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
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
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
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
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
选用一种在RTM双马来酰亚胺树脂(BMI)注射温度下不溶解的含磷聚芳醚酮(P-PAEK)热塑性树脂作为增韧剂,制备层间颗粒增韧碳纤维增强双马来酰亚胺树脂基复合材料.研究了不同热塑树脂含量对树脂浇铸体冲击性能的影响,利用扫描电镜表征了复...选用一种在RTM双马来酰亚胺树脂(BMI)注射温度下不溶解的含磷聚芳醚酮(P-PAEK)热塑性树脂作为增韧剂,制备层间颗粒增韧碳纤维增强双马来酰亚胺树脂基复合材料.研究了不同热塑树脂含量对树脂浇铸体冲击性能的影响,利用扫描电镜表征了复相体系的微观形貌并分析其增韧机制,并通过层间断裂韧性测试表征了RTM双马树脂基复合材料增韧前后的层间韧性性能.结果表明,当附载热塑颗粒面密度为2 g/m2时,复合材料的I型层间断裂韧性(GIC)为0.54 k J/m2,II型层间断裂韧性(G_(IIC))为1.36 k J/m^2,较未增韧复合材料分别提升约56%和42%.增韧后的复合材料在保持原有力学性能的同时,其冲击后压缩强度(CAI)提升约29%,层间剪切强度达到111.7 MPa.展开更多
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.
文摘选用一种在RTM双马来酰亚胺树脂(BMI)注射温度下不溶解的含磷聚芳醚酮(P-PAEK)热塑性树脂作为增韧剂,制备层间颗粒增韧碳纤维增强双马来酰亚胺树脂基复合材料.研究了不同热塑树脂含量对树脂浇铸体冲击性能的影响,利用扫描电镜表征了复相体系的微观形貌并分析其增韧机制,并通过层间断裂韧性测试表征了RTM双马树脂基复合材料增韧前后的层间韧性性能.结果表明,当附载热塑颗粒面密度为2 g/m2时,复合材料的I型层间断裂韧性(GIC)为0.54 k J/m2,II型层间断裂韧性(G_(IIC))为1.36 k J/m^2,较未增韧复合材料分别提升约56%和42%.增韧后的复合材料在保持原有力学性能的同时,其冲击后压缩强度(CAI)提升约29%,层间剪切强度达到111.7 MPa.
