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1.
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   

2.
Two types of multi‐walled carbon nanotubes (MWCNTs), chemically modified and unmodified, were dispersed in epoxy resin with ultrasonication. The light transmittance characteristics of epoxy composites with different ratios of MWCNTs to epoxy resin were measured at wavelengths ranging from 200 to 1100 nm. Results showed that composites with modified MWCNTs had a much higher light transmittance than those with unmodified MWCNTs. This was presumably due to a more uniform dispersion of modified MWCNTs in the epoxy matrix, as indicated by both transmission electron microscopy and optic microscopy. The wavelength dependency of light transmittance of the composites was expressed empirically as a function of weight fraction (fw) of MWCNTs and the light wavelength (λ). POLYM. ENG. SCI. 46:635–642, 2006. © 2006 Society of Plastics Engineers.  相似文献   

3.
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   

4.
Flyash, a waste product generated in large quantities in thermal power plants, has been posing problems of disposal. The purpose of the present work was to make a meaningful utilization of flyash as filler in neat epoxy resin matrix and 2% Polybutyleneterepthalate (PBT)/epoxy blend matrix. For this purpose, the tensile, flexural, compression, impact, chemical resistance, and water absorption properties were studied. Composites were made with varying proportion of flyash in epoxy resin and 2% PBT/epoxy blend matrix. Tensile, flexural, and compression properties were measured on a computerized universal testing machine, according to ASTM procedures. Impact strength was determined using izod impact tester for un‐notched specimens. PBT (2%)/epoxy blend matrix composites showed improved mechanical properties over neat epoxy flyash composites. All the composites were found to have good chemical resistance toward acids, solvents, and alkalies. These composites showed better water resistance over neat epoxy flyash composites. POLYM. ENG. SCI. 46:946–953, 2006. © 2006 Society of Plastics Engineers  相似文献   

5.
Multi‐walled carbon nanotubes (MWCNTs), surface‐treated via chemical functionalization, i.e., oxidation and amidation, were used to reinforce diglycidylether of bisphenol F (DGEBF) epoxy resin. The effects of the functionalization on the dispersion stability, rheological properties, and fracture toughness of DGEBF/MWCNT composites were investigated. The dispersion homogeneity of the MWCNTs in the epoxy matrix improved after functionalization. In addition, isothermal rheology measurements revealed that the DGEBF/dodecyl amine‐functionalized MWCNT (D‐MWCNT) composite had a longer gel time and higher activation energy of cross‐linking than the DGEBF/acid‐treated MWCNT (A‐MWCNT) composite. The fracture toughness of the former was also significantly higher than that of the latter; this resulted from the relatively high dispersion stability of the D‐MWCNTs in the epoxy matrix, owing to the presence of alkyl groups on the D‐MWCNT surface. POLYM. ENG. SCI., 55:2676–2682, 2015. © 2015 Society of Plastics Engineers  相似文献   

6.
Poly(acrylonitrile‐styrene‐butadiene) (ABS) was used to modify diglycidyl ether of bisphenol‐A (DGEBA) type epoxy resin, and the modified epoxy resin was used as the matrix for making multiwaled carbon tubes (MWCNTs) reinforced composites and were cured with diamino diphenyl sulfone (DDS) for better mechanical and thermal properties. The samples were characterized by using infrared spectroscopy, pressure volume temperature analyzer (PVT), thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), thermo mechanical analyzer (TMA), universal testing machine (UTM), and scanning electron microscopy (SEM). Infrared spectroscopy was employed to follow the curing progress in epoxy blend and hybrid composites by determining the decrease of the band intensity due to the epoxide groups. Thermal and dimensional stability was not much affected by the addition of MWCNTs. The hybrid composite induces a significant increase in both impact strength (45%) and fracture toughness (56%) of the epoxy matrix. Field emission scanning electron micrographs (FESEM) of fractured surfaces were examined to understand the toughening mechanism. FESEM micrographs reveal a synergetic effect of both ABS and MWCNTs on the toughness of brittle epoxy matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

7.
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   

8.
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   

9.
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   

10.
Multiwalled carbon nanotubes (MWCNTs) were functionalized through “Friedel‐Craft” acylation with 1,3,5‐Benzenetricarboxylic acid (BTC) in mild polyphosphoric acid (PPA)/ phosphorus pentoxide (P2O5)/phosphoric acid (PA) medium at 130°C. The high‐resolution transmission electron microscopy, Raman spectra, and X‐ray photoelectron spectra (XPS) were used to characterize the surface microstructure nature of functionalized MWCNTs in optimum PPA/P2O5/PA medium. The thermostability of functionalized MWCNTs was characterized by thermogravimetric analysis. The maximum rate of weight loss temperature increased as compared with pristine MWCNTs. The dispersion properties of MWCNTs and the flexural properties of the MWCNTs/epoxy composites affected by MWCNTs functionalization are investigated. It is demonstrated that the functionalized MWCNTs exhibit much better dispersability than pristine MWCNTs. The attached BTC molecules arising from the functionalization effectively improved interfacial adhesion between the epoxy resin and functionalized MWCNTs through covalent bonds, resulting in improved flexural properties compared with those without functionalization. POLYM. COMPOS., 35:1275–1284, 2014. © 2013 Society of Plastics Engineers  相似文献   

11.
Epoxy–clay nanocomposites were prepared by the dispersion of an organically modified layered clay in an epoxy resin (diglycidyl ether of bisphenol A) and curing in the presence of methyl tetrahydro acid anhydride at 80–160°C. The nanometer‐scale dispersion of layered clay within the crosslinked epoxy‐resin matrix was confirmed by X‐ray diffraction and transmission electron microscopy, and the basal spacing of the silicate layer was greater than 100–150 Å. Experiments indicated that the hydroxyethyl groups of the alkyl ammonium ions, which were located in the galleries of organically modified clay, participated in the curing reaction and were directly linked to the epoxy‐resin matrix network. Experimental results showed that the properties of epoxy were improved, evidently because of the loading of organically modified clay. The impact strength and tensile strength of the nanocomposites increased by 87.8 and 20.9%, respectively, when 3 wt % organic clay was loaded, and this demonstrated that the composites were toughened and strengthened. The thermal‐decomposition and heat‐distortion temperatures were heightened in comparison with those of pure epoxy resin, and so were the dynamic mechanical properties, including the storage modulus and glass‐transition temperature. Moreover, experiments showed that most properties of the composites were ameliorated with low clay contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2649–2652, 2004  相似文献   

12.
BACKGROUND: The aim of this work was to study, using differential scanning calorimetry, the effect of carboxylic functionalization of multi‐walled carbon nanotubes (MWCNTs) on the cure reaction of MWCNTs/diglycidyl ether of bisphenol A/2‐ethyl‐4‐methylimidazole (MWCNTs/DGEBA/EMI‐2,4) nanocomposites. This is important for the practical design, analysis and optimization of novel materials processing. RESULTS: Comparing the influence of non‐functionalized MWCNTs and carboxyl‐functionalized MWCNTs, it was found that, at the initial curing stage, both MWCNTs act as catalyst and COOH functionalization of MWCNTs has a catalytic effect on the curing process. Then, at the later curing stage, non‐functionalized MWCNTs prevent the occurrence of vitrification, whereas COOH functionalization of MWCNTs promotes vitrification. Non‐functionalized MWCNTs decrease the degree of curing, as evidenced by lower total heat of reaction and lower glass transition temperatures of nanocomposites compared to neat epoxy; however, COOH functionalization of MWCNTs increases the degree of curing. CONCLUSION: For the development of composites, COOH functionalization of MWCNTs could bring a positive influence to the composite process. Its acceleration of cure could help shorten pre‐cure time or lower pre‐treatment temperature, and its effect of promoting vitrification could help shorten post‐cure time or lower post‐treatment temperature. Copyright © 2009 Society of Chemical Industry  相似文献   

13.
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   

14.
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   

15.
In the present study, an epoxy resin was dynamically cured in a polypropylene (PP)/maleic anhydride–grafted PP (MAH‐g‐PP)/talc matrix to prepare dynamically cured PP/MAH‐g‐PP/talc/epoxy composites. An increase in the torque at equilibrium showed that epoxy resin in the PP/MAH‐g‐PP/talc composites had been cured by 2‐ethylene‐4‐methane‐imidazole. Scanning electron microscopy analysis showed that MAH‐g‐PP and an epoxy resin had effectively increased the interaction adhesion between PP and the talc in the PP/talc composites. Dynamic curing of the epoxy resin further increased the interaction adhesion. The dynamically cured PP/MAH‐g‐PP/talc/epoxy composites had higher crystallization peaks than did the PP/talc composites. Thermogravimetric analysis showed that the addition of MAH‐g‐PP and the epoxy resin into the PP/talc composites caused an obvious improvement in the thermal stability. The dynamically cured PP/MAH‐g‐PP/talc/epoxy composites had the best thermal stability of all the PP/talc composites. The PP/MAH‐g‐PP/talc/epoxy composites had better mechanical properties than did the PP/MAH‐g‐PP/talc composites, and the dynamically cured PP/MAH‐g‐PP/talc/epoxy composites had the best mechanical properties of all the PP/talc composites, which can be attributed to the better interaction adhesion between the PP and the talc. The suitable content of epoxy resin in the composites was about 5 wt %. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

16.
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   

17.
In this article, the potential of amine‐functionalized poly(styrene) (PS) microspheres as toughening agent for epoxy resin has been explored. PS microspheres were prepared by suspension polymerization, where the monomer concentration and stirring speed was varied to control the microsphere dimensions (52–183 µm). The obtained microspheres were chemically functionalized with an aim to improve its dispersion within the epoxy matrix. The amine groups generated on the microsphere surface offer a potential site of covalent linkage with the epoxy matrix, thereby resulting in increased compatibility and improved properties. Epoxy composites containing varying amounts of microspheres (1–7% w/w) were prepared and their mechanical properties were evaluated under both quasi‐static as well as dynamic conditions. The amination of poly(styrene) (APS) led to improved dispersion of the rigid microspheres in the epoxy matrix, which was evident from higher impact strength and fracture energies (GIC) as compared to its neat analogs. The izod impact strength and GIC increased by 33% and 150%, respectively, on introduction of 3% APS. This was accompanied with an increase in the tensile modulus and strength of the epoxy resin. Further increase in loading led to agglomeration of the microspheres, which in turn resulted in lowering of impact strength and toughness. Excellent agreement was found between the experimentally measured modulae and the predictions made on the basis of Halpin–Tsai and Lewis–Neilson models. Fracture surface morphology was studied to arrive at the principal toughening mechanisms behind the experimental findings. POLYM. COMPOS., 36:174–183, 2015. © 2014 Society of Plastics Engineers  相似文献   

18.
The thermal properties of carbon nanofibers (CNF)/epoxy composites, composed of tetraglycidyl‐4,4′‐diaminodiphenylmethane (TGDDM) resin and 4,4′‐diaminodiphenylsulfone (DDS) as a curing agent, were investigated with differential scanning calorimetry (DSC), thermogravimetric analysis, and dynamic mechanical thermal analysis. DSC results showed that the presence of CNF had no pronounced influence on the heat of the cure reaction. However, the incorporation of CNF slightly improved the thermal stability of the epoxy. Furthermore, the storage modulus of the TGDDM/DDS epoxy was significantly enhanced, whereas the glass‐transition temperature was not significantly affected, upon the incorporation of CNFs. The storage modulus of 5 wt % CNF/epoxy composites at 25°C was increased by 35% in comparison with that of the pure epoxy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 295–298, 2006  相似文献   

19.
Epoxies have a wide range of applications in fuel tank fabrication, aerospace, electrical, electronic, and automobile industries. However, these resins are quite brittle, showing poor mechanical performance, especially at cryogenic temperature. The properties of functionalized multi-walled carbon nanotube (MWCNTs)-reinforced epoxy composites were investigated to develop advanced composites for cryogenic use. Two methods were adopted to modify MWCNTs. MWCNTs were first treated by acid mixture, and then maleic anhydride (MA) and isophorone diisocyanate (IPDI) grafting was carried out. At last, the functionalized MWCNTs were integrated into epoxy to prepare MWCNT-reinforced epoxy composites. Raman and XPS analysis proved the effectiveness of acid mixture treatment and confirmed the grafting reaction of MA and IPDI with MWCNTs. TEM analysis indicated that MA and IPDI had been grafted onto the surface of MWCNTs and formed a thin layer. The tensile strength, Young’s modulus, and impact strength of composites at liquid nitrogen temperature (77 K) are all enhanced by the addition of MWCNTs. Results of dynamic mechanical analysis indicated that introducing a small amount of functionalized MWCNTs to epoxy can enhance their storage modulus at 77 K and glass-transition temperature of composites. The results indicated that surface modified MWCNTs can be effectively utilized to enhance the properties of epoxy-based composites at cryogenic temperature.  相似文献   

20.
Direct functionalized carbon nanotubes (CNTs) were utilized to form the heat flow network for epoxy composites through covalent integration. A method of preparing a fully heat flow network between benzenetricarboxylic acid grafted multi-walled carbon nanotubes (BTC-MWCNTs) and epoxy matrix is described. A Friedel-Crafts modification was used to functionalize MWCNTs effectively and without damaging the MWCNT surface. Raman spectra, X-ray photoelectron spectra and thermogravimetric analysis reveal the characteristics of functionalized MWCNTs. The scanning electron microscope images of the fracture surfaces of the epoxy matrix showed BTC-MWCNTs exhibited higher solubility and compatibility than pristine-MWCNTs. The MWCNTs/epoxy composites were prepared by mixing BTC-MWCNTs and epoxy resin in tetrahydrofuran, followed by a cross-linking reaction with a curing agent. The BTC was grafted onto the MWCNTs, creating a rigid covalent bond between MWCNTs and epoxy resin and forming an effective network for heat flow. The effect of functionalized MWCNTs on the formation of the heat flow network and thermal conductivity was also investigated. The thermal conductivity of composites exhibits a significant improvement from 0.13 to 0.96 W/m K (an increase of 684%) with the addition of a small quantity (1-5 vol%) of BTC-MWCNTs.  相似文献   

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