25%, when compared to a neat epoxy composite.

As a result of its impressive 3D network structure form, a great deal of interest has thus been generated among the science community on the hybridization of carbon fiber (CF) and carbon nanotube (CNT). Although there had been a large amount of studies conducted on this novel hybrid material, there are however, limited reviews being published on their fabrication methods and performances in polymer composites. For this reason, apart from collectively introducing and discussing the advantages and limitations of the hybrid CF-CNT based on various fabrication methods such as those of chemical vapour deposition, electrophoretic deposition, electrospray deposition and chemical functionalization, this study had also examined and compared the detailed performances of each of the hybrid CF-CNT reinforced polymer composite based on their fabrication methods through its mechanical, electrical and thermal properties.

Carbon nanotubes-talc (CNTs-talc) hybrid compound has been successfully synthesized via chemical vapour deposition (CVD) method. A gas mixture of methane/nitrogen (CH4/N2) was used as the carbon source and nickel as the metal catalyst for the growth of CNT hybrid compound. Talc works as substrate or support material which is combined with nickel to form a complex metal-talc catalyst that will react with carbon source to produce the hybrid compound. To study the effect of different calcinations temperature, four different calcinations temperature, 300 °C (C-talc300), 500 °C (C-talc500), 700 °C (C-talc700) and 900 °C (C-talc900) were used. Among these four calcination temperatures for synthesis the multi-walled carbon nanotubes (MWCNTs), C-talc500 is the most optimum calcination temperature to perform catalytic decomposition by reacting in methane atmosphere at 800 °C to produce the CNT-talc hybrid compound.

Multiwalled carbon nanotubes/dolomite (MWCNT/dolomite) hybrid compound was synthesized using the Chemical Vapour Deposition (CVD) technique. The catalyst was prepared via the co-precipitation method. The process involves the drying of the precipitate followed by calcination at 900°C.Upon completion of calcinations process, the reduction process was carried under H2at 400°C and growth in a CH4/N2gas mixture at 800°C for 30 minutes The reduction process was carried out under H2and growth in a CH4/N2gas mixture at 800°C for 30 minutes. The morphological assessment using Field Emission Scanning Electron Microscope (FESEM) showed that the CNT was successfully grown on dolomite particle. High Resolution Transmission Electron Microscope (HRTEM) micrograph further confirmed the presence of MWCNT with varied length and geometry on dolomite surfaces, supported the formation of MWCNT on the dolomites particle.

Minerals are always used as filler material in polymer composite application purposely to reduce the price. In order to optimize the use of mineral fillers instead of price reduction, there were several approaches that have been done such as surface treatment, finding suitable coupling agent, and etc. The study on hybridization of minerals with carbon nanotubes (CNT) are rare to be found. CNT has received great attention from researchers due to their superior properties to be used in many applications. Hybridizing CNT with minerals proposes potential fillers for polymer composite. In this study, chemical vapor deposition (CVD) technique was used to synthesize the CNT-minerals hybrid compound. A mixture of CH4/N2was used as the carbon source and nickel as the metal catalyst for the growth of CNT hybrid compound. Three different types of minerals were used namely talc, muscovite and CaCO3are used to synthesize the MWCNT-talc, MWCNT-muscovite and MWCNT-CaCO3hybrid compound. In short, the process involved precipitation of mineral filler with nickel salt. The process was followed by calcinations and reduction of the catalyst, and methane decomposition. The produced hybrid compounds were then analyzed.

Hybridizing multiwalled carbon nanotube (MWCNT) with clay created a new class of functional materials especially for producing polymer layered silicate nanocomposite. The hybrid MWCNT/muscovite compound was produced using chemical vapor deposition (CVD) technique. It is rare to be found that the clay material such as muscovite to be used as a supporting material for MWCNT synthesis. X-ray Diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to characterize the hybrid compound. XRD analysis revealed the existence of carbon element among several clay elements of muscovite clay confirming the deposition of CNT. Microstructural analysis using HRTEM further showed that MWCNT was successfully grown on the surface of muscovite particles.

In this work, the chemical vapor deposition (CVD) technique was used to synthesis the multiwall carbon nanotubes/calcium carbonate (MWCNT/CaCO3) hybrid compound. A gas mixture of CH4/N2was used as the source of carbon and Ni/CaCO3was used as catalyst for the growth of the hybrid compound. The catalyst was prepared using a mixture of nickel salt and CaCO3via co-precipitation method. In short, the process involves the drying of the precipitate followed by calcinations at 900°C. Reduction process was carried under H2at 400°C and growth in CH4/N2mixture at 800°C for 30 minutes .The resulted compound was then analyzed using XRD, SEM and HRTEM. From XRD analysis the CNT/ CaCO3was successfully synthesized. HRTEM micrographs support the formation of MWCNT on the CaCO3surface.

Multiwall carbon nanotube (MWCNT) and alumina hybrid compound prepared via chemical vapour deposition (CVD). The CVD process always reported that the catalyst must undergo calcinations and reduction process before growing the carbon nanotube (CNT). In this work, MWCNT-alumina hybrid was successfully synthesized via simple CVD method. The morphologies study showed that the MWCNT-alumina hybrid with calcination and reduction, and calcination without reduction has been successfully synthesized.

This work focuses on synthesis of MWCNT-alumina hybrid compound via methane decomposition process using nickel catalyst. The catalysts prepared through in situ process by using nickel salt and aluminium powder which then calcined at 900oC followed by methane decomposition process to grow MWCNT on alumina surface. The Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM) images confirmed the formation of MWCNT with homogenous dispersion on alumina particles.

This work focuses on synthesis of MWCNT–alumina hybrid compound via methane decomposition process using Ni–Al2O3 catalyst. The catalysts prepared through in situ process by using nickel salt and aluminium powder which are then calcined at three different calcination temperatures (700 °C, 900 °C and 1100 °C). The catalyst calcined at 900 °C followed by methane decomposition process successfully yielded MWCNT–alumina hybrid compound. No trace of CNT was detected for catalyst calcined at 700 °C and 1100 °C. The scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) micrograph confirmed the formation of MWCNT with homogenous dispersion on alumina particles.