Publications
48 results found
Anthony DB, Bacarreza Nogales OR, Shaffer MSP, et al., 2017, Crack arrest in finger jointed thermoplastic interleaved CFRC, 21st International Conference on Composite Materials, Publisher: Chinese Society for Composite Materials
Pre-cut unidirectional carbon fibre prepreg (M21/194/34%/T800S) composites were tested in tension with a 20 mm overlapped finger joint architectures. In between the overlapping finger jointed region the effect of introducing polyethersulfone (PES) interleaves is investigated. Samples with the addition of a thick PES interleave arrested the initial crack which formed at the pre-cut site. The strain-to-failure of the thick PES interleaved samples was over 3.2%, an increase of 85% compared to the baseline samples, and catastrophic failure was delayed in the majority of instances.
De Luca, Anthony DB, Greenhalgh ES, et al., 2017, Continuous production of carbon nanotube-grafted quartz fibres: Effect of carbon nanotube length on fibre/matrix adhesion, 21st International Conference on Composite Materials, Publisher: Chinese Society for Composite Materials
Here, the continuous production of carbon nanotube-grafted-quartz-fibres was performed in an open chemical vapour deposition reactor with continuous in line catalyst deposition. Highly graphitic carbon nanotubes (CNTs) with controllable lengths ranging from 0.1 μm to 20 μm were grown on the quartz fibre surface by adjusting the reduction and growth times, with shorter fibres growing homogeneously and longer CNTs growing in a splayed “Mohawk” manner. The effect of CNTs length (and thus microstructure) upon the mechanical properties of CNT-grafted-quartz-fibre/epoxy composites was investigated through single fibre pull-out test. The presence of a uniform coverage of sub-micron long CNTs led to an increase in interfacial shear strength of 11% and 29% when compared to sized and de-sized quartz fibres, respectively.
Anthony DB, Qian H, Clancy AJ, et al., 2017, Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition, Nanotechnology, Vol: 28, ISSN: 1361-6528
The application of an in-situ potential difference between carbon fibres and a graphite foil counter electrode (300 V, generating an electric field ca. 0.3 V μm-1 to 0.7 V μm-1) during the chemical vapour deposition synthesis of carbon nanotube (CNT) grafted carbon fibres, significantly improves the uniformity of growth without reducing the tensile properties of the underlying carbon fibres. Grafted carbon nanotubes with diameters around 55 nm and lengths around 10 μm were well attached to the carbon fibre surface, and were grown without the requirement for protective barrier coatings. The grafted CNTs increased the surface area to 185 m2 g-1 compared to the as-received sized carbon fibre 0.24 m2 g-1. The approach is not restricted to batch systems and has the potential to improve carbon nanotube grafted carbon fibre production for continuous processing.
Clancy AJ, anthony D, Fisher S, et al., 2017, Reductive dissolution of supergrowth carbon nanotubes for tougher nanocomposites by reactive coagulation spinning, Nanoscale, Vol: 9, Pages: 8764-8773, ISSN: 2040-3372
Long single-walled carbon nanotubes, with lengths >10 μm, can be spontaneously dissolved by stirring in a sodium naphthalide N,N-dimethylacetamide solution, yielding solutions of individualised nanotubide ions at concentrations up to 0.74 mg mL−1. This process was directly compared to ultrasonication and found to be less damaging while maintaining greater intrinsic length, with increased individualisation, yield, and concentration. Nanotubide solutions were spun into fibres using a new reactive coagulation process, which covalently grafts a poly(vinyl chloride) matrix to the nanotubes directly at the point of fibre formation. The grafting process insulated the nanotubes electrically, significantly enhancing the dielectric constant to 340% of the bulk polymer. For comparison, samples were prepared using both Supergrowth nanotubes and conventional shorter commercial single-walled carbon nanotubes. The resulting nanocomposites showed similar, high loadings (ca. 20 wt%), but the fibres formed with Supergrowth nanotubes showed significantly greater failure strain (up to ∼25%), and hence more than double the toughness (30.8 MJ m−3), compared to composites containing typical ∼1 μm SWCNTs.
Woodward RT, Jobbe-Duval A, Marchesini S, et al., 2017, Hypercrosslinked polyHIPEs as precursors to designable, hierarchically porous carbon foams, Polymer, Vol: 115, Pages: 146-153, ISSN: 0032-3861
Hierarchically porous carbon foams were produced by carbonization of hypercrosslinked polymerized high internal phase water-in-styrene/divinylbenzene emulsions (HIPEs). The hypercrosslinking of these poly(ST-co-DVB)HIPEs was achieved using a dimethoxymethane external crosslinker to ‘knit’ together aromatic groups within the polymers using FriedelCrafts alkylation. By varying the amount of divinylbenzene (DVB) in the HIPE templates and subsequent polymers, the BET surface area and micropore volume of the hypercrosslinked analogues can be varied systematically, allowing for the production of carbon foams, or ‘carboHIPEs’, with varied surface areas, micropore volumes and pore-size distributions. The carboHIPEs retain the emulsion-templated macropores of the original polyHIPE, display excellent electrical conductivities and have surface areas of up to 417 m2/g, all the while eliminating the need for inorganic templates. The use of emulsion templates allows for pourable, mouldable precursors to designable carbonaceous materials.
Anthony DB, bismarck A, blaker JJ, et al., 2016, Development of novel composites through fibre and interface/interphase modification, 37th Risø International Symposium on Materials Science, Publisher: IOP, Pages: 012001-012001, ISSN: 1757-8981
We show how fibre/matrix interface (or interphase) modification can be used to develop a range of novel carbon fibre reinforced polymer (CFRP) composites that open up new applications far beyond those of standard CFRPs. For example, composites that undergo pseudo-ductile failure have been created through laser treatment of carbon fibres. Composites manufactured with thermo-responsive interphases can undergo significant reductions in stiffness at elevated temperatures. Additionally, structural supercapacitors have been developed through a process that involves encapsulating carbon fibres in carbon aerogel.
De Luca H, Anthony DB, Qian H, et al., 2016, Non-damaging and scalable carbon nanotube synthesis on carbon fibres, ECCM17 - 17th European Conference on Composite Materials
The growth of carbon nanotubes (CNTs) on carbon fibres (CFs) to produce a hierarchical fibre with two differing reinforcement length scales, in this instance nanometre and micrometre respectively, is considered a route to improve current state-of-the-art fibre reinforced composites [1]. The scalable production of carbon nanotube-grafted-carbon fibres (CNT-g-CFs) has been limited due to high temperatures, the use of flammable gases and the requirement of inert conditions for CNT synthesis, whist (ideally) maintaining underlying original substrate mechanical properties. Here, the continuous production of CNT-g-CF is demonstrated in an open chemical vapour deposition (CVD) reactor, crucially, whilst retaining the tensile properties of the carbon fibres. As synthesised CNTs have a diameter of sub 20 nm and length ca. 120 nm, which are predicted to provide ideal fibre reinforcement in composites by retaining optimal composite fibre volume fraction (60%), whilst improving interfacial bonding of the matrix and reinforcement [1, 2]. Mild processing techniques enable this modified CVD process to be fully compatible with industrial practices, and have the potential to generate large volumes of hierarchical CNT-g-CF material.
Anthony DB, Grail G, Bismarck A, et al., 2016, Exploring the tensile response in small carbon fibre composite bundles, ECCM17 - 17th European Conference on Composite Materials
Small composite bundles, AS4 carbon fibre epoxy, with a restricted number of reinforcing fibres, ca. 20, showed a progressive failure when tested in tension. In-situ acoustic emission observations under tensile load reveal that numerous fibres fail before ultimate failure of the small composite bundle, suggesting that isolated and individual fibre failures occur without compromising the integrity of the neighboring fibres or the small composite bundle’s overall mechanical performance. The average strength of the carbon fibres in small composite bundles was 9.6% higher than in standard lab-scale composite specimens using the same fibre type.
Blaker JJ, Anthony DB, Tang G, et al., 2016, Property and shape modulation of carbon fibers using lasers, ACS Applied Materials & Interfaces, Vol: 8, Pages: 16351-16358, ISSN: 1944-8244
An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, whilst maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Upon loading the tapered fibers allow for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75 fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes.
Woodward RT, Fam DWH, Anthony DB, et al., 2016, Hierarchically porous carbon foams from pickering high internal phase emulsions, Carbon, Vol: 101, Pages: 253-260, ISSN: 0008-6223
Carbon foams were produced from a macroporous poly(divinylbenzene) (poly(DVB) precursor, synthesized by polymerizing the continuous but minority phase of water-in-oil high internal phase emulsions (HIPEs) stabilized by molecular and/or particulate emulsifiers. Both permeable and non-permeable hierarchically porous carbon foams, or ‘carboHIPEs’, were prepared by carbonization of the resulting macroporous polymers at 800 °C. The carbon yields were as high as 26 wt.% of the original polymer. CarboHIPEs retain the pore structure of the macroporous polymer precursor, but with surface areas of up to 505 m2/g and excellent electrical conductivities of 81 S/m. Contrary to some previous reports, the method does not require further modification, such as sulfonation or additional crosslinking of the polyHIPE prior to carbonization, due to the inherently crosslinked structure of poly(DVB). The use of a pourable, aqueous emulsion-template enables simple moulding, minimises waste and avoids the strong acid treatments used to remove many conventional solid-templates. The retention of the macroporous structure is coupled with the introduction of micropores during carbonization, producing hierarchically porous carboHIPEs, suitable for a wide range of applications as sorbents and electrodes.
Anthony DB, Shaffer MSP, 2016, Process for producing carbon-nanotube grafted substrate, WO 2016009207 A1
The present invention relates to a process for producing a carbon nanotube-grafted substrate, the process comprising: providing a substrate having catalytic material deposited thereon; and synthesising carbon nanotubes on the substrate by a chemical vapour deposition process in a reaction chamber; characterised in that the process comprises providing a counter electrode, applying a potential difference to the substrate in relation to the counter electrode and maintaining the potential difference of the substrate in relation to the counter electrode during the chemical vapour deposition process.
Qian H, Nguyen S, Anthony DB, et al., 2015, Stiff monolithic aerogel matrices for structural fibre composites, 20th International Conference on Composite Materials, Publisher: iccm-central.org
Resorcinol-formaldehyde based aerogel precursors were infused into structural carbon fibreweaves, then gelled and carbonised to generate a continuous monolithic matrix network. Thishierarchical carbon preform was subsequently infused with polymeric resins, both multifunctional andstructural, to produce dense composites. The resulting hierarchical composites have a nanoscalereinforcement in the matrix at up to an order of magnitude higher loadings than typically available byother techniques. Compression, tension, ±45° shear and short beam tests demonstrate the potential ofsuch matrix systems to address matrix dominated failures. However, for the best structuralperformance it will be necessary to re-optimise the fibre-matrix interface, which is degraded by thecurrent processing regime.
Blaker JJ, Anthony DB, Tang G, et al., 2015, Carbon fibres with modulated properties and shape along the fibre length, 20th International Conference on Composite Materials, Publisher: ICCM
This paper presents a detailed experimental examination of the influence of the thickness of flatenergy directors (ED) on the ultrasonic welding (USW) process for carbon fibre/polyetherimidecomposites. Three thicknesses of flat ED were compared: 0.06 mm, 0.25 mm and 0.50 mm. Power anddisplacement data for 0.06 mm-thick EDs did not clearly show the stages of the process and thelocation of the optimum for best weld quality. Consequently, an investigation of samples welded atdifferent stages in the welding process had to be performed. For 0.06 mm-thick EDs, the optimum wasdetermined to occur at the beginning of the downward displacement of the sonotrode in the vibrationphase. The output parameters at the optimum conditions for all thicknesses were compared. Averagelap shear strength was found to be lowest for 0.06 mm-thick EDs. Based on the analysis of the fracturesurfaces, resin flakes and voids were observed when using the thinnest energy directors, indicatingthermal degradation. These observations suggest that thin energy directors are not as efficient asthicker EDs (i.e. 0.25 mm) to achieve preferential heat generation at the weld line, leading to lessconsistent weld quality.
Menzel R, Barg S, Miranda M, et al., 2015, Joule Heating Characteristics of Emulsion-Templated Graphene Aerogels, ADVANCED FUNCTIONAL MATERIALS, Vol: 25, Pages: 28-35, ISSN: 1616-301X
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- Citations: 97
Hodge SA, Tay HH, Anthony DB, et al., 2014, Probing the charging mechanisms of carbon nanomaterial polyelectrolytes, FARADAY DISCUSSIONS, Vol: 172, Pages: 311-325, ISSN: 1359-6640
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- Citations: 23
Anthony D, 2013, Improved synthesis of carbon nanotube grafted carbon fibre: Towards continuous production
Grafting carbon nanotubes (CNTs) onto reinforcing fibre surfaces has been shown to improve composite structural performance, through improved interfacial bonding of the matrix and reinforcement. Sourcing a suitable amount of CNT-grafted fibre has currently limited test coupons geometry and development in the area. The scale-up of current synthesis procedures for grafting CNTs onto carbon fibre (CF) surfaces, using low intensity processing techniques (minimal processing of fibre substrate) compatible with industrial practices has not yet been reported. CNT growth from CF surface (CNT-g-CF) without damaging the mechanical parent fibre properties is a challenge as chemical vapour deposition (CVD) CNT growth typically results in catalyst pitting and surface defects occurring. In this thesis I attempt to address concerns detailed above; through the development of a catalyst system which is easily deposited onto CF, uses a CVD CNT-synthesis method which does not damage the original fibre properties in a potentially continuous scalable manner. I present a simple incipient wetness technique for loading a bi-catalyst precursor mixture onto CF. CF pre-deposited with bi-catalyst precursor under the application of an electric field, using CF as an electrode, in-situ during conventional thermal-CVD demonstrated significant promotion of CNT-synthesis directly from the CF surface. Electric field applied during CVD CNT-synthesis produces CNT-g-CF without apparent mechanical degradation to the parent fibre retaining original mechanical properties. When CVD CNT-synthesis is undertaken without the application of an electric field, degradation of original mechanical properties are witnessed. Batch CVD process was adapted, in an attempt to demonstrate the feasibility of continuous production of CNT-g-CF in a bespoke continuous CVD set-up. Alternative routes for CNT-g-CF including a novel silicon oxide based CNT-synthesis are also discussed.
ANTHONY DB, HOWARD JB, 1976, COAL DEVOLATILIZATION AND HYDROGASIFICATION, AICHE JOURNAL, Vol: 22, Pages: 625-656, ISSN: 0001-1541
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ANTHONY DB, HOTTEL HC, HOWARD JB, et al., 1975, RAPID DEVOLATILIZATION AND HYDROGASIFICATION OF BITUMINOUS COAL, Publisher: AMER CHEMICAL SOC, Pages: 31-31, ISSN: 0065-7727
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- Citations: 1
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