Carbon Fiber Production Research Articles

Climate impact and energy use of structural battery composites in electrical vehicles—a comparative prospective life cycle assessment

PurposeStructural battery composites (SBCs) are multifunctional carbon fibre composites that can be used as structural elements in battery electric vehicles to store energy. By decreasing the weight of the vehicle, energy consumption in the use phase can be reduced, something that could be counteracted by the energy-intensive carbon fibre production. The purpose of this study is to shed light on such life-cycle considerations.MethodProspective life cycle assessment is used to compare the future cradle-to-grave climate impact and energy use of SBCs in battery electric vehicles to conventional metals and lithium-ion batteries. Additionally, the influences from different technology development routes, primarily related to the carbon fibre production, are assessed. The functional unit is the roof, hood, and doors of a battery electric vehicle with maintained flexural stiffness used for 200,000 km. To capture the multifunctionality of the material, the lithium-ion battery is also included in the functional unit.Results and discussionResults show that SBCs have a large potential to decrease the life cycle climate impact and energy use of battery electric vehicles, especially following routes focusing on decreasing the use of fossil resources, both for raw materials and as energy sources. The comparative assessment of multifunctional or recycled materials to conventional materials introduces several methodological challenges, such as defining the functional unit and choice of allocation approach for distributing burdens and benefits between life cycles in recycling. This study illustrates the importance of using both the cut-off and end-of-life recycling allocation approaches to capture extremes and to not provide biased results. This study also highlights the importance of considering the ease of repairability in comparative studies, as damages to car parts made from SBCs are likely more difficult to repair than those made from conventional materials.ConclusionsSBCs have the potential to reduce the life cycle climate impact and energy use for most scenarios compared to conventional materials. Three main methodological challenges were found: the comparison to a material with a well-established recycling system throughout its life cycle, the need for expanding the system boundaries to include the lithium-ion battery, and the difference in repairability of SBCs compared to the conventional material.

Isotropic coal tar pitch-based carbon fibers: Effect of nitric acid towards elimination of air-stabilization step

The remarkable properties exhibited by carbon fibers have generated considerable interest in seeking alternative approaches to replace time-consuming, energy-intensive, and multi-step procedures for their synthesis. Among the various stages involved in carbon fiber synthesis, the stabilization step plays a crucial role as it necessitates an extended duration to transform thermoplastic pitch-fibers into thermosetting fibers, thus preventing them from melting during high-temperature treatments. In this study, isotropic coal tar pitch (ICTP) was transformed into pitch fibers through melt-spinning process and subsequently subjected to chemical treatment for stabilization using varying concentrations (ranging from 5% to 50% v/v) of aqueous nitric acid (HNO3) solutions. The objective was to determine the optimal concentration for effective stabilization. Consequently, this research eliminates the conventional, time-consuming air-stabilization process by treating the pitch fibers with nitric acid prior to carbonization. To produce carbon fibers, all chemically stabilized pitch fibers were directly carbonized at 1000 °C. Comprehensive characterizations including Rheology, Elemental analysis, FTIR, TGA, FE-SEM, XRD, Raman, and XPS were conducted to investigate the chemical and structural transformations occurring during the fiber processing. It was observed that aqueous nitric acid solutions ranging from 15% to 30% (v/v) exhibited superior structural, morphological, and mechanical properties compared to other concentrations of HNO3.

Synthesis and thermal behavior of RAFT-based copolymers of acrylonitrile and 1-vinylimidazole

The copolymers of acrylonitrile and 1-vinylimidazole with a narrow molecular weight distribution (MWD) were synthesized for the first time by the reversible addition–fragmentation chain transfer (RAFT) polymerization in a DMSO solution in the presence of acetic acid. Their thermal behavior difference upon heating in argon and in air along with ability to melt make them promising precursors for carbon fiber production.

Identifying the best mixing procedure practice for ready-mix concrete plant production of carbon fibre reinforced electrically conductive concrete

ABSTRACT Electrically-conductive concrete (ECON) can generate heat for melting pavement ice if an electrical voltage is applied, and this ECON-heated pavement system (HPS) is a viable alternative to the traditional snow removal methods. This study aimed at determining mixture proportions and procedures suitable for ready-mix concrete-plant-produced carbon fibre (CF)-reinforced ECON. Trial batches ECON production involving five different mixture proportions and procedures were performed at a ready-mix concrete plant. Study results suggest that CF begins to degrade with increased mixing time. A twelve-minute mixing time from the start of loading CF onto the mixer until the end produced the best-performing ECON, with an electrical resistivity of 224 Ω-cm and a heat-generation rate of 2°C/min. Scanning electron microscopic (SEM) image analysis shows that CF remained as blobs of fibre instead of being uniformly dispersed. Further research is recommended to find an efficient way of separating individual CF from the blobs and ensuring uniform CF dispersion to reduce the dosage rate and construction cost of ECON.

Mesoscale Simulations of Structure Formation in Polyacrylonitrile Nascent Fibers Induced by Binary Solvent Mixture.

Polyacrylonitrile (PAN) is widely used as a raw material for the production of high-modulus carbon fibers, the internal structure of which is directly affected by the spinning of the precursor. Although PAN fibers have been studied for a long time, the formation of their internal structure has not been sufficiently investigated theoretically. This is due to the large number of stages in the process and the parameters controlling them. In this study, we present a mesoscale model describing the evolution of nascent PAN fibers during the coagulation. It is constructed within the framework of a mesoscale dynamic density functional theory. We use the model to study the influence of a combined solvent of dimethyl sulfoxide (DMSO, a good solvent) and water (a non-solvent) on the microstructure of the fibers. A porous structure of PAN is formed as a result of the microphase separation of the polymer and the residual combined solvent at a high water content in the system. The model shows that one of the possible ways to obtain the homogeneous fiber structure is to slow down the coagulation by increasing the amount of good solvent in the system. This result is in agreement with the existing experimental data and confirms the efficiency of the presented model.

Two-step method to realize continuous multi-wall carbon nanotube grafted on the fibers to improve the interface of carbon fibers/epoxy resin composites based on the Diels-Alder reaction

A new simple and continuous method was developed for chemically grafting multi-wall carbon nanotubes (MWCNTs) onto the surface of carbon fibers (CF) to improve the interlaminar properties of composites. In this method, maleimide-grafted waterborne polyurethane emulsion and furan functionalized MWCNTs were prepared. Then, based on the Diels-Alder reaction under mild reaction conditions (60 °C), CF/MWCNTs multi-scale reinforcements (MSCF) were successfully prepared through a two-step method of MWPU sizing and MWCNTs ultrasonic grafting, which overcame the complex process flow, greatly shortened the preparation time and avoided damage to fibers. The successful grafting of MWCNTs was proved by the results of SEM and HRTEM. After grafting MWCNTs, the interface between the matrix and fibers was enhanced. The interlaminar shear strength (ILSS) and flexural strength of MSCF/epoxy reinforced composites were promoted to 64.54 MPa and 981.95 MPa, which was prominently increased by 52.84% and 32.32%, respectively. In addition, this process could match the current production of carbon fibers for commercialization, but further research was expected to control the grafting amount of MWCNTs and their impact on performance.

Automated trackspinning of aligned lignin fibers as precursors of green carbon nanofibers

At present, most carbon fibers are made from non-renewable polyacrylonitrile. Substantial efforts have been made to replace petroleum-based precursors for carbon fiber production. Interestingly, lignin is a carbon fiber precursor material that is cheap, highly available and sustainable. Submicron-scale lignin-based carbon nanofibers are used in numerous areas, such as electronic devices, batteries, supercapacitors and low-cost, high-performance structural composite materials. Trackspinning (TS) technology offers a way to scale up the versatile, but inefficient contact drawing technique to produce small-diameter lignin fibers from environmentally friendly aqueous solutions. In this study, the effects of TS based on probe drawing of low-concentration lignin nanofibers blended with poly(ethylene oxide) and glycerol in sodium hydroxide (NaOH) solution were investigated. The TS lignin fibers were well aligned and reached diameters as small as 500–1000 nm as the drawing length was increased. Lignin fiber macromolecular alignment was isotropic at low levels of draw, and the dichroic ratio increased from 1 to 2.25 with doubling of the drawing length. The most highly drawn trackspun lignin fibers had a mechanical strength of 3.92 MPa and a Young’s modulus of 2.15 GPa, which were similar to reported values for solvent-electrospun lignin nanofibers. These findings support the potential to utilize TS to produce small-diameter lignin fibers using a simple aqueous solvent approach.

Lignin from Brewers' Spent Grain: Structural and Thermal Evaluations.

Lignocellulose is a renewable ubiquitous material that comprises cellulose, hemicellulose, and lignin. Lignin has been isolated from different lignocellulosic biomass via chemical treatments, but there has been little or no investigation carried out on the processing of lignin from brewers' spent grain (BSG) to the best of authors' knowledge. This material makes up 85% of the brewery industry's byproducts. Its high moisture content hastens its deterioration, which has posed a huge challenge to its preservation and transportation; this eventually causes environmental pollution. One of the methods of solving this environmental menace is the extraction of lignin as a precursor for carbon fiber production from this waste. This study considers the viability of sourcing lignin from BSG with the use of acid solutions at 100 °C. Structural and thermal analyses were carried out on extracted samples, and the results were compared with other biomass-soured lignin to assess the proficiency of this isolation technique. Wet BSG sourced from Nigeria Breweries (NB), Lagos, was washed and sun-dried for 7 days. Tetraoxosulphate (VI) (H2SO4), hydrochloric (HCl), and acetic acid, each of 10 M, were individually reacted with dried BSG at 100 °C for 3 h and designated as H2, HC, and AC lignin. The residue (lignin) was washed and dried for analysis. Wavenumber shift values from Fourier transform infrared spectroscopy (FTIR) show that intra- and intermolecular OH interactions in H2 lignin are the strongest and possess the highest magnitude of hydrogen-bond enthalpy (5.73 kCal/mol). The thermogravimetric analysis (TGA) results show that a higher lignin yield can be achieved when it is isolated from BSG, as 82.9, 79.3, and 70.2% were realized for H2, HC, and AC lignin. The highest size of ordered domains (0.0299 nm) displayed by H2 lignin from X-ray diffraction (XRD) informs that it has the greatest potential of forming nanofibers via electrospinning. The enthalpy of reaction values of 133.3, 126.6, and 114.1 J/g recorded for H2, HC, and AC lignin, respectively, from differential scanning calorimetry (DSC) results affirm that H2 lignin is the most thermally stable with the highest glass transition temperature (Tg = 107 °C).

Estimation of life cycle greenhouse gas emissions of asphaltene-based carbon fibers derived from oil sands bitumen

Bitumen-derived asphaltenes have emerged as a potential precursor for carbon fiber production. The technology to make it possible is in the early stages of research and development and so there are no studies on the GHG emissions from the process, which are critical to compare its carbon footprint with that of polyacrylonitrile (PAN), the standard precursor for carbon fiber production. The asphaltene-based carbon fiber (ACF) life cycle stages are bitumen production, asphaltene separation, precursor manufacturing, and carbon fiber production. In this study, we developed data-intensive models to estimate the life cycle GHG emissions of ACF. Sensitivity and uncertainty analyses were also performed to determine the inputs that have the largest effect on the GHG emissions of ACF. The results show that the life cycle GHG emissions of ACF are 16.2 kg CO2eq/kg CF. This value represents a reduction of 68.7% compared to PAN-based carbon fiber. The carbon fiber production stage is the most emission-intensive, mainly because of the high consumption of electricity. When uncertainty is considered, the life cycle GHG emissions of ACF range from 10.4 to 21.8 kg CO2eq/kg CF. The outcome of this study confirms the potential of asphaltenes as a low-carbon intense raw material for carbon fiber production.

The Investigation of General Properties of Carbon Fiber (CF) Composites - Preliminary Study

The most commonly used materials in the production of high-performance CFs are cellulose, polyacrylonitrile, and pitch. Polyacrylonitrile (PAN)-based fibers dominate the market (representing nearly 90% of total CF production), with some companies producing more than 10,000 tons per year. However, the current technique's high cost (the combined cost of the precursors and stabilization accounts for 70% of total CF synthesis cost) limits the technology's applicability. Carbon fiber manufacturing is characterized by a high energy demand due to long processing times and energy intensive thermal processes. PAN-based CFs are difficult to commercialize due to the time-consuming pre-oxidation step, which significantly raises the manufacturing cost. As a result, advanced processing technologies aimed at reducing CF production costs should be developed. They were consisting of a thin but strong crystalline filament of carbon. This experimental study was to learn the mechanical properties of carbon fiber using Universal Testing Machine (UTM). There was a section where we made a phone case out of Polyacrylonitrile (PAN) carbon fiber and compared it to other materials for phone cases. The phone cases of carbon fiber composites as the one examples of consumer product was made from the woven carbon fiber then was hardened by hard epoxy mixed with resin epoxy. Then, the phone cases were tested with UTM machine to compare the tensile strength and high modulus. Other than that, there were few samples with different composition of PAN powder mixed with different composition of sodium thiocyanate. The results of the testing shows that the carbon fiber had the high tensile strength than the other materials of phone cases which were silicone and thermoplastic polyurethanes (TPU). The microstructure of carbon fiber has a significant impact on its mechanical properties.

Fabrication of Graphitized Carbon Fibers from Fusible Lignin and Their Application in Supercapacitors.

Lignin-based carbon fibers (LCFs) with graphitized structures decorated on their surfaces were successfully prepared using the simultaneous catalyst loading and chemical stabilization of melt-spun lignin fibers, followed by quick carbonization functionalized as catalytic graphitization. This technique not only enables surficial graphitized LCF preparation at a relatively low temperature of 1200 °C but also avoids additional treatments used in conventional carbon fiber production. The LCFs were then used as electrode materials in a supercapacitor assembly. Electrochemical measurements confirmed that LCF-0.4, a sample with a relatively low specific surface area of 89.9 m2 g-1, exhibited the best electrochemical properties. The supercapacitor with LCF-0.4 had a specific capacitance of 10.7 F g-1 at 0.5 A g-1, a power density of 869.5 W kg-1, an energy density of 15.7 Wh kg-1, and a capacitance retention of 100% after 1500 cycles, even without activation.

Ion-Beam Surface Modification of Carbon Fibers

Carbon fibers are used in the production of automobiles, airplanes, sporting goods, energy, and biomedicine due to their unique properties such as high specific strength, high specific tensile strength, low coefficient of thermal expansion, and low density. The research and development of both the technology of carbon fibers production and their modification for a wide range of applications have been and remain relevant. The summary of the accumulated experience in the modification of carbon fibers shows that ion-beam treatment allows to obtain a variety of geometry of the developed surface topography, in particular, whisker-shaped and corrugated oriented across or along the fiber. Such processing compares favorably with ordinary fiber whiskering both by a variety of geometry of the composite interface, and by the absence of the problem of whisker-fiber adhesion. Ion-beam treatment also makes it possible to modify the surface layer structure from amorphized to ordered with different degrees of graphitization. Irradiation with chemically active ions leads to functionalization of carbon fiber due to formation, for example, of nitrides and carbon oxides. The choice of nitrogen ions for the technology of carbon-carbon and carbon-ceramic composites seems to be more preferable due to less stringent requirements for the temperature of the irradiated fiber. For ion-beam corrugation of polyacrylonitrile-based carbon fiber surface, only its heating above the temperature of dynamic annealing of radiation damage is required. The use of helium ions in technological plasma acceleration systems leads to a significant efficiency increase in ion-beam processing.

Study on the relationship between ring formation and properties of pre-oxidized polyacrylonitrile-based fibres

The relationship between the degree of ring formation and the overall properties of the pre-oxidized fibre was studied by treating PAN precursor with KClO3/H2SO4 solution and different pre-oxidation techniques. PFs are polar materials and the dielectric constant increases after solution treatment. The bulk density of Cl-MSFs is always higher than that of MSFs and CSFs in the same temperature zone. The bulk density of Cl-MSFs5 is 1.401 g/cm3, which is 1.6% higher than that of MSFs5. The EOR value of Cl-MSFs5 is 0.767, which is 11.97% higher than the value of MSFs5. The modified polyacrylonitrile precursor showed a high degree of cyclization during microwave heat treatment. The temperature can be reduced by about 40 °C by modifying and microwave heat treatment to achieve the same level of cyclization. Cl-MSFs5 has a higher O content than MSFs5. The microscopic morphology shows that the number of "grooves" and fibre diameter of Cl-MSFs5 is significantly smaller than that of MSFs5, indicating that it has a higher degree of stability. There is no Cl element on the surface of Cl-MSFs5, which indicates that the structure of the pre-oxidized fibre is not affected after the pre-oxidation treatment. In addition, the structural transformation of KClO3-modified PFs during microwave pre-oxidation is proposed. The cyclization reaction occurs first, followed by dehydrogenation and oxidation reactions. In the carbon fibre production process, the pre-oxidation stage takes a long time and consumes a lot of energy. The new composite treatment technology used in this study can effectively reduce the treatment temperature and shorten the treatment time in the pre-oxidation stage, which provides a reference for the development of low-cost and efficient pre-oxidation process.

Characterization of the tensile behavior of continuous carbon fiber reinforced polyamide 6 under self‐resistance electrical heating

AbstractThe stamping molding with self‐resistance electric (SRE) heating is advantageous for the mass production of carbon fiber reinforced thermoplastic (CFRT) because of its short production cycle and energy efficiency. The mechanism of SRE heating is different from traditional oven heating. The impact on CFRT laminates under loading is ambiguous. In this article, the tensile testing systems with SRE heating and traditional heating were designed. The temperature distribution, mechanical response, strain, and failure mode of carbon fiber reinforced polyamide 6 (CFR‐PA6) laminates under SRE heating are studied and contrasted with traditional heating. Specifically, to measure the full‐field strain distribution, digital‐image correlation (DIC) technique and high‐speed camera were introduced. It is found that the electric resistance fluctuates in tensile test with SRE heating and shown temperature sensitivity. Temperature distribution of the specimen under SRE heating is relatively uniform. Besides, the mechanical properties (i.e., tensile strength and elastic modulus) of CFR‐PA6 seem to be insensitive to heating mode. DIC results show that deconsolidation phenomenon makes the specimen fracture randomly. Inversely, heating method has an obvious influence on failure modes. To be specific, there are more shearing damage in traditional heating during high temperature. High current under SRE heating causes corrosion on fiber surface and destroy the fiber‐resin matrix interface.

Surface engineering of carbon fiber via upcycling of waste gases generated during carbon fiber production: A sustainable approach towards high-performance composites

Carbon fiber (CF) prevails as a cutting-edge material, however, considerable waste gases produced in its production place a tremendous burden on the industry and environment. Our previous study proposed a “two-birds-one-stone” strategy to simultaneously convert the gaseous effluents into carbon nanotubes (CNT) and produce multifunctional CNT@CF materials. However, the challenges in the management of iron nanocatalysts and the containment of side effects on the performance of CF composites have significantly affected the scalability of this technique. In the present work, we developed a further comprehensive understanding of cobalt and nickel-based metallic CFs as new catalysts to obtain more controlled and effective catalytic properties and subsequently extend the better performance of CF composite. In-situ capture and solidification of gases generated from the carbonization step of CF production process created more novel CNTs in the tip- and base-growth model. The CNTs with tip-growth model exhibited a better enhancement effect than the base-growth model on the interfacial properties of composites with up to 57% and 54% improvement in interfacial and inter-laminar shear strength, respectively. Moreover, new insights regarding the evolution mechanism of CNTs were provided through qualitative and quantitative analysis of the gas emissions reduction and recycling efficiency, supported by density functional theory. In this work, more available practical parameters governing the catalytic properties of metallic CF provide additional efficiency of gas waste recovery, diversity of CNTs, and potential for emerging applications, which delivers a more comprehensive guarantee for the implementation of this technology on the CF production line in the next step.

Lignin derived carbon fiber and nanofiber: Manufacturing and applications

Concerns over unsustainable technology-driven economies, environmental threats, and the continuous reduction of petroleum feedstocks have stimulated research in green, biodegradable, and naturally available resources. Within this context, lignin is considered one of the promising alternatives for producing sustainable materials, as it is the second most abundant material in Nature after cellulose and has a unique and versatile structure. Despite being highly abundant, lignin has not found a place in economic policies and is often considered an unutilized waste product. In recent years, extensive efforts have been made to develop lignin as an active precursor for carbon fiber (CF) production. CF is typically produced from expensive and unsustainable polyacrylonitrile (PAN) precursors, and lignin offers a low-cost and environmentally friendly alternative. This review provides a detailed insight into the manufacturing process and applications of lignin-derived carbon fiber (CF) and carbon nanofiber (CNF). It also highlights the major challenges that lie ahead for the industrialization of lignin as an established CF precursor. While lignin has yet to effectively penetrate the CF market, standardizing its product, conducting well-organized cost analyses at various stages of production, and developing low-cost processing techniques could pave the way for wider adoption of carbon-based materials."

Carbon Fibers: From PAN to Asphaltene Precursors; A State-of-Art Review

Due to their outstanding material properties, carbon fibers are widely used in various industrial applications as functional or structural materials. This paper reviews the material properties and use of carbon fiber in various applications and industries and compares it with other existing fillers and reinforcing fibers. The review also examines the processing of carbon fibers and the main challenges in their fabrication. At present, two main precursors are primarily utilized to produce carbon fibers, i.e., polyacrylonitrile (PAN) and petroleum pitch. Each of these precursors makes carbon fibers with different properties. However, due to the costly and energy-intensive processes of carbon fiber production based on the existing precursors, there is an increasingly growing need to introduce cheaper precursors to compete with other fibers on the market. A special focus will be given to the most recent development of manufacturing more sustainable and cost-effective carbon fibers derived from petroleum asphaltenes. This review paper demonstrates that low-cost asphaltene-based carbon fibers can be a substitute for costly PAN/pitch-based carbon fibers at least for functional applications. The value proposition, performance/cost advantages, potential market, and market size as well as processing challenges and methods for overcoming these will be discussed.

Economic and environmental assessment of asphaltene-derived carbon fiber production

The asphaltene-derived carbon fiber production route demonstrates significant potential, emerging as a highly cost-effective alternative with promising climate benefits compared to the incumbent carbon fiber production methods.

Topology and structure analysis of carbon fiber-reinforced polyimide composites

This paper describes the production of carbon fiber / high-performance polyimide prepregs and the study of prepreg samples quality by scanning electron microscopy, atomic-force electron microscopy and scanning ion-conductance microscopy. The prepreg samples were produced using a laboratory-designed setup by impregnation of carbon fiber with a polyimide solution. The study of the prepreg structure made it possible to establish the connection between polymer matrix composition and quality of carbon fiber impregnation. Thus, the study shows that the polymer matrix composition containing aliphatic fragment and quaternary carbon atom produces the best performance prepreg suitable for FDM 3D printing.

Redox cationic frontal polymerization: a new strategy towards fast and efficient curing of defect-free fiber reinforced polymer composites.

Frontal polymerization of epoxy-based thermosets is a promising curing technique for the production of carbon fiber reinforced composites (CFRCs). It exploits the exothermicity of polymerization reactions to convert liquid monomers to a solid 3D network. A self-sustaining curing reaction is triggered by heat or UV-radiation, resulting in a localized thermal reaction zone that propagates through the resin formulation. To date, frontal polymerization is limited to CFRCs with a low fiber volume percent as heat losses compromise on the propagation of the heat front, which is crucial for this autocatalytic curing mechanism. In addition, the choice of suitable epoxy monomers and thermal radical initiators is limited, as highly reactive cycloaliphatic epoxies as well as peroxides decarboxylate during radical induced cationic frontal polymerization. The resulting networks suffer from high defect rates and inferior mechanical properties. Herein, we overcome these shortcomings by introducing redox cationic frontal polymerization (RCFP) as a new frontal curing concept. In the first part of this study, the influence of stannous octoate (reducing agent) was studied on a frontally cured bisphenol A diglycidyl ether resin and mechanical and thermal properties were compared to a conventional anhydride cured counterpart. In a subsequent step, a quasi-isotropic CFRC with a fiber volume of >50 vol%, was successfully cured via RCFP. The composite exhibited a glass transition temperature > 100 °C and a low number of defects. Finally, it was demonstrated that the redox agent effectively prevents decarboxylation during frontal polymerization of a cycloaliphatic epoxy, demonstrating the versatility of RCFP in future applications.