Buckypapers(BPs)consist of carbon nanotube(CNT)membranes with good mechanical,thermal and elec-trical properties.We report the modification of CNT buckypapers by the surface deposition of a thin layer of ti-tanium dio...Buckypapers(BPs)consist of carbon nanotube(CNT)membranes with good mechanical,thermal and elec-trical properties.We report the modification of CNT buckypapers by the surface deposition of a thin layer of ti-tanium dioxide and their subsequent photocatalytic use for the removal of three wastewater pollutants:diclofenac(DF),carbofuran(CB)and methylene blue(MB).The results show the following decreases(RE)in the initial concentrations of these pollutants,REDF=99.5%,REMB=96%and RECB=90%after 90 min of exposure to UV-Vis radiation using~0.6 mg of photocatalyst.Experiments also showed that the degradation rate of diclofenac(k=0.1028 min^(−1))is respectively 3.5 and 6 times faster than the values for CB(k=0.0298 min^(−1))and MB(k=0.0174 min^(−1)),probably due to the easier bond cleavage in DF.UV-Vis irradiated solutions of these pollutants were then analyzed by mass spectrometry to identify the species formed during photocatalysis and suggest possible degradation paths for MB,DF,and CB.Data showed that the degradation of DF involves the formation of a photocyclization product through loss of HCl molecule,clearly consuming less energy than that needed for the opening of the central aromatic ring in MB,or the loss of the N-methyl amide functional group for CB.展开更多
A 3D nitrogen⁃doped graphene/multi⁃walled carbon nanotube(CS⁃GO⁃NCNT)crosslinked network mate⁃rial was successfully synthesized utilizing chitosan and melamine as carbon and nitrogen sources,concomitant with the incor...A 3D nitrogen⁃doped graphene/multi⁃walled carbon nanotube(CS⁃GO⁃NCNT)crosslinked network mate⁃rial was successfully synthesized utilizing chitosan and melamine as carbon and nitrogen sources,concomitant with the incorporation of multi⁃wall carbon nanotubes and employing freeze drying technology.The material amalgamates the merits of 1D/2D hybrid carbon materials,wherein 1D carbon nanotubes confer robustness and expedited elec⁃tron transport pathways,while 2D graphene sheets facilitate rapid ion migration.Furthermore,the introduction of nitrogen heteroatoms serves to furnish additional active sites for lithium storage.When served as an anode material for lithium⁃ion batteries,the CS⁃GO⁃NCNT electrode delivered a reversible capacity surpassing 500 mAh·g^(-1),mark⁃edly outperforming commercial graphite anodes.Even after 300 cycles at a high current density of 1 A·g^(-1),it remained a reversible capacity of up to 268 mAh·g^(-1).展开更多
Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanoc...Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.展开更多
Conductive polymer composites(CPCs)are widely used in the flexible strain sensors due to their simple fabrication process and controllable sensing properties.However,temperature has a significance impact on the strain...Conductive polymer composites(CPCs)are widely used in the flexible strain sensors due to their simple fabrication process and controllable sensing properties.However,temperature has a significance impact on the strain sensing performance of CPCs.In this paper,the strain sensing characteristics of MWCNTs/PDMS composites under temperature loading were systematically studied.It was found that the sensitivity decreased with the increase of temperature and the phenomenon of shoulder peak also decreased.Based on the theory of polymer mechanics,it was found that temperature could affect the conductive network by changing the motion degree of PDMS molecular chain,resulting in the change of sensing characteristics.Finally,a mathematical model of the resistance against loading condition(strain and temperature),associated with the force−electrical equivalent relationship of composites,was established to discuss the experimental results as well as the sensing mechanism.The results presented in this paper was believed helpful for the further application of strain sensors in different temperature conditions.展开更多
Molybdenum disilicide(MoSi_2) based composites with various contents of carbon nanotubes(CNTs) were fabricated by spark plasma sintering(SPS) in vacuum under a pressure of 25 MPa.The composites obtained under a sinter...Molybdenum disilicide(MoSi_2) based composites with various contents of carbon nanotubes(CNTs) were fabricated by spark plasma sintering(SPS) in vacuum under a pressure of 25 MPa.The composites obtained under a sintering temperature of 1500 °C and time of 10 min exhibited optimum mechanical properties at room temperature in terms of fracture toughness and transverse rupture strength.MoSi_2 based composite with 6.0% CNTs(volume fraction) had the highest fracture toughness,transverse rupture strength and hardness,which were improved by about 25.7%,51.5% and 24.4% respectively,as compared with pure MoSi_2.A Mo_(4.8)Si_3C_(0.6) phase was detected in CNTs/MoSi_2 composites by both X-ray diffraction(XRD) method and microstructure analysis with scanning electron microscopy(SEM).It is believed that the fine grains and well dispersed small Mo_(4.8)Si_3C_(0.6) particles had led to a higher hardness and strength of CNTs/MoSi_2 composites because of their particle pullout,crack deflection and micro-bridging effects.展开更多
基金MIUR,Italian Ministry for University and Research(EX-60%/2024)。
文摘Buckypapers(BPs)consist of carbon nanotube(CNT)membranes with good mechanical,thermal and elec-trical properties.We report the modification of CNT buckypapers by the surface deposition of a thin layer of ti-tanium dioxide and their subsequent photocatalytic use for the removal of three wastewater pollutants:diclofenac(DF),carbofuran(CB)and methylene blue(MB).The results show the following decreases(RE)in the initial concentrations of these pollutants,REDF=99.5%,REMB=96%and RECB=90%after 90 min of exposure to UV-Vis radiation using~0.6 mg of photocatalyst.Experiments also showed that the degradation rate of diclofenac(k=0.1028 min^(−1))is respectively 3.5 and 6 times faster than the values for CB(k=0.0298 min^(−1))and MB(k=0.0174 min^(−1)),probably due to the easier bond cleavage in DF.UV-Vis irradiated solutions of these pollutants were then analyzed by mass spectrometry to identify the species formed during photocatalysis and suggest possible degradation paths for MB,DF,and CB.Data showed that the degradation of DF involves the formation of a photocyclization product through loss of HCl molecule,clearly consuming less energy than that needed for the opening of the central aromatic ring in MB,or the loss of the N-methyl amide functional group for CB.
文摘A 3D nitrogen⁃doped graphene/multi⁃walled carbon nanotube(CS⁃GO⁃NCNT)crosslinked network mate⁃rial was successfully synthesized utilizing chitosan and melamine as carbon and nitrogen sources,concomitant with the incorporation of multi⁃wall carbon nanotubes and employing freeze drying technology.The material amalgamates the merits of 1D/2D hybrid carbon materials,wherein 1D carbon nanotubes confer robustness and expedited elec⁃tron transport pathways,while 2D graphene sheets facilitate rapid ion migration.Furthermore,the introduction of nitrogen heteroatoms serves to furnish additional active sites for lithium storage.When served as an anode material for lithium⁃ion batteries,the CS⁃GO⁃NCNT electrode delivered a reversible capacity surpassing 500 mAh·g^(-1),mark⁃edly outperforming commercial graphite anodes.Even after 300 cycles at a high current density of 1 A·g^(-1),it remained a reversible capacity of up to 268 mAh·g^(-1).
文摘Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.
基金Project(ZZYJKT2019-05)supported by State Key Laboratory of High Performance Complex Manufacturing,ChinaProject(51605497)supported by the National Natural Science Foundation of ChinaProject(2020CX05)supported by Innovation-Driven Project of Central South University,China。
文摘Conductive polymer composites(CPCs)are widely used in the flexible strain sensors due to their simple fabrication process and controllable sensing properties.However,temperature has a significance impact on the strain sensing performance of CPCs.In this paper,the strain sensing characteristics of MWCNTs/PDMS composites under temperature loading were systematically studied.It was found that the sensitivity decreased with the increase of temperature and the phenomenon of shoulder peak also decreased.Based on the theory of polymer mechanics,it was found that temperature could affect the conductive network by changing the motion degree of PDMS molecular chain,resulting in the change of sensing characteristics.Finally,a mathematical model of the resistance against loading condition(strain and temperature),associated with the force−electrical equivalent relationship of composites,was established to discuss the experimental results as well as the sensing mechanism.The results presented in this paper was believed helpful for the further application of strain sensors in different temperature conditions.
基金Project(51371155)supported by the National Natural Science Foundation of ChinaProject(2014H0046)supported by the Key Science and Technology Project of Fujian Province,China+2 种基金Project(3502Z20143036)supported by the Scientific Research Fund of Xiamen,ChinaProject(JB13149)supported by the Education Department Science and Technology Project of Fujian Province,ChinaProject(2012D131)supported by the Natural Science Foundation Guidance Project of Fujian Province,China
文摘Molybdenum disilicide(MoSi_2) based composites with various contents of carbon nanotubes(CNTs) were fabricated by spark plasma sintering(SPS) in vacuum under a pressure of 25 MPa.The composites obtained under a sintering temperature of 1500 °C and time of 10 min exhibited optimum mechanical properties at room temperature in terms of fracture toughness and transverse rupture strength.MoSi_2 based composite with 6.0% CNTs(volume fraction) had the highest fracture toughness,transverse rupture strength and hardness,which were improved by about 25.7%,51.5% and 24.4% respectively,as compared with pure MoSi_2.A Mo_(4.8)Si_3C_(0.6) phase was detected in CNTs/MoSi_2 composites by both X-ray diffraction(XRD) method and microstructure analysis with scanning electron microscopy(SEM).It is believed that the fine grains and well dispersed small Mo_(4.8)Si_3C_(0.6) particles had led to a higher hardness and strength of CNTs/MoSi_2 composites because of their particle pullout,crack deflection and micro-bridging effects.
