This study focuses on the nanostructure and nanostructural changes of novel graphene/poly（lactic acid） （PLA）/ poly（butylene carbonate） （PBC） nanofibers via electrospinning, which are characterized by different...This study focuses on the nanostructure and nanostructural changes of novel graphene/poly（lactic acid） （PLA）/ poly（butylene carbonate） （PBC） nanofibers via electrospinning, which are characterized by differential scanning calorimetry （DSC）, scanning electron microscopy （SEM）, tensile test and in situ small angle x-ray scattering. DSC indicates that the endothermic peak at 295℃ of pure PLA/PBC nanofibers shifted from 317℃ to lower 290℃ with the increasing graphene content. SEM observations reveal a fine dispersion of graphene in the nanofiber matrices. The graphene/PLA/PBC nanofiSers exhibit good improvements in mechanical property. The tensile strength of nanofibers increases with the addition of 0.01 g graphene but reduces with further addition of 0.04g graphene. The scattering intensities increase dramatically when the strain levels are higher than the yield point due to the nucleation and growth of nanovoids or crystals. However, the increasing content of graphene in the PLA/PBC matrix provokes a strong restriction to the deformation-induced crystals.展开更多
The nanostructures during the tensile drawing of poly（ethylene terephthalate） （PET）/hexadecyl triphenyl phospho- nium bromide montmorillonite （PMMT） nanocomposites were studied by in-situ small angle x-ray scatt...The nanostructures during the tensile drawing of poly（ethylene terephthalate） （PET）/hexadecyl triphenyl phospho- nium bromide montmorillonite （PMMT） nanocomposites were studied by in-situ small angle x-ray scattering. For strain higher than the yield point, the scattering intensity increases dramatically due to the nucleation and growth of nanovoids and crystals. The nanovoids and crystals are significantly dependent on the heating temperature. The effective filling of PMMT in the PET matrix provokes a strong restriction to the long period. The peaks of the long period disappear gradually with the deformation strain increasing from 0% to 34%.展开更多
Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor ...Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy density.In this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom source.Nanocellulose(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing density.Subsequently,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 cycles.Besides,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11405199,U1432104,U1332107,10835008,11305198 and U1232203the Project of Education Department of Heilongjiang Province under Grant Nos 135109211 and 135109214
文摘This study focuses on the nanostructure and nanostructural changes of novel graphene/poly（lactic acid） （PLA）/ poly（butylene carbonate） （PBC） nanofibers via electrospinning, which are characterized by differential scanning calorimetry （DSC）, scanning electron microscopy （SEM）, tensile test and in situ small angle x-ray scattering. DSC indicates that the endothermic peak at 295℃ of pure PLA/PBC nanofibers shifted from 317℃ to lower 290℃ with the increasing graphene content. SEM observations reveal a fine dispersion of graphene in the nanofiber matrices. The graphene/PLA/PBC nanofiSers exhibit good improvements in mechanical property. The tensile strength of nanofibers increases with the addition of 0.01 g graphene but reduces with further addition of 0.04g graphene. The scattering intensities increase dramatically when the strain levels are higher than the yield point due to the nucleation and growth of nanovoids or crystals. However, the increasing content of graphene in the PLA/PBC matrix provokes a strong restriction to the deformation-induced crystals.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1232203,U1432104,U1332107,11305198,and 11405199)the Program for Young Teachers Scientific Research in Qiqihar University,China(Grant No.2012k-Z02)the Natural Science Foundation of Heilongjiang Province,China(Grant No.E201259)
文摘The nanostructures during the tensile drawing of poly（ethylene terephthalate） （PET）/hexadecyl triphenyl phospho- nium bromide montmorillonite （PMMT） nanocomposites were studied by in-situ small angle x-ray scattering. For strain higher than the yield point, the scattering intensity increases dramatically due to the nucleation and growth of nanovoids and crystals. The nanovoids and crystals are significantly dependent on the heating temperature. The effective filling of PMMT in the PET matrix provokes a strong restriction to the long period. The peaks of the long period disappear gradually with the deformation strain increasing from 0% to 34%.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China(No.52072191)Heilongjiang Provincial Natural Science Foundation of China(No.LH2020E126)the Fundamental Research Fund of Heilongjiang Provincial University(No.135509204).
文摘Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy density.In this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom source.Nanocellulose(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing density.Subsequently,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 cycles.Besides,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.
