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Fangfang Wu Yonggen Lu Guilin Shao Fanlong Zeng Qilin Wu 《Polymer International》2012,61(9):1394-1399
Highly oriented molecular structure is essential for high‐performance carbon fibers. The addition of a small amount of graphene sheets may enhance the degree of molecular orientation of precursor fibers during spinning and stabilization by limiting the disorientation of the chain segments. Graphene sheets merge into the carbon fiber structure during carbonization. The structure and properties of polyacrylonitrile containing graphene oxide (GO) prepared by in situ polymerization were investigated. With increasing GO loading, the molecular weight of the polymer decreased gradually from 69 000 g mol?1 for the sample without GO to 60 600 g mol?1 for the sample with 2.5 wt% loading of GO. Scanning electron microscopy and X‐ray diffraction results indicated that GO was dispersed in single layers in the polymer matrix. The degree of crystallization of the polymer with 0.5 wt% GO was increased by 8%. Moreover, differential scanning calorimetry and thermogravimetric analysis showed that an appropriate amount of GO, e.g. 0.5 wt%, made the carbon yield of the polymer increase by 5.0 wt%, because the GO in the composite improved the intermolecular crosslinking reaction. Copyright © 2012 Society of Chemical Industry 相似文献
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Interfacial in situ polymerization of single wall carbon nanotube/nylon 6,6 nanocomposites 总被引:1,自引:0,他引:1
An interfacial polymerization method for nylon 6,6 was adapted to produce nanocomposites with single wall carbon nanotubes (SWNT) via in situ polymerization. SWNT were incorporated in purified, functionalized or surfactant stabilized forms. The functionalization of SWNT was characterized by FTIR, Raman spectroscopy and TGA and the SWNT dispersion was characterized by optical microscopy before and after the in situ polymerization. SWNT functionalization and surfactant stabilization improved the nanotube dispersion in solvents but only functionalized SWNT showed a good dispersion in composites, whereas purified and surfactant stabilized SWNT resulted in poor dispersion and nanotube agglomeration. Weak shear flow induced SWNT flocculation in these nanocomposites. The electrical and mechanical properties of the SWNT/nylon nanocomposites are briefly discussed in terms of SWNT loading, dispersion, length and type of functionalization. 相似文献
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Minsung Kang 《Polymer》2006,47(11):3961-3966
Poly(hexamethylenesebacamide) (nylon 610) nanocomposites containing well dispersed multi-walled carbon nanotubes (MWNTs) were successfully produced via the in situ interfacial polymerization of two liquid phases, one containing hexamethylenediamine in the presence of MWNTs and the other containing sebacoyl chloride. The processing consisted of dispersing acid-treated MWNTs in an aqueous phase containing a Triton X-100 surfactant. Scanning and transmittance electron microscopies showed that the individual MWNTs were uniformly dispersed in the nylon 610 matrix. Tensile tests of the composite sheet showed a 170% increase in the Young's modulus with slight increases in the tensile strength and the elongation at break (about 40 and 25%, respectively). This suggests an interaction between the acid-treated MWNTs and nylon 610. The thermal stability of the composite was also enhanced by the incorporation of MWNT into nylon 610 matrix. 相似文献
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In this study, ultrasonic irradiation and in situ emulsion polymerization were combined to prepare stable poly(methyl methacrylate‐co‐n‐butyl acrylate) (P(MMA‐BA))/carbon nanotubes (CNTs) composite emulsion, which solves the dispersion problem of CNTs in the latex. Two stages were adopted. In Stage I, ultrasonically initiated in situ emulsion polymerization was conducted to disperse CNTs and prepare the seed emulsion containing polymer coated CNTs. In Stage II, conventional in situ emulsion polymerization was conducted to further enhance the monomer conversion and solid content. The dispersion behavior of MWCNTs in aqueous solution under ultrasonic irradiation was investigated by spectrophotometry. The effects of CNTs content on the emulsion stability and mechanical properties of composite film were studied. The results suggest that in the composite emulsion the long CNTs with a diameter of 20–40 nm are separated and dispersed by the formed polymer latex nanoparticles with a size of 20–40 nm. The spherical polymer latex nanoparticles adhere to the wall of CNTs to form a structure like “grapes on the twig.” The smooth, uniform, and flexible polymer/CNTs composite films were prepared from the composite emulsion. The CNTs can be individually dispersed in P(MMA‐BA)/CNTs composite film. Tensile tests suggest that with the increase in the CNTs content, the Young's modulus and the yield strength of the film increase. Only at 1 wt % CNTs, the Young's modulus increases from 124 to 289 MPa, and the yield strength is improved about ~14%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3123–3130, 2006 相似文献
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Stabilization and carbonization of gel spun polyacrylonitrile/single wall carbon nanotube composite fibers 总被引:1,自引:0,他引:1
Han Gi Chae 《Polymer》2007,48(13):3781-3789
Gel spun polyacrylonitrile (PAN) and PAN/single wall carbon nanotube (SWNT) composite fibers have been stabilized in air and subsequently carbonized in argon at 1100 °C. Differential scanning calorimetry (DSC) and infrared spectroscopy suggests that the presence of single wall carbon nanotube affects PAN stabilization. Carbonized PAN/SWNT fibers exhibited 10-30 nm diameter fibrils embedded in brittle carbon matrix, while the control PAN carbonized under the same conditions exhibited brittle fracture with no fibrils. High resolution transmission electron microscopy and Raman spectroscopy suggest the existence of well developed graphitic regions in carbonized PAN/SWNT and mostly disordered carbon in carbonized PAN. Tensile modulus and strength of the carbonized fibers were as high as 250 N/tex and 1.8 N/tex for the composite fibers and 168 N/tex and 1.1 N/tex for the control PAN based carbon fibers, respectively. The addition of 1 wt% carbon nanotubes enhanced the carbon fiber modulus by 49% and strength by 64%. 相似文献
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In this research, multiwalled carbon nanotube (MWNT) was oxidized and then modified to form carboxylic groups (? COOH) on the surface and the end of the tube. After that, the MWNT was added to polyimide matrix to enhance its mechanical and electrical properties by in situ polymerization and blending. The PI/MWNT composites were obtained by spin coating and multistep thermal curing process. The comparison of in situ polymerization and blending as well as the effect of unmodified and modified MWNT were discussed in this study. The results indicate that in situ polymerization is able to make a perfect dispersion by adding modified MWNT into polyimide matrix. Thermal and mechanical properties of the composites can be improved by hydrogen bonding interaction between the modified MWNT and polyimide matrix. Electrical resistance of the composites can be decreased to meet the criterion of electrostatic charge (ESC) mitigation as the surface resistance is reduced into the range of 106–1010 Ω/cm2 by adding modified MWNT. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Meng Cao Zhonglin Luo Ya Yang Yanbin Wang 《Polymer-Plastics Technology and Engineering》2017,56(13):1391-1400
Poly(amide imide)/multiwalled carbon nanotube composites were in situ polymerized through Yamazaki–Higashi phosphorylation method, and the carboxylated multiwalled carbon nanotubes are added in the post-reaction stage. The good dispersion of multiwalled carbon nanotubes in the poly(amide imide) matrix was achieved even at 20?wt% nanotube loading. The electrical conductivity reached 33?S?m?1; meanwhile, the tensile strength and Young’s modulus were 106MPa and 2.52?GPa, respectively. These excellent properties were contributed to the good dispersion of nanotubes and strong multiwalled carbon nanotubes–poly(amide imide) interfacial adhesions. We also demonstrate that the incorporation of multiwalled carbon nanotubes depressed the crystallization characteristics of poly(amide imide) but improve its thermal stability. 相似文献
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将多壁碳纳米管(MWNT)氧化后,酰氯化处理,在氨基封端的PA6聚合时加入,制备PA6/MWNT母粒,将母粒同PA6切片熔融共混纺丝,制备PA6/MWNT纤维。用INSTRON 1122型万能材料试验机测定纤维的力学性能。结果表明,改性MWNT的加入提高了PA6纤维的断裂强度,纤维中MWNT质量分数仅为0.05%时,纤维的断裂强度和初始模量最大,分别增加了60%和86%。用扫描电镜观察复合纤维的结构,发现MWNT均匀地分布在PA6中,并与PA6基体间有相互作用,沿纤维轴向取向。 相似文献
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Multiwalled carbon nanotube/polycaprolactone nanocomposites (MWNT/PCL) were prepared by in situ polymerization, whereby as‐received MWNTs (P‐MWNTs) and purified MWNTs (A‐MWNTs) were used as reinforcing materials. The A‐MWNTs were purified by nitric acid treatment, which introduced the carboxyl groups (COOH) on the MWNT. The micrographs of the fractured surfaces of the nanocomposites showed that the A‐MWNTs in A‐MWNT/PCL were better dispersed than P‐MWNTs in PCL matrix (P‐MWNT/PCL). Percolation thresholds of the P‐MWNT/PCL and A‐MWNT/PCL, which were studied by rheological properties, were found at ~2 wt % of the MWNT. The conductivity of the P‐MWNT/PCL was between 10?1 and 10?2 S/cm by loading of 2 wt % of MWNT although that of the A‐MWNT/PCL reached ~10?2 S/cm by loading of 7 wt % of MWNT. The conductivity of the P‐MWNT/PCL was higher than that of the A‐MWNT/PCL at the entire range of the studied MWNT loading, which might be due to the destruction of π‐network of the MWNT by acid treatment, although the A‐MWNT/PCL was better dispersed than the P‐MWNT/PCL. The amount of the MWNT at which the conductivity of the nanocomposite started to increase was strongly correlated with the percolation threshold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1957–1963, 2007 相似文献
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《Polymer》2014,55(26):6896-6905
Carbon nanotube (CNT) can exhibit electrical conductivity and introduce electric current into polymer. Using dry-jet-wet spin technology, polyacrylonitrile (PAN)/CNT composite fibers with 15 wt% and 20 wt% of CNT content were fabricated. The electrical conductivity of PAN/CNT fibers was enhanced by the annealing process at different temperatures and changed with time. These fibers could also respond to stretching, and the electrical conductivity decreased by 50% when the elongation reached 3%. In addition, electrical current can induce Joule heating effect and thermally transform PAN/CNT composite fibers. With the application of various electrical currents up to 7 mA at a fixed length, conductivity was enhanced from around 25 S/m to higher than 800 S/m, and composite fibers were stabilized in air. The temperature of composite fibers can increase from room temperature to several hundreds of degree Celsius measured by an infra-red (IR) microscope. Joule heating effect can also be estimated according to one-dimensional steady-state heat transfer equation, which reveals the temperature can be high enough to stabilize or carbonize fibers. As a result, this research provides a new idea of heating fabrics for thermal regulation, and a new approach for stabilizing and carbonizing PAN-based carbon fibers. 相似文献
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ABSTRACT: Composite made of multiwalled carbon nanotubes coated with silver was fabricated by an electroless deposition process. The thickness of silver layer is about 40 to 60 nm, characterized as nano-crystalline with (111) crystal orientation along the nanotube's axial direction. The characterization of silver/carbon nanotube [Ag/CNT] nanowire has shown the large current carrying capability, and the electric conductivity is similar to the pure silver nanowires that Ag/CNT would be promising as building blocks for integrated circuits.PACS: 81.05.uj, carbon nanotubes, carbon-based materials, diamond/nanocarbon composites. 相似文献
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Aleksandr A. Zdanovich Nina V. Semikolenova Vladimir L. Kuznetsov Mikhail A. Matsko Sergey I. Moseenkov Vladimir A. Zakharov 《应用聚合物科学杂志》2019,136(46):48212
The peculiarity of formation of Ziegler-type catalytic systems prepared using organoaluminum (AlR3) and organomagnesium (MgR2) on the surface of multi-walled carbon nanotubes (MWCNTs) was revealed. We have found first AlR3 and MgR2 interact with different sites on MWCNT surface. It was demonstrated by IR spectroscopy that organoaluminum compounds were immobilized on the hydroxyl-containing groups on MWCNT surface. Organomagnesium compounds were immobilized on the topological structural defects of MWCNTs; hydroxyl-containing groups were not required for their immobilization. Further interaction between TiCl4 and organomagnesium compound immobilized on the MWCNT surface yielded a catalyst containing titanium and magnesium chlorides (an analogue of the known titanium–magnesium catalysts), which exhibits an enhanced activity in ethylene polymerization. The effect of polymerization conditions on molecular weight characteristics of polyethylene in the MWCNT/PE composite material produced by in situ polymerization over the catalyst immobilized on the MWCNT surface was studied. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48212. 相似文献
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Polyacrylonitrile (PAN)/single wall carbon nanotube (SWNT) composite films have been processed with unique combination of tensile strength (103 MPa), modulus (10.9 GPa), electrical conductivity (1.5×104 S/m), dimensional stability (coefficient of thermal expansion 1.7×10−6/°C), low density (1.08 g/cm3), solvent resistance, and thermal stability. PAN molecular motion above the glass transition temperature (Tg) in the composite film is significantly suppressed, resulting in high PAN/SWNT storage modulus above Tg (40 times the PAN storage modulus). Rope diameter in the SWNT powder was 26 nm, while in 60/40 PAN/SWNT film, the rope diameter was 40 nm. PAN crystallite size from (110) plane in PAN and PAN/SWNT films was 5.3 and 2.9 nm, respectively. This study suggests good interaction between PAN and SWNT. 相似文献
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Yi‐Jhen Wu Liang Chao Ko‐Shan Ho Ying‐Jie Huang Yu‐Lan Huang Chi‐Shiang Yang Bo‐Hao Tseng 《应用聚合物科学杂志》2012,124(6):5270-5278
A multiwalled carbon nanotubes (MWCNTs) were carboxylated after refluxing with sulfuric and nitric acids. These attached carboxylic acid groups were further condensated with o‐phenylene diamine into amide catalyzed by dicyclohexyl carbodiimide (DCC). The obtained amidized MWCNTs were in situ‐polymerized with aniline monomers to graft a conducting polyaniline (PANI) onto MWCNT (ES‐g‐MWCNTs) through the polymerization occurring in the ortho‐ and meta‐positions. The reduced conductivity of the MWCNT after carboxylation can be recovered after grafting with PANI, which owns a strong λmax at the near infrared region due to the extended conjugation from MWCNTs to PANI. Transmission electronic microscopic pictures show a gradual broadening of the MWCNT diameter after carboxylation, amidization, and polymerization. The weight loss from the thermogravimetric thermograms due to the carboxylations of MWCNTs, amidized MWCNTs, and the PANI grafted MWCNTs into CO2 can be used to estimate the degree of carboxylation, amidization, and grafting of PANI. The degree of carboxylation of MWCNT calculated from ESCA spectrum is around 23% close to that estimated from TGA thermogram. The doping level of redoped PANI‐grafted MWCNT is found to be 27.78% much less than the maximum 50% of neat PANI. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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In this work, we analyzed tensile properties of polypropylene‐multiwalled carbon nonotubes composite fibers. The multiwalled carbon nanotubes (MWCNTS) were used in different contents of 0, 1, 2, 3, 4, and 5 wt %. Dispersing agents were used to disperse MWCNTs in polypropylene matrix. After the dispersing agent was removed, the mixture was melt mixed. The fibers were spun by a home‐made melt spinning equipment and stretching was done at a draw ratio of 7.5. By using 1–5 wt % of MWCNTs, the modulus of composite fibers increased by 69–84% and tensile strength increased about 39% when compared with the virgin polypropylene fibers. In addition, the MWCNTs dispersion in the matrix was monitored by scanning electron microscopy and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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A polyamide 6 (PA 6)/silica nanocomposite was obtained through a novel method, in situ polymerization, by first suspending silica particles in ϵ-caproamide under stirring and then polymerizing this mixture at high temperature under a nitrogen atmosphere. The silicas were premodified with aminobutyric acid prior to the polymerization. The effects of the addition of unmodified and modified silicas on the dispersion, interfacial adhesion, isothermal crystallization, and mechanical properties of PA 6 nanocomposites were investigated by using scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, and mechanical tests, respectively. The results show that the silicas dispersed homogeneously in the PA 6 matrix. The addition of silicas increases the glass transition temperature and crystallization rate of PA 6. The mechanical properties such as impact strength, tensile strength, and elongation at break of the PA 6/modified silica nanocomposites showed a tendency to increase and decrease with increase of the silica content and have maximum values at 5% silica content, whereas those of the PA 6/unmodified silica system decreased gradually. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 355–361, 1998 相似文献