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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.
Multi‐walled carbon nanotubes/carbon fiber (MWCNTs/CF) hybrid fillers are employed to prepare MWCNTs/CF/epoxy composites. Results reveal that a great improvement of the thermal conductivities of the epoxy composites with the addition of MWCNTs/CF hybrid fillers, and the thermal conductivity of the MWCNTs/CF/epoxy composites is 1.426 W/mK with 8 vol% treated MWCNTs/CF hybrid fillers (5 vol% MWCNTs + 3 vol% CF). Both the flexural and impact strength of the MWCNTs/CF/epoxy composites are increased firstly, but decreased with the excessive addition of MWCNTs. The flexural and impact strength of the MWCNTs/epoxy composites are optimal with 2 vol% MWCNTs. For a given MWCNTs/CF hybrid fillers loading, the surface treatment of MWCNTs/CF hybrid fillers can further increase the thermal conductivities and mechanical properties of the MWCNTs/CF/epoxy composites. POLYM. COMPOS., 35:2150–2153, 2014. © 2014 Society of Plastics Engineers  相似文献   

3.
Multiwall carbon nanotubes (MWCNTs) were amino‐functionalized by 1,2‐ethylenediamine (EDA)' triethylenetetramine (TETA), and dodecylamine (DDA), and investigated by fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA). The dispersion of the DDA functionalized MWCNT in DMF is better than that of the MWCNT functionalized by the EDA and the TETA. Carbon nanotubes reinforced epoxy resin composites were prepared, and the effect of the amino‐functionalization on the properties of the composites was investigated by differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), and TGA. The composites reinforced by the MWCNTs demonstrate improvement in various mechanical properties. The increase of Tg of the composites with the addition of amino‐functionalized MWCNT compared to the Tg of the composites with the addition of unfunctionalized MWCNT was due to the chemical combination and the physical entanglements between amino group from modified MWNTs and epoxy group from the epoxy resin. The interfacial bonding between the epoxy and the amino group of the EDA and the TETA‐modified MWCNT is more important than the well dispersion of DDA‐modified MWCNT in the composites for the improvement of the mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

4.
The isothermal crystallization behaviour of the polypropylene (PP) phase in PP/multi‐walled carbon nanotubes (MWCNTs) composites has been investigated via differential scanning calorimetric analysis, which showed the influence of the varying dispersion level of MWCNTs in the respective PP matrix. PP/MWCNTs composites were prepared via melt‐blending technique, wherein two different grades of MWCNTs of varying average “agglomerate” size and varying entanglements (N‐MWCNTs and D‐MWCNTs) were utilized. Furthermore, the influence of melt‐viscosity of the PP phase was investigated on the crystallization kinetics of the PP/MWCNTs composites. Heterogeneous nucleation ability of MWCNTs has resulted in a decrease in half time of crystallization (t 1/2) from ~14 min for pure PP to ~6 min for PP/N‐MWCNTs and ~11 min for PP/D‐MWCNTs composites at 1 wt% of MWCNTs at 132 °C. Overall rate of crystallization (k) has significantly increased to 4.9 × 10?2 min?1 for PP/N‐MWCNTs composite as compared with 6.2 × 10?3 min?1 for PP/D‐MWCNTs composite at 0.5 wt% of MWCNTs at 132 °C. Moreover, the effect of a novel organic modifier, Li‐salt of 6‐amino hexanoic acid along with a compatibilizer (PP‐g‐MA) has also been investigated on the crystallization kinetics of the PP phase in PP/MWCNTs composites. POLYM. ENG. SCI., 57:1136–1146, 2017. © 2017 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.
The effects of functionalized multi‐walled carbon nanotubes (MWCNTs) on thermal and chemorheological behaviors of an epoxy‐based nanocomposite system were investigated. Chemical functionalization of MWCNTs by acid modification (A‐MWCNTs) and chemical amidation (D‐MWCNTs) was confirmed using Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found that the D‐MWCNTs had a significant effect on the chemorheological behaviors of the epoxy‐based nanocomposite. Compared to the epoxy/A‐MWCNT nanocomposite, the epoxy/D‐MWCNTs nanocomposite showed a significant increase in gel time, as obtained from isothermal rheology measurements. Also, the storage modulus of the diglycidylether of bisphenol F (DGEBF)/D‐MWCNTs nanocomposite was higher than that of the DGEBF/D‐MWCNTs nanocomposite and gradually increased with an increase of frequency. This could be interpreted by the relatively strongly interconnected structure of the D‐MWCNTs in the DGEBF epoxy resin, which arises from the functionalized alkyl groups of the D‐MWCNTs in dispersion phases with the DGEBF epoxy resin. Copyright © 2012 Society of Chemical Industry  相似文献   

7.
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   

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.
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   

10.
Multi‐walled carbon nanotubes (MWCNTs) filled polypropylene (PP) composites were prepared by a corotating intermeshing twin screw extruder. To improve the dispersion of MWCNTs, the surface of MWCNT was modified with 1,10‐diaminodecane, and maleic anhydride grafted polypropylene (MA‐g‐PP) was used as a compatibilizer. Micrographs of well dispersed functionalized MWCNTs (diamine‐MWCNT) were observed due to the reaction between MA‐g‐PP and diamine‐MWCNT in PP/MA‐g‐PP/diamine‐MWCNTs composites. The different behaviors in crystallization and melting temperatures of PP/MA‐g‐PP/diamine‐MWCNTs composite were observed compared to PP and PP/neat‐MWCNT. Especially, the decomposition temperature of the composite was increased by 50°C compared to PP. PP/MA‐g‐PP/diamine‐MWCNTs composite showed the highest complex viscosity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

11.
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   

12.
Damping materials are used to control mechanical vibrations, and piezoelectric damping composite is a very promising material due to its unique mechanism. In this study, a potential piezoelectric damping composite was developed by simply melt mixing poly(vinylidene fluoride) (PVDF) with small amounts of organic modified montmorillonite (OMMT) and multi‐walled carbon nanotubes (MWCNTs). The piezoelectric, mechanical and electrical properties were investigated using a dynamic mechanical analyser, direct current electrical resistivity measurements, X‐ray diffraction, Fourier transform infrared spectroscopy and the direct quasi‐static d33 piezoelectric coefficient method. It was found that the damping property of PVDF can be greatly improved by adding both MWCNTs and OMMT, and the composite containing 1.9 wt% of MWCNTs and 3 wt% of OMMT showed the best damping property. A model and an approximate calculation were applied to explain the improved damping property. Moreover, similar mechanical properties of PVDF composites were observed in the tensile testing and dynamic mechanical analyser measurements. Copyright © 2012 Society of Chemical Industry  相似文献   

13.
《Polymer Composites》2017,38(9):1873-1880
The influence of multi‐walled carbon nanotubes (MWCNTs) on thermosetting epoxy is examined using dynamic mechanical analysis, thermogravimetric analysis, and differential scanning calorimetry (DSC). Specimens are prepared with loadings of 0.1 and 1 wt% MWCNTs which are dispersed in the resin using two different dispersion methods. While the storage modulus of the specimens is improved, both the glass transition temperature and the thermal stability are reduced by the addition of MWCNTs with both effects being greater for the higher MWCNT loading, for both dispersion systems. The DSC results additionally indicate that the level of residual unreacted epoxy increases progressively with the addition of the nanotubes. This finding is considered as confirmation that the MWCNTs obstruct crosslinking of the epoxy resin. POLYM. COMPOS., 38:1873–1880, 2017. © 2015 Society of Plastics Engineers  相似文献   

14.
The introduction of carbon nanotubes in a polymer matrix can markedly improve its mechanical properties and electrical conductivity, and much effort has been devoted to achieve homogeneous dispersions of carbon nanotubes in various polymers. Our group previously performed successfully fluorine‐grafted modification on the sidewalls of multi‐walled carbon nanotubes (MWCNTs), using homemade equipment for CF4 plasma irradiation. As a continuation of our previous work, in the present study CF4 plasma‐treated MWCNTs (F‐MWCNTs) were used as a nanofiller with poly(ethylene terephthalate) (PET), which is a practical example of the application of such F‐MWCNTs to prepare polyester/MWCNTs nanocomposites with ideal nanoscale structure and excellent properties. As confirmed from scanning electron microscopy observations, the F‐MWCNTs could easily be homogeneously dispersed in the PET matrix during the in situ polymerization preparation process. It was found that a very low content of F‐MWCNTs dramatically altered the crystallization behavior and mechanical properties of the nanocomposites. For example, a 15 °C increase in crystallization temperature was achieved by adding only 0.01 wt% F‐MWCNTs, implying that the well‐dispersed F‐MWCNTs act as highly effective nucleating agents to initiate PET crystallization at high temperature. Meanwhile, an abnormal phenomenon was found in that the melt point of the nanocomposites is lower than that of the pure PET. The mechanism of the tailoring of the properties of PET resin by incorporation of F‐MWCNTs is discussed, based on structure–property relationships. The good dispersion of the F‐MWCNTs and strong interfacial interaction between matrix and nanofiller are responsible for the improvement in mechanical properties and high nucleating efficiency. The abnormal melting behavior is attributed to the recrystallization transition of PET occurring at the early stage of crystal melting being retarded on incorporation of F‐MWCNTs. Copyright © 2009 Society of Chemical Industry  相似文献   

15.
《Polymer Composites》2017,38(11):2433-2439
The extrudate swell behavior of polypropylene (PP) composite melts filled with multi‐walled carbon nanotubes (MWCNTs) was studied using a capillary rheometer in a temperature range from 190 to 230°C and at various apparent shear rates varying from 50 to 800 s−1. It was found that the values of the extrudate swell ratio of the composites increased nonlinearly with increasing apparent shear rates, while the values of the extrudate swell ratio decreased almost linearly with increasing temperature. The values of the melt extrudate swell ratio increased approximately linearly with increasing shear stress, while decreased approximately nonlinearly with an increase of the MWCNT weight fraction. In addition, the extrudate swell mechanisms were discussed with observation of the fracture surface of the extrudate using a scanning electronic microscopy. This study provides a basis for further development of MWCNTs reinforced polymer composites with desirable mechanical and thermal properties. POLYM. COMPOS., 38:2433–2439, 2017. © 2015 Society of Plastics Engineers  相似文献   

16.
聚酰亚胺的前聚体,聚酰胺酸,是通过4,4-二氨基二苯醚(ODA)与3,3,4,4二苯甲酮四羧酸二酐(BTDA)反应制备的。未改性的、酸改性和胺改性的多壁碳纳米管(MWCNT)被分别地单独加入到聚酰胺酸溶液中,并加热至300℃,从而制成聚酰亚胺/碳纳米管复合材料。扫描型电子显微镜(SEM)和透射电子显微镜(TEM)的显微照片表明,酸改性的多壁碳纳米管和胺改性多壁碳纳米管在聚酰亚胺基体中被均匀一致地分散开。通过对酸和胺改性的多壁碳纳米管MWCNTS对多壁碳纳米管/聚酰亚胺复合材料的表面和体积电阻率的影响进行了研究。了解到该纳米复合材料的表面电阻率ITES从1.28×10^(15)Ω/cm^(2)(纯聚酰亚胺),降到7.59×10^(6)Ω/cm^(2)(26.98%的未改性的多壁碳纳米管含量)。除此之外,添加多壁碳纳米管影响了纳米复合材料的玻璃化转变温度。改性多壁碳纳米管意义就是提高了纳米复合材料的机械性能。多壁碳纳米管/聚酰亚胺复合材料的拉伸强度从10^(2)MPa(纯的聚酰亚胺)增加到134 MPa(6.98%酸改性多壁碳纳米管/聚酰亚胺复合材料)。  相似文献   

17.
In order to prepare the bio‐based polymeric materials, a gallic acid epoxy resin (GA‐ER) is synthesized by using biodegradable gallic acid, and the nanocomposites of GA‐ER/glycidyl methacrylate (GMA)/multiwalled carbon nanotubes (MWCNTs) were prepared by dual hybrid cationic ring‐opening reaction. Differential scanning calorimetry (DSC) results show that the curing reaction temperature of the nanocomposites is between 150 and 225°C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results suggest that MWCNTs are homodispersing in the GA‐ER/GMA matrix when the MWCNTs content is not more than 1.0 wt%. The glass transition temperature of the nanocomposite with 0.5 wt% MWCNTs is 9.3°C higher than that of pure resin system. The initial thermal degradation temperature and degradation activation energies Ea of the nanocomposite with 1.0 wt% MWCNTs is 10°C and 68.6 kJ/mol higher than that the pure resin system, respectively. POLYM. COMPOS., 37:3093–3102, 2016. © 2015 Society of Plastics Engineers  相似文献   

18.
A branched random copolymer, poly[(hydroxyethyl acrylate)‐r‐(N‐vinylcarbazole)] (BPHNV), was synthesized through a facile one‐pot free radical polymerization with hydroxyethyl acrylate and N‐vinylcarbazole monomers, using 4‐vinylmethylmercaptan as the chain transfer agent. BPHNV was employed to noncovalently modify multiwall carbon nanotubes (MWCNTs) by π–π interaction. The as‐modified MWCNTs were then incorporated into epoxy resin to improve the thermal conductivity and mechanical properties of epoxy thermosets. The results suggest that, due to both the conjugation structure and the epoxy‐philic component, BPHNV could form a polymer layer on the wall of MWCNTs and inhibit entanglement, helping the uniform dispersion of MWCNTs in epoxy matrix. Owing to the unprecedented thermal conductivity of MWCNTs and the enhancement in the interfacial interaction between fillers and matrix, the thermal conductivity of epoxy/MWCNTs/BPHNV composites increases by 78% at extremely low filler loadings, while the electrical resistivity is still maintained on account of the insulating polymer layer. Meanwhile, the mechanical properties and glass transition temperature (Tg) of the thermosets are elevated effectively, with no significant decrease occurring to the modulus. The addition of as little as 0.1 wt% of MWCNTs decorated with 1.0 wt% of BPHNV to an epoxy matrix affords a great increase of 130% in impact strength for the epoxy thermosets, as well as an increase of over 13 °C in Tg. © 2018 Society of Chemical Industry  相似文献   

19.
Multi‐walled carbon nanotube was modified with polymethyl methacrylate (MWCNT‐PMMA) by in situ solution radical polymerization in the presence of 2,2′‐Azobis (isobutyronitrile) as an initiator. The products with different addition of methyl methacrylate (MMA) were pressed into slices to prepare specimens for electrical conductivity testing. It was found that the MWCNT‐PMMA nanocomposites demonstrate excellent electrical conductivity. To investigate the microsphere morphology and the colloidal surfactant of MWCNTs in MWCNT‐PMMA composites, samples were submitted to scanning electron microscopy and transmission electron microscopy. The thermogravimetric analysis of the prepared composites confirmed that MWCNTs as a thermal stabilizer for PMMA, which could have a wide range of potential applications, such as in catalysts, sensors, environmental remediation, and energy storage. Two series of poly(lactic acid) (PLA) based biocomposites with different MMA additions and MWCNT‐PMMA composites contents were prepared with twin‐screw extruding and injection molding. The results show the mechanical properties changed a little with the MMA and MWCNT‐PMMA composites contents increasing, which suggested the well compatibility between MWCNT‐PMMA composites and PLA. POLYM. COMPOS., 37:503–511, 2016. © 2014 Society of Plastics Engineers  相似文献   

20.
Huihui Wang  Jinbao Guo  Jia Li  Jie Wei 《Carbon》2011,(3):779-786
A method for the fabrication of electrically-conducting polymer composites has been developed by mixing modified multi-walled carbon nanotubes (MWCNTs) functionalized by bimetallic nanoparticles (Ag/Ni/MWCNTs) into a UV curable resin. MWCNTs were treated by a concentrated H2SO4/HNO3 mixture followed by ultrasonication with AgNO3 and NiSO4 in an ethylene glycol solution, producing MWCNTs decorated with Ag and Ni nanoparticles. The microstructure and surface morphology of the Ag/Ni/MWCNTs were investigated by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectrometry. It was found that the addition sequences of NiSO4 and AgNO3 influence the morphology of the Ag/Ni/MWCNTs. The electrically-conducting polymer composites were obtained by dispersing the prefabricated Ag/Ni/MWCNTs in UV curable resin, the curing process of which was tracked by Fourier transform infrared spectroscopy, and the electrical resistance was measured using the four-probe method. The fabrication of microelectronic patterns made by screen printing on different substrates was described.  相似文献   

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