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In recent years, structural batteries have received great attention for future automotive application in which a load-bearing car panel is used as an energy storage. However, based on the current advances, achieving both high ionic conductivity and mechanical performance has remained a challenge. To address this challenge, this study introduces a cellulose nanocrystal (CNC) reinforced structural battery electrolyte (CSBE) consisting of CNC, triethylene glycol dimethyl ether (TriG) electrolyte containing a quasi-solid additive, e.g., cyclohexanedimethanol (CHDM), in a vinyl ester polymer. This green and renewable CSBE electrolyte system was

Our research aims to develop a shear forming envelope for the preforming of textiles, a critical step in the manufacture of fibre-reinforced composite materials. This paper demonstrates the progress towards this aim by conducting picture frame tests to empirically determine the locking angle of non-crimp fabrics with different fibre orientations. While conventional shear tests typically utilise woven textile samples with orthogonal fibre directions of 0°/90°, the investigation of non-crimp fabrics, especially with non-standard fibre orientations, is less common. As a result, there is little knowledge about the shear deformation behaviour of these fabric types, despite their relevance to the aerospace industry. In this study, the shear locking angles of various carbon fibre non-crimp fabrics are investigated, gradually reducing the relative fibre angles of the textile materials from ±45° to ±22.5°. Previously, it was observed that unidirectional 0° reinforcement layers induce draping defects when forming multiaxial non-crimp fabric stacks into curved aerospace stiffeners. Their substitution by reinforcements with smaller cross-ply angles such as ±30° resulted in better formability and reduced defects. It is however unclear, how the shear locking angle decreases with more acute cross-ply angles. Here, we report for the first time a correlation between the fibre orientation of the non-crimp fabric and its shear locking angle. The resulting shear forming envelope provides composite design and manufacturing guidance for an enhanced utilisation of the advantageous but anisotropic properties of carbon fibre textiles.

Aggregation induced photoluminescent quenching of graphene quantum dots (GQDs) is a well-known effect, although there are limited reports of multicolour light emissions from such aggregates. In the present work, we demonstrate a novel aggregation induced bathochromic shift in emission similar to J-aggregates observed in dye molecules. Nitrogen-doped graphene quantum dots (N-GQDs) prepared in the presence of diethylenetriamine show blue emission which is attributed to monomers at low concentration (58 μg/ml) while cyan (1.75 mg/ml), and greenish yellow (3.5 mg/ml) emissions are observed at higher concentrations under 365 nm UV lamp. These materials for the first time show yellow and orange emission from drop cast film of N-GQDs under 365 nm UV-light while the parent powder gives orange emission. The variety of emission colours that could be made simply by controlling the degree of aggregation presents exciting possibilities in a range of applications such as sensing, bioimaging, solar harvesting and forensic science.

Graphene and its associated compounds have been identified as extraordinary structural nano-fillers that can tailor the properties of new polymer-based composites with specific functionalities. Graphene possesses perfect 2D atomic architecture and has a large surface area that enhances the bonding, with tailored functional groups on its surface with polymer chains to form high strength composites. Recently, a lot of research has focused on developing composites with high specific strength, high electrical and thermal conductivities, high impact resistance, excellent energy storage capability and ability to maintain their strength at low-temperature environments by using graphene, graphene oxide (GO), reduced graphene oxide (rGO) or carbon nanotube/graphene. Ultimate goals are to design composites that can meet specific requirements for different engineering applications. In this paper, the discussion on all aspects in relation to the use of graphene and its associated compounds for advanced composites will be given in detail. The potentiality of using these materials for high-tech applications will be explored. Up to date, it has been proved that the use of graphene-based nanofillers does improve the mechanical, interfacial bonding, electrical, thermal and electromagnetic interference shield properties of polymer-based materials. Appropriately adding a small amount of these nanofillers do make a big difference to the properties of host materials.

Plasma-polymerised tetramethyldisiloxane (TMDSO) films are frequently applied as coatings for their abrasion resistance and barrier properties. By manipulating the deposition parameters, the chemical structure and thus mechanical properties of the films can also be controlled. These mechanical properties make them attractive as energy adsorbing layers for a range of applications, including carbon fibre composites. In this study, a new radio frequency (RF) plasma-enhanced chemical vapour deposition (PECVD) plasma reactor was designed with the capability to coat fibres with an energy adsorbing film. A key characterisation step for the system was establishing how the properties of the TMDSO films could be modified and compared with those deposited using a well-characterized microwave (MW) PECVD reactor. Film thickness and chemistry were determined with ellipsometry and X-ray photoelectron spectroscopy, respectively. The mechanical properties were investigated by nanoindentation and atomic force microscopy with peak-force quantitative nanomechanical mapping. The RF PECVD films had a greater range of Young’s modulus and hardness values than the MW PECVD films, with values as high as 56.4 GPa and 7.5 GPa, respectively. These results demonstrated the varied properties of TMDSO films that could in turn be deposited onto carbon fibres using a custom-built RF PECVD reactor.

A novel method to employ graphene oxide (GO) onto the surface of carbon fabrics to fabricate multi-scaled reinforced polymer composites by electrophoretic deposition has been popularly used in industry. In this study, various voltage supplies for depositing GO onto the surface of carbon fabrics with a controlled deposition time were applied. The flexural properties of GO/CFRP composites with different GO contents (0, 0.25, 0.5,0.75 and 1 wt%) conditioned at both room temperature and low temperature environments were investigated. Experimental results showed that 0.5 wt% and 0.25 wt% were the optimal GO contents to achieve better flexural strength and modulus of the composites by 20–54% at the room temperature and low temperature respectively as compared to pristine composites at room temperature. The addition of GO into CFRP composites helps improve the mechanical interlocking between carbon fibre and the matrix. The improvement of properties of GO/CFRP composites at low temperature is also attributed to the additional clamping force from contracted epoxy matrix to the expanded GO. Only 0.25 wt% of GO is sufficient to achieve the optimal flexural properties at low temperature due to the higher effectiveness of crack deflection provided by GO on the surface of carbon fabrics, leading to a high efficiency of energy dissipation by carbon fibre. Further increasing the GO content will form clusters, which may act as crack initiation sites.

Development of high-performance composites operating in harsh conditions is gaining tremendous attention due to the broad range of applications such as mass transport, defense, energy, manufacturin...

Epoxy resin will continue to be in the forefront of many thermoset applications due to its versatile properties. However, with advancement in manufacturing, changing societal outlook for the chemic...

Nanocellulose, as a biobased versatile nanomaterial that can be derived with tailorable surface functionalities, dimensions, and morphologies, has considerable implications for modifying the rheology, mechanical reinforcement, and influencing the carbonization efficiency in the production of polyacrylonitrile (PAN)-based carbon fibers. Herein, we report the influence of three different nanocellulose types, varying in the derivatization method, source, and aspect ratio, on the mechanical properties and thermal transformations of solution-spun PAN/nanocellulose nanocomposite fibers into carbon fibers. The incorporation of 0.1 wt % nanocellulose into solution-spun PAN fibers led to a 7-19% increase in tensile modulus and 0-27% increase in tensile strength in the solution-spun fibers, compared to a control PAN fiber. These improvements varied depending on the nanocellulose type. After low-temperature carbonization at 1200 °C, improvements in the mechanical properties of the nanocellulose-reinforced carbon fibers, compared with a PAN fiber, were also observed. In contrast to the precursor fibers, the improvement % in the carbonized fibers was found to be dependent on the nanocellulose morphology and was linearly correlated with increasing aspect ratio of nanocellulose. For example, in carbon fibers with a cotton-derived low-aspect-ratio cellulose nanocrystal and spinifex-derived high-aspect-ratio CNC and nanofiber, up to 4, 87, and 172% improvements in tensile moduli were observed, respectively. Due to the processing methods used, the nanocellulose aspect ratio and crystallinity are inversely related, and as such, the increase in the carbon fiber mechanical properties was also related to a decrease in crystallinity of the nanocellulose reinforcers. Raman spectra and electron microscopy analysis suggest that mechanical improvement after carbonization is due to internal reinforcement by highly ordered regions surrounding the carbonized nanocellulose, within the turbostratic carbon fibers.

In this study, graphene oxide (GO) was used to improve the mechanical properties of carbon fibre reinforced polymer (CFRP) composites at room temperature (RT) and cryogenic temperature (CT). It was found that GO could effectively improve the mechanical properties of CFRP composites at both temperature conditions as compared to pristine composites, particularly at CT due to its unique thermal response. Two approaches of employing GO into CFRP composites, either dispersing GO into epoxy matrix or coating it onto the surface of carbon woven fabric (CWF) were also investigated and compared. The results showed that GO devoted to a more significant improvement in the mechanical properties of composites when it was employed on the surface of CWF. It was also discovered that the flexural strength and modulus of CFRP composites were reduced at CT by 8.74% and 10.63% respectively, but the addition of GO would help restrict the degradation of matrix and limit the reduction to 1.15% and 2.09% respectively, and thus retain its enhanced mechanical properties.

We report the synthesis of giant carbon particles with spherical and interconnected porous morphologies. Direct organic–organic self-assembly between phenolic resin and polystyrene-block-poly(ethylene oxide) (PS-b-PEO) was employed to prepare these highly ordered carbon particles. Mesoporous carbon nanoparticles with tunable textural characteristics such as large surface area, uniform pore structure, and high thermal properties were achieved by simply adjusting the ratio between the block copolymer to phenol without using acid, base, or activating agents. The synthesized nanoparticles possess a very high surface area of up to 832 m2 g–1, and ultrasmall pore size, as small as 3 nm, and exhibited excellent electrochemical performance when used as active electrodes for lithium-ion batteries. Making use of the secondary interactions between the functional groups of the block copolymer and phenol, this study created tunable nanoparticles with excellent surface area and uniform morphologies that can be used in ...

Graphene has become an important research focus in many current fields of science including composite manufacturing. Developmental work in the field of graphene‐enhanced composites has revealed several functional and structural characteristics that promise great benefits for their use in a broad range of applications. There has been much interest in the production of multiscale high‐performance, lightweight, yet robust, multifunctional graphene‐enhanced fiber‐reinforced polymer (gFRP) composites. Although there are many reports that document performance enhancement in materials through the inclusion of graphene nanomaterials into a matrix, or its integration onto the reinforcing fiber component, only a few graphene‐based products have actually made the transition to the marketplace. The primary focus of this work concerns the structural gFRPs and discussion on the corresponding manufacturing methodologies for the effective incorporation of graphene into these systems. Another important aspect of this work is to present recent results and highlight the excellent functional and structural properties of the resulting gFRP materials with a view to their future applications. Development of clear standards for the assessment of graphene material properties, improvement of existing materials and scalable manufacturing technologies, and specific regulations concerning human health and environmental safety are key factors to accelerate the successful commercialization of gFRPs., This work considers the key approaches for the introduction of graphene nanomaterials into fiber‐reinforced polymer composites so‐called nanoaugmentation and nanoengineering methods to produce multiscale smart composites. The ultimate goal of this work is to facilitate the faster industrial adoption of graphene products by filling current barriers that the technology faces, including supply chain challenges, lack of safety and standardization regulations, as well as the research gaps.

Attachment of amine-bearing molecules, denoted surface grafted molecules (SGMs), onto the surface of carbon fibre has been previously shown to enhance interfacial interactions at the carbon fibre/epoxy interface. However, the design principles inherent to optimising this enhancement are not yet established. Here, we investigate the influence of SGM design criteria on the interfacial mechanical response for three types of SGM via predictions based on molecular dynamics simulations, and by experimental measurements. The SGMs are covalently grafted to the graphitic fibre surface via in situ generated and decomposed phenyl diazo salts. All three SGMs possess a phenyl ring as the surface attachment point, and differ by the number and/or position (meta or para) of the amine-terminated side-chain(s) attached to the ring. The single-chain meta-substituted SGM produces the least interfacial enhancement, while the double-chain meta-substituted SGM enhances the interfacial shear strength by 29% relative to the control. In contrast, the single-chain para-SGM performs almost comparably to the double-chain meta-SGM. Our modelling predictions recover this trend and offer molecular-scale explanations for these findings, providing guidance in the design of effective surface-tailoring strategies to realise enhancements in the shear response of carbon fibre–epoxy interfaces.

An accelerated aging study on silicone rubber exploring the effects of exposure to a functional oil (polyalkylene glycol) at elevated temperature (195°C) is reported in this paper. Variations in mechanical (tensile, tear, hardness) and thermal (conductivity, specific heat capacity) properties were monitored versus aging time while permanent deformation of the rubber was evaluated through creep and recovery measurements. Morphology and surface chemistry of the aged rubber were also investigated through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. Aging had a significant impact on the mechanical properties with the ultimate tensile strength and elongation at break decreasing from 7.4 MPa and 2250% in unaged samples to 1.5 MPa and 760% in 6-week aged samples, respectively. The tear strength and hardness exhibited an initial increase during the early stages of aging, followed by a decreasing trend. In contrast, the thermal properties did not chan...

Graphene-related materials (GRMs) have been identified as excellent nano-reinforcements for carbon fibre reinforced polymers (CFRPs) with regard to a wide range of engineering applications. GRMs are easily produced from their chief source, graphite, which is relatively affordable and abundantly available around the globe. The outstanding properties of GRMs, such as their large surface area, high mechanical strength and low manufacturing cost bring them to be distinguished nano-reinforcements for CFRPs to form multi-functional and multiscale composites. In this paper, the importance of using GRMs to enhance the properties of CFRPs is highlighted. Different synthesis methods for depositing GRMs onto the surface of carbon fibre and their effectiveness of improving the properties of host materials are reviewed and discussed. At this stage, more works are still needed to understand the basic stress transfer mechanism of GRM-coated CF composites. Their property enhancement at cryogenic environment are crucial for new aircraft and space engineering development.

Graphene has emerged as one of the promising nanoscale components of polymer nanocomposites owing to its exceptional properties. The 2D graphene material, when distributed appropriately in the host polymer can significantly alter the load, electron, and phonon transfer behavior of the nanocomposites. The in-plane strong covalent bonds in graphene are accountable for these unique properties, whereas the weak van der Waals forces existing between the adjacent monolayer graphene planes are responsible for the re-stacking or agglomeration of layers. Hence, the most critical challenge in translating these properties in high-performance graphene polymer nanocomposite is to alleviate the agglomeration of graphene. This can be achieved by improving the distribution states of graphene in the matrix by; (1) enhancing the dispersion and (2) controlling the relative lattice orientation of graphene in substrates to create an alignment or orientation. Mitigating the agglomerates during the composite fabrication will significantly extend the benefits of graphene's inherent properties to the nanocomposite. In this review article, various methods for improving dispersion and orientation of graphene in polymer nanocomposites is elucidated. A decision flowchart on the choice of dispersion or orientation based on the properties is considered and the techniques to quantify and verify the same is deliberated. Furthermore, composites' performance in terms of mechanical, electronic, and thermal enhancements due to the molecular level dispersion or anisotropic orientation of graphene is discussed. This review provides a constructive guidance in the composite processing methods and to correlate the enhancement of properties with the distribution state of graphene in composites.

Process modelling and simulation for composites manufacturing have advanced remarkably lately, evolving from just an assistive design tool to playing a pivotal role in the optimisation of Liquid Composite Moulding (LCM) processes. In particular, to improve the mould filling stage, the placement optimisation of resin injection gates and air vents on the mould design has received great research attention due to their substantial influence on the manufacturing efficiency and product quality. When optimisation algorithms are introduced into predictive numerical simulations to assist mould design, the notion of simulation-based optimisation is formed. This review provides a comprehensive literature compilation on the state-of-the-art of simulation-based optimisation of gates and vents configuration for LCM processes, focusing on the optimisation algorithms adopted and their respective search strategies. The search performance, solution optimality and application suitability of each algorithm with respect to different moulding scenarios are discussed to provide helpful guidelines for future optimisation studies.

A single material combining the unique properties of stable radical moieties with the versatility of the epoxy polymer is presented. Electrical conduction for any material is mostly achieved using metals, metal-organics, or organic conductors with extended π-orbital frameworks. However, in this combined material, intrinsic electronic conduction is enabled into the non-conjugated and amorphous epoxy thermoset. Furthermore, using the classical epoxy-amine curing ensures that only a highly crosslinked network with a rigid topology is formed. This design is a departure from other macroradicals with flexible backbones. The hole mobility of the neat macroradical epoxy thermoset is quantified to be ~3.1 × 10−6 cm2 V−1 s−1, already in the regime of traditional semiconductors. This electronic conduction can only be a result of radical-toradical hopping because the thermoset still retains active radicals after polymerization with a short alkyl amine when measured by electron spin resonance (EPR) spectroscopy. In the scientific literature, the synthesis of macroradicals using the direct approach is scarce. Herein, to obtain the novel radical epoxy monomer, a very mature yet simple amino-epoxide chemistry is employed to prepare a diglycidylamine based on 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl using the direct approach. EPR spectroscopy also reveals that the radical center remained stable even after epoxidation of the precursor. Consequently, this effort offers a change in thinking on how electronic conduction in open shell polymers operates especially on a rigid backbone and paves for a reassessment of the traditional epoxy polymer as enduring materials for frontier applications.

In this study, the electromechanical properties and strain monitoring behavior of graphene-coated glass fiber reinforced epoxy (GGFRE) composites were investigated. Glass fabrics were first coated with 2 wt% graphene dispersions using a blade coating method and composites of these graphene-coated glass fabrics were manufactured using vacuum resin infusion. As-prepared GGFRE showed an increase in normalized resistance (ΔR/R0) by 4.46%, 10.5%, 11.07% and 11.27% proportional to the applied cyclic tensile forces up to 2000N, 3000N, 4000N and 5000N, respectively. The corresponding gauge factors were calculated to be 14.56 ± 1, 13.32 ± 1, 11.23 ± 0.5 and 8.69 ± 2, respectively. It was also observed that under cyclic tensile loadings at 2000N, ΔR/R0 values were consistent within 11 cycles indicating a reliable sensing performance. The integration of graphene into the composite has shown to decrease the tensile strength as well as flexural strength and flexural modulus by 26%, 37% and 39%, respectively. This drop is believed to be caused by the lower fiber volume content in the GGFRE compared to that of the neat glass fiber composite and the ineffective interfacial interaction between the glass fiber and the graphene dispersion. The piezo-resistive behavior indicated by GGFRE along with their scalable manufacturing method suggest them as promising potential candidates for strain sensing applications.

There remain major concerns over the increasing use and waste of materials and energy resources in multiple manufacturing sectors. To address these concerns, some manufacturers have begun to align their R&D efforts with the circular economy principles: Reduce, Reuse, Recycle and Replace (RRRR). Focusing on advanced composites manufacturing sector, this paper presents an innovative approach for process design and analysis of a new waste heat recovery system for carbon fiber manufacturing. Namely, the stabilization process is known to be one of the most critical steps in the production of carbon fibers, as it consumes the most energy, has the largest factory footprint, is a complex system composed of many components, and is the largest capital investment within the factory line. The heat recovery system in this step of the manufacturing can notably reduce energy consumption, emission, cost, and conversion time, while aiming to maintain the mechanical properties of the final product. Here, via an actual industry-scale fibre production setting, the energy consumption factors were obtained and used to model the total energy and its balance in the thermal stabilization step. Two machine learning approaches with limited data, Artificial Neural Network and Non-Linear Regression were then constructed to predict the energy consumption. Results suggested that using the recovery system by means of a heat exchanger, can yield over 62.7 kW recovery, corresponding to 64% of total exhausted energy from the entire process. The electric energy consumption was reduced from 73.3 kW to 10.2 kW, which corresponded to an 86% improvement in the total energy efficiency. The model also confirmed that, by preheating the make-up air with the recovered energy, the energy performance index of the thermal stabilization can be increased from 0.08 to 0.44, along with a reduction in the process carbon footprint by 28.5 t/y. This is especially crucial as we are turning on smart digitalisation in manufacturing inspired by industry 4.0 concept with limited data.

Here we report on the role of oxygen in the evolution of radial heterogeneity in the fibre structure and properties of PAN fibres stabilized in air and vacuum at different temperatures. Modulus mapping by Nano-indentation showed heterogeneous modulus distribution in the fibres treated in air, while no variation in modulus was observed in fibres processed in vacuum. Raman spectroscopy and elemental analysis revealed that the temperature dependent oxygen diffusion from skin to core of the fibres assisted in the evolution of higher extent of sp2-hybridized carbons in the skin compared to core of the air treated samples. Conversely, no radial structure variations were observed in the vacuum treated fibres. Higher modulus in the skin of air-treated fibres was due to the formation of compact structures which was associated with the enhanced intermolecular interactions facilitated by the formation of C=C bonds within the polymer backbone, promoted by oxidative-dehydrogenation reaction. Supporting these observations, the fracture morphology examined by SEM showed a brittle fracture in the skin and ductile fracture in the core.

The energy requirements for the production of high quality carbon fiber and other carbon-based materials made by carbonization is a key factor limiting the commercial application of these materials. With the aim of enhancing the carbonization efficiency, we have prepared polyacrylonitrile (PAN) based precursor materials doped with high aspect-ratio cellulose nanofibers (CNF) derived from Australian spinifex grass (T. pungens). This was achieved by systematically investigating the rheology and electrospinning properties of composite fibers of PAN and CNF prepared at various CNF concentration levels and subsequently stabilized and carbonized. The carbon properties were characterized by X-ray diffraction and Raman spectroscopy. Upon carbonization, the incorporation of CNF into the PAN precursor led to changes in the crystallite and graphitic structure of the carbon materials, and these changes found to be closely related to the CNF concentration. CNF loadings of 0.5–2 wt % resulted in spinnable solutions wit...

Thermal stabilization of polyacrylonitrile (PAN) fibres is an essential step in the carbon fibre manufacturing process. The formation of radial heterogeneity in polyacrylonitrile precursor fibres in the thermal stabilization process is an important issue that is not well understood and needs to be addressed as it affects the quality of the resultant carbon fibres. Hence, in this review we put forward the recent developments on the evolution of radial heterogeneity in the PAN fibres during the thermal stabilization process.

The transformation of functional groups and development of radial structural heterogeneity during the thermal stabilization of polyacrylonitrile (PAN) precursor fibres were quantitatively defined for the first time using high resolution spectroscopic imaging techniques. The infrared imaging of isothermally treated fibre cross-sections reveals the radial distribution of specific functional groups (CN, CN, CH2, CH and CO) that forms the ladder polymer structure, the most critical stage in the precursor stabilization process. Apparently, it was found that the cyclization reaction of PAN polymer chains occurred at a faster rate in the core of the fibre during heating where it further selectively promoted the dehydrogenation reaction. On the other hand, the conversion of sp3 to sp2 hybridized carbon atoms was found to be higher around the skin layer compared to the core of the fibres, thus providing evidence for different cross-linking mechanisms in these regions. The simultaneous occurrence of a higher extent of cyclization and dehydrogenation reactions due to the excess heat developed in the core and a delay of oxygen diffusion in to the core of the fibres played a critical role in the polymer chain cross-linking in the skin and core regions that further led to the evolution of radial heterogeneity in the fibres. It was also found that the mechanical properties were built upon the structural transformations and the variation in the modulus across the fibre cross-section further confirmed the reaction mechanism.

A convenient and effective strategy to control the surface chemistry of carbon fibres is presented, comprising electro-chemical reduction of aryl diazonium salts onto the surface, followed by ‘click chemistry’ to tether the desired surface characteristic of choice. The power of this approach was demonstrated by engineering a small-molecule interface between carbon fibre and an epoxy matrix improving interfacial shear strength by up to 220%, relative to unmodified control fibres. The techniques used in this work do not impede the fibre performance in tensile strength or Young's modulus. This work provides a platform upon which any carbon fibre-to-resin interface can be easily and rapidly designed and implemented.

Microporous carbon material was fabricated via the in-depth sulfonation and carbonization of commercial polyethylene (PE) pellets for the first time. The change in thermal-stability, chemical structure, crystallinity and morphology of PE during the fabrication process was systematically analyzed. Porous polyethylene (PPE) clumps were firstly fabricated in a toluene/water mixed system via reprecipitation. Due to the efficient and homogenous sulfonation of PPE, the thermal-stability of sulfonated PE was improved significantly, with a weight retention as high as 51.9% at 700 °C. Sulfonation lead to the appearance of alkenyl and aromatic carbons. differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses showed that the crystallinity of PE decreased significantly after sulfonation. The crystallinity results obtained from DSC are much lower than those from XRD due to the decomposition involved in the DSC testing. Furthermore, many new pores were formed in PPE during sulfonation and the subsequent loss of the sulphonate groups. These pores were further expanded during the carbonization process which may be due to the direct solid weight loss as well as the fast diffusion of the gases produced in pyrolysis. This study opens a simple and new approach for the fabrication of microporous carbon material via in-depth sulfonation of PE.

Cross-linking multiple strands improves strength and toughness of polyacrylonitrile fibers

Carbon fibers undergo aqueous electrolytic oxidation during manufacturing to remove surface graphitic layers. Significant cost reduction and lower environmental impact could however be achieved by replacing electrolytic oxidation with a dry process, such as plasma treatment. This study demonstrates how air plasma treatment can be used as a dry surface modification process for carbon fibers, thus aiding in the understanding of the influence of surface treatment on surface chemistry, mechanical properties and fiber-matrix interactions. Greater oxygen incorporation resulted from electrolytic oxidation than air plasma treatment but had similar interfacial shear strengths, indicating that chemistry may have less of an effect on fiber-matrix adhesion than previously suggested. The removal of weakly bound surface graphitic layers and increases in surface roughness, which were achieved by both methods, appear to be the most important factors influencing fiber-matrix adhesion, thereby suggesting that dry plasma treatment could replace the current wet processing.

Graphene oxide (GO) films can be used in structural dielectric capacitors (SDCs) as both primary structures and energy storage devices for large transportation equipment like aircraft. To meet the high requirements for aviation application, in this paper the mechanical and dielectric properties of GO films were optimized by concisely tailoring their carbon-to-oxygen (C/O) ratio. Our results show that both the mechanical and electrical conductivity of GO films increase with increasing the C/O ratio. This work also demonstrates that both mechanical and dielectric properties of GO films can be enhanced simultaneously through a mild reduction whilst retaining the electrical insulating nature of GO for SDC applications. The insights provided in this work would be beneficial not only for SDC applications but also for fundamental studies and developments of GO related materials.

The present work deals with the characterization of multi-walled carbon nanotubes (MWCNTs) filled and unfilled short carbon fiber reinforced epoxy resin composites. Short carbon fibers (10 mm) were selected at various processing stages such as (i) white color polyacrylonitrile fibers (PAN); (ii) pre-carbonized carbon fibers (Precarb-CF); (iii) oxidized carbon fibers (OCF); (iv) fully carbonized carbon fibers (CF-low); and (v) sized carbon fibers (CF Sized). The investigated composites were characterized by three points bending test, hardness test, dynamic mechanical thermal analysis (DMTA), electrical conductivity test, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results show that the mechanical and electrical properties of the investigated materials markedly depend on the type of short carbon fibers and on the presence of MWCNTs. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers