Multi-walled Carbon Nanotubes Content Research Articles

Selective laser sintering 3D-Printed conductive thermoplastic polyether-block-amide elastomer/carbon nanotube composites for strain sensing system and electro-induced shape memory

A novel mixed powders made up of laboratory-made thermoplastic polyether-block-amide (TPAE) and multiwalled carbon nanotubes (MWCNTs) for the selective laser sintering (SLS) 3D printing have been prepared through an environment-friendly approach and the carbon nanotube conductive network structure is established in the SLS-processed nanocomposite devices. The electrical properties, strain sensing property and electro-induced shape memory effect of flexible TPAE/MWCNTs nanocomposites are fully investigated. The conductivity of TPAE/MWCNTs nanocomposites increases as the MWCNTs content increases owing to the interconnected MWCNTs conductive network. During compressing test with different deformation strain and speed, the SLS-processed flexible sensor exhibits a regular, fast, sensitive and stable cyclic response which shows its great potential for artificial electronic skin, human-machine interface and health monitoring. The TPAE-5.0C nanocomposite also possessed an excellent shape recovery ability during electro-induced shape memory cycle which was triggered by Joule heat under DC voltage. The MWCNTs-TPAE powder prepared here provides a novel material for SLS 3D-printing and the SLS-processed devices with outstanding performance and multiple functions will be very useful for developing flexible and lightweight wearables in the future.

Uniform grafting of amino-functionalized multi-walled carbon nanotubes on the surface of oxidized bamboo fiber to enhance the interfacial strength with epoxy resin

The objective of this paper is to improve the interfacial bonding between the oxidized bamboo fiber and epoxy resin by grafting amino-functionalized multi-walled carbon nanotubes. Bamboo fiber was oxidized by a 2,2,6,6-Tetramethylpiperidine-1-oxyl oxidation system. The amino-functionalized multi-walled carbon nanotubes were then grafted on its surface by impregnation method. It was found by single fiber pull-out testing that the interfacial bonding between the bamboo fiber and epoxy resin was improved by 31.5% after the oxidation treatment of the fiber. After further grafting 0.5 wt% amino-functionalized multi-walled carbon nanotubes, the interfacial bonding was improved by 106.4%. The fracture morphologies and AFM scanning results of individual sample revealed the mechanism of the treatment from amino-functionalized multi-walled carbon nanotubes strengthens interfacial bonding between the fiber and epoxy. The effect of the amino-functionalized multi-walled carbon nanotubes content on the interfacial properties of the bamboo fiber/epoxy resin was investigated, a threshold for the content was identified.

Study on the Mechanics and Pore Characteristics of Coal Seam Drilling Sealing Materials Based on Nanomaterial Optimization.

In order to modify and optimize the performance of cement-based sealing materials and improve the gas drainage rate of boreholes. In this paper, nanosilica (NS), multiwalled carbon nanotubes (MWCNT), and graphene oxide (GO) were used to modify cement and optimize the pore structure. Uniaxial compression tests, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and combined fractal theory were used to analyze the mechanics and pore characteristics. The results show that the synergy of the three nanomaterials promotes the generation of hydration products such as calcium silicate hydrate (C–S–H) and ettringite (AFt), improves the total pore fractal dimension (Dw) and seepage pore fractal dimension (Ds), and optimizes the microscopic pore structure. However, when the content of NS increases from 2 to 4 wt %, the improvement in the mechanical properties is obviously weakened. The best ratio is where the SiO2 content is 2 wt %, the MWCNT content is 0.1 wt %, and the GO content is 0.03 wt %. Compared with pure cement, the fractal dimension increases significantly, the mechanical properties are increased by 24.7%, and the total porosity is reduced by 23.9%. This paper is of great significance for improving the efficiency of gas mining.

Antimicrobial Properties of Highly Elastic Conductive Poly(ethylene terephthalate)/Multiwalled Carbon Nanotube Fabrics

This research focused on understanding the microbe killing mechanism of the antimicrobial properties of highly elastic conductive poly(ethylene terephthalate) (PET)/multi-walled carbon nanotube (MWCNT) powernet fabrics with the help of electric fields and highly elastic structure. In this study, PET/MWCNT fabrics containing three different percentages of MWCNT were knitted and characterized with antimicrobial activity, cytotoxicity, electromagnetic shielding properties, DSC analyses, stiffness tests, and pressure measurements using wireless pressure sensors. Results show that MWCNT has a statistically significant effect on antibacterial activity, cytotoxicity, electromagnetic shielding, stiffness, and exerted pressures. PET/MWCNT fabrics showed excellent antibacterial activity against tested germs; S. aureus and E. coli. A statistically significant increase in percentage reduction of bacteria was observed with the increase in carbon nanotube nanoparticle concentration, accompanied by a good laudering durability even after 20 washing cycle. In terms of cytotoxicity tests, all PET/MWCNT samples were found to have over 70% average relative cell viability, indicating that they are noncytotoxic without interrupting the cell line and primary cell growth in vitro. The materials have provided longer conductive networks and formed electromagnetic shielding at the range of 22.79 dB-25.77 dB at the frequency of 0–1.30 GHz. Moreover, MWCNT concentration did not lead to considerable changes in physical properties like stiffness and exerted pressure properties. Characterization analyses confirmed the changes in the chemical structure of the PET/MWCNT.

Young's Modulus and Vickers Hardness of the Hydroxyapatite Bioceramics with a Small Amount of the Multi-Walled Carbon Nanotubes.

The Vickers hardness and Young’s modulus of the hydroxyapatite (HA) bioceramics with a small amount of the multi-walled carbon nanotubes (MWCNTs) were studied by using ultramicrotester Shimadzu for dynamic tests DUH-211. Small concentrations of MWCNTs were from 0.05 to 0.5 wt.%. The argon inert atmosphere and vacuum condition were taken for the prevention of the MWCNTs oxidation. The Brunauer–Emmett–Teller (BET) surface area SBET of the HA-MWCNTs composites was determined by thermal adsorption-desorption of nitrogen. It was found that for HA-MWCNTs sintered in the Ar atmosphere, an increase in the concentration of nanotubes up to 0.5 wt.% leads to a decrease in porosity near 3 times in comparison to HA without MWCNTs additives. The small amount of additives of multi-walled carbon nanotubes leads to an increase in hardness of 1.3 times and compression strength of composite and compression strength of composite that is comparable in absolute values with the literature data of enamel hardness (3–5 GPa) and compression strength (95–370 MPa). The absolute values increase close to linearly with the increase of nanotube concentrations. The Young’s modulus of sintered composite slightly changes with the variation of concentrations of nanotubes and close to the enamel (75–100 GPa). The ratio of plastic work to total work and the ratio of elastic (reversible) work to the total work of deformation of composite HA/MWCNTs are practically constant at a studied range of MWCNTs concentration. The additives of the multi-walled carbon nanotubes lead to both an increase in the elasticity index of ~1.5 times and an increase in the resistance to plastic deformation of ~3 times, which improved the tribological performance of the surface. Plastic and elastic (reversible) work slightly changed.

Physical Properties of PVA:PVP blend reinforced by MWCNT

The polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP), PVA-PVP blend, and reinforced-sample with multi-walled carbon nanotubes (MWCNTs) were prepared in different proportions by casting technique. X-ray diffraction testing denotes a blending of copolymers and the added CNTs. The FE-SEM images illustrate rubber-like entangled of pure PVA-PVP blend. The MWCNTs of 1% ratio completely imbedded within the polymer and the blend appeared higher compact. The stress-strain curves for PVA-PVP blend sample and samples reinforced with CNTs show that the sample stiffness increased, where the elongation reduced when the carbon nanotube added increased to 1.5 wt% due to the contribution of binding to the added MWCNTs which limits the flexibility of the sample. The sample delivery behaviour greatly affected the charge carriers hopping over the barriers between neighbouring localized states. Increasing the MWCNT contents leads to an increase in the AC conductivity due to the creation of more localized states or by reducing the potential barriers. The dielectric constant (ε1) of the PVA-PVP blend samples decreased with increasing frequency until it reached quasi-constant at higher frequencies. The dielectric constant also decreased with the increase of the carbon nanotube contents. The dielectric loss (ε2) also decreases with frequency. These results demonstrated that the conductivity and dielectric parameters of the copolymer samples strongly depend on frequency and are significantly affected by the proportion of the added MWCNTs.

Fabrication of a Novel (PVDF/MWCNT/Polypyrrole) Antifouling High Flux Ultrafiltration Membrane for Crude Oil Wastewater Treatment

The present work deals with the fabrication of novel poly(vinylidene fluoride) (PVDF)/Multi-wall Carbon Nanotubes (MWCNT)/Polypyrrole (PPy) ultrafiltration membrane by phase inversion technique for the removal of crude oil from refinery wastewater. In situ polymerization of pyrrole with different concentrations of MWCNT ranging from 0.025 wt.% to 0.3 wt.% in PVDF prepared solutions. Measurement of permeability, porosity, contact angle, tensile strength, zeta potential, rejection studies and morphological characterization by scanning electron microscopy (SEM) were conducted. The results showed that membrane with (0.05% MWCNT) concentration had the highest permeability flux (850 LMH/bar), about 17 folds improvement of permeability compared to pristine PVDF membrane. Moreover, membrane rejection of crude oil reached about 99.9%. The excellent performance of this nanocomposite membrane suggests that novel PVDF modification with polypyrrole had a considerable effect on permeability with high potential for use in the treatment of oily wastewater in the refinery industry.

Effects of MWCNTs on Char Layer Structure and Physicochemical Reaction in Ethylene Propylene Diene Monomer Insulators.

As one of the most promising ablative fillers, multi-walled carbon nanotubes (MWCNTs) have been used to improve the ablative resistance of Ethylene–Propylene–Diene Monomer (EPDM) insulators by facilitating the carbothermal reduction reaction of silica. However, the contribution of MWCNTs to char layer structure of the insulators was unclear. In this work, the effects of MWCNTs on char layer structure and ablative resistance were investigated in different EPDM-based insulators with and without silica. The results showed that adding only 3 phr MWCNTs can reduce the linear ablation rate of EPDM-based insulators without silica by 31.7%, while 6 phr MWCNTs are required to obtain similar results in EPDM-based insulators with silica. The char layer morphology of the two insulators gradually evolved into a dense porous structure as MWCNTs content increased, but their formation mechanisms were different. The XRD and Raman spectrum showed that different physicochemical reactions occurred around MWCNTs under different charring components. The proposed ablation mechanism was further verified by designing alternating multilayer distribution of MWCNTs and silica. This work can guide the construction of desirable char layer structure for increasing the ablative resistance of EPDM-based insulators.

Multi-walled Carbon Nanotubes Remediate the Phytotoxicity of Quinclorac to Tomato.

In order to remediate the phytotoxicity of quinclorac to tomato by multi-walled carbon nanotubes (MWCNTs), the adsorption of quinclorac to MWCNTs was monitored and the effect of MWCNTs on the phytotoxicity of quinclorac to tomato in soil were studied. The results showed that the Linear equation and Freundlich equation can well fit the adsorption isotherm of quinclorac in the soil containing MWCNTs. The adsorption of quinclorac in soil was significantly enhanced by the addition of MWCNTs; the Kd of soil (1% MWCNTs) was 28.7 times of pure soil. The quinclorac had an obvious inhibitory effect on the growth of tomatoes; serious phytotoxicity was also induced even at the lowest concentration of 0.025mg/kg. With the MWCNTs content in soil increased to 0.5% and 1%, the phytotoxicity of quinclorac to tomatoes decreased significantly, and the height and fresh weight of tomatoes were even higher than those of the control group, indicating that MWCNTs can promote the growth of tomato. These results provide a reference for resolving the problem of phytotoxicity induced by residual herbicides in farmland.

Optical, optoelectronic, structural, and chemical characterizations of (PEO-PVA)/MWCNT nanocomposite films

Nanocomposite films were fabricated from polyethylene oxide (PEO) and polyvinyl alcohol (PVA) incorporated with variant contents of multi-walled carbon nanotubes (MWCNTs) deposited on the glass substrates. FTIR and XRD techniques determined the chemical and structural characteristics of (PEO-PVA)/MWCNTs nanocomposite films. The optical properties, including refractive index, extinction coefficient, and dielectric functions, were comprehended via UV-Vis spectroscopy's transmittance and reflectance spectra. Classical and quantum models, including Al-Bataineh, Urbach, Spitzer-Fan, and Drude models, are employed to determine optical and optoelectronic characteristics. The optical bandgap energy of the PEO-PVA film was found to be 4.032 eV. Introducing MWCNTs to PEO-PVA films leads to a decrease in bandgap energy. The effective medium models (EMMs) described the diluted MWCNTs in the host PEO-PVA matrix. Our samples obey the Maxwell-Garnett model indicating a considerable distance between the MWCNTs in the polymer matrix with predicted possible interactions between the nanotubes and the host polymer chain. In addition, electrical conductivity increased as increasing MWCNT in PEO-PVA films.

Fabrication and testing of functionalized multi-walled carbon nanotubes/deproteinized natural rubber composites for bending actuation under electric field

Compliant electrodes (CEs) were prepared from deproteinized natural rubber (DPNR) and multi-walled carbon nanotubes (MWCNTs) using Triton X-100 as a dispersing agent. Dielectric elastomers (DEs) were fabricated, from the DPNR incorporated with functionalized MWCNTs as a high dielectric constant filler, by film casting and the UV-curing process. The effect of MWCNT concentrations on mechanical and electrical properties of the CEs and DEs were individually examined. The defection responses and the dielectrophoresis forces of DEs and DEs attached on one side with CEs (DEs/CEs) were investigated as functions of electric field strength. The 5% v/v MWCNTs composite (CE_5) showed the highest conductivity of 19.7 S/cm and was subsequently used in the DEs/CEs bending experiment. The 2.5 phr of functionalized MWCNTs composite (DE_2.5) showed the highest dielectric constant of 15.4, but a relatively low bending actuation due to its initial high rigidity. The DE_1/CE_5 bilayer composite possessed the highest bending actuation, namely the largest bending distance and the dielectrophoresis force, presumably from the additional polarizations within CE_5 and the interactions with DE_5.

Mechanical characterization of 3D printed MWCNTs/HDPE nanocomposites

The development of polymer nanocomposite blends using multi-walled carbon nanotubes (MWCNTs) and high-density polyethylene (HDPE) is presented in this paper. Fused Filament Fabrication (FFF) based 3D printer is used to realize MWCNT (0.5, 1, 3, and 5 by wt. %)/HDPE nanocomposite (NC) 3D printed samples. The addition of MWCNT increases TCryst, αCryst and TMelt. Thermogravimetric analysis (TGA) of neat HDPE and MWCNT/HDPE NCs is also carried out to check their thermal stability at higher working temperatures. The degradation temperature of MWCNT/HDPE NCs is observed to be higher than neat HDPE and increasing with MWCNT content. The filaments are tested for tensile, while specimens are tested for both tensile and flexural properties. It is observed that tensile and flexural modulus and strength improve with increasing MWCNT. Finally, the results of the tensile tested specimens are compared to those of various HDPE composites found in the literature.

Influence of multi‐walled carbon nanotube content on electromagnetic wave absorption and mechanical properties of carbon nanotube/polyamide 12 composite

AbstractThree‐dimensional printing has proven to be a convenient and effective method for manufacturing structured electromagnetic wave (EMW) absorbers with adjustable EMW absorption characteristics. In this study, composites of multi‐walled carbon nanotube (MWCNT) and polyamide 12 (PA12) were prepared via wet dispersion and mechanical ball milling followed by melt extrusion. The effects of different levels of MWCNT content on the EMW absorption and mechanical properties of the MWCNT/PA12 composite were examined. Within the MWCNT content from 7 to 12 wt%, the flexural strength of the composite increases with the addition of MWCNT, and the impact strength, tensile strength, and volume resistivity of the composite decrease with the addition MWCNT. With regard to the best impedance matching, when sodium dodecylbenzene sulfonate was used as the dispersant, the lowest reflection loss observed herein for the MWCNT/PA12 composite was −20 dB, which was achieved with an MWCNT content of 10 wt%. Furthermore, the composite exhibited superior mechanical properties. The tensile and flexural moduli of the composite were 18.85% and 33.97% higher than those of pure PA12, respectively. Moreover, the MWCNT/PA12 composite was proven to be a high performance modeling material suitable for fused deposition modeling. And the tensile strength, flexural modulus, and impact strength of the printed samples can reach 94.45%, 92.94%, and 85.51% of those of the injection‐molded samples, respectively.

Piezoresistive sensing performance of multifunctional MWCNT/HDPE auxetic structures enabled by additive manufacturing

Herein, we report the mechanical and piezoresistive sensing performance of 3D printed auxetic nanocomposite structures composed of a high-density polyethylene (HDPE) matrix and multi-walled carbon nanotubes (MWCNTs). The multifunctional performance of MWCNT/HDPE auxetic structures were measured under tensile loading. The results indicate that by varying the MWCNT content, as well as the relative density and cell topology (S-shaped, Chiral and Re-entrant) of the structure, we can achieve a tunable piezoresistive response. The results indicate that the S-shaped cellular structure possesses superior mechanical and piezoresistive characteristics, reporting a gauge factor of 7.6 at 4 wt % MWCNT loading, which is ∼300% higher than those measured for the Re-entrant and Chiral structures. We also present an empirical scaling equation that relates the structure's sensitivity factor to its relative density. The findings of this study provide useful guidelines for the design and fabrication of self-sensing smart materials and structures with tunable sensitivity.

Influences of carbon nanotube on structures and properties of compatibilized polylactide/polypropylene blend-based ternary nanocomposites

To attain eco-friendly and multifunctional thermoplastic composites for advanced applications, a series of ternary nanocomposites based on compatibilized polylactide/glycidyl methacrylate-grafted polypropylene (PLA/PGMA, 80/20 by wt%) blend matrix and 0.5–10 wt% multi-walled carbon nanotube (MWCNT) filler is manufactured by efficient masterbatch melt-compounding. Effects of MWCNT on the morphology, thermal, mechanical, rheological, electrical, and EMI shielding properties of the ternary nanocomposites are investigated. It is revealed that PGMA/MWCNT domains are partially formed owing to the selective interaction of MWCNT with PGMA in the blend matrix. MWCNTs contribute to accelerating the crystallization rates of PGMA and PLA matrix components in the ternary nanocomposites. The dynamic mechanical modulus and thermal stability of the ternary nanocomposites are improved with the increment of MWCNT loading. The electrical conductivity of the nanocomposites increases significantly from ∼10−11 S/cm to ∼10−3 S/cm with increasing the MWCNT content up to 10 wt%. The electrical percolation threshold of ∼4.0 wt% MWCNT is also found to be in good agreement with the rheologically estimated percolation threshold. The EMI shielding effectiveness of 1 mm thick ternary nanocomposite with 10 wt% MWCNT is measured to be ∼13.4 dB at 8 GHz, which indicates the shielding efficiency of ∼95.4% to incident EM waves.

Experimental study on physical and mechanical properties and micro mechanism of carbon nanotubes cement-based composites

Carbon nanotubes are considered as a promising material for the development of high performance concrete. In order to study the effects of Multi walled carbon nanotubes (MWCNTs) content, water cement ratio and addition method on the mechanical properties and microstructure of cement-based composites, specimens with MWCNTs content of 0%, 0.05%, 0.08%, 0.10%, 0.15%, 0.20%, and 0.30% were prepared when the water cement ratio was 0.25, 0.3, 0.35, and 0.4, respectively. The physical properties, mechanical properties and microstructure were tested. The test results show that with the increase of MWCNTs content, the flexural strength and compressive strength of cement-based composites increase first and then decrease. The DIC test shows that the displacement and strain of the specimen with MWCNTs are smaller than the blank sample under the same concentrated load, while it is opposite before the failure of sample. The SEM test shows that MWCNTs play the role of bridging and filling in the matrix. The EDS analysis results show that the five main elements of carbon, oxygen, aluminum, silicon, and calcium in the composite are evenly distributed in the cement matrix.

Effect of Carbon Nanotube Content and Mechanical Milling Conditions on the Manufacture of AA7075/MWCNT Composites

Aluminium matrix composites (AlMCs) of AA7075 aluminium alloy reinforced with 0.5 and 1 wt.% multiwall carbon nanotubes (MWCNTs) were fabricated with powder metallurgy techniques using three different mechanical milling strategies, varying the milling energy and the stage in which the reinforcements were added to the pre-alloyed matrix powders. In this paper, we focus on the influence of these parameters on the dispersion of MWCNTs. Characterization of the obtained composite powders by X-ray diffraction and scanning electron microscopy showed that the evolution of the particle size and morphology of the composite powders is influenced by milling conditions and MWCNT content; however, under the conditions tested in this study, there were no significant differences in crystallite size and lattice strain. The best distribution of the reinforcements was obtained after milling 7075 powders and MWCNTs in a high-energy cycle (HEBM), varying the rotation speed between 1200 and 1300 rpm. Raman spectroscopy was used to assess the damage induced by the milling process in the nanotubes, and no reaction products were detected under any of the tested conditions. Nanoindentation tests were performed to measure the elastic modulus and hardness of the composite powders, revealing that the best mechanical behaviour was achieved by the 7075-0.5 wt.% MWCNT composites obtained by the HEBM route.

Development of single‐polypropylene composites interleaved with MWCNT‐doped melt‐blown fine fiber mats

AbstractIn this article, we demonstrate fabricating polypropylene (PP)/multiwalled carbon nanotube (MWCNT) nanocomposite fiber veils and use them as interleaves in single‐polymer composites (SPCs) to enhance their thermal and mechanical properties. With this regard, we produced a hierarchical composite structure made of a film, a woven fabric and a fine fiber mat made of the same polymer. The nanocomposite fiber mats were generated by melt‐blowing. Results implied that incorporating MWCNT increased the viscosity of the melt blowing grade PP resin. Increasing MWCNT content increased the average fiber diameter and pore size by 2.1‐fold and 2.5‐fold, respectively. Incorporating MWCNT enhanced the melt‐blown (MB) fiber mat's specific strength by 78% and improved the thermal stability. We generated multiscale SPCs by film‐stacking, for which we applied a PP film as a matrix, a PP‐woven fabric as the primary reinforcement, and the MB fiber mats as interleaves. The SPC's tensile modulus was improved by 37% by the interleaving. Our findings implied that the MWCNT‐doped PP fiber mat interleaving provides a robust interfacial adhesion and higher damage tolerance under tensile load. Master curves were constructed from dynamic mechanical analysis frequency sweep tests based on the time–temperature superposition principle. The storage modulus increased by 33%, while the tanδ decreased around 10% with PP/MWCNT fiber mat interleaving. The developed multiscale SPC with MWCNT fiber mat interleaving veils may be easily integrated into engineering composite applications due to its cost‐efficiency, fair recycling, straightforward processing, enhanced stiffness, and interfacial adhesion.

Influence of multi-walled carbon nanotubes (MWCNTs) content on metal friction and wear in thermally cracked carbon black (CBp) formulation system during mixing

As the essential mixing equipment, long hours of work can cause wear and tear on the end face of the compactor. The wear of the end faces leads to an increase in the gap between the chamber and the end faces, which leads to leakage, reduces the mixing effect, and ultimately affects the rubber properties. Therefore, it is necessary to study the end face metal wear during the mixing process. Thermally cracked carbon black, as recycled material for scrap rubber, can be used as a substitute for other carbon blacks in some fields, vastly reducing the production cost and promoting the reuse of scrap rubber. In this paper, thermally cracked carbon black (CBp) was mixed with multi-walled carbon nanotubes (MWCNTs) and added rubber by mechanical blending to obtain CBp/MWCNTs composites. The synergistic mechanism of CBp and MWCNTs was investigated to analyze the effect of CBp/MWCNTs ratios on the frictional wear of metal on the end face of the compactor. The results showed that MWCNTs cooperated with CBp particles to form a three-dimensional “grape bunch” network structure. On the one hand, the three-dimensional “grape bunch” network structure can adsorb CBp particles to promote the dispersion of CBp particles. On the other hand, the three-dimensional “grape bunch” network structure can also hinder the overflow of aromatic oil and affect oil film formation. At the same time, the three-dimensional “grape bunch” network structure can also form a physical isolation layer between the rubber and the metal. This significantly influences the degree of CBp particle dispersion, friction coefficient, metal surface roughness, and metal wear. It seems that the synergistic effect between MWCNTs and CBp particles is maximized when the content of MWCNTs in CBp/MWCNTs composites is 4 phr, the area of CBp/MWCNTs three-dimensional mesh is maximized, the dispersion of CBp particles is the best, and the wear of CBp/MWCNTs composites on metal is the lowest.

Erosion resistance of ethylene propylene diene monomer insulations reinforced with precoated multi-walled carbon nanotubes

Condensed particles in the internal flow field of a solid rocket motor can cause serious erosion to thermal insulations under overload flight condition. Multi-walled carbon nanotubes (MWCNTs) can improve erosion resistance of insulations but at the cost of reduced thermal insulation performance. In this study, MWCNTs were precoated with pyrolytic carbon via chemical vapor deposition to reduce their thermal conductivity. Further, ethylene propylene diene monomer insulations reinforced with different contents of MWCNTs and precoated MWCNTs were prepared. Moreover, their ablation performances under simulated overload ablation conditions were tested and compared. Experimental results show that precoated MWCNTs can not only improve thermal insulation performance but also significantly increase particle erosion resistance of ethylene propylene diene monomer insulation materials. Charring ablation rate of the formula with 10phr precoated MWCNTs is 44.3% lower than that of basic formula and 41.6% lower than that of the formula with 3phr MWCNTs which has the same pure MWCNTs content. The char layers of MWCNTs reinforced formulas are more complete than basic formula, indicating that MWCNTs can improve char layer structure under particle erosion condition. The precoated MWCNTs can also promote the CVD reaction of pyrolysis gas in char layers during ablation, decreasing the porosity of char layers, which can increase the particle erosion resistance of insulation.