The extensive use of carbon fiber-reinforced plastics (CFRP) in aerospace, civil engineering, and other fields has resulted in a significant amount of waste, leading to serious environmental issues. ...Finding appropriate methods for recycling CFRP waste and effectively reusing recycled carbon fibers (rCFs) has become a challenging task. This paper presents an overview of the current status of CFRP waste and provides a systematic review and analysis of recycling technologies. In addition to discussing mechanical recycling, thermal decomposition, and chemical solvent degradation methods, the organic alkali/organic solvent method for recycling resins is also elucidated. By introducing the recycling conditions and outcomes of the organic alkali/organic solvent method, the study highlights its significance as a reference for carbon fiber recycling. Furthermore, the paper reviews the current state of rCFs utilization based on its application domains, focusing on research advancements in fiber composites and cementitious composites. Based on these findings, the paper summarizes the existing research limitations and identifies specific areas that require further attention in recycling techniques and rCFs utilization. Lastly, this review provides a prospect on the future of recycling and reusing CFRP waste.
The practical application of Zn‐metal anodes (ZMAs) is mainly impeded by the limited lifespan and low Coulombic efficiency (CE) resulting from the Zn dendrite growth and side reactions. Herein, a 3D ...multifunctional host consisting of N‐doped carbon fibers embedded with Cu nanoboxes (denoted as Cu NBs@NCFs) is rationally designed and developed for stable ZMAs. The 3D macroporous configuration and hollow structure can lower the local current density and alleviate the large volume change during the repeated cycling processes. Furthermore, zincophilic Cu and in‐situ‐formed Cu–Zn alloy can act as homogeneous nucleation sites to minimize the Zn nucleation overpotential, further guiding uniform and dense Zn deposition. As a result, this Cu NBs@NCFs host exhibits high CE of Zn plating/stripping for 1000 cycles. The Cu NBs@NCFs–Zn electrode shows low voltage hysteresis and prolonged cycling life (450 h) with dendrite‐free behaviors. As a proof‐of‐concept demonstration, a Zn‐ion full cell is fabricated based on this Cu NBs@NCFs–Zn anode, which demonstrates decent rate capability and improved cycling performance.
A 3D framework consisting of N‐doped carbon fibers embedded with Cu nanoboxes (Cu NBs@NCFs) is constructed as a multifunctional host for dendrite‐free and stable Zn anodes. Benefiting from the macroporous network, hollow structures, and rich zincophilic sites, the Cu NBs@NCFs host shows low voltage hysteresis, high Coulombic efficiency, and impressive cycling stability in both symmetric and full cells.
Carbon fiber felt (CFF) has a broad range of applications in electromagnetic interference (EMI) shielding because it is a multi-functional rigid material with a conductive property. In the present ...work, the flexible and intelligent CFF/poly(ethylene-co-vinyl acetate) (EVA) EMI shielding composites with electrothermal-driven shape memory performance was prepared by hot-pressing method, which provide precise and convenient control-method for driving EMI shielding conversion. As revealed, the CFF/EVA composites can achieve an EMI shielding effect of 45.6 dB in X-band and maintain a ca. 99% shape memory recovery ratio. Moreover, the composites can quickly return to the original shape at low voltage, and realize accurate and fast remote emergency control EMI shielding. The excellent flexible, intelligent and controllable high-performance EMI shielding effect of the CFF/EVA composites will play a key role in the frontier fields of flexible electronic equipment, actuators, chip protection, and information security.
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Polyacrylonitrile (PAN) is a versatile man-made polymer and has been used in a large array of products since its first mass production in the mid 40s. Among all applications of PAN the widely used ...application is in manufacture of precursor fiber for fabrication of carbon fibers. The process of PAN-based carbon fiber production comprises fiber spinning, thermal stabilization and carbonization stages. Carbon fiber properties are significantly dependent on the quality of PAN precursor fiber and in particular the process parameters involved in thermal stabilization. This paper is the first comprehensive review that provides a general understanding of the links between PAN fiber structure, properties, and its stabilization process along with the use of mathematical modelling as a powerful tool in prediction and optimization of the processes involved. Since the promise of the mathematical modelling is to predict the future behaviour of the system and the value of the variables for the unseen or unmeasured domain of variables; and in the era of industry 4.0 rise, this review will be valuable in further understanding of the intricate processes of carbon fiber manufacture and utilising the advanced mathematical modelling using machine learning techniques to predict and optimize a range of critical factors that control the quality of PAN and resultant carbon fibers.
According to surface chemistry and topography of different high-modulus carbon fiber (HMCF), interfacial properties of various HMCF composite were evaluated, and nanoscale wetting analysis of HMCF ...were studied using experimental methods and molecular dynamics simulation. Hierarchical amount of active functional groups and nanoscale grooves were detected on the surface of pristine HMCF (p-HMCF), anodic oxidized HMCF (a-HMCF) and sized HMCF (s-HMCF). Remarkable enhancements in interfacial properties of a-HMCF and s-HMCF composites were obtained, which was ascribed to free-void interface from improved surface energy and wettability. Poor interfacial bonding of p-HMCF composites was due to generation of many nanobubbles with pinned contact lines during the wetting of the surface microgrooves with high aspect ratio and chemical inertness. Schematic of interfacial compatibility mechanisms was proposed to illustrate the correlation between surface features of carbon surface and interfacial properties of their composites.
Inspired by nacre's sophisticated “brick-and-mortar” structure, multilayered polyether amine (PEA)/graphene oxide (GO) hybrid building blocks were incorporated onto the surface of carbon fiber via ...Layer-by-Layer (LbL) assembly to strengthen and toughen the interphase of composites. Impressive improvements of 67.7% and 129.0% in interfacial strength and toughness over those of untreated fiber composites are achieved for composites with 9 layers of PEA/GO on fiber surface. The synergistic effects stemming from covalent bonds, hydrogen bonds and π-π interaction, as well as crack deflection caused by homogeneous GO layers, improved surface energy and wettability are major reasons for the increase in interfacial adhesion. The major toughening mechanisms are attributed to interfacial micro-cracks, viscoplastic energy dissipation of PEA and GO slippage. This work provides a promising route of bio-inspired structural composites with excellent strength and toughness.
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Graphene inclusion in a polymer matrix is a promising route to significantly enhance the mechanical properties of low-grade carbon fibers (CFs). Using ReaxFF molecular dynamics simulation, the ...atomistic mechanism leading to this enhancement is investigated. We demonstrate that the graphene edges along with the nitrogen and oxygen functional groups play a catalytic role and act as seeds to expedite alignment of the all-carbon rings, which are starting sites for the growth of graphitic structures. To examine the role of this proposed mechanism that enhances the graphitic structure of PAN/graphene CFs, we discuss the experimental results wherein the PAN/graphene CFs carbonized at 1250 °C demonstrate 91% (from 632 to 1207 MPa) increase in strength and 101% (from 88 to 177 GPa) enhancement in Young’s modulus compared to PAN-based CFs carbonized at 1500 °C. These enhanced mechanical properties of low-grade carbon fibers achieved via graphene inclusion at decreased carbonization temperature provide a means to realize both energy savings and cost reduction.
Display omitted The graphene edges play a catalytic role and act as seeds in expedite graphitic structure growth, while the graphene surface carbon atoms are relatively inactive due to their conjugated sp2 electronic configuration.
Potassium‐based dual‐ion batteries (KDIBs) have emerged as a new generation of rechargeable batteries, due to their high cell voltage, low cost, and the natural abundance of potassium resources. ...However, the low capacity and poor cycling stability largely hinder the further development of KDIBs. Herein, the fabrication of hierarchically porous N‐doped carbon fibers (HPNCFs) as a free‐standing anode for high‐performance KDIBs is reported. With a free‐standing hierarchical structure (micro/meso/macropores and nanochannels) and high‐content of nitrogen doping, the HPNCFs not only provide intrinsic electron pathways and efficient ion transport channels, but also afford sufficient free space to tolerate the volume change during cycling. Consequently, the KDIBs made from a graphite cathode and an optimized HPNCFs anode deliver a high reversible capacity of 197 mAh g−1 at a specific current of 50 mA g−1, and excellent cycling stability (65 mAh g−1 after 346 cycles at a specific current of 100 mA g−1, the capacity calculation of the KDIBs is based on the mass of the anode). These results indicate that the properly designed HPNCFs can effectively improve the capacity and cycling stability of the KDIBs, indicating a great potential for applications in the field of high‐performance energy‐storage devices.
A potassium‐based dual‐ion batteries (KDIBs) are made from a hierarchically porous N‐doped carbon fibers (HPNCFs) anode and a graphite cathode. During the charging process, the anions (PF6−) intercalates into the graphite cathode, while the cations (K+) intercalate into the HPNCFs anode. During the discharge process, anions and cations de‐intercalate from the corresponding electrode, returning to the electrolyte. The KDIBs manifest high working voltage and high reversible capacity.
The paper presents the current volume of international production and global markets of carbon fiber reinforced polymer composites, also regarding the potential development trends. Examples were ...provided on how to effectively recycle carbon fiber reinforced polymer composites. Legally binding legislation in the EU on polymer composite recycling was given.
The damage properties of carbon fiber reinforced polymer (CFRP) laminates exposed to combined lightning components D and C were explored by standardized artificial lightning tests, and then evaluated ...by visual inspection and ultrasonic scan. To interpret the heating mechanism of CFRPs under the combined lightning components D and C, a mathematical model of lightning arc was involved in the finite element analysis, the results of which agreed well with experimental data. It was revealed that the component D controlled the in-plane damage area, while the sequential injection of component C aggravated the in-plane damage extent and tended to induce in-depth damage. The simulated results indicated that the resistive heating effect played a leading role in thermal damage of CFRPs during component D, whereas the damage occurred in component C was dominated by lightning arc heating effect.
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