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1.
Amino‐functionalization of multiwalled carbon nanotubes (MWCNTs) was carried out by grafting triethylenetetramine (TETA) on the surfaces of MWCNTs through the acid–thionyl chloride way. The amino‐functionalized MWCNTs show improved compatibility with epoxy resin and, as a result, more homogenous dispersion in the matrix. The mechanical, optical, and thermal properties of the amino‐functionalized MWCNT/epoxy composites were also investigated. It was found that introducing the amino‐functionalized MWCNTs into epoxy resin greatly increased the charpy impact strength, glass transition temperature, and initial decomposing temperature of cured epoxy resin. In addition, introducing unfunctionalized MWCNTs into epoxy resin was found greatly depressing the light transmission properties, which would affirmatively confine the application of the MWCNTs/epoxy composites in the future, while much higher light transmittance than that of unfunctionalized MWCNTs/epoxy composites was found for amino‐functionalized MWCNTs/epoxy composites. SEM of the impact cross section and TEM of ultrathin film of the amino‐functionalized MWCNTs/epoxy composites showed that the amino‐functionalized MWCNTs were wetted well by epoxy matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 97–104, 2006  相似文献   

2.
This study investigates the effect of the thiol‐ene click reaction on thermal conductivity and shear strength of the epoxy composites reinforced by various silane‐functionalized hybrids of sulfhydryl‐grafted multi‐walled carbon nanotubes (SH‐MWCNTs) and vinyl‐grafted MWCNTs (CC‐MWCNTs). The results of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM) show that the sulfhydryl groups and vinyl groups are successfully grafted onto the surface of MWCNTs, after treatment of MWCNT with triethoxyvinylsilane and 3‐mercaptopropyltrimethoxysilane, respectively. Scanning electron microscopy (SEM), HotDisk thermal constant analyzer (HotDisk), optical microscope, and differential scanning calorimetry (DSC) are used to characterize the resultant composites. It is demonstrated that the hybrid of 75 wt % SH‐MWCNTs and 25 wt % CC‐MWCNTs has better dispersion and stability in epoxy matrix, and shows a stronger synergistic effect in improving the thermal conductivity of epoxy composite via the thiol‐ene click reaction with 2,2′‐azobis(2‐methylpropionitrile) as thermal initiator. Furthermore, the tensile shear strength results of MWCNT/epoxy composites and the optical microscopy photographs of shear failure section indicate that the composite with the hybrid MWCNTs has higher shear strength than that with raw MWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44579.  相似文献   

3.
Multiwalled carbon nanotubes (MWCNTs), both oxidized and amine functionalized (triethylenetetramine—TETA), have been used to improve the mechanical properties of nanocomposites based on epoxy resin. The TGA and XPS analysis allowed the evaluation of the degree of chemical modification on MWCNTs. Nanocomposites were manufactured by a three‐roll milling process with 0.1, 0.5, and 1.0 wt % of MWCNT–COOH and MWCNT–COTETA. A series of nanocomposites with 5.0 wt % of reactive diluent was also prepared. Tensile and impact tests were conducted to evaluate the effects of the nanofillers and diluent on the mechanical properties of the nanocomposites. The results showed higher gains (258% increase) in the impact strength for nanocomposites manufactured with aminated MWCNTs. Optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to investigate the overall filler distribution, the dispersion of individual nanotubes, and the interface adhesion on the nanocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42587.  相似文献   

4.
In this study, the effect of diamine molecular structure, attached to the multiwalled carbon nanotubes (MWCNTs), on the interfacial interactions of the MWCNTs and the epoxy matrix was studied. Pristine MWCNTs were successfully functionalized with multiple aliphatic and aromatic diamines. It has been found that, compared to aliphatic molecules, aromatic diamines can yield higher functionalization degree, due to higher activity and longer half‐life of aromatic intermediates. However, at the same functionalization degree, the aliphatic ligands were more successful in reacting with epoxy chains and forming covalent bonds between the MWCNTs and the matrix. Considerable improvements were achieved in the mechanical properties of functionalized MWCNT‐reinforced epoxy composites in comparison with the pristine MWCNT‐reinforced composites. Fractography observations revealed distinct differences in the failure modes of reinforced composites after functionalization of the MWCNTs with diamines. POLYM. ENG. SCI., 59:1905–1910, 2019. © 2019 Society of Plastics Engineers  相似文献   

5.
This study describes the influence of triethylenetetramine (TETA) grafting of multi‐walled carbon nanotubes (MWCNTs) on the dispersion state, interfacial interaction, and thermal properties of epoxy nanocomposites. MWCNTs were first treated by a 3:1 (v/v) mixture of concentrated H2SO4/HNO3, and then TETA grafting was performed. Chemically grafted MWCNT/bisphenol‐A glycidol ether epoxy resin/2‐ethyl‐4‐methylimidazole nanocomposites were prepared. TETA grafting could establish the connection of MWCNTs to the epoxy matrix and transform the smooth and nonreactive MWCNT surface into a hybrid material that possesses the characteristics of both MWCNTs and TETA, which facilitates homogeneous dispersion of MWCNTs and improves nanotube‐epoxy interfacial interaction. Therefore, the impact property, glass transition temperature, thermal stability, and thermal conductivity of epoxy nanocomposites are enhanced. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers  相似文献   

6.
Directly functionalized multiwalled carbon nanotubes (MWCNTs) with benzene‐1,3,5‐tricarboxylic acid (BTC) and 3,5‐diaminobenzoic acid (DAB) were successfully accomplished with less structural damage as confirmed by XPS and FT‐Raman results. Their dispersibility and thermal stability were achieved after the functionalization. The functional groups on MWCNT surfaces can accelerate the curing reaction of epoxy composites remarkable inducing rather low exothermic peak temperature (Tp) and exothermic heat of reaction (ΔH). The values of activation energy (Ea) obtained from Kissinger and Ozawa methods obviously decreased with the introduction of MWCNTs, especially DAB‐MWCNTs. The dynamic mechanical properties notably enhanced with the incorporation of unmodified and functionalized MWCNTs. The crosslink density (ρ) increased and free volume fraction (fg) decreased, resulting in dramatic increase of glass transition temperatures (Tg) and decrease of coefficient of thermal expansion. Additionally, epoxy composites exhibited low dielectric constant close to that of neat epoxy resin. From these remarkable properties, MWCNT/epoxy composites can be considered as a good candidate for high performance insulation materials. POLYM. ENG. SCI., 53:2194–2204, 2013. © 2013 Society of Plastics Engineers  相似文献   

7.
The effect of polyether polyol and amino‐functionalized multiwalled carbon nanotubes (NH2‐MWCNTs) on the thermal stability of three‐phase (epoxy/polyol/NH2‐MWCNTs) epoxy composites was investigated. Thermal stability and degradation characteristics of polyol/MWCNTs modified epoxy composites was evaluated using thermogravimetric analysis. The kinetics of thermal degradation was assessed from data scanned at 5, 10, and 20°C/min. Activation energy for degradation of epoxy nanocomposites was calculated using different differential and integral methods, that is, Kissinger's, Flynn–Wall–Ozawa, Coats–Redfern, and Horowitz–Metzger methods. In addition, the integral procedure decomposition temperature was determined to evaluate the inherent thermal stability of the modified composite system. Rate of thermal degradation in MWCNT/Polyol samples was found to be reduced significantly while activation energy of degradation was increased compared to unmodified epoxy composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41558.  相似文献   

8.
The ultrasonically assisted preparation and characterization of poly(amide‐imide) (PAI) composites containing functionalized multi‐walled carbon nanotubes (MWCNTs) are reported. To improve the dispersion in and compatibility with the polymer matrix, the MWCNTs were surface‐modified with p‐aminophenol (p‐AP) under microwave irradiation. The process is fast, one‐pot, easy and results in a high degree of functionalization as well as dispersibility in organic solvents. The p‐AP‐functionalized MWCNTs (MWCNTs‐AP) were analysed by means of field emission and transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction and thermogravimetric analysis (TGA). The results consistently confirm the formation of p‐AP functionalities on MWCNTs which are able to undergo additional reactions, while the structure of the MWCNTs remains relatively intact. MWCNTs‐AP/PAI hybrid films were prepared with various MWCNTs‐AP contents (5–15 wt%) using a solution‐casting technique. Microscopic observations show that the dispersion of the MWCNTs‐AP is improved as a result of the organic groups on the MWCNT surface and functional groups in the PAI structure. The properties of the obtained composites were characterized extensively using the aforementioned techniques. TGA results show that the hybrid films exhibit a good thermal stability. Tensile mechanical testing was performed for the prepared composites, the results of which indicate an increase in the elastic modulus and tensile strength with increasing MWCNTs‐AP content. © 2013 Society of Chemical Industry  相似文献   

9.
Chemically functionalized multi-walled carbon nanotube (MWCNT)/bisphenol-A glycidol ether epoxy resin/2-ethyl-4-methylimidazole composites were prepared. MWCNTs were first treated by a 3:1 (v/v) mixture of concentrated H2SO4/HNO3, and then triethylenetetramine (TETA) grafting was carried out. X-ray photoelectron spectroscopy analysis proved the effectiveness of H2SO4/HNO3 treatment and confirmed the TETA functionalization mechanism. Chemical functionalization decreases the crystalline content of MWCNTs, however, it did not greatly disrupt their structure. Transmission electron microscopy showed that there was a TETA thin layer on the MWCNT surface, which contributes to the homogenous dispersion of MWCNTs in epoxy matrix and the improvement of the MWCNT-epoxy interfacial interaction. Thus the impact strength, bending strength and thermal conductivity of the composites are enhanced.  相似文献   

10.
Woven glass‐fiber‐reinforced cyanate ester/epoxy composites modified with plasma‐functionalized multiwalled carbon nanotubes (MWCNTs) were prepared. The mechanical, thermal, and electrical properties of the composites were investigated at different temperatures. The results show that the interlaminar shear strength, thermal conductivity, and electrical conductivity of the composites at room temperature and the cryogenic temperatures were enhanced simultaneously by the incorporation of MWCNTs, whereas the nonconductive behavior of the composites as electrical insulating materials was not changed. Meanwhile, the reinforcing mechanism was also examined on the basis of the microstructure of the composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41418.  相似文献   

11.
Amino‐functinonalized carbon fibers were achieved via electron‐beam (EB) irradiation in Diethylenetriamine (DETA) solution and triethylene tetramine (TETA) solution at 200 kGy. Different graft monomer concentrations were investigated to find the optimal concentration of each graft monomer. X‐ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy were applied to investigate chemical composition and functional groups, topography and disorder degree of amino‐functionalized carbon fibers surface. Meanwhile, adsorption ability and interfacial adhesion between modified carbon fibers and epoxy resin were determined by TGA and interlaminar shear strength (ILSS). It is found that amino‐functionalized carbon fibers which had rougher and more active surface performed better adsorption ability on epoxy resin than untreated fibers. The optimal ILSS values of carbon fiber (treated with DETA and TETA) reinforced composites were 21.37 MPa and 18.28 MPa, which were much higher than that of untreated fiber reinforced composites. The comprehensive results demonstrated that in this condition, the optimal grafting concentrations of both DETA and TETA were 1.5 mol/L. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40274.  相似文献   

12.
The influences of different gravity environments on the curing process and the cured products of carbon‐nanotube‐reinforced epoxy composites were investigated in this study. Different gravity environments were simulated with a superconducting magnet on the basis of which resin matrix composites with different amino‐functionalized multiwalled carbon nanotube (NH2‐MWCNT) concentrations of 0.1, 0.3, 0.5, and 1 wt % were tested. Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, thermomechanical analysis (TMA), thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and three‐point bending tests were used to analyze the characteristics of different curing processes and cured products. From the results, we observed that the curing rate of the epoxy composites was influenced by different gravity values, and there was anisotropy in the NH2‐MWCNT‐reinforced epoxy composites cured in the simulated microgravity environment. More effects of gravity on the curing process and cured products could be obtained through detailed experiments and discussion; this is important and fundamental for improving and enhancing the properties of composite materials used in different gravity environments. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41413.  相似文献   

13.
In this study, the effects of multi‐walled carbon nanotubes (MWCNT), and its hybrids with iron oxide (Fe2O3) and copper oxide (CuO) nanoparticles on mechanical characteristics and thermal properties of epoxy binder was evaluated. Furthermore, simultaneous effects of using MWCNT with TiO2 as pigment and CaCO3 as filler for epoxy composites were determined. To investigate effects of nano‐ and micro‐particles on epoxy matrix, the samples were evaluated by TGA and DTA. It was found that the hybrid of MWCNT with nano metal oxides caused considerable increment in the tensile and flexural properties of epoxy samples in comparison to the single MWCNT containing samples at the same filler contents. Significant improvement in the thermal conductivity of epoxy samples was obtained by using TiO2 pigment along with MWCNT. The TiO2 pigment also caused considerable improvement in mechanical properties of the epoxy matrix and the MWCNT containing nanocomposite. The best mechanical and thermal properties of epoxy nanocomposites were obtained at 1.5 wt % of MWCNT and 7 wt % of TiO2 that it should be attributed to particle network forming of the particles which cause better nano/micro dispersion and properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43834.  相似文献   

14.
The epoxy resin used as the bonding agent in carbon fiber-reinforced polymer (CFRP) strengthening systems was modified by the infusion of multiwalled carbon nanotubes (MWCNTs). Two types of surfactants, Triton X-100 and C12E8, were used to disperse the nanotubes in the epoxy resin employing ultrasonic mixing. Dynamic mechanical analysis and tensile tests were conducted to study the effect of the surfactant-assisted dispersion of nanotubes on the thermal and mechanical properties of epoxy composites. The morphology of the epoxy composites was interpreted using scanning electron microscopy (SEM). Moreover, the effect of surfactant treatment on the structure of nanotubes was investigated by Fourier transform infrared (FT-IR). Based on the experimental results, the tensile strength and the storage modulus of the epoxy resin were increased by 32% and 26%, respectively, by the addition of MWCNTs. This was attributed to the homogeneous dispersion of nanotubes in the epoxy resin according to the SEM images. Another reason for the enhancement in the tensile properties was the reinforced nanotube/epoxy interaction as a result of the surfactant anchoring effect which was proved by FT-IR. A moderate improvement in the glass transition temperature (T g) was recorded for the composite fabricated using Triton X-100, which was due to the restricted molecular motions in the epoxy matrix. To characterize the temperature-dependent tensile behavior of the modified epoxy composites, tensile tests were conducted at elevated temperatures. It was revealed that the MWCNT modification using surfactant substantially improves the tensile performance of the epoxy adhesive at temperatures above the T g of the neat epoxy.  相似文献   

15.
In this research, poly(L ‐lactide‐co‐ε‐caprolactone) (PLACL) reinforced with well‐dispersed multiwalled carbon nanotubes (MWCNTs) nanocomposites were prepared by oxidization and functionalization of the MWCNT surfaces using oligomeric L ‐lactide (LA) and ε‐caprolactone (CL). It is found that the surface functionalization can effectively improve the dispersion and adhesion of MWCNTs in PLACL. The surface functionalization will have a significant effect on the physical, thermomechanical, and degradation properties of MWCNT/PLACL composites. The tensile modulus, yield stress, tensile strength, and elongation at break of composite increased 49%, 60%, 70%, and 94%, respectively, when the concentration of functionalized MWCNTs in composite is 2 wt %. The in vitro degradation rate of nanocomposites in phosphate buffer solution increased about 100%. The glass transition temperature (Tg) of composites was decreased when the concentration of functionalized MWCNTs is 0.5 wt %. With further increasing the concentration of functionalized MWCNTs, the Tg was increased. The degradation kinetics of nanocomposites can be engineered and functionalized by varying the contents of pristine or functionalized MWCNTs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

16.
Different amounts of multiwalled carbon tubes (MWCNTs) were incorporated into an epoxy resin based on diglycidyl ether of bisphenol A and both epoxy precursor and composite were cured with 4,4′‐diamino diphenyl sulfone. Transmission and scanning electron microscopy demonstrated that the carbon nanotubes are dispersed well in the epoxy matrix. Differential scanning calorimetry measurements confirmed the decrease in overall cure by the addition of MWCNTs. A decrease in volume shrinkage of the epoxy matrix caused by the addition of MWCNTs was observed by pressure–volume–temperature measurements. Thermomechanical and dynamic mechanical analysis were performed for the MWCNT/epoxy composites, showing that the Tg was slightly affected, whereas the dimensional stability and stiffness are improved by the addition of MWCNTs. Electrical conductivity measurements of the composite samples showed that an insulator to conductor transition takes place between 0.019 and 0.037 wt % MWCNTs. The addition of MWCNTs induces an increase in both impact strength (18%) and fracture toughness (38%) of the epoxy matrix with very low filler content. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

17.
A new compatibilizer [P(GMA‐co‐VCz) copolymer] containing carbazole moiety and reactive epoxide group, which can functionalize multiwalled carbon nanotubes (MWCNTs) for making superior epoxy composites, was prepared by a simple one‐pot free radical polymerization. The designed compatibilizer could noncovalently functionalize multiwalled carbon nanotube (MWCNTs) via π‐π interaction as evidenced from fluorescence, Raman, and FTIR spectra analysis, and efficiently disperse MWCNTs in organic solvents. TEM images suggest a good wrapping of P(GMA‐co‐VCz) on MWCNTs surface. P(GMA‐co‐VCz) functionalized MWCNTs were more homogeneously dispersed in epoxy matrix than the case without compatibilizer, indicating that the compatibilizer improves the compatibility between MWCNTs and epoxy resin. In addition, the presence of epoxide groups in compatibilizer could generate covalent bonds with the epoxy matrix and improve the interface interaction between MWCNTs and epoxy matrix. As a result, mechanical and electrical properties of the epoxy composites with compatibilizer were largely improved as compared with those of composites without compatibilizer. The addition of as little as 0.15 wt % of MWCNTs to epoxy matrix affords a great increase of 40% in storage modulus and 52.5% in elongation at break. Furthermore, a sharp decrease of almost 9 orders of magnitude in volume resistivity of epoxy composite is observed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45022.  相似文献   

18.
Surface functionalization of multiwall carbon nanotubes (MWCNTs) was carried out by introducing a ylide group containing anchored phenol structures. Epoxy nanocomposites filled with modified and pristine carbon nanotubes were prepared, and their mechanical, electrical, and thermal properties were evaluated. Mechanical properties such as tensile strengths and Young’s moduli of the epoxy nanocomposites increased significantly with the addition of the modified MWCNTs compared to the pristine MWCNTs, due to the strong interaction between the modified MWCNTs and the epoxy matrix. Scanning electron microscopy of the fractured epoxy systems revealed that the functionalized MWCNTs were finely dispersed in the matrix, as opposed to the pristine carbon nanotubes. The epoxy/functionalized MWCNT nanocomposite had a lower surface electrical resistance than the epoxy/pristine MWCNT nanocomposite, confirming the effect of functionalization.  相似文献   

19.
In this paper, γ‐ray radiation technique was utilized to simply functionalize multi‐walled carbon nanotube (MWCNT) with amino groups. The successful amino functionalization of MWCNTs (MWCNTs‐Am) was proven and the physicochemical properties of MWCNTs before and after radiation grafting modifications were characterized using FT‐IR, X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the γ‐ray radiation had the visible effects on the surface properties of MWCNTs. The effects of various functionalized MWCNTs on morphological, thermal, and mechanical properties of an epoxy‐based nanocomposite system were investigated. Utilizing in situ polymerization, 1 wt% loading of MWCNT was used to prepare epoxy‐based nanocomposites. Compared to the neat epoxy system, nanocomposites prepared with MWCNT‐Am showed 13.0% increase in tensile strength, 20.0% increase in tensile modulus, and 24.1% increase in thermal decomposition temperature. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers  相似文献   

20.
The homogeneous nanocomposites (NC) films of amino modified and metal decorated multiwall carbon nanotubes (MWCNTs) with polymethylmethacrylate (PMMA) were synthesized through in‐situ free radical polymerization. Silver metal nanohybrids (Ag/MWCNTs) were prepared by two strategies, that is, reduction of metal salt in presence of sodium dodecyl sulfate and in‐situ growth from AgNO3 aqueous solution. The amino functionalization by ball milling enhanced the dispersion of MWCNT in monomer and produced a new class of radiation resistant NC. These synthesized films were characterized by FTIR, TGA, TEM, EDX, TC, DMA, and optical microscopy to ascertain their structural morphologies, thermal stability, and mechanical strength. Microscopic studies reflect the homogeneous mixing of amino functionalized and metal decorated MWCNTs in polymer matrix contributing in the enhancement of thermal stability, thermo‐mechanical strength, glass transition temperatures, and thermal conductivity of NC even at 0.25 wt% addition of modified nanofiller. The thermal stability of NC film at 0.25 wt% loading was increased around ≂50°C and the raise of thermo‐mechanical properties was observed up to 85% at 100°C in the presence of adsorbed surfactant. Thermal and thermomechanical behavior of pre and post UV/O3 irradiated NC films has been compared with neat polymer. The results revealed that amino modified nanofiller embedded network in polymer matrix can effectively disperse the radiation and has a dramatic reinforcement effect on the nature of degradation of PMMA matrix. POLYM. COMPOS., 35:1807–1817, 2014. © 2013 Society of Plastics Engineers  相似文献   

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