Carbon Fibers: Formation, Structure, and Properties
Abstract
Carbon Fibers presents an up-to-date review of the progress pertaining to the formation of carbon fibers from rayon, acrylic, and pitch precursors. The book emphasizes the preparation, characterization, and properties of commercial materials. It also considers the compressive properties of carbon fibers, the lack of correlation between surface characterization and fiber-matrix interactions, and the discrepancy between surface composition as determined by XPS and the reaction of surface groups with chemical reagents. Other topics discussed include:.
... The last step of the procedure is graphitization, occurring by heating the carbonized filaments at 3000 • C in an inert environment to raise the orderly arrangements of carbon atoms, which are arranged into a crystalline construction of layers oriented in the direction of the fiber axis, which is a significant feature in affording high-modulus fibers. Carbon fibers have been used in protective operations against skin irritation, and protection of processing equipment, auxiliary electric and electronic devices [31][32][33]. ...
... The last step of the procedure is graphitization, occurring by heating the carbonized filaments at 3000 °C in an inert environment to raise the orderly arrangements of carbon atoms, which are arranged into a crystalline construction of layers oriented in the direction of the fiber axis, which is a significant feature in affording high-modulus fibers. Carbon fibers have been used in protective operations against skin irritation, and protection of processing equipment, auxiliary electric and electronic devices [31][32][33]. ...
... The most widespread textile fibers existing in the market of technical textiles are cotton and a number of coarser plant fibers, such as jute, flax and sisal. Due to their good tensile strength and stiffness, some natural fibers have been employed in technical textiles for different purposes, such as packaging, automotive, aerospace and fiber-reinforced composites [33]. ...
Textile manufacturing has been one of the highest polluting industrial sectors. It represents about one-fifth of worldwide industrial water pollution. It uses a huge number of chemicals, numerous of which are carcinogenic. The textile industry releases many harmful chemicals, such as heavy metals and formaldehyde, into water streams and soil, as well as toxic gases such as suspended particulate matter and sulphur dioxide to air. These hazardous wastes, may cause diseases and severe problems to human health such as respiratory and heart diseases. Pollution caused by the worldwide textile manufacturing units results in unimaginable harm, such as textile polymers, auxiliaries and dyes, to the environment. This review presents a systematic and comprehensive survey of all recently produced high-performance textiles; and will therefore assist a deeper understanding of technical textiles providing a bridge between manufacturer and end-user. Moreover, the achievements in advanced applications of textile material will be extensively studied. Many classes of technical textiles were proved in a variety of applications of different fields. The introductory material- and process-correlated identifications regarding raw materials and their transformation into yarns, fibers and fabrics followed by dyeing, printing, finishing of technical textiles and their further processing will be explored. Thus, the environmental impacts of technical textiles on soil, air and water are discussed.
... Carbonaceous mesophases are discotic nematic liquid crystals (DNLCs) that are precursors for carbon-based materials, including fibers, composites, and films which possess excellent mechanical and thermal transport properties[1,2]. Fiber melt spinning of carbonaceous mesophase precursors usually lead to a variety of cross-sectional textures, such as the radial, onion, and bi-polar textures[1,2]. ...
... Carbonaceous mesophases are discotic nematic liquid crystals (DNLCs) that are precursors for carbon-based materials, including fibers, composites, and films which possess excellent mechanical and thermal transport properties[1,2]. Fiber melt spinning of carbonaceous mesophase precursors usually lead to a variety of cross-sectional textures, such as the radial, onion, and bi-polar textures[1,2]. Fiber melt spinning consist of a sequence of processing flows, including Poiseuille capillary flow, converging die flow, and extensional spinline flow. ...
... Fiber melt spinning consist of a sequence of processing flows, including Poiseuille capillary flow, converging die flow, and extensional spinline flow. The flow-induced textural transformations due to the processing flow sequence is an active area of research due to its significance in eventually optimizing and controlling product properties[1,2]. In this paper, we focus on the important onion texture/Poiseuille pair using the Ericksen–Leslie theory[3][4][5][6][7]for uniaxial NLCs. ...
The Poiseuille capillary flow of discotic nematic liquid crystals (DNLCs) is analyzed using the Ericksen–Leslie theory, for three families of static patterns known as escaped and defect core onion textures, defined by the orientation at the capillary’ centerline. The escaped textures have low-elastic energy and high dissipation cores. The defect core texture has a high elastic energy-low dissipation core. The Poiseuille flow of these textures exhibits non-parabolic velocity profiles and their apparent viscosities display shear thickening, with exponents close to 1/5±0.07. Up to an Ericksen number of a thousand, core conditions have a strong effect on the non-Newtonian rheology of discotic nematics displaying the onion texture.
... The inclination angle of the fracture plane was measured as ±45° at almost every fracture point in our investigation, this indicated a brittle C-fiber failure due to ductile shear failure under compression as proposed in [36]. ...
... This means that stress discontinuities along the C-fiber have to be considered, caused by a sequence of bonding and nonbonding regions, as stated in [32]. Observing C-fiber failure due to compression in several planes is an indication of a very good adhesion between the substituents [36,37]. Hence, for the considered specimens, a good adhesion can be assumed. ...
The benefit of fiber-reinforced composites originates from the interaction between the fiber reinforcement and the matrix. This interplay controls many of its mechanical properties and is of utmost importance to enable its unique performance as a lightweight material. However, measuring the fiber−matrix interphase strength with micromechanical tests, like the Broutman test, is challenging, due to the many, often unknown boundary conditions. Therefore, this study uses state-of-the-art, high-resolution X-ray computed microtomography (XRM) as a tool to investigate post mortem the failure mechanisms of single carbon fibers within an epoxy matrix. This was conducted at the example of single carbon fiber Broutman test specimens. The capabilities of today's XRM analysis were shown in comparison to classically obtained light microscopy. A simple finite element model was used to enhance the understanding of the observed fracture patterns. In total, this research reveals the possibilities and limitations of XRM to visualize and assess compression-induced single fiber fracture patterns. Furthermore, comparing two different matrix systems with each other illustrates that the failure mechanisms originate from differences in the fiber−matrix interphases. The carbon fiber seems to fail due to brittleness under compression stress. Observation of the fiber slippage and deformed small fracture pieces between the fragments suggests a nonzero stress state at the fragment ends after fiber failure. Even more, these results demonstrate the usefulness of XRM as an additional tool for the characterization of the fiber−matrix interphase.
... Carbon fibers (CFs) possess outstanding specific strength and modulus, which is almost four times that of steel. [1][2][3] The abso- lute tensile strength of CFs used in primary structural applica- tions can approach 7 GPa, which is the highest value for any commercial reinforcing fibers. CFs possessing a high degree of graphitic content have a modulus as large as 830 GPa. ...
... However, the solution-based wet-spinning process itself involves the use of hazardous solvents, and the nitrile groups in PAN generate toxic byproducts (viz., hydrogen cyanide) during heat treatment. 2,3 The environmental concerns and the related costs associated with this process can be partially overcome by using bio-based precursors. Among naturally occurring biomass, lig- nin and cellulose are regarded as potential CF precursors because of their low cost and carbon-forming chemical struc- ture. ...
High-performance carbon fibers (CFs) are currently produced primarily from polyacrylonitrile (PAN). However, the high cost of such CFs and the environmental concerns during its manufacturing (from PAN) are stimulating research on alternative bio-based precursors and environmentally friendly processing routes. This review summarizes the recent research studies on the pathways for converting cellulose and lignin (most abundant and renewable biomass) into suitable precursor fibers and CFs. The role of various bio-based precursors, fiber spinning routes, and process conditions on the final properties of CFs is discussed. Although bio-based CFs reported in the current research studies have limited strength and modulus to be considered for high-performance aerospace applications, further progress in precursor purification and optimized fiber processing may lead to their application in less demanding structural applications such as automotive and industrial. Even in their current state, a lack of graphitic crystallinity results in a lower conductivity for the resulting CFs and makes them suitable for ultrahigh temperature insulative applications. Furthermore, the noncrystalline form of carbon obtained from bio-based precursors clearly indicates a significant potential of carbon nanofibers, mats, and activated CFs in nonstructural applications that require a large specific surface area, such as electrochemical energy storage and purification.
... Pyrolysis is an essential method used in different fields such as the production of carbon nanomaterials, 80-82 bulk carbon, 83,84 carbon-based devices, 85-87 the production of fuel from organic waste, and the use of gas chromatography-mass spectrometry for the study of molecules. [88][89][90] Noteworthy carbon materials synthesized through pyrolysis encompass graphene, 72,[91][92][93][94][95][96] CNTs, 97 carbon fibers (CFs), 94,95,98,99 diamond-like carbon (DLC) coatings, 100,101 as well as other industrial carbons like glass-like carbon (GC) and graphite. 83,102,103 Unlike metals, carbon manufacturing mostly depends on synthetic methods. ...
Carbon is one of the most abundant minerals in the universe. The world's energy needs are being unmet due to the exponential rise in population. Since its inception 20 years ago, carbon and its allotropes, including fullerenes, carbon nanotubes, and graphene, have been marketed as potential energy storage and generation materials. By solving important issues like accumulation and inadequate thermodynamic compatibility, carbon fiber, expanded graphite, and carbon nanotubes are promising functional materials that can be used to improve the performance of bipolar plates further. There are several potential uses for carbon-based nanomaterials (CBNMs) in the energy area. This mini-review provides an overview of the synthetic routes employed for producing CBNMs, categorizing them based on their types, elucidating their diverse applications in fuel energy systems, and emphasising the uses of CBNMs in energy. The advantages and disadvantages of several synthetic processes have been examined and compared. The types of CBNMs, like carbon nanotubes, graphene, carbon dots, and fullerenes, are explored in terms of their unique structural properties and fabrication methods. Furthermore, the utilization of CBNMs in fuel energy systems, such as fuel cells, energy storage devices, and catalysis, is comprehensively reviewed. Highlights-Carbon-based nanomaterials show promise in fuel energy applications, with a focus on fuel cells, energy storage devices, and catalysis.-The mini-review provides a comprehensive overview of synthetic routes for carbon-based nanomaterial production.-The study explores diverse carbon-based nanomaterials, including carbon nanotubes, graphene, carbon dots, and fullerenes.-A critical analysis of synthetic processes, like arc discharge, and chemical vapor deposition, reveals their respective advantages and disadvantages.
... These encompass exceptional tensile strength (varying between 2 to 7 GPa), elevated Young's modulus (ranging from 200 to 900 GPa), low density (falling within the range of 1.75 to 2.20 g/cm³), minimal thermal expansion alongside remarkable thermal and electrical conductivity (approximately 800 Wm⁻¹K⁻¹). Moreover, carbon fibers display robust chemical resistance to most chemical substances, barring exposure to high temperatures or flames 22-24, [47][48][49] . A compelling aspect is that carbon fiber's weight is approximately four times lower than that of steel, while its strength surpasses that of steel 23,24 . ...
The manufacturing sector perpetually seeks high-quality materials capable of meeting the requirements for enhanced mechanical properties, thereby enabling their widespread application across various industries. Integrating Carbon Fibers (CFs) into metal matrices has demonstrated significant efficacy in augmenting the comprehensive attributes of the resultant composites. This comprehensive review focuses on the latest advancements and techniques involving the utilization of carbon fibers in conjunction with metal matrix material, aimed at augmenting a spectrum of mechanical attributes. Various methods used to synthesize carbon fiber reinforced metal composites have been discussed and summarized. Liquid metallurgy technique is playing important role in the fabrication of the carbon fiber reinforced metal composites.
... Because of the rheological qualities of molten pitch, melt spinning is challenging, and very precise processing conditions are necessary. The viscosity of the mesophase is very temperature-dependent, and the jet temperature should be precisely regulated, as a change of 3.5 °C at the jet face causes a 15% change in diameter [27] . Due to poor viscosity, too high a temperature causes thermal deterioration of the pitch or dripping. ...
Global energy demand is rising, fossil fuel prices are rising, fossil fuel reserves are running out, and fossil fuel use contributes to the greenhouse effect. As a clean alternative source of energy to fossil fuels, biomass is becoming more and more essential. Carbon fiber (CF), often known as graphite fiber, is a thin, strong, and adaptable material utilized in both structural (capacity) and non-structural applications (e.g., thermal insulation). Precursors are the raw materials used to create carbon fiber, which is mostly derived from fossil fuels. Because of the high cost of precursors and manufacture, carbon fiber has only found employment in a few numbers of high-performance structural materials (e.g., aerospace). To reduce the price of CF and reliance on fossil fuels, numerous alternative precursors have been studied throughout the years, including biomass-derived precursors such as rayon, lignin, glycerol, and lignocellulosic polysaccharides. This study's goal is to present a detailed study of biomass-derived CF precursors and their market potential. The authors look into the viability of producing CF from these precursors, as well as the state of technology, potential applications, and cost of production (when data are available). We go over their benefits and drawbacks. We also talk about the physical characteristics of CF made from biomass and contrast them with CF made from polyacrylonitrile (PAN). Additionally, we go into bio-based CF manufacturing and end-product concerns, logistics for biomass feedstock and plant sites, feedstock competition, and risk-reduction techniques. This paper offers a comprehensive overview of the CF potential from all biomass sources and can be used as a resource by both novice and seasoned professionals who are interested in producing CF from non-traditional sources.
... Because of the rheological qualities of molten pitch, melt spinning is challenging, and very precise processing conditions are necessary. The viscosity of the mesophase is very temperature-dependent, and the jet temperature should be precisely regulated, as a change of 3.5 °C at the jet face causes a 15% change in diameter [27] . Due to poor viscosity, too high a temperature causes thermal deterioration of the pitch or dripping. ...
Global energy demand is rising, fossil fuel prices are rising, fossil fuel reserves are running out, and fossil fuel use contributes to the greenhouse effect. As a clean alternative source of energy to fossil fuels, biomass is becoming more and more essential. Carbon fiber (CF), often known as graphite fiber, is a thin, strong, and adaptable material utilized in both structural (capacity) and non-structural applications (e.g., thermal insulation).Precursors are the raw materials used to create carbon fiber, which is mostly derived from fossil fuels. Because of the high cost of precursors and manufacture, carbon fiber has only found employment in a few numbers of high-performance structural materials (e.g., aerospace). To reduce the price of CF and reliance on fossil fuels, numerous alternative precursors have been studied throughout the years, including biomass-derived precursors including rayon, lignin, glycerol, and lignocellulosic polysaccharides. This study's goal is to present a detailed study of biomass-derived CF precursors and their market potential. We look into the viability of producing CF from these precursors, as well as the state of technology, potential applications, and cost of production (when data are available). We go over their benefits and drawbacks. We also talk about the physical characteristics of CF made from biomass and contrast them with CF made from polyacrylonitrile (PAN). Additionally, we go into bio-based CF manufacturing and end-product concerns, logistics for biomass feedstock and plant sites, feedstock competition, and risk-reduction techniques. This paper offers a comprehensive overview of the CF potential from all biomass sources and can be used as a resource by both novice and seasoned professionals who are interested in producing CF from non-traditional sources.
... Only a limited number of reports describing the preparation of biomass-derived silicon-carbon composites employ native silicon or discuss energystorage applications [12]. Rice hulls used as silicon-fixing biomass are mainly composed of cellulose (~33%), hemicellulose (~26%), lignin (~7%), and amorphous silicon dioxide (~20%) [13]. Therefore, it is crucial to develop methods that enable full exploitation of the inherent advantages of the biomass resources. ...
A simple and effective mixing carbonization-activation process was developed to prepare rice hull-derived porous Si–carbon materials. The morphologies and pore structures of the materials were controlled effectively without any loading or additions at various carbonization temperatures. The structures of the samples changed from large pores and thick walls after 800 ∘C carbonization to small pores and thin walls after 1000 ∘C carbonization. An additional alkali activation–carbonization process led to coral reef-like structures surrounded by squama in the sample that underwent 900 ∘C carbonization (Act-RH-900). This optimal material (Act-RH-900) had a large specific surface area (768 m2 g−1), relatively stable specific capacitance (150.8 F g−1), high energy density (31.9 Wh kg−1), and high-power density (309.2 w kg−1) at a current density of 0.5 A g−1 in 1 M KOH electrolyte, as well as a good rate performance and high stability (capacitance retention > 87.88% after 5000 cycles). The results indicated that Act-RH-900 is a promising candidate for capacitive applications. This work overcomes the restrictions imposed by the complex internal structure of biomass, implements a simple reaction environment, and broadens the potential applicability of biomass waste in the field of supercapacitors.
... Breaking strength of carbon fibers is determined by the characteristics of the defect and subjected to the Weibull distribution [52][53][54], as shown in Eq. (1): ...
The surface microstructure of 10 samples of CCF800 carbon fibers was quantitatively characterized by the number, width, depth and distribution of grooves. With the help of self-programmed Matlab, the fractured cross-section SEM images were binarization processed and contour extracted, and then the linear equation tangent method was used to identify grooves and to measure width and depth of each groove. Using Weibull distribution equation, shape factor of carbon fiber was calculated by width distribution, as well as roughness by depth distribution. Meanwhile, monofilament tensile strength of each sample was acquired in accordance with ASTM D3379. The comprehensive effect of width, depth, shape factor and roughness on the strength was discussed.
... This requires the development of materials which have both high absorption capacity and a small bulk density, high thermal and chemical resistance. The materials that could satisfy this set of requirements are fibrous sorbents: active carbon fibers [1][2][3], synthetic fiber-based chemosorbents [4] and inorganic fibers with high silica content [5,6]. ...
At different flow rates, the hydrodynamic properties of the fixed layer of fibrous adsorbent were investigated with high content of silicon dioxide, with different fiber lengths, and varying degrees of layer density. The parameters of the layer were defined: porosity, equivalent diameter of the channel and specific geometric and usable surfaces.
... This requires the development of materials which have both high absorption capacity and a small bulk density, high thermal and chemical resistance. The materials that could satisfy this set of requirements are fibrous sorbents: active carbon fibers [1][2][3], synthetic fiber-based chemosorbents [4] and inorganic fibers with high silica content [5,6]. ...
At different flow rates, the hydrodynamic properties of the fixed layer of fibrous adsorbent were investigated with high content of silicon dioxide, with different fiber lengths, and varying degrees of layer density. The parameters of the layer were defined: porosity, equivalent diameter of the channel and specific geometric and usable surfaces.
... Carbon fiber is considered a useful reinforcement for composites due to its excellent properties, such as its high modulus, dimensional stability, and excellent thermal and electrical conductivities [5][6][7][8][9]. Commercial production has been achieved from only three kinds of precursors: PAN, rayon, and pitches [10]. The pitch-based CFs can be further classified into two types: isotropic pitch and anisotropic (or mesophase) pitch [11,12]. ...
In this study, isotropic pitch-based carbon fibers were prepared from a mixture of petroleum residue and graphene nanoplatelets with different contents. The softening point and synthetic yield of synthesized isotropic pitches were analyzed and compared to characterize the nature of the pitches. The surface and thermal characteristics of the fibers were observed using scanning electron microscopy and thermogravimetric analysis (TGA), respectively. From the results, it was observed that the prepared carbon fibers had an interesting core-shell structure. In the TGA analysis with air, the carbon fiber having 0.1 wt.% of graphene showed a higher residue yield than that of the sample having 1.0 wt.% of graphene. This result can be explained due to the graphene being placed on the surface region of the carbon fibers and directly helping to increase the surface area of the carbon fibers, resulting in rapid oxidation due to the enhanced contact area with oxygen.
... It was already explored that compressive strength of a materials depends upon size of crystallite, orientation of the crystalline planes, density, inter-planar distance between the graphitic planes, and void space in the materials [62,63]. It was also found that compressive strength of PAN and pitchbased CF is inversely related with each other [64,65]. For a specific modulus-based CF, compressive strength can be improved by perfect orientation and creation of smaller-size crystallites [66,67]. ...
The high strength to weight ratio of carbon fiber has made it as an attractive energy-saving material over the conventional strength-bearing materials like steel. Realizing the trend, the high-weight steel is being progressively replaced by the low-weight and corrosion-resistant carbon fiber composites in many strength applications. The carbon fiber-reinforced polymer matrix composite (PMC) have thereby become forefront material in aerospace, automobile, sporting goods, and other applications which demand high strength and high modulus. Moreover, the gradual reduction of its cost curtsy to the extensive research in the field of carbon fiber technology in recent years has been opened its market in different construction applications. This review is the discussion of carbon fiber loaded a variety of polymer matrix composites where the structural importance of these composites has been emphasized. The objective of this discussion is to provide information on the whole spectrum of carbon fiber-based polymeric composites. It also includes brief discussion about preparation and properties of carbon fibers along with processing, fabrication, and structural applications of these carbon fiber-based polymer composites.
Graphical abstract
... The isolation of lignin from plants can generally be pursued in two ways. [21] In one route, carbohydrate is hydrolyzed by using enzymes and is dissolved away from lignin, which is obtained as an insoluble material. This method typically involves a pretreatment of the feedstock because enzymatic hydrolysis cannot be directly applied to woody biomass. ...
Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure-property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon, are discussed.
... Anisotropes Pech, das auch Mesophasenpech genannt wird, muss einige Bedingungen erfüllen: [42] * Reinheit: Das Material darf keine Partikel enthalten und muss einen Aschegehalt von deutlich unter d = 1000 ppm auf- weisen. * Orientierung: Das Material muss sich im Zuge des Spinnprozesses ausrichten lassen. ...
Dieser Aufsatz gibt einen Überblick über Präkursorsysteme, deren Verarbeitung und die resultierenden Eigenschaften der Carbonfasern (CF) in Abhängigkeit des Präkursors und berücksichtigt dabei die neuesten Entwicklungen auf dem Gebiet der alternativen Präkursoren für die Herstellung von preisgünstigeren CF. Es werden folgende Präkursoren behandelt: Polyacrylnitril-basierte Copolymere, Pech, Cellulose, Lignin, Polyethylen und neue synthetische Polymerpräkursoren für hochwertige CF. Außerdem werden Zusammenhänge zwischen Struktur und Eigenschaften aufgezeigt, und es werden verschiedene Modelle vorgestellt, die sowohl die Struktur als auch die Morphologie von CF beschreiben.
... Anisotropic pitch, also called mesophase pitch, has to fulfill some requirements: [42] * Cleanness: The material has to be free of particles and the ash content must be well below 1000 ppm. * Orientation: The material must be orientable during the course of the spinning process. ...
This Review gives an overview of precursor systems, their processing, and the final precursor-dependent structure of carbon fibers (CFs) including new developments in precursor systems for low-cost CFs. The following CF precursor systems are discussed: poly(acrylonitrile)-based copolymers, pitch, cellulose, lignin, poly(ethylene), and new synthetic polymeric precursors for high-end CFs. In addition, structure-property relationships and the different models for describing both the structure and morphology of CFs will be presented.
... Both theoretical and experimental studies have shown that the elastic modulus of a carbon nanotube (CNT) is in the range of 1-5 TPa [1][2][3][4], which is significantly higher than that of a carbon fiber of 0.1-0.8 TPa [5]. Such a superior property makes CNTs a promising reinforcing material. ...
This paper investigates some mechanical and rheological properties of low density polyethylene (LDPE) composites reinforced by multi-walled carbon nanotubes (MWNTs). It was found that the Young’s modulus and tensile strength of the composites can increase by 89% and 56%, respectively, when the nanotube loading reaches 10wt%. The curving and coiling of MWNTs play an important role in the enhancement of the composite modulus. It was also found that the materials experience a fluid–solid transition at the composition of 4.8wt%, beyond which a continuous MWNT network forms throughout the matrix and in turn promotes the reinforcement of the MWNTs.
Bu çalışmada, rejenere selüloz liflerinden olan viskoz rayon lifinin karbonizasyon aşaması öncesinde termal stabilizasyon sırasında meydana gelen yapısal değişimleri incelenmiştir. Viskoz rayon lifleri, oda sıcaklığında %4’lük sulu fosforik asit (FA) çözeltisi içerisinde 30 dk. kimyasal ön işleme tabi tutulmasının ardından, ön kurutma işlemi ve farklı stabilizasyon (oksidasyon) sıcaklıklarında (150-175-200-225 ve 250°C) ısıl işleme alınmıştır. Termal stabilizasyon sonrasında numuneler üzerinde; iplik numara ölçümü, renk değişim analizi, yoğunluk, mikroskop lif kalınlık çalışması ve iplik mukavemeti gibi birtakım fiziksel ve yapısal özelliklerdeki değişimler incelenmiştir. Bununla birlikte numunelerin yapısal karakterizasyon kombinasyonu için yakma testi, SEM, diferansiyel taramalı kalorimetri (DSC), termogravimetrik analiz (TGA) ve kızılötesi (FTIR) spektroskopi ölçümleri ve mekanik testler yapılmıştır. Termal stabilizasyon işlem sıcaklığının artmasına bağlı olarak iplik numarası ve lif kalınlığı değerlerinin azaldığı saptanmıştır. Bununla birlikte termal stabilizasyon işlemlerinden sonra viskoz rayon numunelerinin görüntüsü beyaz renkten karbon siyahına doğru değişirken, 225 ve 250 °C’de ısıl işlem gören numuneler yanmazlık özelliği kazanmıştır. Yapılan mukavemet analizlerinde 225 °C’lik stabilizasyon sıcaklığına kadar çekme dayanımı ve kopma uzaması değerleri azalırken 250 °C’lik stabilizasyon işleminden sonra bu değerlerde kısmen artış gözlenmiştir. Stabilizasyon sıcaklığına bağlı olarak, sıcaklık arttıkça stabilizasyon numunelerinin kristal yapısındaki değişimler sebebiyle bozunma endotermi azalmış ve 250 °C’lik ısıl işlem sonrasında neredeyse kaybolmuştur.
Futuristic wearable electronics desperately need power sources with similar flexibility and durability. In this regard, the authors, therefore, propose a scalable PAN‒PMMA blend‐derived electrospinning protocol to fabricate free‐standing electrodes comprised of cobalt hexacyanoferrate nanocube cathode and tin metal organic framework‐derived nanosphere anode, respectively, for flexible sodium‐ion batteries. The resulting unique inter‐networked nanofiber mesh offers several advantages such as robust structural stability towards repeated bending and twisting stresses along with appreciable electronic/ionic conductivity retention without any additional post‐synthesis processing. The fabricated flexible sodium ion full cells deliver a high working voltage of 3.0 V, an energy density of 273 Wh·kg⁻¹, and a power density of 2.36 kW·kg⁻¹. The full cells retain up to 86.73% of the initial capacity after 1000 cycles at a 1.0 C rate. After intensive flexibility tests, the full cells also retain 78.26% and 90.78% of the initial capacity after 1000 bending and twisting cycles (5 mm radius bending and 40o axial twisting), respectively. This work proves that the proposed approach can also be employed to construct similar robust, free‐standing nanofiber mesh‐based electrodes for mass‐producible, ultra‐flexible, and durable sodium ion full cells with commercial viability.
Thermally induced chemical decomposition of organic materials in the absence of oxygen is defined as pyrolysis. This process has four major application areas: (i) production of carbon materials, (ii) fabrication of pre-patterned micro and nano carbon-based structures, (iii) fragmentation of complex organic molecules for analytical purposes and (iv) waste treatment. While the underlying process principles remain the same in all cases, the target products differ owing to the phase and composition of the organic precursor, heat-treatment temperature, influence of catalysts and the presence of post-pyrolysis steps during heat-treatment. Due to its fundamental nature, pyrolysis is often studied in the context of one particular application rather than as an independent operation. In this review article an effort is made to understand each aspect of pyrolysis in a comprehensive fashion, ensuring that all state-of-the-art applications are approached from the core process parameters that influence the ensuing product. Representative publications from recent years for each application are reviewed and analyzed. Some classical scientific findings that laid the foundation of the modern-day carbon material production methods are also revisited. In addition, classification of pyrolysis, its history and nomenclature and the plausible integration of different application areas are discussed.
The influences of polymerization conditions, viz. the kind of catalyst, solvent medium and temperature, on thermal, molecular and structural characteristics of carbon fiber precursor polymer were investigated. The dependence of the exothermic peak temperature (Tpk) and heat release rate on the kind of polymerization process was established. An aqueous redox slurry polymer had narrow exothermic peaks (Tpk = 294–297 °C) and relatively high heat release rates (∆H/∆T = 0.96–3.3 J g−1 s−1), and polymers prepared in solid state, solution and bulk had a broader exotherms with Tpk in the range 264–318 °C and low heat release rates in the range 1.15–3.9 J g−1 s−1. Dynamic and thermomechanical analyses indicate three glass transition temperature ranges, i.e., 42–54 °C, 80–98 °C, and 140–142 °C, which are similar irrespective of catalysts. Branching tendency in aqueous redox slurry polymer was notable beyond the intrinsic viscosity of 250 cm3/g. Bulk densities of the polymers were found to be in the range 0.25–0.45 g cm−3.
Fracture characteristics were used to effectively evaluate the performance of fiber-reinforced cementitious composites. The fracture parameters provided the basis for crack stability analysis, service performance, safety evaluation, and protection. Much research has been carried out in the proposed study field over the previous two decades. Therefore, it was required to analyze the research trend from the available bibliometric data. In this study, the scientometric analysis and science mapping techniques were performed along with a comprehensive discussion to identify the relevant publication field, highly used keywords, most active authors, most cited articles, and regions with largest impact on the field of fracture properties of cement-based materials (CBMs). Furthermore, the characteristic of various fibers such as steel, polymeric, inorganic, and carbon fibers are discussed, and the factors affecting the fracture properties of fiber-reinforced CBMs (FRCBMs) are reviewed. In addition, future gaps are identified. The graphical representation based on the scientometric review could be helpful for research scholars from different countries in developing research cooperation, creating joint ventures, and exchanging innovative technologies and ideas.
The article discusses the task of assessing the damage of carbon plastics that arose as a result of the destructive effect of x-ray radiation using the diagnostic capabilities of ultra-jet technology. A technique is proposed for determining the thickness of a carbon fiber package that can protect an imaginary interior from the negative effects of x-ray waves. As informative diagnostic parameters in the method, the geometrical dimensions of the cavern arising on the surface of the sample as a result of exposure to a high-speed jet of liquid (water) are used. Based on the results of the experiments, it was found that a decrease in the depth value indicates a decrease in the penetrating effect of x-ray radiation and the destruction of the binder in the structure of the composite material. The studies were carried out under the grants of the Russian Foundation for Basic Research 18-29-18081, a grant from the President of the Russian Federation for state support of leading scientific schools of the Russian Federation NSh-3778.2018.8
Lignin/polyacrylonitrile (PAN) composite precursors and PAN precursors were prepared by wet spinning and then converted into carbon fibers together under different carbonization temperatures. The microscopic morphology, mechanical properties and microstructure of the carbon fibers were studied. All the carbon fibers had dense structure without any visible macrovoids. Carbon fibers with tensile strength of 2.1 GPa and tensile modulus of 224 GPa were obtained from the lignin/PAN composite precursor by carbonizing at 1200 °C. Interestingly, the lignin/PAN-based carbon fibers had a unique uniform disordered carbon structure. They were expected to be applied in the fields of electrothermal conversion and thermal insulation, besides composites.
The article is deal with the questions of assessing the applicability of the method of ultra-jet diagnostics of carbon plastics. In the work, phenomenological ideas about the process of destruction of carbon plastics under the action of a high-speed-jet of liquid are considered. The experimental part of the work is related to the implementation of the diagnostic effect of the ultra-jet on the surface of the carbon fiber reinforced plastic, the assessment of the geometric parameters of the hydraulic caverns and the qualitative assessment of the state of the fibers and the adhesion in the binder-fiber structure. In this experiment, carbon fiber samples were used both in the initial state and after the inhibitory effect of x-ray radiation. Such a technique made it possible to carry out a comparative analysis of the samples and evaluate the information content of the ultra-jet diagnostics method as applied to the materials under consideration.
Most recycling methods remove the essential sizing from reinforcing fibres, and many studies indicate the importance of applying sizing on recycled fibres, a process we will denote here as resizing. Recycled fibres are not continuous, which dissociates their sizing and composite lay-up processes from virgin fibres. In this study, commercial polypropylene and polyurethane-based sizing formulations with an aminosilane coupling agent were used to resize recycled glass and carbon fibres. The impact of sizing concentration and batch process variables on the tensile properties of fibre-reinforced polypropylene and polyamide composites were investigated. Resized fibres were characterized with thermal analysis, infrared spectroscopy and electron microscopy, and the tensile properties of the composites were analysed to confirm the achievable level of performance. For glass fibres, an optimal mass fraction of sizing on the fibres was found, as an excess amount of film former has a plasticising effect. For recycled carbon fibres, the sizing had little effect on the mechanical properties but led to significant improvement of handling and post-processing properties. A comparison between experimental results and theoretical prediction using the Halpin-Tsai model showed up to 81% reinforcing efficiency for glass fibres and up to 74% for carbon fibres.
Low carbon yield is a major limitation for the use of cellulose-based filaments as carbon fiber precursors. The present study aims to investigate the use of an abundant biopolymer chitosan as a natural charring agent particularly on enhancing the carbon yield of the cellulose-derived carbon fiber. The ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH]OAc) was used for direct dissolution of cellulose and chitosan, and to spin cellulose-chitosan composite fibers through a dry-jet wet spinning process (Ioncell). The homogenous distribution and tight packing of cellulose and chitosan revealed by X-ray scattering experiments, enables synergistic interaction between the two polymers during the pyrolysis reaction, resulting in a substantial increase of carbon yield and preservation of mechanical properties of cellulose fiber compared to other co-biopolymers such as lignin and xylan.
Nano-silica (NS) is deposited onto Carbon fibers (CFs) using electrophoretic deposition (EPD) to improve their bond to cementitious matrices. Two different voltage ranges and two deposition times were applied. The mobility of the negatively charged NS-colloids in deionized water in a controlled electric field was proven by zeta potential measurements and cyclic voltammetry (CV). Scanning electron microscopy and energy dispersive X-ray analysis (EDX) showed homogeneously distributed nano-silica particles on the surfaces of the CF. Thermo-gravimetric analysis (TGA) and single-fiber tensile tests were conducted to assess the impact of the parameters under investigation on the CF properties. Single-fiber pullout tests from a cement-based matrix showed markedly enhanced bond strength of the modified filaments, indicating improved reinforcing action of CF in cementitious composites. Storing the modified fibers in a cement pore solution showed that nano-silica deposits act as nucleating seeds for building calcium silicate hydrate (C–S–H) and calcite. This explains the enhanced bond properties.
Carbon–carbon composites, as developed from various pitch precursors and chopped carbon fiber reinforcement, have been characterized and compared on the prime basis of the precursor materials used as the matrix. Evaluation of the properties and characterization have been carried out by various techniques such as thermal analysis by thermogravimetric analysis, thermomechanical analysis, and flame ablation method, microstructural characterization by scanning electron microscopy and optical microscope, mechanical characterization by Universal Testing Machine (UTM), IZOD impact, and hardness and frictional characterization by a pin on disc tribometer were carried out. Petroleum pitch, coal tar pitch, and the mixture of both the kinds of the pitch have shown a difference in the ultimate properties on the finished composite materials. The presence of volatiles, quinoline insoluble content, and various softening point have proved to impart differences in behavior for different systems. Composites developed to form the three systems have shown robust characteristics with superior mechanical and thermal behavior. Microstructural analysis has shown good compatibility between the reinforcement and matrix, while it is also evidence of a uniform distribution of the reinforcement. The fiber–matrix interaction in all the three systems is appreciably weak, which is favorable for non-catastrophic failure.
Thermal oxidation and carbonization of Armos and Phenylon fibers are studied. Relationships among the chemical and physical structures of these fibers and the properties of carbon materials obtained from them are found.
The aim of this work is to describe a novel methodology for optimizing the stabilization of polyacrylonitrile (PAN) fibers, through designing of proper thermal treatment. The methodology is based on a set of design rules and the procedure for implementing them, utilizing the time‐temperature‐transition (TTT) and the maximum permittable stress (max.stress) plots. The proposed approach is implemented in order to optimize the stabilization of commercial PAN fibers, resulting in a series of multistage thermal treatments. The changes of both physical and chemical structures of PAN during the progress of the multistage treatments were investigated and showed that the fibers were progressively converted into completely stabilized material; this gradual transformation permitted improvement of fiber annealing and minimized the effect of the decomposition reactions. The proposed methodology can be universally applied for achieving the global optimum of the stabilization process for any PAN precursor.
Natural carbonaceous materials (NCMs) have recently emerged as promising organic semiconducting materials for electronics and catalysis, although the fundamental picture of charge transport within NCM systems is still incomplete. Morphologically, NCMs exhibit reminiscence of disordered organic solids, yet the experimental measurements demonstrate a transport regime that surprisingly follows Mott's formula derived for variable‐range hopping in inorganic noncrystalline materials. With ab initio and kinetic Monte Carlo simulations, a temperature scaling is revealed between the Gaussian‐defect model log(σ) ∼ T−2 typical for organic matter and the Mott‐like log(σ) ∼ T−1/4 for a wide spectrum of intermolecular connectivity. As dominant transport descriptors, energy levels and coupling strengths are screened among 30 small molecules with varying sizes, shapes, sp2/sp3 ratios, side chains, and functional groups. These analyses provide insight for the design of NCM electronics, and should also be applicable to disordered molecular materials in general. Structure–property relation of charge transport in highly disordered natural carbonaceous materials (NCM) is revealed by atomic‐scale simulations. A temperature scaling between the Gaussian‐defect model and the Mott‐like model is observed for prototype networks with various intermolecular connectivities. A new set of graphic descriptors for NCMs is developed to characterize the energy and coupling variations.
Fiber is a symbol of human civilization, being ubiquitous but obscure in society over most of history. Fiber has been revived upon the advent of fiber‐based electronic devices in the past two decades. This is due to its desirable lightweight, flexible, and conformable characteristics, which enable it to play a fundamental role in the electronic and information era. Numerous fiber‐based electronic devices have sprung up in energy conversion, energy storage, sensing, actuation, etc. A possibility is thereby conceived that they can be integrated into smart systems compatible with the human body, consisting of biotic fiber‐based organs and tissues, which possess similar but more advanced functions. However, the design of mono‐/multifibers, the construction of fiber‐based devices, and the integration of these smart systems represent great challenges in fundamental understanding and practical implementation. A systematic review of the current state of the art with respect to the design and fabrication of electronic fiber materials, construction of fiber‐based devices, and integration of smart systems is presented. In addition, limitations of current fiber‐based devices and perspectives are explored toward potential and promising smart integration. Interest in fiber has been revived in the past two decades following the advent of fiber‐based electronic devices. This is due to its lightweight, flexible, and conformable characteristics, which enable it to play a fundamental role in the information era. The state of the art regarding the design and fabrication of fibers and construction of fiber‐based devices is reviewed, toward the integration of smart systems for diverse applications.
This paper relates to a computational investigation of nanomechanical properties of graphene spirals. The molecular dynamics simulation method was used to investigate the mechanical properties including the stress–strain and force–strain diagrams under tensile tests as well as the fracture characteristics of the single- and double-layer graphene spirals. The adaptive intermolecular reactive empirical bond order potential was employed to model the covalent bonds and van der Waals interactions between the carbon atoms. Also, in the last section of the paper, the mechanical behavior of the spirals is scrutinized with respect to nitrogen and boron doping with various percentages and the Young’s moduli of the graphene spirals are presented as the functions of size and doping ratios according to the stress–strain diagrams. The results reveal three major deformation phases namely, elastic due to the van der Waals interactions, elastic due to the covalent bonds, and inelastic regimes. According to the results, the graphene spirals have superelastic characteristics in the range of 2000–3000% strains and very high strength values depending on the nanostructure size.
Benzersiz fiziksel, kimyasal ve biyolojik özelliklere sahip olan karbon fiber, hekzagonal yapıda dizilmiş karbon atomlarından oluşan lif şeklinde çok yönlü bir malzemedir. Günden güne potansiyel uygulama alanları gelişmekte olan karbon fiberlerin endüstriyel üretiminde genel olarak PAN (poliakrilonitril) kullanılmaktadır. Ancak, PAN esaslı karbon fiber üretiminin mevcut olan üretim teknolojileri, ürün maliyetinin azaltılmasını sağlayamamaktadır. Pazar payı PAN’a oranla daha az olan zift esaslı karbon fiber üretimi ile, PAN esaslı karbon fiberlere göre daha ucuz ve daha yüksek verimlerle karbon fiber üretimi mümkündür. Günümüzde, farklı kaynaklardan sentezlenebilecek izotropik ve mezofaz ziftlerden karbon fiber eldesi, üretim süreçlerinin ve son ürün özelliklerinin geliştirilmesi üzerine birçok çalışma yürütülmektedir. Bu çalışmada, zift esaslı karbon fiber üretimi hakkında bir literatür taraması yapılarak, üretim süreçleri incelenmiştir.
Although extensive improvement has been done on the brake pad for vehicles, most recent materials used still encounter wear rate, friction, stopping distance and time deficiencies. In this regards, this study developed a polymer-based nanocomposite brake pad. Here, a combination of carbon-based materials, including those at a nanoscale, was used to produce the brake pad. Tribological performance, such as friction coefficient, wear rate and stopping distances of developed brake pad was investigated using an inertial dynamometer. The results revealed that the stopping distance, the coefficient of friction and wear rate varies with the brake pad formation and velocity. The micrographs show changes in the structural formation after the incorporation of carbon-based fillers. It also shows the smooth structure and uniform dispersion of the carbon fibre. The smooth surface of the worn brake pad is an indication of a tougher structure. Hence, it was deduced that the fabricated polymer-based hybrid composite had good tribological property. This improved property is suggestive of materials that may be successfully used for brake pad application.
In the present work, composites were developed with novel combination of particular fillers and fibers for an automotive brake system. The influence of short carbon fiber (SCF) on wear rate, coefficient of friction (CoF), modulus, compressive strength, hardness, and surface morphology of worn surface were examined. This investigation confirmed that 0.1% multiwalled carbon nanotubes (MWCNTs) reduced wear rate, CoF for all combinations of composite with carbon fiber. Results indicate that 0.1% (MWCNTs) and 10% SCF-filled composite had superior properties. This performance may be attributed to the uniform dispersion of fiber and the synergistic effect of SCF and MWCNTs, acting in concert that formed a more stable structure resulting in a high strength, stiffness, tougher, and high-heat absorption. Scanning electron microscopy (SEM) microstructure subsequently performed show change in structural development with a corresponding increase of the incorporation of SCF and MWCNTs, which eventually explained the improved properties of composite.
This chapter gives an overview of carbon fibers manufacturing from different precursor systems and their corresponding thermal transporting properties. The precursor-dependent structures and properties of the resulting carbon fibers will be discussed, particularly for the carbon nanotubes- and graphene-based carbon fibers due to their high potential for developing high performance carbon fibers with high thermal and electrical conductivity. In addition, the thermal transporting properties of individual carbon fibers manufactured from different precursors, and in their corresponding carbon fibers reinforced polymer nanocomposites will be presented in this chapter.
Activated carbon fibers (ACF) are interesting candidates for electrodes in electrochemical energy storage devices; however, one major drawback for practical application is their low density. In the present work, monoliths were synthesized from two different ACFs, reaching 3 times higher densities than the original ACFs’ apparent densities. The porosity of the monoliths was only slightly decreased with respect to the pristine ACFs, the employed PVDC binder developing additional porosity upon carbonization. The ACF monoliths are essentially microporous and reach BET surface areas of up to 1838 m ² g ⁻¹ . SEM analysis reveals that the ACFs are well embedded into the monolith structure and that their length was significantly reduced due to the monolith preparation process. The carbonized monoliths were studied as supercapacitor electrodes in two- and three-electrode cells having 2 M H 2 SO 4 as electrolyte. Maximum capacitances of around 200 F g ⁻¹ were reached. The results confirm that the capacitance of the bisulfate anions essentially originates from the double layer, while hydronium cations contribute with a mixture of both, double layer capacitance and pseudocapacitance.
The available information on production, properties of carbon fibres from lignin is presented in this chapter.
Properties of carbon fibre and its processing are presented in this chapter.
This chapter gives the details of various synthetic fibres (both organic and inorganic such as glass, carbon, aramides, polyolefins, ceramic fibres, etc.) used to reinforce composite materials for conventional as well as very high-tech applications. Production and properties of these fibres and also the most common applications in fibre reinforced composites are included in this chapter.
Factors affecting the performance of short fiber-reinforced polymer (SFRP) composites are reviewed with an emphasis on the factors such as fiber orientation and volume fraction, fiber length, and matrix–fiber interfacial properties. The review is followed by a case study on short carbon fiber-reinforced polycarbonate (PC) composites of varying volume fraction (1 %, 3 %, 5 %, 7 %, 10 %, and 15 %). Tensile and three bending tests reveal an increase in the modulus and yield strength of the composites with increasing fiber content. To evaluate the effect of interface in each matrix and fiber system with changing matrix mobility dynamic mechanical analysis is performed, which reveal an increase in the storage modulus of the composites and a shift in the glass transition temperature caused by the introduction of CFs. The surface morphology of the fractured specimens revealed homogenous dispersion of CF in the polymer matrix.
We have shown that the E2g, A1g and second-order (~ 2700 cm-1) Raman band positions of Hercules HMS4 carbon fibres shift as a function of incident laser power. These shifts arise as a result of changes in the local fibre temperature. The sensitivity of band position to varying laser power is different from fibre to fibre within the same tow — thus equally strained fibres subjected to the same laser power can show widely different band positions and so different apparent strains. The same effect can be observed from point to point on individual fibres. If laser power is not carefully controlled (both in magnitude and stability), errors in the accuracy of the measured strain can be greater than the measured strain itself, and have been shown to approach 70% of the breaking strain. These results mean that strain measurements obtained from composite materials containing this fibre must be interpreted with caution unless the laser beam intensity at the fibre is precisely controlled. This effect will also be important with other types of carbon fibre, since in previous work we have observed that laser-induced sample heating occurs with a wide range of materials from cokes to pitch-based fibres.