Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy...Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy）,XRD（X-ray diffraction）and TGA（thermogravimetric analysis）.Transmission electron microscope images of the PVP/Fe3O4 nanofibers show that the Fe3O4 nanoparticles with a diameter about 10.5 nm were dispersed in PVP fiber matrices.The XRD results show that the particles in PVP fibers were indeed Fe3O4 nanoparticles.And the TGA of PVP/Fe3O4 nanofibers show that the content of Fe3O4 nanoparticles in the composite was about 36.8%（mass fraction）.The PVP/Fe3O4 nanofibers were found to be superparamagnetic.The hysteresis loop at room temperature showed a high saturated magnetization（M s=15.1 emu/g）and a low coercive force（μ c=0）.展开更多
Ultrafine polystyrene(PS) nanofibers were prepared via the simple electrospinning technique.Uniform and smooth PS nanofibers were obtained with adding the organic salt BTEAC into the PS solutions and adjusting the con...Ultrafine polystyrene(PS) nanofibers were prepared via the simple electrospinning technique.Uniform and smooth PS nanofibers were obtained with adding the organic salt BTEAC into the PS solutions and adjusting the concentration of PS solutions.Without the addition of BTEAC,PS fibers with few beads could be achieved with a PS mass fraction of 20%,and the average diameter of the fibers was 280 nm.The addition of the organic salt BTEAC could lower the critical concentration for the fiber formation and reduce the amount of beads on the fibers.Unltrafine PS fibers without any beads were obtained with a PS mass fraction of 10% and an ionic salt mass fraction of 0.5%.The average diameter of the fiber was successfully reduced to 100 nm.The influence of the salt concentration on the morphology and diameter of the PS fibers was also investigated.The viscosity and surface tension changes were measured with changing the concentration of BTEAC.The results show that the changes were so small that these factors could be ignored.It was suggested that variations of the fiber diameter should be mainly resulted from the changes of conductivity and conformation of the polymer chain as the concentration of BTEAC is varied.展开更多
Composites of high molecular weight polyaniline with various weight percentages of multi-walled carbon nanotubes(MWNTs) were synthesized in the presence of selected dissolved neutral salt by in situ polymerization.The...Composites of high molecular weight polyaniline with various weight percentages of multi-walled carbon nanotubes(MWNTs) were synthesized in the presence of selected dissolved neutral salt by in situ polymerization.The composites were characterized by means of SEM,FTIR and XRD,four-point probe conductivity measurements.The results indicate that the composites possess very different morphologies,high electrical conductivities and good crystallization compared with high molecular weight polyaniline.展开更多
Silver nanoparticles were prepared in the channels of mesoporous silica SBA-15 through silver mirror reaction.The results of X-ray diffraction(XRD) and transmission electron microscopy(TEM) reveal that Ag nanoparticle...Silver nanoparticles were prepared in the channels of mesoporous silica SBA-15 through silver mirror reaction.The results of X-ray diffraction(XRD) and transmission electron microscopy(TEM) reveal that Ag nanoparticles with uniform size about 2-3 nm were dispersed inside the channels of mesoporous SBA-15.UV-Vis absorption spectra indicate the quantum size effect of the Ag nanoparticles.Bacteriological tests were performed in Luria-Bertani(LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of Ag/SBA-15.This nanocomposite was shown to be an effective bactericide against Staphylococcus.展开更多
The preparation and formation mechanism of silica/polyvinylpyrrolidone（PVP）-polyacrylonitrile（PAN） coaxial nanofibers were presented in this paper. The PVP-PAN composite nanofibers were obtained via an electrospin...The preparation and formation mechanism of silica/polyvinylpyrrolidone（PVP）-polyacrylonitrile（PAN） coaxial nanofibers were presented in this paper. The PVP-PAN composite nanofibers were obtained via an electrospinning technique, while SiO2 nanoparticles were prepared according to a Stber method. The measurements of water contact angle（WCA）, the compared results of silica coating PVP-PAN composite nanofibers with PAN nanofibers indicate that much PVP resided on the composite nanofiber surface, which results in the occurrence of SiO2@polymer coaxial nanofibers due to the formation of hydrogen bonding between silica and composite nanofibers and subsequent adsorption of silica on the fiber surface.展开更多
Sulfated zirconia/silica(SZ/SiO2) complex nanofibers were prepared by combining electronspinning technique and sol-gel method.First,a silica sol was electrospun at a voltage of 12 kV,then the as-electrospun silica nan...Sulfated zirconia/silica(SZ/SiO2) complex nanofibers were prepared by combining electronspinning technique and sol-gel method.First,a silica sol was electrospun at a voltage of 12 kV,then the as-electrospun silica nanofibers were immersed into a sulfated zirconia sol afterwards with a thermal treatment to obtain the SZ/SiO2 complex nanofibers.These fibers were examined by SEM,TEM,FTIR, XRD and SPS.The results indicate that the SZ nanopaticles with the average diameter of about 8 nm were disspered on the surface of silica fibers which had an average diameter of about 170 nm.The complex nanofibers had an amorphous structure.The observation of the surface-related transitions at the SPS spectrum indicates the presence of positive charges on the surface of the complex fibers.展开更多
A novel dichioro-monomer 4,4’-bis(N-’phenyl-4-chloro-1,8-naphthalimide) ether(BCNPI) was successfully prepared. We obtain novel polyethernaphthalimide(PENI) from BCNPI and Bisphenol A salt in the present of sulfolan...A novel dichioro-monomer 4,4’-bis(N-’phenyl-4-chloro-1,8-naphthalimide) ether(BCNPI) was successfully prepared. We obtain novel polyethernaphthalimide(PENI) from BCNPI and Bisphenol A salt in the present of sulfolane. The polymer possess high molecular weight from test of intrinsic viscosity and high Tg from the differential scanning calorimetry. The polyetherimide exhibited excellent thermal and thermooxidative stabilities,and it has high modulus,strength and elongation from the test of the mechanical properties.展开更多
A novel controllable cross\|linking PEEK was synthesized by introducing thioether moieties into PEEK rigid chain, in which sulfur acts as a cross\|linking point. It is found that the cross\|linking reaction could take...A novel controllable cross\|linking PEEK was synthesized by introducing thioether moieties into PEEK rigid chain, in which sulfur acts as a cross\|linking point. It is found that the cross\|linking reaction could take place at 623 K over a period of 5 h. The novel material has an excellent thermal stability and mechanical properties. It can be processed as convenient as that of pure PEEK before cross\|linking and has a high application temperature as thermosetting resin after cross\|linking.展开更多
We present an electrospray ionization technology(ESI) to fabricate Cu-core/PVA-shell nanoparticles. The transition of nanofiber-to-nanoparticle is achieved by adjusting the mass fraction of PVA shell material containi...We present an electrospray ionization technology(ESI) to fabricate Cu-core/PVA-shell nanoparticles. The transition of nanofiber-to-nanoparticle is achieved by adjusting the mass fraction of PVA shell material containing Cu nanoparticles.展开更多
Nonisothermal melt crystallization kinetics of thio-ether-contained poly(ether ether ketone ketone) copolymers was studied by DSC. The result shows that the crystallization activation energy was increased accompanied ...Nonisothermal melt crystallization kinetics of thio-ether-contained poly(ether ether ketone ketone) copolymers was studied by DSC. The result shows that the crystallization activation energy was increased accompanied by the introduction of thio-ether structure. The random copolymer possesses a higher crystallization activation energy than the block one at the same thio-ether ratio.展开更多
A novel cross-linkable poly(ether ether ketone ketone) alternating copolymer was synthesized by introducing thio-ether moiety to PEEKK rigid main chain. The copolymer can be processed at 628 K and be cross-linked by a...A novel cross-linkable poly(ether ether ketone ketone) alternating copolymer was synthesized by introducing thio-ether moiety to PEEKK rigid main chain. The copolymer can be processed at 628 K and be cross-linked by annealing at 653 K for 5 h. The cross-linking reaction was caused by the introduced thio-ether moiety instead of the PEEKK moiety. The cross-linked material has better mechanical properties and thermal stability that uncross-liked one. The results will give proof to the further research on controllable cross-linking PEEKK. This material is anticipated to be processed as a thermoplastic material as well as used a as thermosetting material after being cross-linked. [WT5HZ]展开更多
A type of novel crosslinkable poly(aryl ether ketone)s containing pendent phenylethynyl moieties(PEP-PAEK-Fn) were synthesized. The polymers were prepared by copolycondensation reaction of difluoro-monomer with potass...A type of novel crosslinkable poly(aryl ether ketone)s containing pendent phenylethynyl moieties(PEP-PAEK-Fn) were synthesized. The polymers were prepared by copolycondensation reaction of difluoro-monomer with potassium salt of 4-phenylethynylphenyl hydroquinone(PEP-PH) and 4,4′-isopropylidenediphenol(BPA). The Mns and Mw/Mns of polymers determined by GPC with polystyrene standard were 46700, 100000 and 1.6, respectively. The resulting polymers were thermally crosslinked at 370 ℃ for 2 h in N2 atmosphere. The glass transition temperature is increased after crosslinking. The cured polymers show a good chemical resistance and high thermal stability up to 500 ℃ under nitrogen.展开更多
文摘Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy）,XRD（X-ray diffraction）and TGA（thermogravimetric analysis）.Transmission electron microscope images of the PVP/Fe3O4 nanofibers show that the Fe3O4 nanoparticles with a diameter about 10.5 nm were dispersed in PVP fiber matrices.The XRD results show that the particles in PVP fibers were indeed Fe3O4 nanoparticles.And the TGA of PVP/Fe3O4 nanofibers show that the content of Fe3O4 nanoparticles in the composite was about 36.8%（mass fraction）.The PVP/Fe3O4 nanofibers were found to be superparamagnetic.The hysteresis loop at room temperature showed a high saturated magnetization（M s=15.1 emu/g）and a low coercive force（μ c=0）.
文摘Ultrafine polystyrene(PS) nanofibers were prepared via the simple electrospinning technique.Uniform and smooth PS nanofibers were obtained with adding the organic salt BTEAC into the PS solutions and adjusting the concentration of PS solutions.Without the addition of BTEAC,PS fibers with few beads could be achieved with a PS mass fraction of 20%,and the average diameter of the fibers was 280 nm.The addition of the organic salt BTEAC could lower the critical concentration for the fiber formation and reduce the amount of beads on the fibers.Unltrafine PS fibers without any beads were obtained with a PS mass fraction of 10% and an ionic salt mass fraction of 0.5%.The average diameter of the fiber was successfully reduced to 100 nm.The influence of the salt concentration on the morphology and diameter of the PS fibers was also investigated.The viscosity and surface tension changes were measured with changing the concentration of BTEAC.The results show that the changes were so small that these factors could be ignored.It was suggested that variations of the fiber diameter should be mainly resulted from the changes of conductivity and conformation of the polymer chain as the concentration of BTEAC is varied.
文摘Composites of high molecular weight polyaniline with various weight percentages of multi-walled carbon nanotubes(MWNTs) were synthesized in the presence of selected dissolved neutral salt by in situ polymerization.The composites were characterized by means of SEM,FTIR and XRD,four-point probe conductivity measurements.The results indicate that the composites possess very different morphologies,high electrical conductivities and good crystallization compared with high molecular weight polyaniline.
文摘Silver nanoparticles were prepared in the channels of mesoporous silica SBA-15 through silver mirror reaction.The results of X-ray diffraction(XRD) and transmission electron microscopy(TEM) reveal that Ag nanoparticles with uniform size about 2-3 nm were dispersed inside the channels of mesoporous SBA-15.UV-Vis absorption spectra indicate the quantum size effect of the Ag nanoparticles.Bacteriological tests were performed in Luria-Bertani(LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of Ag/SBA-15.This nanocomposite was shown to be an effective bactericide against Staphylococcus.
文摘The preparation and formation mechanism of silica/polyvinylpyrrolidone（PVP）-polyacrylonitrile（PAN） coaxial nanofibers were presented in this paper. The PVP-PAN composite nanofibers were obtained via an electrospinning technique, while SiO2 nanoparticles were prepared according to a Stber method. The measurements of water contact angle（WCA）, the compared results of silica coating PVP-PAN composite nanofibers with PAN nanofibers indicate that much PVP resided on the composite nanofiber surface, which results in the occurrence of SiO2@polymer coaxial nanofibers due to the formation of hydrogen bonding between silica and composite nanofibers and subsequent adsorption of silica on the fiber surface.
文摘Sulfated zirconia/silica(SZ/SiO2) complex nanofibers were prepared by combining electronspinning technique and sol-gel method.First,a silica sol was electrospun at a voltage of 12 kV,then the as-electrospun silica nanofibers were immersed into a sulfated zirconia sol afterwards with a thermal treatment to obtain the SZ/SiO2 complex nanofibers.These fibers were examined by SEM,TEM,FTIR, XRD and SPS.The results indicate that the SZ nanopaticles with the average diameter of about 8 nm were disspered on the surface of silica fibers which had an average diameter of about 170 nm.The complex nanofibers had an amorphous structure.The observation of the surface-related transitions at the SPS spectrum indicates the presence of positive charges on the surface of the complex fibers.
文摘A novel dichioro-monomer 4,4’-bis(N-’phenyl-4-chloro-1,8-naphthalimide) ether(BCNPI) was successfully prepared. We obtain novel polyethernaphthalimide(PENI) from BCNPI and Bisphenol A salt in the present of sulfolane. The polymer possess high molecular weight from test of intrinsic viscosity and high Tg from the differential scanning calorimetry. The polyetherimide exhibited excellent thermal and thermooxidative stabilities,and it has high modulus,strength and elongation from the test of the mechanical properties.
文摘A novel controllable cross\|linking PEEK was synthesized by introducing thioether moieties into PEEK rigid chain, in which sulfur acts as a cross\|linking point. It is found that the cross\|linking reaction could take place at 623 K over a period of 5 h. The novel material has an excellent thermal stability and mechanical properties. It can be processed as convenient as that of pure PEEK before cross\|linking and has a high application temperature as thermosetting resin after cross\|linking.
文摘We present an electrospray ionization technology(ESI) to fabricate Cu-core/PVA-shell nanoparticles. The transition of nanofiber-to-nanoparticle is achieved by adjusting the mass fraction of PVA shell material containing Cu nanoparticles.
文摘Nonisothermal melt crystallization kinetics of thio-ether-contained poly(ether ether ketone ketone) copolymers was studied by DSC. The result shows that the crystallization activation energy was increased accompanied by the introduction of thio-ether structure. The random copolymer possesses a higher crystallization activation energy than the block one at the same thio-ether ratio.
文摘A novel cross-linkable poly(ether ether ketone ketone) alternating copolymer was synthesized by introducing thio-ether moiety to PEEKK rigid main chain. The copolymer can be processed at 628 K and be cross-linked by annealing at 653 K for 5 h. The cross-linking reaction was caused by the introduced thio-ether moiety instead of the PEEKK moiety. The cross-linked material has better mechanical properties and thermal stability that uncross-liked one. The results will give proof to the further research on controllable cross-linking PEEKK. This material is anticipated to be processed as a thermoplastic material as well as used a as thermosetting material after being cross-linked. [WT5HZ]
文摘A type of novel crosslinkable poly(aryl ether ketone)s containing pendent phenylethynyl moieties(PEP-PAEK-Fn) were synthesized. The polymers were prepared by copolycondensation reaction of difluoro-monomer with potassium salt of 4-phenylethynylphenyl hydroquinone(PEP-PH) and 4,4′-isopropylidenediphenol(BPA). The Mns and Mw/Mns of polymers determined by GPC with polystyrene standard were 46700, 100000 and 1.6, respectively. The resulting polymers were thermally crosslinked at 370 ℃ for 2 h in N2 atmosphere. The glass transition temperature is increased after crosslinking. The cured polymers show a good chemical resistance and high thermal stability up to 500 ℃ under nitrogen.
