The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microsc...The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.展开更多
Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition we...Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.展开更多
Catalysis and regeneration efficiency of granular activated carbon (GAC) and activated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer...Catalysis and regeneration efficiency of granular activated carbon (GAC) and activated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange (MO) by the combined treatment can increase 22% (for GAC) and 24% (for ACF) respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.展开更多
The development of surface acidity on rayon-based carbon fibers during mild electrochemical treatment was investigated. Conductimetric titration was the primary method used to investigate the functionalities on the ca...The development of surface acidity on rayon-based carbon fibers during mild electrochemical treatment was investigated. Conductimetric titration was the primary method used to investigate the functionalities on the carbon fiber surface. The acidity on the surface of the untreated carbon fiber was very low, while for the treated fibers, the acidity increased significantly.Moreover, with the treatment extent proceeded, the acidity on the fiber surface also increased. SEM analysis shows electrochemical treatment under intense treatment degree caused considerable etch on the fiber surface.Cavities and grooves can be observed on the surface via the SEM microphotograph. While in a more mild treatment, electrochemical treatment didn't cause great etch on the surface of the fiber.展开更多
Carbon fibers (CF) were surface treated with air-oxidation and rare earths (RE), respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroeth...Carbon fibers (CF) were surface treated with air-oxidation and rare earths (RE), respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites was invest/gated. Experimental results revealed that RE was superior to air ox/dation in improving the tensile strength, elongation, and the tensile modulus of CF reinforced PTFE (CF/PTFE) composite. Compared to the untreated and air-oxidated CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under a given applied load and reciprocating sliding frequency. The RE treatment effectively improved the interfacial adhesion between CF and PTFE. With strong interfacial coupling, the carbon fibers carried most of the load, and direct contact and adhesion between PTFE and the counterpart were reduced, accordingly the friction and wear properties of the composite were improved.展开更多
Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at tempe...Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at temperatures between 450℃ and 900℃ in N2 artmosphere. Then, in a successive activation stage, the product carbonized at 600℃ was activated in steam at 450 - 900℃ for 30 min, and at 600℃for 5- 30 min. The other carbonization products were activated at 600 and 900℃ for 30 min respectively. The products activated at 900℃ were then activated at 450℃ for 30 min again. The starting material, carbonized products and all activation products were examined by FT-IR spectroscopy and some products were examined by X-ray photoelectron spectroscope (XPS). And the yields of the carbonized and activated products were calculated. By analysing these spectra, the amount of oxygen-containing functional groups of the activated products attained under various activation time, various activation temperature and various previous carbonization temperature was determined.展开更多
The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechani...The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers u'ere characterized by the combiination use of densities, wide-angle X-ray diffraction (WAXD), X-ray photoelectron speetroscopy (XPS), elemental analysis ( EA ), Fourier traasform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM), etc.KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor.fiber, and transform C≡N groups to C≡N ones, meamchile , it can decreuse the crystal .size increuse the orientation index and the costallinity index, furthermore it can increuse the densities of modified PAN precursors and resuhing thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 31.25 % and an improvement in elongation of 77.78 % , but a decrease of 16. 52% in Young's modulus.展开更多
Combined nitric acid oxidation method and polyaniline (PANI)-coated method were applied to modify the surface properties of short carbon fibers (SCF). The electrical and mechanical properties of acrylic coatings w...Combined nitric acid oxidation method and polyaniline (PANI)-coated method were applied to modify the surface properties of short carbon fibers (SCF). The electrical and mechanical properties of acrylic coatings with 50 wt pct PANI-coated carbon fiber were investigated by using scanning electron microscope (SEM), UV-Vis spectrophotometer, four-probe method and the coaxial cable method. The results of the pH measurement and XPS (X-ray photoelectron spectroscopy) patterns showed that the oxygen functional groups, such as -OH and -COOH, were attached on the carbon fiber surfaces after oxidation treatment. The XPS analysis of PANl-coated oxidized SCF (PAOSCF) revealed that PANI may bond on the surface of oxidized SCF with chemical bonds. SEM images and surface roughness analyses showed that PANl-coated layer changed the surface morphology. Compared with SCF/acrylic coating, the surface resistivity of PAOSCF/acrylic coating decreased from17.1 to 5.3 Ω/sq and the shielding efficiency (SE) value increased from 1.54 to 23.3 dB.展开更多
Cathode activity plays an important role in the improvement of the microbial fuel cells on ocean floor(BMFCs). A comparison study between Rayon-based(CF-R) and PAN-based carbon fiber(CF-P) cathodes is conducted in the...Cathode activity plays an important role in the improvement of the microbial fuel cells on ocean floor(BMFCs). A comparison study between Rayon-based(CF-R) and PAN-based carbon fiber(CF-P) cathodes is conducted in the paper. The two carbon fibers were heat treated to improve cell performance(CF-R-H & CF-P-H), and were used to build a new BMFCs structure with a foamy carbon anode. The maximum power density was 112.42 mW m-for CF-R-H, followed by 66.6 mW m-2 for CF-R, 49.7 mW m-2 for CF-P-H and 21.6 mW m-2 for CF-P respectively. The higher specific area and deep groove make CF-R have a better power output than with CF-P. Meanwhile, heat treatment of carbon fiber can improve cell power, nearly two-fold higher than heat treatment of plain fiber. This improvement may be due to the quinones group formation to accelerate the reduction of oxygen and electron transfer on the fiber surface in the three phase boundary after heat treatment. Compared to PAN-based carbon fiber, Rayon-based carbon fiber would be preferentially selected as cathode in novel BMFCs design due to its high surface area, low cost and higher power. The comparison research is significant for cathode material selection and cell design.展开更多
The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-t reated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened ...The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-t reated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened body was discussed . The results show that the reinforcing effect is optimal as the aspect ratio is 375 and the additive amount is 0.3%(mass fraction). Under this condition,the c ompressive strength is increased by 55% (maximum 63.46 MPa),and the bending st rength is nearly increased by 100% (maximum 11.95 MPa),respectively. However,if the additive quantity and aspect ratio are too high,the effect of the carbon fibers is limited because it can not be dispersed uniformly in the hardened bod y. The biological evaluation indicates that the calcium phosphate cement reinfor ced by carbon fibers has good biocompatibility.展开更多
The composites obtained from carbon fibers have poor interlaminar shear strength beacuse ofthe few active polar groups on the carbon fiber surface and the weak bonding between the carbonfiber and the resin matrix. An ...The composites obtained from carbon fibers have poor interlaminar shear strength beacuse ofthe few active polar groups on the carbon fiber surface and the weak bonding between the carbonfiber and the resin matrix. An electrolysis study to increase the surface acidic groups of the carbonfiber was investigated in this paper. Experimental results showed that the surface acidic groups,tensile strength, peeling strength of the carbon fabrics increased under certain electrolytic condi-tions, but the breaking elongations decreased. When the electrolytic conditions were too strong,tensile strength and peeling strength dropped down. Electronic scanning micrographs showed theengraved surfaces of carbon fibers after electrolysis.展开更多
The semi-carbonization method is a kind of waste treatment to carbonize rice straw fiber at low semi-carbon temperature. The rice straw fiber is carbonized incompletely, which serves as building materials additive. Th...The semi-carbonization method is a kind of waste treatment to carbonize rice straw fiber at low semi-carbon temperature. The rice straw fiber is carbonized incompletely, which serves as building materials additive. The results reveal that the optimized carbonization condition is at 313 ℃ for 20-40 min with H3PO4 as activator. The structure of semi-carbonized straw fiber displays a large quantity of micropores, with which the wall thickness and the pore diameter are in the range of 1-4 μm, presenting the iodine sorption value of 1 320-1 470 mL/g and the methylene blue sorption value of 1 330-1 460 mg/g, respectively. Moreover, the acidic oxygen-containing groups impart the structure higher sorption of polar molecules. The semi-carbonized rice straw fiber with open and closed micro-mesopores demonstrates good hygroscopicity, implying the potential application as a functional additive in building materials.展开更多
Functionalized multi-walled carbon nanotubes( fMWNTs) were prepared with chitosan via controlled surface deposition and crosslinking process and scanning electron microscopy( SEM),Fourier translation infrared spectros...Functionalized multi-walled carbon nanotubes( fMWNTs) were prepared with chitosan via controlled surface deposition and crosslinking process and scanning electron microscopy( SEM),Fourier translation infrared spectroscopy( FT-IR) and Xray diffraction( XRD) are used to character properties. A novel high-density chitosan( HCS) was dissolved in f-MWNTs dispersed dilute acetic acid with a maximal concentration of 5. 8%. The hollow fibers can be made by extruding the solution into a dilute alkali solution through a wet-spinning process and the tensile properties of the materials were evaluated by universal tester. The surface property of fibers,pretreated by Helium( He) and the following grafted with gelatin was evaluated with X-ray photoelectron spectroscopy( XPS).As the hollow fibers were intended for neural tissue engineering,its suitability was evaluated in vitro using rat Schwann cells( RSC96) as model cells. The cells attachment,proliferation and morphology,were studied by various microscopic techniques. Based on the results,the gelatin grafted HCS / f-MWNTs hollow fibers could be used as a potential cell carrier in neural tissue engineering.展开更多
Prussian blue(PB) was used as catalyst to improve the extent of graphitization of polyacrylonitrile(PAN)-based carbon fibers.PB was deposited on carbon fibers by anodic electrodeposition and the thickness of PB coatin...Prussian blue(PB) was used as catalyst to improve the extent of graphitization of polyacrylonitrile(PAN)-based carbon fibers.PB was deposited on carbon fibers by anodic electrodeposition and the thickness of PB coating(PB content) was controlled by adjusting the electrodeposition time.PAN-based carbon fibers with PB coating were heat-treated and the extent of graphitization was measured by X-ray diffractometry and Raman spectroscopy.The results indicate that the extent of graphitization of PAN-based carbon fibers is enhanced in the presence of the coating.When the PB-coated carbon fibers were heat-treated at 1 900 ℃,interlayer spacing(d002) and crystallite size(Lc) reach 0.336 8 and 21.2 nm respectively.Contrarily,the values of d002 and Lc are 0.341 4 and 7.4 nm respectively when the bare carbon fibers were heat-treated at 2 800 ℃.Compared with the bare carbon fibers,PB can make the heat treatment temperature(HTT) drop more than 500 ℃ in order to reach the same extent of graphitization.Furthermore,the research results show that PB content also has a certain influence on the extent of graphitization at the same HTT.展开更多
基金Sponsored by the Scientific Research Foundation of Harbin Institute of Technology(Grant No. HIT. 2003.57)
文摘The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.
基金Project (2003AA302210) supported by the National High Technology Research and Development Program of Chinaproject(04JJ3083) supported by the Elite Foundation of Hunan Province+1 种基金 China project (030615) supported by the Innovation Pro
文摘Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.
基金National Natural Science Foundation of China(Nos.20576079,20776159)
文摘Catalysis and regeneration efficiency of granular activated carbon (GAC) and activated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange (MO) by the combined treatment can increase 22% (for GAC) and 24% (for ACF) respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.
文摘The development of surface acidity on rayon-based carbon fibers during mild electrochemical treatment was investigated. Conductimetric titration was the primary method used to investigate the functionalities on the carbon fiber surface. The acidity on the surface of the untreated carbon fiber was very low, while for the treated fibers, the acidity increased significantly.Moreover, with the treatment extent proceeded, the acidity on the fiber surface also increased. SEM analysis shows electrochemical treatment under intense treatment degree caused considerable etch on the fiber surface.Cavities and grooves can be observed on the surface via the SEM microphotograph. While in a more mild treatment, electrochemical treatment didn't cause great etch on the surface of the fiber.
基金Project supported by the National Natural Science Foundation of China (50275093)
文摘Carbon fibers (CF) were surface treated with air-oxidation and rare earths (RE), respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites was invest/gated. Experimental results revealed that RE was superior to air ox/dation in improving the tensile strength, elongation, and the tensile modulus of CF reinforced PTFE (CF/PTFE) composite. Compared to the untreated and air-oxidated CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under a given applied load and reciprocating sliding frequency. The RE treatment effectively improved the interfacial adhesion between CF and PTFE. With strong interfacial coupling, the carbon fibers carried most of the load, and direct contact and adhesion between PTFE and the counterpart were reduced, accordingly the friction and wear properties of the composite were improved.
文摘Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at temperatures between 450℃ and 900℃ in N2 artmosphere. Then, in a successive activation stage, the product carbonized at 600℃ was activated in steam at 450 - 900℃ for 30 min, and at 600℃for 5- 30 min. The other carbonization products were activated at 600 and 900℃ for 30 min respectively. The products activated at 900℃ were then activated at 450℃ for 30 min again. The starting material, carbonized products and all activation products were examined by FT-IR spectroscopy and some products were examined by X-ray photoelectron spectroscope (XPS). And the yields of the carbonized and activated products were calculated. By analysing these spectra, the amount of oxygen-containing functional groups of the activated products attained under various activation time, various activation temperature and various previous carbonization temperature was determined.
基金Founded by the National Natural Science Foundation of China(No.50333070)
文摘The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers u'ere characterized by the combiination use of densities, wide-angle X-ray diffraction (WAXD), X-ray photoelectron speetroscopy (XPS), elemental analysis ( EA ), Fourier traasform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM), etc.KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor.fiber, and transform C≡N groups to C≡N ones, meamchile , it can decreuse the crystal .size increuse the orientation index and the costallinity index, furthermore it can increuse the densities of modified PAN precursors and resuhing thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 31.25 % and an improvement in elongation of 77.78 % , but a decrease of 16. 52% in Young's modulus.
文摘Combined nitric acid oxidation method and polyaniline (PANI)-coated method were applied to modify the surface properties of short carbon fibers (SCF). The electrical and mechanical properties of acrylic coatings with 50 wt pct PANI-coated carbon fiber were investigated by using scanning electron microscope (SEM), UV-Vis spectrophotometer, four-probe method and the coaxial cable method. The results of the pH measurement and XPS (X-ray photoelectron spectroscopy) patterns showed that the oxygen functional groups, such as -OH and -COOH, were attached on the carbon fiber surfaces after oxidation treatment. The XPS analysis of PANl-coated oxidized SCF (PAOSCF) revealed that PANI may bond on the surface of oxidized SCF with chemical bonds. SEM images and surface roughness analyses showed that PANl-coated layer changed the surface morphology. Compared with SCF/acrylic coating, the surface resistivity of PAOSCF/acrylic coating decreased from17.1 to 5.3 Ω/sq and the shielding efficiency (SE) value increased from 1.54 to 23.3 dB.
基金support by the Key Project of Nature Science Fund of Shandong Province, China (ZR2011B Z008)the Special Fund of Marine Renewable Energy from China’s State Oceanic Administration (GHME 2011GD04)
文摘Cathode activity plays an important role in the improvement of the microbial fuel cells on ocean floor(BMFCs). A comparison study between Rayon-based(CF-R) and PAN-based carbon fiber(CF-P) cathodes is conducted in the paper. The two carbon fibers were heat treated to improve cell performance(CF-R-H & CF-P-H), and were used to build a new BMFCs structure with a foamy carbon anode. The maximum power density was 112.42 mW m-for CF-R-H, followed by 66.6 mW m-2 for CF-R, 49.7 mW m-2 for CF-P-H and 21.6 mW m-2 for CF-P respectively. The higher specific area and deep groove make CF-R have a better power output than with CF-P. Meanwhile, heat treatment of carbon fiber can improve cell power, nearly two-fold higher than heat treatment of plain fiber. This improvement may be due to the quinones group formation to accelerate the reduction of oxygen and electron transfer on the fiber surface in the three phase boundary after heat treatment. Compared to PAN-based carbon fiber, Rayon-based carbon fiber would be preferentially selected as cathode in novel BMFCs design due to its high surface area, low cost and higher power. The comparison research is significant for cathode material selection and cell design.
文摘The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-t reated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened body was discussed . The results show that the reinforcing effect is optimal as the aspect ratio is 375 and the additive amount is 0.3%(mass fraction). Under this condition,the c ompressive strength is increased by 55% (maximum 63.46 MPa),and the bending st rength is nearly increased by 100% (maximum 11.95 MPa),respectively. However,if the additive quantity and aspect ratio are too high,the effect of the carbon fibers is limited because it can not be dispersed uniformly in the hardened bod y. The biological evaluation indicates that the calcium phosphate cement reinfor ced by carbon fibers has good biocompatibility.
基金This paper was presented to Sino-Japan Symposium on Dyeing Finishing on October 7, 1990 at China Textile University
文摘The composites obtained from carbon fibers have poor interlaminar shear strength beacuse ofthe few active polar groups on the carbon fiber surface and the weak bonding between the carbonfiber and the resin matrix. An electrolysis study to increase the surface acidic groups of the carbonfiber was investigated in this paper. Experimental results showed that the surface acidic groups,tensile strength, peeling strength of the carbon fabrics increased under certain electrolytic condi-tions, but the breaking elongations decreased. When the electrolytic conditions were too strong,tensile strength and peeling strength dropped down. Electronic scanning micrographs showed theengraved surfaces of carbon fibers after electrolysis.
基金Funded by Key Projects of the National Science&Technology Pillar Program(No.2013BAC13B01)Independent Research of State Key Laboratory of Silicate Materials for Architectures
文摘The semi-carbonization method is a kind of waste treatment to carbonize rice straw fiber at low semi-carbon temperature. The rice straw fiber is carbonized incompletely, which serves as building materials additive. The results reveal that the optimized carbonization condition is at 313 ℃ for 20-40 min with H3PO4 as activator. The structure of semi-carbonized straw fiber displays a large quantity of micropores, with which the wall thickness and the pore diameter are in the range of 1-4 μm, presenting the iodine sorption value of 1 320-1 470 mL/g and the methylene blue sorption value of 1 330-1 460 mg/g, respectively. Moreover, the acidic oxygen-containing groups impart the structure higher sorption of polar molecules. The semi-carbonized rice straw fiber with open and closed micro-mesopores demonstrates good hygroscopicity, implying the potential application as a functional additive in building materials.
基金State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,China(No.LZ0902)Shanghai Science and Technical Committee,China(No.12DZ194030)
文摘Functionalized multi-walled carbon nanotubes( fMWNTs) were prepared with chitosan via controlled surface deposition and crosslinking process and scanning electron microscopy( SEM),Fourier translation infrared spectroscopy( FT-IR) and Xray diffraction( XRD) are used to character properties. A novel high-density chitosan( HCS) was dissolved in f-MWNTs dispersed dilute acetic acid with a maximal concentration of 5. 8%. The hollow fibers can be made by extruding the solution into a dilute alkali solution through a wet-spinning process and the tensile properties of the materials were evaluated by universal tester. The surface property of fibers,pretreated by Helium( He) and the following grafted with gelatin was evaluated with X-ray photoelectron spectroscopy( XPS).As the hollow fibers were intended for neural tissue engineering,its suitability was evaluated in vitro using rat Schwann cells( RSC96) as model cells. The cells attachment,proliferation and morphology,were studied by various microscopic techniques. Based on the results,the gelatin grafted HCS / f-MWNTs hollow fibers could be used as a potential cell carrier in neural tissue engineering.
基金Project(2006CB600903) supported by the National Basic Research Program of China
文摘Prussian blue(PB) was used as catalyst to improve the extent of graphitization of polyacrylonitrile(PAN)-based carbon fibers.PB was deposited on carbon fibers by anodic electrodeposition and the thickness of PB coating(PB content) was controlled by adjusting the electrodeposition time.PAN-based carbon fibers with PB coating were heat-treated and the extent of graphitization was measured by X-ray diffractometry and Raman spectroscopy.The results indicate that the extent of graphitization of PAN-based carbon fibers is enhanced in the presence of the coating.When the PB-coated carbon fibers were heat-treated at 1 900 ℃,interlayer spacing(d002) and crystallite size(Lc) reach 0.336 8 and 21.2 nm respectively.Contrarily,the values of d002 and Lc are 0.341 4 and 7.4 nm respectively when the bare carbon fibers were heat-treated at 2 800 ℃.Compared with the bare carbon fibers,PB can make the heat treatment temperature(HTT) drop more than 500 ℃ in order to reach the same extent of graphitization.Furthermore,the research results show that PB content also has a certain influence on the extent of graphitization at the same HTT.