The Lonversion of polyacrylonitrile(PAN)fibre to carbon fibre consists of an oxidative stabili-zation process in which the PAN fibre is heated between 200-300℃ in air to give a thermally co-herent structure.The struc...The Lonversion of polyacrylonitrile(PAN)fibre to carbon fibre consists of an oxidative stabili-zation process in which the PAN fibre is heated between 200-300℃ in air to give a thermally co-herent structure.The structural changes of PAN fibres during stabilization have been investigatedusing Fourier Transform Infrared Spectroscopy(FTIR)and Differential Scanning Calorimetry(DSC).An attempt has also been made to follow the conversion of the structure using Ramanspectroscopy as a complementary technique.The FTIR spectra of the fibres subjected to variousdegree of heat treatment show a continuous decrease in nitrile absorption and a simultaneous in-crease in intensity of the C=N and/or C=C bands as the stabilization proceeds.A conversion ra-tio(CR)is defined as the intensity of the C=N and/or C=C bands relative to that of the nitrilegroups.The exotherm present in the DSC experiments was observed to weaken progressively dur-ing the stabilization process.It is confirmed that the original PAN structure is dissipating and thenew ladder polymer is being formed.展开更多
Polyacrylonitrile preoxided fibre PANOF is an intermediate in carbon fibre preparation. Thequality of PANOF is closely related to the property and structure of carbon fibre. In this paper, thermal mechanical analysis(...Polyacrylonitrile preoxided fibre PANOF is an intermediate in carbon fibre preparation. Thequality of PANOF is closely related to the property and structure of carbon fibre. In this paper, thermal mechanical analysis(TMA), thermogravimetric analysis(TGA), swell-ing differential scanning calorimetry(SDSC)and X-ray photoelectron spectroscopy(XPS)wereused to study the increase in tenacity of PANOF from the precursor treated with cuprous salt It has been discovered that the cuprous salt reacts strongly with the uncyclized CN of PANOF,resulting in an increase in the tenacity of PANOF by 30%. The results shwo that the cause of thistenacity improvement is the formation of coordinated complex. Cu^+is the central ion, and PANOFthe ligand. It is due to the coordinate bond that the network structure is formed from uncyclizedCN of PANOF. Therefore the tenacity of PANOF is remarkably increased.展开更多
A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4 electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbo...A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4 electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbon fibers in a uniformly dispersed Mo-B sol.The as-treated carbon fibers were then graphitized at 2 400 ℃ for 2 h.The structural changes were characterized by X-ray diffractometry(XRD),Raman spectroscopy,scanning electron microscopy(SEM) and high-resolution transmission electronic microscopy(HRTEM).The results show that much better graphitization can be achieved in the presence of Mo-B,with an interlayer spacing(d002) of 0.335 8 nm and a crystalline size(Lc) of 28 nm.展开更多
The method of preparing the multi-walled carbon nanotubes (MWNTs)-polyacrylonitriIe (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discu...The method of preparing the multi-walled carbon nanotubes (MWNTs)-polyacrylonitriIe (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discussed. The results show that the degrees of MWNTs dispersion in the polymer matrix have much effect on the mechanical properties.展开更多
The dynamic property of polyacrylonitrile (PAN) muscles was tested. The test results can help us to master PAN muscles' mechanical and chemical behaviors, which are indispensable for us to build dynamic model for ...The dynamic property of polyacrylonitrile (PAN) muscles was tested. The test results can help us to master PAN muscles' mechanical and chemical behaviors, which are indispensable for us to build dynamic model for the artificial muscle. Furthermore, here we provide an important experimental way to study gel muscles.展开更多
Supercapacitors have huge potential applications in the field of wearable electronic devices,such as flexible displays,flexible biosensors and implantable multimedia devices,due to their high-power density,fast charge...Supercapacitors have huge potential applications in the field of wearable electronic devices,such as flexible displays,flexible biosensors and implantable multimedia devices,due to their high-power density,fast charge-discharge rates,long cycling life,and relatively simple configuration.In this paper,we demonstrated hierarchically porous and continuous reduced graphene oxide-polyacrylonitrile@polyacrylonitrile(rGO-PAN@PAN)coaxial fibers with certain strength,excellent electrochemical performance through coaxial wet spinning and thermal reduction.Coaxial fibers are carbonized at high temperature and have a graded porous structure with a conductivity of 1703 S/m.The areal specific capacitance of the supercapacitor assembled by polyvinyl alcohol/sulfuric acid(PVA/H_(2)SO_(4))gel electrolyte is 11.56 mF/cm^(2),and its energy density reaches 0.21 mW·h/cm3,showing good electrochemical performance.Graphene-based coaxial fibers prepared by wet spinning have a great prospect of application in electronic devices due to their excellent properties.展开更多
Plantago psyllium mucilage(PSY),an anionic natural polysaccharide consisting of pentosan and uronic acidobtained from the seeds of Plantago psyllium(Plantago family),was grafted with acrylonitrile(AN).Graft copolymers...Plantago psyllium mucilage(PSY),an anionic natural polysaccharide consisting of pentosan and uronic acidobtained from the seeds of Plantago psyllium(Plantago family),was grafted with acrylonitrile(AN).Graft copolymers wereprepared by ceric ion initiated solution polymerization technique and were characterized by FT-IR spectroscopy,scanningelectron microscopy and differential scanning calorimetry.These copolymers are good flocculating agents for removal ofsuspended(SS)and total dissolved solid(TDS)in sewage wastewater treatment.The effects of copolymer dose,pH andcontact time on flocculation capacity of one selected copolymer sample were studied by jar test method.The suitable pHrange for maximum solid removal was 7.0 to 9.2 and the optimum copolymer dose was 1.2 mg/L.The overall process forsolid removal took 4 h.X-ray diffraction(XRD)patterns of grafted copolymer,PSY grafted polyacrylonitrile(PSY-g-PAN)and solid waste,before and after treatment are used to suggest the interaction of the solid waste with PSY-g-PAN copolymer.展开更多
文摘The Lonversion of polyacrylonitrile(PAN)fibre to carbon fibre consists of an oxidative stabili-zation process in which the PAN fibre is heated between 200-300℃ in air to give a thermally co-herent structure.The structural changes of PAN fibres during stabilization have been investigatedusing Fourier Transform Infrared Spectroscopy(FTIR)and Differential Scanning Calorimetry(DSC).An attempt has also been made to follow the conversion of the structure using Ramanspectroscopy as a complementary technique.The FTIR spectra of the fibres subjected to variousdegree of heat treatment show a continuous decrease in nitrile absorption and a simultaneous in-crease in intensity of the C=N and/or C=C bands as the stabilization proceeds.A conversion ra-tio(CR)is defined as the intensity of the C=N and/or C=C bands relative to that of the nitrilegroups.The exotherm present in the DSC experiments was observed to weaken progressively dur-ing the stabilization process.It is confirmed that the original PAN structure is dissipating and thenew ladder polymer is being formed.
文摘Polyacrylonitrile preoxided fibre PANOF is an intermediate in carbon fibre preparation. Thequality of PANOF is closely related to the property and structure of carbon fibre. In this paper, thermal mechanical analysis(TMA), thermogravimetric analysis(TGA), swell-ing differential scanning calorimetry(SDSC)and X-ray photoelectron spectroscopy(XPS)wereused to study the increase in tenacity of PANOF from the precursor treated with cuprous salt It has been discovered that the cuprous salt reacts strongly with the uncyclized CN of PANOF,resulting in an increase in the tenacity of PANOF by 30%. The results shwo that the cause of thistenacity improvement is the formation of coordinated complex. Cu^+is the central ion, and PANOFthe ligand. It is due to the coordinate bond that the network structure is formed from uncyclizedCN of PANOF. Therefore the tenacity of PANOF is remarkably increased.
基金Project(2006CB600903) supported by the National Basic Research Program of China
文摘A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4 electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbon fibers in a uniformly dispersed Mo-B sol.The as-treated carbon fibers were then graphitized at 2 400 ℃ for 2 h.The structural changes were characterized by X-ray diffractometry(XRD),Raman spectroscopy,scanning electron microscopy(SEM) and high-resolution transmission electronic microscopy(HRTEM).The results show that much better graphitization can be achieved in the presence of Mo-B,with an interlayer spacing(d002) of 0.335 8 nm and a crystalline size(Lc) of 28 nm.
文摘The method of preparing the multi-walled carbon nanotubes (MWNTs)-polyacrylonitriIe (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discussed. The results show that the degrees of MWNTs dispersion in the polymer matrix have much effect on the mechanical properties.
文摘The dynamic property of polyacrylonitrile (PAN) muscles was tested. The test results can help us to master PAN muscles' mechanical and chemical behaviors, which are indispensable for us to build dynamic model for the artificial muscle. Furthermore, here we provide an important experimental way to study gel muscles.
基金National Natural Science Foundation of China(No.51876115)China Postdoctoral Science Foundation(No.2019M661324)。
文摘Supercapacitors have huge potential applications in the field of wearable electronic devices,such as flexible displays,flexible biosensors and implantable multimedia devices,due to their high-power density,fast charge-discharge rates,long cycling life,and relatively simple configuration.In this paper,we demonstrated hierarchically porous and continuous reduced graphene oxide-polyacrylonitrile@polyacrylonitrile(rGO-PAN@PAN)coaxial fibers with certain strength,excellent electrochemical performance through coaxial wet spinning and thermal reduction.Coaxial fibers are carbonized at high temperature and have a graded porous structure with a conductivity of 1703 S/m.The areal specific capacitance of the supercapacitor assembled by polyvinyl alcohol/sulfuric acid(PVA/H_(2)SO_(4))gel electrolyte is 11.56 mF/cm^(2),and its energy density reaches 0.21 mW·h/cm3,showing good electrochemical performance.Graphene-based coaxial fibers prepared by wet spinning have a great prospect of application in electronic devices due to their excellent properties.
基金This work was financially support by Council of ScientificIndustrial Research,India
文摘Plantago psyllium mucilage(PSY),an anionic natural polysaccharide consisting of pentosan and uronic acidobtained from the seeds of Plantago psyllium(Plantago family),was grafted with acrylonitrile(AN).Graft copolymers wereprepared by ceric ion initiated solution polymerization technique and were characterized by FT-IR spectroscopy,scanningelectron microscopy and differential scanning calorimetry.These copolymers are good flocculating agents for removal ofsuspended(SS)and total dissolved solid(TDS)in sewage wastewater treatment.The effects of copolymer dose,pH andcontact time on flocculation capacity of one selected copolymer sample were studied by jar test method.The suitable pHrange for maximum solid removal was 7.0 to 9.2 and the optimum copolymer dose was 1.2 mg/L.The overall process forsolid removal took 4 h.X-ray diffraction(XRD)patterns of grafted copolymer,PSY grafted polyacrylonitrile(PSY-g-PAN)and solid waste,before and after treatment are used to suggest the interaction of the solid waste with PSY-g-PAN copolymer.
