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Carbon Nanotube/poly (carbon + poly)
Selected AbstractsDispersion-Polymerized Carbon Nanotube/Poly(methyl methacrylate) Composite Particles and their Electrorheological CharacteristicsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 5 2007Sung Tae Kim Abstract An in situ dispersion polymerization method was adopted to synthesize particulate composites of MWNTs and PMMA, mainly for the investigation of their electrorheological characteristics. The morphology of the PMMA microparticles synthesized in the presence of the MWNTs was examined by both SEM and TEM, showing that the MWNTs were not only grafted onto the surface of the PMMA microbeads, but were also embedded inside the synthesized microbeads. The synthesized MWNT/PMMA particulate composites were also characterized by zeta-potential measurements and TGA for electric and thermal stability studies, respectively. A suspension of the MWNT/PMMA microparticles dispersed in silicone oil was found to show enhanced electrorheological properties on the increase of shear stresses when subjected to an external electric field, exhibiting high yield stresses despite the tiny amount of the MWNT associated. [source] A Facile Approach to Single-Wall Carbon Nanotube/Poly(allylamine) Nanocomposites,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2007Jong-Boem Kim Abstract A facile approach to polymer nanocomposites with single-wall carbon nanotubes and cationic polymers is reported. The composite material was synthesized by producing carboxylic acid groups at the nanotube termini followed by a reaction with poly(allylamine) in water. Fourier transform infrared spectral and thermogravimetric analyses corroborate that the poly(allylamine) chains were wrapped on the surface of the carbon nanotubes. The scanning electron microscopic (SEM) image shows that the nanotubes were dispersed with little aggregation, thus, strongly suggesting that the poly(allylamine) chains have covered the single-wall carbon nanotubes, which was further evidenced by transmission electron microscopy. The composites are soluble in water, and this solubilization process opens up new opportunities in the solution chemistry on pristine nanotubes. [source] Carbon nanotube/poly(methyl methacrylate) composite electrode for capillary electrophoretic measurement of honokiol and magnolol in Cortex Magnoliae OfficinalisELECTROPHORESIS, Issue 16 2006Xiao Yao Abstract This paper describes the development and the application of a novel carbon nanotube/poly(methyl methacrylate) (CNT/PMMA) composite electrode as a sensitive amperometric detector of CE. The composite electrode was fabricated on the basis of the in,situ polymerization of a mixture of CNT and prepolymerized methylmethacrylate in the microchannel of a piece of fused-silica capillary under heat. The performance of this unique system has been demonstrated by separating and detecting honokiol and magnolol in traditional Chinese medicine, Cortex Magnoliae Officinalis. Factors influencing their separation and detection processes were examined and optimized. Honokiol and magnolol were well separated within 7,min in a 40 cm long capillary at a separation voltage of 15,kV using a 50 mM borate buffer (pH,9.2). The new CNT-based CE detector offered significantly lower operating potentials, yielded substantially enhanced S/N characteristics, and exhibited resistance to surface fouling and hence enhanced stability. It demonstrated long-term stability and reproducibility with RSDs of less than 5% for the peak current (n = 9) and should also find a wide range of applications in microchip CE, flowing injection analysis, and other microfluidic analysis systems. [source] Formation of in situ CB/PET Microfibers in CB/PET/PE Composites by Slit Die Extrusion and Hot StretchingMACROMOLECULAR MATERIALS & ENGINEERING, Issue 6 2004Xiang-Bin Xu Abstract Summary: In this present study, the in situ fabrication of a microfibrillar composite based on poly(ethylene terephthalate) (PET), polyethylene (PE), and carbon black (CB) is attempted. PET and CB were first melt mixed. The CB/PET compound and PE were subsequently melt extruded through a slit die and then hot stretched. The morphological observation of the as-stretched extrudate indicated that well-defined microfibers of CB/PET compound could be generated at appropriate CB contents and a fixed hot stretch ratio. In addition, CB was always selectively located in PET. The microfibrillar CB/PET/PE composite has the potential to be a new electrically conductive polymer composite. Morphology of the carbon black/poly(ethylene terephthalate)/polyethylene (PE) composite after additional mixing in the mixer at the processing temperature of PE. [source] Carbon nanotube/poly(methyl methacrylate) composite electrode for capillary electrophoretic measurement of honokiol and magnolol in Cortex Magnoliae OfficinalisELECTROPHORESIS, Issue 16 2006Xiao Yao Abstract This paper describes the development and the application of a novel carbon nanotube/poly(methyl methacrylate) (CNT/PMMA) composite electrode as a sensitive amperometric detector of CE. The composite electrode was fabricated on the basis of the in,situ polymerization of a mixture of CNT and prepolymerized methylmethacrylate in the microchannel of a piece of fused-silica capillary under heat. The performance of this unique system has been demonstrated by separating and detecting honokiol and magnolol in traditional Chinese medicine, Cortex Magnoliae Officinalis. Factors influencing their separation and detection processes were examined and optimized. Honokiol and magnolol were well separated within 7,min in a 40 cm long capillary at a separation voltage of 15,kV using a 50 mM borate buffer (pH,9.2). The new CNT-based CE detector offered significantly lower operating potentials, yielded substantially enhanced S/N characteristics, and exhibited resistance to surface fouling and hence enhanced stability. It demonstrated long-term stability and reproducibility with RSDs of less than 5% for the peak current (n = 9) and should also find a wide range of applications in microchip CE, flowing injection analysis, and other microfluidic analysis systems. [source] Fabrication and properties of clay-supported carbon nanotube/poly (vinyl alcohol) nanocompositesPOLYMER COMPOSITES, Issue 6 2009Yong-Qing Zhao Clay-supported carbon nanotubes (Cs-CNTs) were used as novel nanofillers to improve the thermal and mechanical properties of a polymer. Cs-CNT/poly (vinyl alcohol) (PVA) nanocomposite films were successfully fabricated, and their relative properties were investigated by using differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. Experimental results showed that the thermal stability and dynamic mechanical properties of PVA were remarkably enhanced by incorporating the Cs-CNTs into PVA matrix. The largest Tg difference of 14°C was obtained between pure PVA and PVA nanocomposite with 7 wt% Cs-CNTs. Moreover, the storage modulus of PVA was significantly improved by 133% at 50°C, when 7 wt% Cs-CNTs was added to PVA matrix. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Crystallization and thermal behavior of multiwalled carbon nanotube/poly(butylenes terephthalate) compositesPOLYMER ENGINEERING & SCIENCE, Issue 6 2008Defeng Wu Multiwalled carbon nanotube/poly(butylene terephthalate) composites (PCTs) were prepared by melt mixing. The nonisothermal crystallization and thermal behavior of PCTs were respectively investigated by X-ray diffractometer, polarized optical microscope, differential scanning calorimeter, dynamic mechanical thermal analyzer, and thermogravimetric analyzer. The presence of nanotubes has two disparate effects on the crystallization of PBT: the nucleation effect promotes kinetics, while the impeding effect reduces the chain mobility and retards crystallization. The kinetics was then analyzed using Ozawa, Mo, Kissinger, Lauritzen-Hoffman, and Ziabicki model, and the results reveal that the nucleation effect is always the dominant role on the crystallization of PBT matrix. Thus the crystallizability increases with increase of nanotube loadings. In addition, the presence of nanotubes nearly has no remarkable contribution to thermal stability because nanotubes also play two disparate roles on the degradation of PBT matrix: the Lewis acid sites to facilitate decomposition and the physical hindrance to retard decomposition. Hence the nanotubes act merely as inert-like filler to thermal stability. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Preparation and shear properties of carbon nanotubes/poly(butyl methacrylate) hybrid materialPOLYMER COMPOSITES, Issue 9 2008Wen-Hua Li Composites containing carbon nanotubes (CNTs) in a poly(butyl methacrylate) (PBMA) have been prepared by in situ polymerization. Scanning electron microscopy and high-resolution transmission electron microscope showed that CNTs were well dispersed into PBMA matrix and wrapped with PBMA. The infrared spectrum illustrated that CNTs were covalently linked with PBMA through a CC bond. Owing to this covalent linkage, the composites had a better solubility in organic solvents and had higher thermal stability over pure PBMA. The direct shear testing showed strong mechanical behavior with up to 200% increase in Young's modulus. The possible strengthening mechanism was discussed. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Effect of thermal aging on the crystal structural characteristics of poly(tetra fluoro ethylene)POLYMER ENGINEERING & SCIENCE, Issue 11 2007Anjana Jain The residual effects of cumulative thermal aging on the crystal structural characteristics of the fluoro carbon poly(tetra fluoro ethylene) (PTFE) have been studied by X-ray diffraction methods. The initial hexagonal arrangement of the PTFE chains in a 157 helical conformation is left unaffected by the exposures to temperatures (T), up to and beyond its melting point, Tm. The unit cell registers a residual anisotropic volume expansion. The anisotropy arises from the enhanced enlargement of the basal plane dimension a compared with the axial dimension c. Conformational changes contributing to the observed increase in the chain length have been examined. Enhancement of residual crystallinity of samples aged at T's < Tm suggests that the selective thermal aging could be used as an effective tool to improve the initial crystallinity of commercially available PTFE. The activation energy for 50% enhancement in initial crystallinity has been estimated as 53.9 kJ mol,1. Aging at 400°C, a temperature above Tm, is accompanied by markedly different features viz., deterioration in crystallinity and other structural characteristics. The overall behavior of thermally aged PTFE bears a marked similarity to many polyamides. POLYM. ENG. SCI., 47:1724,1729, 2007. © 2007 Society of Plastics Engineers [source] | ||||||||||