Carbon Yarns Research Articles

Insertion of Dye-Sensitized Solar Cells in Textiles using a Conventional Weaving Process.

Increasing demands for wearable energy sources and highly flexible, lightweight photovoltaic devices have stimulated the development of textile-structured solar cells. However, the former approach of wire-type solar cell fabrication, followed by weaving of these devices, has had limited success, due to device failure caused by high friction forces and tension forces during the weaving process. To overcome this limitation, we present a new approach for textile solar cell fabrication, in which dye-sensitized solar cell (DSSC) electrodes are incorporated into the textile during the weaving process, using the textile warp as a spacer to maintain the DSSC structure. Porous, dye-loaded TiO2-coated holed metal ribbon and Pt nanoparticle-loaded carbon yarn were used as the photoanode and counterelectrode, respectively. The highly flexible textile-based solar cell was fabricated using a common weaving process with a loom. The inserted DSSCs in the textile demonstrated an energy conversion efficiency of 2.63% (at 1 sun, 1.5 A.M.). Our results revealed that additional performance enhancement was possible by considering other electrode materials and textile structures, as well as where and how the DSSC electrodes are inserted. In addition, we demonstrated that the inserted DSSCs could be electrically connected using a parallel configuration.

Non-Invasive Sensor for Quantitative Determination of Lactate in Sweat

Lactic acid is a key biomarker of anaerobic respiration and descriptor of an individual’s health state. Currently, lactate monitoring is performed though continuous invasive blood sampling and sample processing which is inconvenient and unpractical when trying to obtain real time measurements of an active individual. Non-invasive sensing methods are needed for monitoring human performance in sports, military and health care fields. Lactate is found in various bodily fluids including sweat and a correlation between blood and sweat lactate concentration has been determined (1). Hence, monitoring sweat lactate levels is a good noninvasive alternative to blood sampling methods. Here we report the development, characterization and optimization of an amperometric lactate sensor based on a lactate dehydrogenase and carbon nanotube chitosan electrode coupling system previously developed by our group (3). Due to the high overpotential of NADH oxidation, the electrocatalyst, polymethylene green (PMG) was electrochemically deposited onto the surface of multi-walled carbon nanotube (CNT) material called Bucky paper for NAD⁺ regeneration. Lactate dehydrogenase was immobilized onto the Bucky paper-PMG electrode with a chitosan-based carbon nanotubes (CNT) mixture. The bioelectrodes were tested in a standard three-electrode polycarbonate cell hardware consisting of enzymatic working electrode, Ag/AgCl reference and platinum wire counter electrode and operated in a chronoamperometric regime. Sweat composition varies between individuals and different parts of the human body resulting in variations in pH, salt concentration (related to conductivity,) and lactate levels before and after exercise with rates of release decreasing over time. In order to address some of these issues, calibration curves at various buffer pHs and buffer concentrations were created (Fig 1). The variation of pH of solutions from 5 to 7 showed an increase in bioelectrode response. The slope of the current/lactate concentration linear dependence was strongly influenced by the solution pH with low pH leading to decreased sensitivity most likely as a result of influenced enzyme activity. A similar trend was observed when the concentration of the electrolyte was varied from 0.01 to 0.245 M. The slope of the calibration curve was strongly influenced by the solution conductivity with low values leading to decreased reproducibility and sensitivity. In all cases the electrode response was linear with lactate concentration allowing one to tailor the system based on individual needs. An artificial sweat was prepared, composed of NaCl, urea, pH 6.5, glucose, NAD⁺, and having a conductivity of 16.6 mS/cm. As it was expected the initial tests of the LDH-electrode with the artificial sweat showed lower sensitivity most likely due to low conductivity of the solution, the generated current form the lactate oxidation followed linear dependence from lactate concentration (data not shown). The strong dependence of the slope of the sensor calibration curve from the electrolyte conductivity and pH can be minimized by buffering the sweat, which in real conditions is performed by impregnation of the sensor sweat collector with a buffer salts. A prototype of a patch lactate sensor was developed composed of a LDH-working electrode, a Ag/AgCl reference electrode and carbon yarn counter electrode. The three electrodes were placed on a medical adhesive and covered with a bandage, preventing a contact between electrodes and the skin and at the same time adsorbing and collecting the sweat. The designed patch sensor displayed an increase in current density with increasing lactate concentration with high sensitivity. To avoid artificial introduction of NAD+ in the sweat, a method for NAD+immobilization of the electrode surface will be implemented along with encapsulation of the enzyme into silica gel matrix, which improve the linearity of the response and prolong the life -time of the sensor. The proposed amperometric enzyme electrode coupling approach along with optimization experiments provides the opportunity to monitor noninvasively and in real-time sweat lactate concentrations. (1) Sakharov, D.A. et al., 2010. Relationship between lactate concentrations in active muscle sweat and whole blood. Bull. Exp. Biol. Med.. 150 (1) 83-5. (2) Nikolaus, N., and Strehlitz B., 2008. Review. Amperometric lactate biosensors and their application in (sports) medicine, for life quality and wellbeing. Microchim Acta. 160, 15-55. (3). Narvaez Villarrubia C.W. et al., 2011. Biofuel cell anodes integrating NAD⁺-dependent enzymes and multiwalled carbón nanotube papers. ACS Appl. Mater Interfaces. 2011, 3(7), p. 2402-9 (7) Figure 1

J2310102 硬式野球用複合バットに関する研究

Hollow barrel baseball bats have higher batting performance than wooden bats. Generally, hollow metal bats are made from aluminum alloy tubes, and hollow composite baseball bats are madewith fiber glass, carbon yarn and others. In this study, a hollow composite baseball bat, which has a better batting performance than current commercial metal or composite bats, was proposed. The materials of the proposed composite bat include: an aluminum alloy in the grip part, coupled with an aluminum alloy and CFRP (Carbon Fiber Reinforced Plastics) in the barrel part. The effects of the bending and hoop modes of the hollow metal and composite barrel bats were investigated by modal analysis. Collisions between the bat and baseballs thrown using the pitch types of no-spin (knuckle ball) and back-spin (fastball), and the vertical offset distance (the height of the center distance between the bat and ball) varying between 0 to 20 mm were simulated. From the results of the simulations, the proposed new bat was found to have a high BBCOR (Bat-Ball Coefficient of Restitution) compared to metal baseball bats. It has been shown that the new composite barrel bat increases the performance of the hollow baseball bat.

Treatment of domestic and distillery wastewater in high surface microbial fuel cells

Microbial fuel cells (MFCs) are bio-electrochemical devices that couple organic carbon removal from wastewater and electricity production. Full-scale application of MFCs in a wastewater treatment plant (WWTP) requires high surface, lowcost electrodes to maximize microbial growth and power output. In this study, a high surface MFC anode is constructed by interlacing carbon yarn with stainless steel. The anode is arranged in a double-air cathode MFC configuration with 6 ± 1 Ω internal resistance. When closed on 100 Ω external resistances in batch mode, the MFCs produce maximum power densities of 621 ± 17 and 364 ± 11 mW m−2 for domestic and distillery wastewater, respectively. The chemical oxygen demand (COD) removal is 68% and 58% with a columbic efficiency of 47% and 27% for domestic and distillery wastewater, respectively. The biofouling layer on the Nafion membrane is twofold thicker in the domestic wastewater MFC, thereby suggesting that the power output and COD removal in distillery wastewater MFC are not limited by the cation transport across the membrane, but rather by the chemical composition of the distillery wastewater that does not support an efficient electrochemically active microbial community.

Effects of elevated temperatures on the interface properties of carbon textile-reinforced concrete

This work reports on an experimental investigation of the influence of elevated temperatures on the interface between carbon yarns and a Portland cement based matrix. Polymer-coated and uncoated carbon yarns were tested at temperatures of 20°C under a double-sided pullout test configuration after being subjected to a heating regime at temperatures of 100, 150, 200, 400 and 600°C. The degradation mechanisms of the cementitious matrix were investigated by X-ray diffraction and thermal analysis. Using an environmental scanning electron microscope, micro-structural analysis was performed to evaluate the degradation of the carbon yarn and of its interface with the matrix. After preheating up to 150°C, samples with coated fibres showed significant increases in maximum pullout load and, correspondingly, work to pullout. On a micro-scale this is related to a polymer interlocking mechanism in the yarn–matrix interface, which is generated during the heating and cooling of the polymer yarn coating. Above 400°C no further typical fibre pullout behaviour was observed; the reinforcing yarn failed suddenly after the cracking of the matrix. For uncoated yarn preheating up to 200°C had no significant impact on the maximum pullout load. At 600°C the matrix and fibres showed major signs of deterioration; no further typical fibre pullout behaviour other than failure of the reinforcing yarn could be observed.

Influence of weaving structure and hybridization on the tensile properties of woven carbon-epoxy composites

In this study, the mechanical properties of composite materials obtained from carbon and carbon-aramid hybrid woven fabrics produced in different constructions with the same yarn and under the same production conditions were determined, and the effects of weaving structure and hybridization on the mechanical properties were investigated. For this purpose, the geometric properties of carbon fabrics made from 12 K carbon yarn with four different weaving structures and two carbon-aramid hybrid fabrics made of 12 K carbon yarn and aramid yarn with two different structures were defined, and the mechanical properties of the composite materials were investigated under uniaxial tensile loading. The mechanical properties of the composite materials produced from the carbon and carbon-aramid hybrid fabrics were compared. The effects of weaving structure and hybridization on the mechanical properties were determined. Based on the weaving construction, Young’s modulus and the tensile strength declined approximately 34–39% and 24–27%, respectively. However, Young’s modulus was 16–63% higher than the expected value for the hybrid composites.

Study on the Properties of Coffee Carbon Filament Yarns

Coffee carbon fiber is a kind of functional polyester fiber. Waste coffee grounds is milled into nanometer powder and then added to the polyester spinning fluid. Coffee carbon filament yarns have the functions of antibacterial deodorant, sending anion, and thermal insulation. In this paper, the morphology and properties of coffee carbon filament yarns were tested, such as scanning electron microscopy, tensile, moisture regain and cohesion. Polyethylene terephthalate filament yarns were selected for comparison with coffee carbon yarns. The results show that coffee carbon powder is distributed both on the surface and inside of filament yarns; the moisture regain of coffee carbon filament yarns is higher than that of PET yarns; the strength and elongation of coffee carbon filament yarns and of PET filament yarns is close; the boiling water shrinkage of coffee carbon filament yarns is lower than that of PET filament yarns; the addition of carbon powder can not reduce the cohesion of coffee carbon filament yarns.

Influence of bundle coating on the tensile behavior, bonding, cracking and fluid transport of fabric cement-based composites

The goal of this work was to study the mechanical performance and fluid ingress of fabric cement based components made of epoxy coated and non-coated multifilament carbon fabrics. Direct tensile, pullout, and fluid transport tests were performed. Cracking was observed using four test geometries: (i) tensile tests, (ii) pullout tests, (iii) restrained shrinkage tests, and (iv) wedge splitting tests. The results show that coating multifilament carbon yarns improves mechanical behavior and bonding of the composite when compared with non-coated carbon yarn composites. The non-coated carbon systems may be problematic due to poor bonding as well as their potential to permit fluid ingress along the bundle–matrix interface and through the empty spaces between filaments. In addition, it was also found that fabric with coated bundles reduces crack width and develops dense branched network cracks. However, these additional fine cracks were found to increase fluid ingress into the matrix as compared with the plain cement paste.

Modelling and simulation of damage in woven fabric composites on meso-macro level using the independent mesh method

Composite material with woven architectures has become a common material in today’s in-service aircraft with applications in primary and secondary structures. Within the research community the simulation of woven composites with its complex microstructures including undulations and fibre waviness is still an active topic. A common approach for simulation of these types of composites often includes homogenisation of the local fabric response (meso level) for macro level analysis and consequently losing the spatial variations in the laminate. In this paper, a modelling and simulation method is presented for woven composites on a combined meso and macro scale to preserve this spatial variation. The carbon yarns are embedded in the matrix material using the independent mesh method. This is combined with a progressive damage model for the yarns and plasticity for the matrix material. The results of the presented approach are encouraging and can be used to gather detailed information on the local stress state and damage in the woven structure and therefore a better prediction on higher levels in the structure.

Thermal Activation of Asymetrical Composites for Vibration Control

The CBCM (Controlled Behaviour Composite Material) is a thermal active composite, which has been developed for morphing applications. The thermal activation is made by a source of heating generated within the composite structure. The coupling between the induced thermal field and the thermomechanical properties of the various components of the composite structure leads to the change of the structure shape. The heat source is generated by Joule effect, Carbon yarns inserted in the composite, are connected to a power supply. The application field of CBCM technology is the domain of shape modification and active assembly. The objective of this work is to illustrate the capabilities of CBCM in the domain of vibration control. We will study several reference plates with different constitution. The influences of these different constitutions, of the CBCM effect and the loss of stiffness for the matrix will be highlighted, for two boundary conditions, free/free and embedded/embedded.

Thermaly Active Structures for Shape Morphing Applications

For shape morphing application, thermal activation coupling to a bimetallic strip effect can be a substitute for classical actuators, piezoelectrical or shape memory alloys. The controlled behaviour of composite material (CBCM) is a thermaly activated composite material. The thermal activation is made thanks to carbon yarns which are connected to a power supply. If the anisotropy of the structure is well organized, the desired deformation is reached when the temperature within the composite is rising. To obtain a CBCM morphing composite structure, it is necessary to design a specific structure. The aim of this work is to show that it is possible to adapt the CBCM principle in order to transform any kind of classical composite structure to an active structure. The first part of this work consists in presenting the experimental results for two examples of composite beams. The second part is about the active structure FEM modeling and the development of adapted tools for this particular design.

Studies on Properties of the Coconut Carbon Fiber and Yarn

A new health care fiber-coconut carbon fiber, and yarn use coconut carbon fiber and cotton blended into are introduced in this paper. And a series of performance testing and analysis about scanning electron microscopy, infrared spectrum, strength, hairiness, moisture content and acid and alkali resistance are done to the carbon fiber and coconut yam.

Identification of the effective bundle length in a multifilament yarn from the size effect response

The article proposes a method for characterizing the in situ interaction between filaments in a multifilament yarn. The stress transfer between neighboring filaments causes the reactivation of a broken filament at some distance from the break. The utilized statistical bundle models predict a change in the slope of the mean size effect curve once the specimen length becomes longer than the stress transfer length. This fact can be exploited in order to determine the stress transfer length indirectly using the yarn tensile test with appropriately chosen test lengths. The identification procedure is demonstrated using two test series of tensile tests with AR-glass and carbon yarns.

Heat durability of carbon fiber reinforced nickel composites

Carbon fiber is a highly heat resistive material in an oxygen free atmosphere. Nickel is also a heat resistive metal and an important element for a superalloy. We can expect an excellent heat durable composite when they are combined. Nickel was electroplated on a carbon yarn to form a monofilament composite. When the high strength fiber was tested, the composite started to lose its strength at 600°C. The deterioration was caused by graphitization of the carbon in the fiber. This is caused by the difference of the graphitization degree between crystallites in a fiber. A high modulus carbon fiber has little difference of the graphitization degree in a fiber. The high modulus fiber did not react when tested and the fiber strength was maintained after heat treatment at 1100°C for 9 h. From the results, the high modulus carbon fiber composite is promising to be durable at a high temperature.

Electrical resistance measurement for damage analysis of carbon yarns

In order to study the applicability of the electrical resistance measurement for damage analysis of carbon yarns, pullout tests on yarns embedded in concrete as well as tensile tests on yarns were carried out. A qualitative correlation between the load drop and the increase of the electrical resistance could be observed in the pullout tests and tensile tests, respectively. The resistance measurement in the tensile tests further showed that even though all filaments were ruptured only a small change in the resistance occurred. The reason for this is the bridging of filament ruptures by cross-contacts between the individual filaments whose influence is further analysed with the aid of current flow simulations using the FEM tool ANSYS.

Structurally stitched NCF preforms: Quasi-static response

Experimental data are presented for a typical structurally stitched preform, composed of carbon fibre non-crimp fabrics (NCFs) and impregnated with an epoxy resin. The term ‘structural’ presumes here that the stitching yarn does not only consolidate the layers (as the non-structural one does for NCF plies) but forms also a through-the-thickness reinforcement. One stitching technique—tufting—is studied, with 67 tex carbon yarn and several stitching lengths. The test results (in-plane tension, out-plane compression, and 3-point bending) are compared and discussed revealing an influence of stitching and specifics of damage development. The stitching, on the one hand, decreases delaminations and increases the ultimate load. On the other hand, the stitching creates stress–strain concentrators which lead to earlier damage initiation.

Mechanical performances of a thermal activated composite

The Controlled Behavior Composite Material (CBCM) is a thermal activated composite material. The thermal activation is made thanks to carbon yarns connected to a power supply. Two sorts of CBCM plates are tested. A three-point bending test is performed to obtain the characteristic curves of the plates and a “free deflection” as well as a “blocking force” are defined as relevant parameters. Response times, mechanical powers and yields are calculated to evaluate the performances of the CBCM plates. The influence of some working (intensity per yarn) and design (orientation of the main reinforcement) parameters is studied. Organization in the anisotropy of the structure is a key point for the thermo-mechanical behavior of the CBCM. The loss of matrix rigidity due to the rise in temperature is quantified and the results show that it can be partially offset by the CBCM effect.

Effects of Carbon Yarn Size on the Mechanical Properties of Plain Woven C/SiC Composites

The effects of yarn size on the mechanical properties of silicon carbide composites reinforced with a plain woven carbon cloth with two sizes of yarns (1 and 3 k) were investigated. The experimental results show that the composite fabricated with 1 k yarns exhibits greater stiffness and strength than the composite fabricated with 3 k yarns. Microstructural observations revealed the existence of matrix microcracks in both the composites under the as‐processed condition due to the large difference of thermal expansion between the fibers and the matrix, which are more severe for the composite with 3 k yarns. The fractured surfaces of the composite with 1 k yarns showed extensive fiber pull‐out in contrast to the yarn pull‐out in the composite with 3 k yarns. The larger interyarn and intrayarn voids due to difficulties of matrix infiltration in the composite with 3 k yarns represent the primary contribution to the diminished mechanical properties. Unequal yarn sizes give rise to different yarn waviness, which may be another source of difference in the mechanical properties of composites.

Strong electrospun nanometer-diameter polyacrylonitrile carbon fiber yarns

Nanometer-diameter electrospun PAN yarns with different degrees of alignment were stabilized and carbonized and their properties evaluated. The parameters varied during production included draw ratio, temperature, heating rate and time in order to determine the ideal oxidation and carbonization conditions. The 10% PAN carbon yarn made at 16 kV and 9.8 m s −1 take-up velocity had the highest ultimate strength of approximately 1 GPa while maintaining constant length conditions during the process. The ultimate strength increased to approximately 1.7 GPa after the yarns were impregnated with an adhesive to make nano-sized unidirectional composite samples. The ultimate strength of PAN yarns generally increased with increasing take-up velocity because of the increase of molecular orientation.

Thermomechanical Modelization of a New Active Material

The controlled behavior of composite material (CBCM) is a thermomechanical active composite using Joule effect and heterogeneous thermal elongation properties as an actuator within composite structures. An ‘active layer’ made of carbon yarns is used as internal source of heat. To help the design of this composite a simple model based on thermomechanical and composite homogenization considerations is presented. A three-point bending test is used to compare the calculated results to experimental results. A good accordance between the relevant data (maximum of deflection and temperature on the plate) at stabilization being observed, the model is used to study the influence of some parameters. The position of the active layer, a design parameter of great importance, is particularly studied and an optimized solution is proposed. Then, the model is used for a sensitivity analysis of some design and working parameters. Finally, the results of a FEM model are compared to the previous.