Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin...Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin-curing of carbon fiber/epoxy resin composite that was composed of discontinuous carbon fibers of 130 μm or 3 mm were investigated. The mechanical properties of carbon fiber/epoxy resin composite cured by microwave irradiation for 20 min at 120°C were similar to ones of the sample prepared by conventional oven for 180 min at 120°C. Microwavecured carbon fiber/epoxy resin composite had higher glass transition temperature than the one prepared by conventional oven. The relation between curing time and flexural modulus indicated that the curing velocity of microwave-irradiated carbon fiber/epoxy resin composite was 9 times faster than the one prepared by conventional oven. Furthermore, activation energies for resincuring reaction on microwave and conventional-cured carbon fiber/epoxy resin composite were estimated. The resin-curing reaction in carbon fiber/epoxy resin composite was promoted by microwave irradiation.展开更多
A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybr...A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.展开更多
Phenolic resins were employed to prepare electrospun porous carbon nanofibers with a high specific surface area as free-standing electrodes for high-performance supercapacitors.However,the sustainable development of c...Phenolic resins were employed to prepare electrospun porous carbon nanofibers with a high specific surface area as free-standing electrodes for high-performance supercapacitors.However,the sustainable development of conventional phenolic resin has been challenged by petroleum-based phenol and formaldehyde.Lignin with abundant phenolic hydroxyl groups is the main non-petroleum resource that can provide renewable aromatic compounds.Hence,lignin,phenol,and furfural were used to synthesize bio-based phenolic resins,and the activated carbon nanofibers were obtained by electrospinning and one-step carbonization activation.Fourier transform infrared and differential scanning calorimetry were used to characterize the structural and thermal properties.The results reveal that the apparent activation energy of the curing reaction is 89.21 kJ·mol–1 and the reaction order is 0.78.The activated carbon nanofibers show a uniform diameter,specific surface area up to 1100 m^(2)·g^(-1),and total pore volume of 0.62 cm^(3)·g^(-1).The electrode demonstrates a specific capacitance of 238 F·g^(-1)(0.1 A·g^(-1))and good rate capability.The symmetric supercapacitor yields a high energy density of 26.39 W·h·kg^(-1)at 100 W·kg^(-1)and an excellent capacitance retention of 98%after 10000 cycles.These results confirm that the activated carbon nanofiber from bio-based phenolic resins can be applied as electrode material for high-performance supercapacitors.展开更多
Using porous diatomite ceramic as carrier and phenolic resin as carbon precursor, the activated carbon functional ceramic with the activated carbon fixed into porous ceramic was prepared by the impregnation load pheno...Using porous diatomite ceramic as carrier and phenolic resin as carbon precursor, the activated carbon functional ceramic with the activated carbon fixed into porous ceramic was prepared by the impregnation load phenolic resin, carbonization and activation isolated air. The influences of impregnation, curing, carbonization, activation etc. on the material property were discussed. The iodine value, SEM, elemental analyzer, BET and spectrum analysis chart were used to characterize the microstructures and performance of material at different conditions. The results showed that the excellent comprehensive property of activated carbon functional ceramic was gained when it adsorbed phenolic resin in 4 h under vacuum condition at curing temperature of 150 ℃ for 0.5 h and carbonization temperature of 600 ℃ for 1.0 h, and then put into 25wt% KOH for 4.0 h at activation temperature of 700 ℃ for 1.5 h. The iodine value is 176.9 mg/g, the specific surface area can reach 86.3 m2/g and the yield of carbonization is 50.48%.展开更多
Activated carbon was fabricated by using oil asphalt as carbon source, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-di...Activated carbon was fabricated by using oil asphalt as carbon source, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5-9.0 nm. Supercapacitors based on the sample AC （Activated carbon） have low ESR and excellent power property.展开更多
Radioactive iodine element mainly in CH3I is a key fission product of concern in the nuclear fuel cycle,which directly threat-ens human health if released into the environment.Effective capture of the I element is ess...Radioactive iodine element mainly in CH3I is a key fission product of concern in the nuclear fuel cycle,which directly threat-ens human health if released into the environment.Effective capture of the I element is essential for human health protection.The iodine filter,consisting of an activated carbon inner core and cotton filter,is the most common radioactive iodine pro-tection product.Currently,the activated carbon inside the iodine filter suffers from the weak adsorption efficiency and high cost.Herein,a process based on a strong alkali activation method was developed to significantly improve iodine absorption and reduce the cost.A series of flexible porous carbon fibers with a high specific surface area(up to about 1,500~2,200 m^(2)/g)were prepared by carbonation of the phenolic resin fibers(PF,prepared through melt spinning and crosslink)followed by activation via KOH treatment.Meanwhile,the nitrogen-doped sp^(2)-heterogeneous carbon atoms were prepared by add-ing nitrogen sources such as urea which led to a high surface area nano-porous fibers with an average pore size of~2.4 nm.The nitrogen-doped porous carbon fibers exhibit very high adsorption for liquid iodine and iodine vapor.The liquid iodine adsorption capacity of nitrogen-doped porous carbon NDAC-4 prepared under 800°C reaches 2,120 mg/g,which is 2.1 times higher than that of the commercial iodine filter,and for iodine vapor the capacity can reach 5,330 mg/g.Meanwhile,the CH_(3)I adsorption capacity is 510 mg/g,which is 3.4 times higher than that of commercial unmodified viscose fibers and has greater stability and circularity.Importantly,the research has met the requirements of industrial production,and the fabrication of phenolic-fibers-based protection equipment can be widely used in the nuclear radiation industry.展开更多
Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the sample...Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that： Supercapacitors based on the sample AC-3 have low Equivalent series resistanceb （ESR） and excellent power property.展开更多
Activated carbon （AC） was fabricated by using phenolic resin as carbon source, silica gel as inorganic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cy...Activated carbon （AC） was fabricated by using phenolic resin as carbon source, silica gel as inorganic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5 9.0 nm. Supercapacitors based on the sample AC-3 have low equivalent series resistanceb （ESR） and excellent power property.展开更多
文摘Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin-curing of carbon fiber/epoxy resin composite that was composed of discontinuous carbon fibers of 130 μm or 3 mm were investigated. The mechanical properties of carbon fiber/epoxy resin composite cured by microwave irradiation for 20 min at 120°C were similar to ones of the sample prepared by conventional oven for 180 min at 120°C. Microwavecured carbon fiber/epoxy resin composite had higher glass transition temperature than the one prepared by conventional oven. The relation between curing time and flexural modulus indicated that the curing velocity of microwave-irradiated carbon fiber/epoxy resin composite was 9 times faster than the one prepared by conventional oven. Furthermore, activation energies for resincuring reaction on microwave and conventional-cured carbon fiber/epoxy resin composite were estimated. The resin-curing reaction in carbon fiber/epoxy resin composite was promoted by microwave irradiation.
文摘A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.
基金supported by the National Natural Science Foundation of China(Grant Nos.21908204,52074244)the Henan Provincial Key Research and Development Program(Grant No.192102310202).
文摘Phenolic resins were employed to prepare electrospun porous carbon nanofibers with a high specific surface area as free-standing electrodes for high-performance supercapacitors.However,the sustainable development of conventional phenolic resin has been challenged by petroleum-based phenol and formaldehyde.Lignin with abundant phenolic hydroxyl groups is the main non-petroleum resource that can provide renewable aromatic compounds.Hence,lignin,phenol,and furfural were used to synthesize bio-based phenolic resins,and the activated carbon nanofibers were obtained by electrospinning and one-step carbonization activation.Fourier transform infrared and differential scanning calorimetry were used to characterize the structural and thermal properties.The results reveal that the apparent activation energy of the curing reaction is 89.21 kJ·mol–1 and the reaction order is 0.78.The activated carbon nanofibers show a uniform diameter,specific surface area up to 1100 m^(2)·g^(-1),and total pore volume of 0.62 cm^(3)·g^(-1).The electrode demonstrates a specific capacitance of 238 F·g^(-1)(0.1 A·g^(-1))and good rate capability.The symmetric supercapacitor yields a high energy density of 26.39 W·h·kg^(-1)at 100 W·kg^(-1)and an excellent capacitance retention of 98%after 10000 cycles.These results confirm that the activated carbon nanofiber from bio-based phenolic resins can be applied as electrode material for high-performance supercapacitors.
基金Sponsored by the 2007 Fujian University and College New Century Excellent Talent Support Program (No. XSJRC2007-17)Natural Science Foundation of Fujian Province (No. 2010J01279)
文摘Using porous diatomite ceramic as carrier and phenolic resin as carbon precursor, the activated carbon functional ceramic with the activated carbon fixed into porous ceramic was prepared by the impregnation load phenolic resin, carbonization and activation isolated air. The influences of impregnation, curing, carbonization, activation etc. on the material property were discussed. The iodine value, SEM, elemental analyzer, BET and spectrum analysis chart were used to characterize the microstructures and performance of material at different conditions. The results showed that the excellent comprehensive property of activated carbon functional ceramic was gained when it adsorbed phenolic resin in 4 h under vacuum condition at curing temperature of 150 ℃ for 0.5 h and carbonization temperature of 600 ℃ for 1.0 h, and then put into 25wt% KOH for 4.0 h at activation temperature of 700 ℃ for 1.5 h. The iodine value is 176.9 mg/g, the specific surface area can reach 86.3 m2/g and the yield of carbonization is 50.48%.
文摘Activated carbon was fabricated by using oil asphalt as carbon source, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5-9.0 nm. Supercapacitors based on the sample AC （Activated carbon） have low ESR and excellent power property.
基金The authors acknowledge the financial support from Key-Area Research and Development Program of Guangdong Province(2019B010941001)Science and Technology Program of Shenzhen(JSGG20200924171000001)+3 种基金Shenzhen Science and Technology Innovation Committee(no.JCYJ20200109140812302)2019 Dong guan Postgraduate Joint Training(Practice)Workstation Project(Grant No.2019707126017)Department of Science and Technology of Guangdong Province(2017ZT07Z479)Atomic-resolution high-angle annular darkfield(HAADF)-scanning TEM(STEM)was carried out on microscope Titan Themis G260-300 maintained by Southern University of Science and Technology Core Research facilities.
文摘Radioactive iodine element mainly in CH3I is a key fission product of concern in the nuclear fuel cycle,which directly threat-ens human health if released into the environment.Effective capture of the I element is essential for human health protection.The iodine filter,consisting of an activated carbon inner core and cotton filter,is the most common radioactive iodine pro-tection product.Currently,the activated carbon inside the iodine filter suffers from the weak adsorption efficiency and high cost.Herein,a process based on a strong alkali activation method was developed to significantly improve iodine absorption and reduce the cost.A series of flexible porous carbon fibers with a high specific surface area(up to about 1,500~2,200 m^(2)/g)were prepared by carbonation of the phenolic resin fibers(PF,prepared through melt spinning and crosslink)followed by activation via KOH treatment.Meanwhile,the nitrogen-doped sp^(2)-heterogeneous carbon atoms were prepared by add-ing nitrogen sources such as urea which led to a high surface area nano-porous fibers with an average pore size of~2.4 nm.The nitrogen-doped porous carbon fibers exhibit very high adsorption for liquid iodine and iodine vapor.The liquid iodine adsorption capacity of nitrogen-doped porous carbon NDAC-4 prepared under 800°C reaches 2,120 mg/g,which is 2.1 times higher than that of the commercial iodine filter,and for iodine vapor the capacity can reach 5,330 mg/g.Meanwhile,the CH_(3)I adsorption capacity is 510 mg/g,which is 3.4 times higher than that of commercial unmodified viscose fibers and has greater stability and circularity.Importantly,the research has met the requirements of industrial production,and the fabrication of phenolic-fibers-based protection equipment can be widely used in the nuclear radiation industry.
文摘Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that： Supercapacitors based on the sample AC-3 have low Equivalent series resistanceb （ESR） and excellent power property.
文摘Activated carbon （AC） was fabricated by using phenolic resin as carbon source, silica gel as inorganic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5 9.0 nm. Supercapacitors based on the sample AC-3 have low equivalent series resistanceb （ESR） and excellent power property.
