Mechanical Properties Of Carbon Research Articles

Self‐emulsifying anionic polyester sizing agents for enhancing the interfacial and mechanical properties of carbon fiber/vinyl ester resin composites

AbstractWith the increasing emphasis on environmental protection, there is a growing focus on the synthesis of water‐solvent self‐emulsifying sizing agents. In this study, five types of anionic polyester sizing agents with varying molecular weights were synthesized to explore the effect of molecular weight on the interfacial bonding strength of carbon fiber (CF) reinforced vinyl resin composites. The results demonstrated that the molecular weights of the synthesized sizing agents were precise; the particles in the sizing agents were nanometer‐sized, monodisperse, and exhibited high thermal stability. When the molecular weight was 8000, it exhibited optimal wettability for CF, leading to a substantial improvement in the interlaminar shear strength, reaching 71.8 MPa, which represents a significant increase of 22.7% compared with commercial CFs (CFF). Additionally, the interfacial shear strength was maximized at 13.23 MPa, which was significantly increased by 14.2% compared with CCF. These significant improvements in surface properties and mechanical performance were attributed to the excellent wettability of the CF surface, effective spreading performance of the sizing agent, the presence of double bonds in the sizing agent facilitating reactions with free radicals on the CF surface, and the residual double bonds further undergoing curing with the vinyl resin, promoting the reinforcement of interface bonding.

Physical, Thermal and Mechanical Properties of Carbon Fibre/Polyphenylene Sulfide (CF/PPS) Composite at Different Tool Temperatures Fabricated by Hot Press

Carbon fibre/polyphenylene sulfide (CF/PPS) composites have gained the attention in the aerospace industry due to its excellent impact strength, fire/smoke/toxicity (FST) performance, and chemical resistance. This study investigated the effect of hot press tool temperatures (Tt) on the physical, thermal, and mechanical on CF/PPS composites. The experimental procedure involved using PCL of CF/PPS composite and subjecting it to hot press forming at different tool temperatures ranging from 150°C to 195°C. The physical properties was characterized by surface energy measurement using the sessile drop method. Thermal properties were evaluated through the degree of crystallinity (DoC) determination using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) where the percentage of the residual weight is calculated. The mechanical properties was assessed using tensile test. From the results, increasing the Ttwill enhances the surface energy, improving the adhesion and bonding between the matrix and CF, and the thermal stability of the composite materials. At Tt 180°C, the physical, thermal, and mechanical properties of CF/PPS composite component is at their best with the value of surface energy is 35.13%, the DoC is 25.00%, TGA is 74.74% and tensile strength is 793.80 MPa. This study provides valuable insights into the relationship between tool temperature and the physical, thermal, and mechanical properties of CF/PPS composites, offering guidance for manufacturing processes and composite material design in aerospace and other industries.

Preparation of unsaturated self-emulsifying polyester sizing agents for improving interfacial and mechanical properties of carbon fiber/vinyl ester resin composites

In order to promote the interfacial adhesion between carbon fiber and vinyl ester matrix, a series of unsaturated self-emulsifying anionic polyester sizing agents were designed. The results indicated that the sizing agents exhibited a uniform particle size distribution at the nanometer level and demonstrated favorable thermal stability below 200 °C. As the content of double bonds of sizing agents increases, the glass transition temperature also increases, and the moisture absorption of sized carbon fiber decreases. The carbon fiber surface becomes smoother after sizing. Moreover, the interlaminar shear strength and interfacial shear strength increased by 18.8 % and 43.4 %, respectively, compared to the commercial carbon fiber. This is mainly due to the unsaturated bonds in the sizing agent react with the free radicals on the surface of the carbon fiber, which enhance the interface bonding strength between the sizing agent and the surface of the carbon fiber and the vinyl ester matrix.

Optimizing ball milling parameters for controlling the internal microstructure and tensile characteristics of a laminated carbon nanotube/aluminum-copper-magnesium composite

This research investigates how different ball milling conditions influence the microstructure and mechanical properties of carbon nanotube/aluminum alloys. The study examines varying rotation speeds, specifically 200, 300, and 400 rpm. The results highlight the significant impact of milling conditions on grain size and mechanical properties. Notably, milling at 300 rpm /4 h and at 400 rpm/2 h led to higher tensile strength but lower uniform elongation compared to milling at 200 rpm/6 h. The alloy milled at 300 rpm/4 h displayed a refined microstructure, increased density, and the strongest fiber texture along the (111) direction. At 300 rpm/4 h, the presence of a moderate grain size promoted ductility, resulting in the highest uniform elongation (∼9.1%) combined with high strength (∼515 MPa). This in turn means an increase in UTS by 23% and uniform elongation by 3.4% compared to 400 rpm/2 h. The formation of MgAl2O4 at higher rotational speeds positively influences the CNT–Al interface by alleviating the adverse effects of interfacial oxide (Al2O3), resulting in improved bonding and, consequently, enhanced tensile properties. This study provides valuable insights into the effects of ball milling on the microstructure and mechanical properties of metals and alloys, contributing to the optimization of milling conditions to achieve desired material characteristics.

Enhancing interfacial solvent resistance and mechanical properties of carbon fiber/polyether ether ketone composites with water‐borne sizing agents based on cross‐linkable polyphthalonitrile

AbstractThe inherent structural properties and elevated processing temperatures of thermoplastic resins present new challenges in the realm of carbon fiber (CF) sizing agents. Consequently, a water‐based cross‐linkable nitro‐phthalonitrile capped polyfluorenyl ether ketone sizing agent was meticulously designed. The sizing agent exhibits superior storage stability, encapsulating particles spanning dimensions from 66.51 to 87.71 nm. The inherent mechanism during the hot‐pressing stage involves a self‐crosslinking of nitrile groups toward stable structures with unparalleled resistance to solvents. The crosslinked sizing agent boasts a remarkable glass‐transition temperature of 290°C. Noteworthy, significance is the consequential 40.1% augmentation in maximum flexural strength, along with a commendable 35% increase in interlaminar shear strength for CF‐1.5/PEEK composites in contrast to their unsized CF/PEEK counterparts. In summary, the focal aspiration of this research endeavor lies in offering a straightforward and viable methodology for the exploration of cross‐linkable sizing agents, strategically catering to both “thermoplastic processing” and “thermosetting applications.”Highlights Bulky fluorenyl unit increases the intermolecular volume of copolymer poly(fluorenyl ether ketone). The introduction of the BPF unit to the molecular elevates the thermal stability of the copolymer. Unique electron‐donating proclivity of the fluorenyl group drastically improved its reactivity. The polymerization was accomplished at a relatively low temperature of 150°C for practical applications. The ILSS, IFSS, and bending strength were noteworthy increased by 35%, 74.02%, and 40.1%

Enhanced interfacial and mechanical properties of carbon fabric/PA12 composites via grafting silanized nano hexagonal boron nitride onto the fibers

ABSTRACT The purpose of this work was to create thermoplastic composites based on carbon fiber fabric reinforced enhanced mechanical and interfacial properties, based on PA12 (polyamide 12). In line with these objectives, it is aimed to develop carbon fiber reinforced thermoplastic composite materials with improved interfaces by sizing chemical modification and interfacial compatibility suspension development using hBN (hexagonal boron nitride) nanomaterial. The production of bare and silanized hBN sizing grafted CF (carbon fiber)-PA12 plates was followed by various mechanical, thermal, and SEM analyses. When the mechanical test results of CF-PA12 and hBN-APTES (3-Aminopropyltriethoxysilane) Sizing Coated Composite Specimens are compared; it is proved that hBN-APTES sizing improves the mechanical properties. Furthermore, sizing coated CF-PA12 composite specimens showed improvements in flexural strength of 20.67% and compressive strength of 19%, respectively. The significance of these results is to enhance the critical interfacial properties in the manufacturing of carbon fiber composite materials based on PA12, and to produce high-quality products that can be used in a variety of industries, including sports equipment, automotive, and aerospace, all of which have a constant demand worldwide.

Optimizing ball milling parameters for controlling the internal microstructure and tensile characteristics of a laminated carbon nanotube/aluminum–copper–magnesium composite

This research investigates how different ball milling conditions influence the microstructure and mechanical properties of carbon nanotube/aluminum alloys. The study examines varying rotation speeds, specifically 200, 300, and 400 rpm. The results highlight the significant impact of milling conditions on grain size and mechanical properties. Notably, milling at 300 rpm/4 h and at 400 rpm/2 h led to higher tensile strength but lower uniform elongation compared to milling at 200 rpm/6 h. The alloy milled at 300 rpm/4 h displayed a refined microstructure, increased density, and the strongest fiber texture along the (111) direction. The presence of a moderate grain size facilitated ductility, resulting in the highest uniform elongation (∼9.1%) while maintaining high strength (∼515 MPa). This study provides valuable insights into the effects of ball milling on the microstructure and mechanical properties of metals and alloys, contributing to the optimization of milling conditions to achieve desired material characteristics.

Enhancement of the Fracture Toughness of Carbon-Reinforced Plastics by Introducing a Thermoplastic Phase into an Epoxy Matrix

The effect of modifying additives of polyphenylene sulfone or a nonwoven polyamide material on the thermal and mechanical properties of carbon fabric/epoxy resin polymer composite materials prepared by vacuum forming and vacuum infusion was studied. The addition of 10 wt % polyphenylene sulfone leads to slight improvement of the mechanical properties of the composite material, whereas introduction of the nonwoven material leads to a 15% decrease in the compression strength and to a 6% decrease in the interlayer shear strength. The specific peel work increases by 15 and 270% for the composites modified with polyphenylene sulfone and nonwoven cloth, respectively. Introduction of 4 wt % nonwoven material enhances the fracture toughness of the polymer composite material by a factor of 3.7.

Electronic, Thermal and Mechanical Properties of Carbon and Boron Nitride Holey Graphyne Monolayers.

In a recent experimental accomplishment, a two-dimensional holey graphyne semiconducting nanosheet with unusual annulative π-extension has been fabricated. Motivated by the aforementioned advance, herein we theoretically explore the electronic, dynamical stability, thermal and mechanical properties of carbon (C) and boron nitride (BN) holey graphyne (HGY) monolayers. Density functional theory (DFT) results reveal that while the C-HGY monolayer shows an appealing direct gap of 1.00 (0.50) eV according to the HSE06(PBE) functional, the BNHGY monolayer is an indirect insulator with large band gaps of 5.58 (4.20) eV. Furthermore, the elastic modulus (ultimate tensile strength) values of the single-layer C- and BN-HGY are predicted to be 127(41) and 105(29) GPa, respectively. The phononic and thermal properties are further investigated using machine learning interatomic potentials (MLIPs). The predicted phonon spectra confirm the dynamical stability of these novel nanoporous lattices. The room temperature lattice thermal conductivity of the considered monolayers is estimated to be very close, around 14.0 ± 1.5 W/mK. At room temperature, the C-HGY and BN-HGY monolayers are predicted to yield an ultrahigh negative thermal expansion coefficient, by more than one order of magnitude larger than that of the graphene. The presented results reveal decent stability, anomalously low elastic modulus to tensile strength ratio, ultrahigh negative thermal expansion coefficients and moderate lattice thermal conductivity of the semiconducting C-HGY and insulating BN-HGY monolayers.

Improving mechanical properties of high-temperature resistant carbon fiber/phthalonitrile composites via surface modification: a comparative study on modification methods

ABSTRACT The interfacial bonding is of essential importance for the mechanical properties of high-temperature resistant carbon fiber/phthalonitrile composite materials. To promote the interfacial adhesion of carbon fiber/phthalonitrile composites, three surface modification methods, namely HP302 sizing, diazotization modification, and oxidation-diazotization modification, were applied and compared. The results showed that the de-sizing treatment barely affected the mechanical properties of the composites. Both re-sizing with HP302 agent and diazotization modification improved the mechanical properties, while the mechanical properties were drastically decreased via the oxidation-diazotization modification. Among these surface modification methods, the diazotization treatment derived the best mechanical properties of carbon fiber/phthalonitrile composites both at room and high temperature. Specifically, the flexural strengths were 345 MPa (RT), 525 MPa (300°C), and 442 MPa (400°C), which were 47%, 302%, and 281% higher than those of the pristine composites. The interlaminar shear strengths were 33 MPa (RT), 26 MPa (300°C), and 27 MPa (400°C), which were all over twofold than those of the original counterparts.

Effect of Loop Yarns on Mechanical Properties of Carbon Fibre/Epoxy Composites

Effect of Loop Yarns on Mechanical Properties of Carbon Fibre/Epoxy Composites

Thermal insulation and mechanical properties of carbon fiber‐reinforced thermoplastic polyphthalazine ether sulfone ketone composites reinforced by hollow glass beads

AbstractIn the high‐tech field, there is an urgent need for materials that possess thermal insulation, mechanical properties, and processing properties. One promising option is Carbon fiber reinforced thermoplastic composites (CFRTPs), which exhibit excellent characteristics such as light weight, high strength, and high temperature resistance. The effects and mechanisms of hollow glass beads (HGB) on the thermal insulation and mechanical properties of carbon fiber‐reinforced thermoplastic polyphthalazine ether sulfone ketone composites (CF/PPESK) were investigated. The introduction of 15 wt% HGB improved the material's thermal insulation performance by 32.74% perpendicular to the fiber direction and 44.95% parallel to the fiber direction. Furthermore, the addition of 3 wt% HGB increased the interlaminar shear strength, compression strength, and flexural strength by 21.34%, 17.49%, and 5.53%, respectively. Additionally, the dynamic mechanical analysis confirmed that the HGB/CF/PPESK composite has superior high‐temperature mechanical properties, which holds great promise for CFRTPs applications.Highlights Modification of CF/PPESK with HGB improved its thermal insulation properties. Analysis of the mechanism of CF/PPESK for thermal insulation performance. HGB improved the mechanical properties by delaying the expansion of microcracks. Agglomeration of HGB leads to a rapid rise in thermal insulation properties.

Mechanical properties of carbon fiber/polypropylene composites using carboxylic-acid-modified polypropylene without and with oxazoline-containing polymer coated on carbon fiber

There have been many reports on the use of maleic-anhydride-modified polypropylene (MAn-g-PP) as a compatibilizer for carbon fiber (CF)/polypropylene (PP) composites, but there are very few examples using carboxylic-acid-modified PP. The purpose of this paper is to investigate the effect of hydrogen bonding at the CF/PP interface contributed by the addition of carboxylic-acid-modified PP on the mechanical properties of composites, and to propose a new interface design for improving the mechanical properties of composites by combining a poly-2-vinyl-2-oxazoline (Pvozo) coating on the CF surface with the addition of carboxylic-acid-modified PP to composites. For this purpose, poly methacrylic acid-grafted polypropylene (PMAA-g-PP) was synthesized independently and added to the CF/PP composite. The addition of PMAA-g-PP enhanced the tensile properties of the composites due to the effect of hydrogen bonding at the CF/PP interface. The combination of PMAA-g-PP addition to the composites and the use of Pvozo-coated CF resulted in better interfacial adhesion and further improved the tensile properties of the composites. Increased entanglement with matrix PP molecules due to carboxylic-acid-modified PP being grafted onto the CF surface and different bonding modes at the CF/PP interface were suggested to contribute to the mechanical properties of the composite.

Synergistic influence of MWCNTs/RGO on low-velocity impact response and mechanical properties of carbon fiber/epoxy composite

Nanoparticles can be used to enhance and improve the mechanical properties and low-velocity impact response of carbon fiber-reinforced polymer (CFRP) composites both simultaneously and individually. Also, the synergistic influence of two nanoparticles can be improved the mechanical properties and low-velocity impact response of CFRP composites. In this paper, the effects of reduced graphene oxide (RGO) and multi-walled carbon nanotubes (MWCNTs) on the mechanical properties, low-velocity impact response and damage area of epoxy/fiber carbon composites are investigated both simultaneously and individually. Composite specimens are fabricated with 0.4 weight percentages (wt.%) of RGO, 0.06 wt.% of MWCNTs individually, and a combination of RGO and MWCNTs with 0.6 and 0.06 wt.%, respectively. For comparison of the results, the neat epoxy specimens are fabricated and also tested. Direct homogenization technique is applied for preparation of nanocomposite mixture and then each layer of carbon fiber reinforced nanocomposite is fabricated using a hand lay-up process. Tensile modulus, tensile strength, variations of load, displacement, velocity, and absorbed energy of specimens versus time are obtained. For specimens with MWCNTs/RGO tensile modulus and tensile strength increased by about 21.30% and 17.12%, respectively, and the load peak increased by 15.15% at 1 J, 13.35% at 2 J, 39.62% at 3 J, and 39.62% at 3 J. It is concluded that the synergistic influence of MWCNTs and RGO on the results is more significant and has a higher effect on the impact responses. After the impact tests, Optical microscopy and SEM method are used to analyze fracture surfaces.

Effects of Orientation and Dispersion on Electrical Conductivity and Mechanical Properties of Carbon Nanotube/Polypropylene Composite.

The orientation and dispersion of nanoparticles can greatly influence the conductivity and mechanical properties of nanocomposites. In this study, the Polypropylene/ Carbon Nanotubes (PP/CNTs) nanocomposites were produced using three different molding methods, i.e., compression molding (CM), conventional injection molding (IM), and interval injection molding (IntM). Various CNTs content and shear conditions give CNTs different dispersion and orientation states. Then, three electrical percolation thresholds (4 wt.% CM, 6 wt.% IM, and 9 wt.% IntM) were obtained by various CNTs dispersion and orientations. Agglomerate dispersion (Adis), agglomerate orientation (Aori), and molecular orientation (Mori) are used to quantify the CNTs dispersion and orientation degree. IntM uses high shear to break the agglomerates and promote the Aori, Mori, and Adis. Large Aori and Mori can create a path along the flow direction, which lead to an electrical anisotropy of nearly six orders of magnitude in the flow and transverse direction. On the other hand, when CM and IM samples already build the conductive network, IntM can triple the Adis and destroy the network. Moreover, mechanical properties are also been discussed, such as the increase in tensile strength with Aori and Mori but showing independence with Adis. This paper proves that the high dispersion of CNTs agglomerate goes against forming a conductivity network. At the same time, the increased orientation of CNTs causes the electric current to flow only in the orientation direction. It helps to prepare PP/CNTs nanocomposites on demand by understanding the influence of CNTs dispersion and orientation on mechanical and electrical properties.

Novel preparation of nano-SiO2 core-shell hybrid inorganic-organic sizing agents for enhanced interfacial and mechanical properties of carbon fibers/epoxy composites

The interfacial properties of carbon fibers (CFs) composites were improved by modifying the self-emulsifying amphiphilic epoxy sizing agent with nano-SiO2 particles. Herein, a series of inorganic–organic nano-SiO2 core-cationic epoxy shell hybrid sizing agents (referred to as nano-SiO2 core–shell hybrid sizing agents) with various nano-SiO2 contents were synthesized and used to enhance the mechanical properties of CF/EP. The study indicated that the nano-SiO2 core–shell hybrid sizing agents had the characteristics of the perfect core–shell structure, single dispersion, particle sizes controllable, good storage and high heat resistance. Nano-SiO2 core–shell hybrid sizing agents significantly increased the surface roughness and the surface energy of CFs compared to the unmodified sizing agent. Nano-SiO2 core–shell hybrid sizing agents (7.2% SiO2) increased ILSS, IFSS by 16.92%, 21% and nano-SiO2 core–shell hybrid sizing agents (5.8% SiO2) increased tensile force of monofilament CF by 23.78%, respectively, compared with the unmodified agent. These reinforcements may have been caused by the enhancement of the stress transference of nano-particles in the interface between CFs and EP through an interlocking mechanism. As a result, the nano-SiO2 core–shell sizing agent overcomes the lack of adhesion of traditional nano modification methods and shows remarkable adhesion properties.

Influence of Stacking Sequences on Mechanical Properties of Carbon, Glass, Flax - Epoxy Reinforced Hybrid Composites

Influence of Stacking Sequences on Mechanical Properties of Carbon, Glass, Flax - Epoxy Reinforced Hybrid Composites

Influence of post-heat treatment over structural network and mechanical properties of carbon (C)-incorporated CVD TiCN thin-film coating

Influence of post-heat treatment over structural network and mechanical properties of carbon (C)-incorporated CVD TiCN thin-film coating

Flame retardant and mechanical properties of carbon fiber/novel phenolic resin sandwich composite laminates

This study investigated a novel phenolic resin that possesses the advantages of both epoxy and phenolic resins and significantly improves their disadvantages. This novel phenolic resin was impregnated into the carbon fiber woven to prepare a sandwich composite. Composites with sandwich structures were analyzed for their flame retardant and mechanical properties. The flame retardancy of the novel phenolic resin composite was similar to that of a pure phenolic resin composite without the processing disadvantages of pure phenolic resin, and these two composites were better than epoxy sandwich composites. The mechanical properties, such as facesheet, and core shear test results of the sandwich composite revealed that both epoxy and novel phenolic composites with a flame retardant added had poor interfacial bonding, resulting in lower strength than that of the neat sandwich composite.

Effects of vacuum thermal cycling, ultraviolet radiation and atomic oxygen on the mechanical properties of carbon fiber/epoxy shape memory polymer composite

The use of shape memory polymer composites as novel materials for next generation space deployable structures requires the study of the effect of space environment upon their properties. The resistance of carbon fiber/epoxy shape memory polymer composite to vacuum thermal cycling, ultraviolet radiation and atomic oxygen has been evaluated separately by using ground-based simulation facilities. The thermal cycling condition has a temperature range of −100 °C to +100 °C with cycle times of 0, 15, 30, and 45. The irradiation times of ultraviolet with a wavelength range of 250 nm–400 nm are 0, 80, 160, and 240 h. The atomic oxygen radiation has a translational energy of about 5 eV and a flux of about 2 × 1015 atoms/cm2 at the sample position, and the irradiation times are 0, 33, 66, and 100 h. The shape memory polymer composite specimens are compared in terms of morphology, tensile modulus, breaking strength and elongation at break before and after irradiation. Results show that thermal cycling increases tensile modulus but decreases the breaking strength and the elongation at break of material after 45 cycles. The effect of ultraviolet radiation on mechanical properties of materials depends on the radiation dose received. Atomic oxygen can negatively but slightly affect the mechanical properties of the material.