Uniform Dispersion Of Carbon Nanotubes Research Articles

Microstructural and mechanical properties study of various lattice structures of SS316L-CNTs nano composites fabricated through additive manufacturing

Abstract In this work, various lattice structures, such as FCC (face-centered), BCC (body-centered), GD (Gyroid), and BGD (bare gyroid (without CNTs)) with four different porosities (60%, 70%, 80%, and 90%), were prepared through the SLM (selective laser melting) additive manufacturing process. Stainless Steel (SS) 316L alloy was utilized as the base material, while 0.2 wt.% functionalized CNTs (Carbon Nanotubes) were employed as reinforcement. The uniform dispersion of CNTs was analyzed using FESEM, TEM, and Raman spectroscopy. The results indicated that the plateau stress increases with the addition of CNTs, as well as with relative density, whereas energy absorption increases with the addition of CNTs. However, with increasing relative densities, energy absorption nature changes from increasing to decreasing. The results showed that among all lattice structures formed with CNTs addition, the Gyroid lattice exhibited the highest plateau stress, while the BCC lattice exhibited the lowest plateau stress.

An effective utilization of raw fly ash obtained from thermal power plants using thermal spray technique to improve corrosion resistance for marine applications

Marine-grade steel structures in offshore environments often corrode due to the aggressive environmental conditions. Many ceramic materials can cater to this demand. However, as per economic and ecological concerns, fly ash (FA), an industrial waste, can be another strong contender to control corrosion. Therefore, the present study developed composite coatings of fly ash with additives ((50-48) wt.% Al2O3; 0–2 wt% carbon nanotube (CNT)) onto marine-grade steel using a plasma spray technique to improve its corrosion resistance. The microstructure of 1 wt% CNT-reinforced alumina-FA (1CAF) coating was denser than 2 wt% CNT-reinforced alumina-FA (2CAF) coating due to the uniform dispersion of CNT and, thereby, uniform remelting of coating at localized sites. Consequently, the microhardness and adhesion strength of the 1CAF coating were improved by ∼14.66 % and ∼15.96 %, respectively. Further, Rietveld's analysis of coatings showed that quartz, being the primary phase for corrosion control, was 19.23 ± 0.87 %, 16.33 ± 1.04 % and 14.60 ± 1.87 % for alumina-FA (AF), 1CAF, and 2CAF, respectively. The electrochemical impedance spectroscopy and the salt spray corrosion tests showed that 1CAF coating corrosion resistance was improved by ∼11.2 % compared to AF coating, even with a lower quartz phase (∼15.08 %) due to the densification of coating. This densification was due to the remelting by CNT to seal pores in the coating. Furthermore, for the same reason, an increase in coating resistance and charge transfer resistance of 1CAF coating by ∼80.9 % and ∼19.93 %, respectively, were seen in the equivalent circuit analysis, showing great promise in controlling interfacial corrosion. Further post-treatments like plasma or laser treatments can seal the coatings further to improve corrosion resistance. Therefore, such coatings are expected to withstand harsh, corrosive environments and are well-suited for marine applications.

Bonding performance of ethylene vinyl acetate reinforced carbon nanotube repair materials

Inorganic repair materials have significant advantages such as high durability, high strength, and good corrosion resistance. However, their low bonding strength and inadequate tensile performance are clear disadvantages, which often results in problems like cracking, delamination, and insufficient repairing strength. In the current study, a new repair material is developed, which enhances the interfacial bonding performance of carbon nanotubes (CNTs) repair materials by introducing ethylene vinyl acetate (EVA). The bonding strength of composite specimens was tested by splitting tensile test. Then the microstructure analysis of the repaired materials was conducted by X-ray computed tomography, backscattered electron imaging, and scanning electron microscopy. The phase composition of the repair material was further analyzed by Fourier transform infrared spectroscopy. Finally, the bonding mechanisms of EVA reinforced CNTs repair materials were discussed. The results indicate that the interaction between EVA and CNTs can enhance the bonding performance of repair materials. Additionally, the polymer film formed by EVA within the repair material can refine the pores, thereby reducing the porosity of the interfacial transition zone and that of repair materials. The electrostatic repulsion between EVA and CNTs contributes to the uniform dispersion of CNTs within repair materials.

The Electromagnetic Shielding Properties of Biodegradable Carbon Nanotube–Polymer Composites

In this article, the electromagnetic shielding properties of carbon nanotube–polymer nanocomposites are presented. The composite fabrication technique is spray-drying, the usage of which leads to a uniform dispersion of carbon nanotubes (CNTs) in a polymer matrix. Obtaining good filler dispersion is necessary to form a continuous, electrically conductive network of CNTs inside the polymer matrix. In the described nanocomposites, the network of conductive filler particles acts as an electromagnetic radiation barrier. For this reason, developing a highly effective fabrication method is very important. Also, the method should be simple enough to be easily adopted in an industrial environment. The authors shows in this text that both goals mentioned are achieved. The obtained nanocomposite material not only has electrostatic shielding capabilities but comprises electromagnetic shielding properties, which fulfills the main goal of the presented work. It is also worth mentioning that the developed manufacturing method allows for the usage of different fillers and polymers and thus the fabrication of materials capable of meeting a wide range of requirements.

Review on Use of Nanomaterials in Concrete

Abstract: Various studies have highlighted the benefits of incorporating carbon nanotubes (CNTs) in concrete. They enhance compressive and flexural strength, prevent cracking, and improve durability. Different methods like sonication ensure uniform dispersion of CNTs in concrete. Additionally, research focuses on optimizing CNT concentrations to avoid adverse effects on properties like shrinkage and thermal conductivity. Overall, CNTs offer a promising solution to reinforce concrete and improve its mechanical properties effectively

A dual-crosslinking electroactive hydrogel based on gelatin methacrylate and dibenzaldehyde-terminated telechelic polyethylene glycol for 3D bio-printing

Gelatin was widely used as scaffold materials in 3D bio-printing due to its excellent bioactivity and availability and especially that their arginine–glycine–aspartic acid (RGD) sequences could efficiently promote cell adhesion and proliferation. In this study, an electroactive and 3D bio-printable hydrogel was prepared through a two-step chemical cross-linking process. Specifically, residual free amino groups of methacrylated gelatin (GelMA) were cross-linked with the aldehyde groups of dibenzaldehyde-terminated telechelic polyethylene glycol (DF-PEG) via Schiff base bonds, forming a gel at 37 °C. During the subsequent 3D bio-printing process, GelMA underwent UV curing, forming a secondary cross-linked network to the mechanical strength and stability of the printed structure. The uniform dispersion of carbon nanotubes (CNTs) in the GelMA/DF-PEG composite hydrogel significantly increased its conductivity. The optimized GelMA/DF-PEG composite hydrogel, i.e., 30% GelMA and 25% DF-PEG (G30D25-CNTs), exhibited superior bio-printability. When the content of CNTs was above 4%, the conductivity of G30D25-CNTs hydrogel exceeded 10–2 S/m, which satisfied the needs of cells for micro-current stimulation. Furthermore, the pore microstructures, swelling behavior, degradation ability and cell toxicity of G30D25-CNTs electroactive hydrogels were thoroughly evaluated. Thus, the G30D25-CNTs hydrogel with 4% MWCNTs could be considered for further application in electrical stimulation of tissue regeneration such as muscle and cardiac nerve tissue repair.

Preparation and characterization of CNTs/CaCu3Ti4O12/silicone rubber composites with improved dielectric and mechanical properties

AbstractThe dielectric performance of Silicone rubber (SR) composites can be significantly enhanced by carbon nanotubes. However, carbon nanotubes are easy to agglomerate in the polymer matrix. Adding low‐dimensional materials of different dimensions may be a solution. In this article, one‐dimensional multiwall carbon nanotubes (CNTs) and zero‐dimensional copper calcium titanate (CaCu3Ti4O12, CCTO) ceramic fillers were simultaneously added to prepare silicone dielectric elastomer composites. SEM results showed that the CNTs were distributed uniformly in the SR matrix due to the addition of CCTO. When 2 wt% CNTs and 10 wt% CCTO were added, the dielectric constant of the composite increased from 2.79 (pure silicone rubber) to 5.72, with a low loss tangent of 0.0012. Due to the uniform dispersion of CNTs with the addition of CCTO particles, dielectric performance of the composites were enhanced. The tensile stress was 986 kPa, the elongation at break was 333%, while the elastic modulus was not more than 613 kPa (2 wt% CNTs and 5 wt% CCTO in the SR composite). In addition, the composites had a wide temperature range up to 400°C. Therefore, the prepared CNTs/CCTO/SR composites have good dielectric and mechanical properties, and good thermal stability. It has a good reference value for this kind of composites as dielectric elastomer materials.

Overcome strength and toughness trade-off in Cu-decorated carbon nanotubes reinforced magnesium matrix composites by chemical reaction interface and grain refinement

The trade-off of strength and toughness limits the development of magnesium matrix composites. In this paper, the strong interface bonding and uniform dispersion of carbon nanotubes (CNTs) were achieved in CNTs reinforced magnesium matrix (CNTs/Mg) composite through electroless copper plating of CNTs, ball milling, sintering and extrusion. The composite was characterized by SEM, HRTEM, tensile test, etc. The structure characterization shows that the CuMg2 interfacial phase, with coherent and semi-coherent interface, forms by the reaction between the decorated copper of CNTs and the magnesium matrix, thus improving the interfacial bonding. Furthermore, CNTs are uniformly distributed at the grain boundary, which hinder the process of discontinuous dynamic recrystallization and play the role of grain refinement. As a result, the strengthening and toughening efficiency of CNTs/Mg composite reach 325% and 264%, respectively, by adding only 0.125 vol% of CNTs. The calculation model of its strength is established.

Effect of dispersibility of carbon nanotubes on the hardness and thermal properties of polyphenylene sulphide/carbon nanotube composites obtained using solution mixing and melt blending methods

Polyphenylene sulphide (PPS)/carbon nanotube (CNT) composite materials (combining PPS and multi-walled CNTs modified with carboxyl groups) were blended using two methods: (1) solution mixing with 1-chloronaphthalene and (2) melt blending. The dispersion states of CNTs in PPS prepared by the two methods were evaluated using Raman spectroscopic mapping. The effect of the dispersibility of CNTs on the physical properties of the composite materials was evaluated by measuring their thermal behaviour and Vickers hardness. Raman spectroscopic mapping revealed that the dispersion states of CNTs in composites obtained via the solution mixing method were more uniform than in those obtained via melt blending methods. This improved uniformity in the dispersion states of CNTs in the solution mixing method can be attributed to the prior dispersion of CNTs in the solution. Additionally, thermal properties such as the crystallisation and glass transition temperatures, and mechanical properties such as the Vickers hardness of the solution-mixed composite material were higher than those of the melt-blended composite. These results indicate that the uniform dispersion of CNTs increases the contact area between PPS and CNTs, which causes an increase in the crystallisation temperature and a further hardness effect.

Cellular-structured carbon nanotube composite films with broadband microwave absorption and shape memory

Carbon nanotube (CNT) composite films consisting of a microcellular structure are prepared by layer-by-layer deposition and phase separation processing. Polyvinyl butyral (PVB) and CNTs form a continuous network of cell walls of less than 100 nm thick and epoxy resin (EP) spheres of 4–6 μm in diameter constitute the cell cores with Ba-ferrite lamella aggregated among the cells. The layer-by-layer deposition of CNTs ensures a uniform dispersion of CNTs, and the EP spheres separate CNTs and Ba-ferrite to form a dielectric-magnetic coupling network. The resultant cell structure is conducive not only to achieve electromagnetic impedance matching but also to induce wave attenuation by multiple mechanisms. The composite film with optimal electromagnetic loss and impedance matching has a broad effective bandwidth of 11.5 GHz in microwave absorption at a thickness of only 0.3 mm, superior over most carbon-based microwave absorbing materials reported so far. In addition, the composite film also shows good thermal response for shape memory. This study provides a microcellular strategy for developing materials with light weight, thin thickness, broadband absorption, and shape memory for applications in civil and military fields.

Microfluidic Channel-Based Soft Electrodes and Their Application in Capacitive Pressure Sensing.

Flexible and stretchable electrodes are essential components in soft artificial sensory systems. Despite recent advances in flexible electronics, most electrodes are either restricted by the patterning resolution or the capability of inkjet printing with high-viscosity super-elastic materials. In this paper, we present a simple strategy to fabricate microchannel-based stretchable composite electrodes, which can be achieved by scraping elastic conductive polymer composites (ECPCs) into lithographically embossed microfluidic channels. The ECPCs were prepared by a volatile solvent evaporation method, which achieves a uniform dispersion of carbon nanotubes (CNTs) in a polydimethylsiloxane (PDMS) matrix. Compared to conventional fabrication methods, the proposed technique can facilitate the rapid fabrication of well-defined stretchable electrodes with high-viscosity slurry. Since the electrodes in this work were made up of all-elastomeric materials, strong interlinks can be formed between the ECPCs-based electrodes and the PDMS-based substrate at the interfaces of the microchannel walls, which allows the electrodes to exhibit mechanical robustness under high tensile strains. In addition, the mechanical-electric response of the electrodes was also systematically studied. Finally, a soft pressure sensor was developed by combining a dielectric silicone foam and an interdigitated electrodes (IDE) layer, and this demonstrated great potential for pressure sensors in soft robotic tactile sensing applications.

Improving Dispersion of Carbon Nanotubes in Natural Rubber by Using Waterjet-Produced Rubber Powder as a Carrier.

Carbon nanotube (CNT), as reinforcing agents in natural rubber (NR), has gained a large amount of consideration due to their excellent properties. Uniform dispersion of CNT is the key to obtaining high-performance NR nanocomposites. In this contribution, a novel ultrasonic grinding dispersion method of CNT with waterjet-produced rubber powder (WPRP) as a carrier is proposed. Microscopic morphologies show that a Xanthium-like structure with WPRP as the core and CNTs as the spikes is formed, which significantly improves the dispersion of CNT in the NR matrix and simultaneously strengthens the bonding of the WPRP and NR matrix. With the increase in the WPRP loading, the Payne effect of CNT/WPRP/NR composites decreases, indicating the effectiveness of the dispersion method. The vulcanization MH and ML value and crosslinking density increase with the increase in the WPRP loading, whereas the scorch time and cure time exhibit a decreasing trend when the WPRP loading is less than 15 phr. It is found that the CNT/WPRP/NR composites filled with 5 phr WPRP have a 4% increase in 300% modulus, a 3% increase in tensile strength, while a 5% decrease in Akron abrasion loss, compared to CNT/NR composites.

In-situ growth of carbon nanotubes on ZnO to enhance thermoelectric and mechanical properties

As a high-temperature thermoelectric (TE) material, ZnO offers advantages of non-toxicity, chemical stability, and oxidation resistance, and shows considerable promise as a true ready-to-use module under air conditions. However, poor electrical conductivity and high thermal conductivity severely hinder its application. Carbon nanotubes (CNTs) are often used as a reinforcing phase in composites, but it is difficult to achieve uniform dispersion of CNTs due to van der Waals forces. Herein, we developed an effective in-situ growth strategy of homogeneous CNTs on ZnO nanoparticles by exploiting the chemical vapor deposition (CVD) technology, in order to improve their electrical conductivity and mechanical properties, as well as reducing the thermal conductivity. Meanwhile, magnetic nickel (Ni) nanoparticles are introduced as catalysts for promoting the formation of CNTs, which can also enhance the electrical and thermal transportation of ZnO matrices. Notably, the electrical conductivity of ZnO is significantly boosted from 26 to 79 S·cm−1 due to the formation of dense and uniform conductive CNT networks. The lattice thermal conductivity (κL) is obviously declined by the intensification of phonon scattering, resulting from the abundant grain boundaries and interfaces in ZnO-CNT composites. Importantly, the maximum dimensionless figure of merit (zT) of 0.04 at 800 K is obtained in 2.0% Ni-CNTs/ZnO, which is three times larger than that of CNTs/ZnO prepared by traditional ultrasonic method. In addition, the mechanical properties of composites including Vickers hardness (HV) and fracture toughness (KIC) are also reinforced. This work provides a valuable reference for dispersing nano-phases in TE materials to enhance both TE and mechanical properties.

Nanostructural Engineering of Electrospun Poly(vinyl alcohol)/Carbon Nanotube Mats into Dense Films for Alcohol Dehydration

Pervaporation is a green process that consumes low energy and does not require solvents for separation. In this work, interfacial engineering of poly(vinyl alcohol) (PVA)/carbon nanotube (CNT) electrospun fibers was attempted to fabricate dense membranes for pervaporation. Ethanol and water were used as nonsolvent and solvent, respectively, to alter the nanoscopic configuration of the fibers through interfacial solvent interactions. PVA and PVA/CNT mats with micron-sized pores (>100 μm) were prepared by optimizing electrospinning conditions. The mats were compacted via immersion in ethanol. They exhibited asymmetric close-packed top and bottom layers and porous intermediate layers. Further consolidation was achieved using water to fuse the fibers. The mats with more than 1.5 wt % CNT loading were stable against water owing to the cross-linking between CNTs and PVA. Because of the uniform dispersion of CNTs into the PVA matrix, the PVA/CNT dense films exhibited higher water/ethanol selectivity and water flux than those exhibited by similar films prepared by solution-casting. Thus, simple interfacial engineering of electrospun mats presented in this work successfully generates high-performance PVA/CNT membranes. A high alcohol dehydration performance and time-efficient membrane fabrication are achieved.

Well-Distributed Polysilsesquioxane-Modified Carbon Nanotubes for Thermal Conductive Insulating Silicone Rubbers

Despite carbon nanotubes (CNTs) have garnered tremendous research interests for enhancing the electrical and thermal conductivity of polymers, it is still a considerable challenge to achieve the uniform dispersion of carbon nanotubes in polymer matrix. Herein, inspired by the mussel-inspired chemistry, we adopted the strategy of coating CNTs with polydopamine. And the polysilsesquioxane-modified CNTs (CNTs-PSQ) were obtained based on the click chemistry reaction. The FT-IR, Raman, XRD, and TGA collectively demonstrated the successful modification of PSQ on the surface of CNTs. The incorporation of PSQ could significantly improve the dispersion of CNTs in the silicon rubbers, and a strong interfacial interaction was formed between CNTs-PSQ and silicon rubber matrix, as observed from TEM images of silicon rubber/CNTs-PSQ nanocomposites. Meanwhile, compared with the nanocomposites with neat CNTs, the ones with CNTs-PSQ exhibited simultaneously improved electrical conductivity and insulating performance. This strategy proposed for the preparation of PSQ-modified CNTs provides insights toward highly insulating and thermal conducting polymers.

Highly enhanced microwave absorption for carbon nanotube/barium ferrite composite with ultra-low carbon nanotube loading

• A facile approach for fabricated carbon nanotube (CNT)/barium ferrite (BaFe 12 O 19 ) composite with good dispersion of carbon nanotube was developed. • In view of the thermal stability of CNT in different atmosphere and the formation mechanism of BaFe 12 O 19 , uniform dispersion of CNT was achieved in the CNT-BaFe 12 O 19 composite. • The as-prepared CNT/BaFe 12 O 19 composite exhibits excellent microwave absorption ability. Barium ferrite (BaFe 12 O 19 ) is considered as potential microwave absorption (MA) material thanks to the large saturation magnetization, high Curie temperature, and excellent chemical stability. The integration of carbon nanotube (CNT) can improve the dielectric loss of BaFe 12 O 19 for further enhanced MA performance, nevertheless, the MA performance is still not desirable because of the poor CNT dispersion in the CNT/BaFe 12 O 19 composites, which usually prepared via the ball-milling method, unless high CNT loading was used. Herein, according to the thermal stability of CNT in different atmosphere and the formation mechanism of BaFe 12 O 19 from precursor, CNT was introduced in the precursor of BaFe 12 O 19 uniformly during auto-ignition process and calcined under different atmosphere. When CNT loading is only 2.0 wt%, the CNT/BaFe 12 O 19 composites obtained exhibits a minimum reflection loss ( R L min ) of -43.9 dB and effective bandwidth (with RL < -10 dB) of 3.9 GHz with the thickness of 1.5 mm, which are much superior to -10.2 dB and 2.2 GHz for pure BaFe 12 O 19 , and -13.6 dB and 2.5 GHz for CNT/BaFe 12 O 19 composite prepared by ball-milling method. These results may pave the way to design high-performance BaFe 12 O 19 based microwave absorbers.

In-situ synthesizing carbon nanotubes on cement to develop self-sensing cementitious composites for smart high-speed rail infrastructures

Self-sensing cementitious composites (SSCCs) with carbon nanotubes (CNTs) have attracted extensive attention because of their excellent mechanical and durability properties combined with multifunctional benefits. However, their performance modulation, as well as scalable manufacturing and application, are limited by the uniform dispersion of CNTs inside them. Here, a straightforward approach to in-situ synthesizing CNTs on cement (CNT@Cem) toward alleviating the CNTs’ dispersion issue and enhancing their composite efficiency and effectiveness is explored. Due to the inherently containing silicate and ferrite phases, microscale cement particles act as effective substrate-bound catalysts, facilitating high-yield and strongly anchored CNTs growth. The hierarchically structured CNT@Cem integrates the dual functions of reinforcement and conduction, significantly affecting early-age hydration, mechanical, electrical, and self-sensing properties of the final SSCCs with CNT@Cem. The CNT@Cem structure can promote early-age hydration while slowing the later hydration rate and hindering the strength development of the SSCCs. The addition of CNT@Cem can be effective in tailoring the electrical microstructures to enhance the electrical conductivity and self-sensing sensitivity of the SSCCs. The SSCCs with CNT@Cem achieved a maximum stress sensitivity of 2.87%/MPa with a gauge factor of 748. They demonstrated excellent repeatability and stability, outstanding adaptability to various applied conditions, and fast response and recovery. The developed SSCCs-engineered smart track slab is competent in axle counting and speed detection. It opens up a new territory to develop high-performance and versatile SSCCs-engineered smart components/structures for long-term, wide distribution, and low-cost monitoring of high-speed rail (HSR) infrastructures.

Mechanical, morphological, and fracture-deformation behavior of MWCNTs-reinforced (Al–Cu–Mg–T351) alloy cast nanocomposites fabricated by optimized mechanical milling and powder metallurgy techniques

AbstractThe carbon nanotube (CNT) is becoming more popular due to their low-density, high-strengthetc.Among CNTs, multi-walled carbon nanotubes (MWCNTs) are gaining more importance due to their enhanced thermal and electrical conductivity. The present research is exploring the applicability of MWCNTs reinforced with AA2024-T351 alloys for electromechanical applications. This study is currently undertaken for using MWCNTs as a reinforcing particulate for the purpose to enhance the characteristics including low density, high strength, and hardness together with excellent thermal and electrical conductivity of the aluminum alloy matrices. Therefore, this article provides a state-of-the-art experimental approach to fabricate and furthermore, to evaluate the mechanical characteristics, microstructural analysis, and fatigue behavior of Al–Cu–Mg–T351/MWCNT composites under both the mechanical and thermal loading by utilizing powder technology processing route. The uniform dispersion of CNTs has been exposed using ball milling process. Results revealed that the MWCNTs provide extraordinary synergistic strength, enhances fatigue resistance, creep resistance, ductility, and other mechanical characteristics of the aluminum-based composites. The mechanical loading of the composite exhibited increased properties as compared to thermal-loaded aluminum-MWCNT composites. Findings conclude that the maximum hardness of 35Hv obtained for sintered AA2024-T351 and 45Hv for 0.5% MWCNT heat-treated samples indicate that the addition of MWCNT enhances the hardness which may be because CNT is evenly dispersed at the interfacial space. Maximum UTS of 105.21 MPa was obtained with 0.5% MWCNT for sintered composites. Microstructural analysis of the Al–Cu–Mg–T351/MWCNTs composite exhibits reasonably uniform distribution, void formation, and good interfacial bonding. X-ray Diffraction method patterns of fabricated composite shows that the CNT is present at 2β= 23.6 and 44.6°, whereas high peaks of aluminum are present at uniform dispersed positions. Transmission electron magnifying instrument study further substantiates the above research. Fracture micrographs of the Al–Cu–Mg–T351/MWCNTs composite portray the resistant nature of the nanotubes due to the presence of CNTs, Al–Cu, and aluminum carbide elements in the alloy and the reactions that happened during heat treatment. This significant improvement was attributed to the shear interactions among the constituents and high load carrying capacity of the CNT, uniform dispersion, and interface bond strength among the matrix and constituents. The findings in the study will undoubtedly be beneficial for the development of high-strength, MWCNTs/Al–Cu–Mg–T351, matrix composites in future for multifunctional applications on broader spectrum.

Effect of carbon nanotube on thermal, tribological and mechanical properties of 3D printing polyphenylene sulfide

Due to its high temperature (maintain stable performance at 200 ℃), corrosion resistance (resistant to strong acids and alkalis) and high mechanical strength, polyphenylene sulfide (PPS) has been attracting more attention in recent years, but research about PPS and 3D printing reinforced composites remains low. Pure PPS has lower application potential compared to its composites. In this study, carbon nanotube (CNT) reinforced PPS 3D printing filaments with uniform CNT dispersion were prepared and CNT uniformity was ensured by coating maleimide polymers (MIPs). Systematically analyzed CNT (contents between 0 and 0.9 wt%) effects on tribological, mechanical and thermal performance of 3D printing PPS. Compared to pure PPS, tensile and bending strengths increased 26% and 29%, respectively. Crystallinity of PPS printed parts improved through thermal conductivity and diffusivity. Wear rate reduced from 1.14E-3 mm 3 N −1 m −1 to 1.838E-5 mm 3 N −1 m −1 . Both fracture and worn surfaces were observed by SEM. As result, this research expects to improve engineering application values of 3D printing PPS. • Prepared carbon nanotube polyphenylene sulfide composite material for 3D printing. • A non-covalent method was used to realize carbon nanotube dispersion in printing filament. • Composite materials’ wear resistance and mechanical properties significantly improved. • Analyzed influence mechanisms of carbon nanotube performance.

In-situ growth of CNTs in silica powder by polymer pyrolysis chemical vapor deposition and their separation resistances

ABSTRACT This study investigated the in-situ growth of carbon nanotubes (CNTs) in silica (SiO2) powder by polymer pyrolysis chemical vapor deposition with a polyethylene glycol (PEG) carbon source and cobalt nitrate catalyst. The mass ratio of PEG:citric acid:cobalt nitrate was determined to control the microstructures of the in-situ CNTs. Results indicated that with an increase in the mass ratio of PEG:citric acid:cobalt nitrate, the in-situ generated CNTs content in the SiO2 powder increased, the CNTs diameters (approximately 40 nm) did not significantly change, and the CNTs lengths decreased from 400–800 nm to 200–400 nm. Additionally, the in-situ CNTs that were anchored on the surfaces of SiO2 particles presented fewer defects and a high degree of graphitization. However, when the mass ratio of PEG:citric acid:cobalt nitrate exceeded the critical value, excessive amounts of amorphous carbon grown in situ on SiO2 particles were obtained. The suspension experiments showed that unlike the CNTs/SiO2 powders prepared by a combination of surfactant and ultrasonic methods with commercial CNTs, in-situ CNTs grown in SiO2 powders exhibited improved separation resistance in water. This would favor the uniform dispersion of CNTs within the matrix, improving the performance of nanocarbon-modified cement-based composites.