We report on the synthesis and characterizations of TiO2 nanoparticles embedded in polyamide-6composite nanofibers by using electrospinning technique. The influence of substrate on the electrical characteristics of po...We report on the synthesis and characterizations of TiO2 nanoparticles embedded in polyamide-6composite nanofibers by using electrospinning technique. The influence of substrate on the electrical characteristics of polyamide-6/TiO2 composite nanofibers was investigated. The resultant nanofibers exhibit good incorporation of TiO2 nanoparticles. The doping of TiO2 nanoparticles into the polyamide-6 nanofibers were confirmed by high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Photoluminescence（PL） and cathodoluminescence（CL） spectroscopy were also used to characterize the samples.The PL and CL spectra reveal that the as-spun polyamide-6/TiO2 composite nanofibers consisted of overlapping of two broad emission bands due to the contribution of polyamide-6（centered at about 475 nm）, which might originate from organic functional groups of polyamide-6 and TiO2 nanoparticles（centered around 550 nm）. The electrical conductivity of the polyamide-6/TiO2 composite nanofibers on different substrates was carried out.It was found that the electrical conductivity of the polyamide-6/TiO2 composite nanofibers on silicon substrate was in the range of 13 μA, and about 1 to 20 p A for the paper and glass substrates.展开更多
A series of wear and flame resistant polyamide 6(PA6)composites were prepared using glass fiber(GF)and talc(T)as reinforcer,polytetrafluoroethylene(PTFE)and graphite(Gr)as solid lubricants,red phosphorus(RP)and zinc b...A series of wear and flame resistant polyamide 6(PA6)composites were prepared using glass fiber(GF)and talc(T)as reinforcer,polytetrafluoroethylene(PTFE)and graphite(Gr)as solid lubricants,red phosphorus(RP)and zinc borate(ZB)as flame retardant.The tribological property,mechanical property,flame retardant property and the flame retardant mechanism were investigated.The tests show that the formula of the wear resistant PA6 composite(WRPA 6)is PA6/GF/T/PTFE/Gr in the ratio of 100/15/5/10/5 by mass.Because this composite exhibits the lowest friction coefficient(0.1429)and no wear mass loss,the introduction of RP and ZB can increase the flame resistance of WRPA6,and the synergistic effect of RP and ZB is obtained.Detailedly,the composite with 4 parts of ZB and 12 parts of RP shows the best flame retardant property,achieving the highest limiting oxygen index(LOI)(30.2 vol%)and a UL94 V-0 rating,and the flame retardant mechanisms may be gas phase along with condense phase mechanism.展开更多
The growth kinetics of microarc oxidation(MAO)coatings on Ti6Al4V alloy was studied by designing an electrolyte with low PO_(4)^(3−)content and high B_(4)O_(7)^(2−)content,using scanning electron microscopy,transmissi...The growth kinetics of microarc oxidation(MAO)coatings on Ti6Al4V alloy was studied by designing an electrolyte with low PO_(4)^(3−)content and high B_(4)O_(7)^(2−)content,using scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and potentiodynamic polarization.The results showed that B_(4)O_(7)^(2−)increased the spark intensity and dissolved most of the oxides at high temperatures.Then,a thicker barrier layer at the coating/substrate interface was produced,which increased the polarization resistance of the coating.PO_(4)^(3−)at a low concentration also promoted the uniform growth of the MAO coating and the formation of hat-shaped holes in the outer deposition layer.The thickness of the MAO coatings obtained in Na_(2)B_(4)O_(7) electrolytes exhibited an exponential increase with time at spark discharge stage,while that of the MAO coating obtained in phosphate–tetraborate electrolytes showed a linear trend as the PO_(4)^(3−)content increased.展开更多
Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable f...Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable for their applications in many fields.Hence,impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs.Herein,CsPb X3(X=Cl,Br)NCs are coated with Cs4PbX6 shell to impede anion exchange and reduce anion mobility.The Cs4PbX6 shell is facily fabricated on CsPbX3 NCs through high temperature injection method.Anion exchange experiments demonstrate that the Cs4 PbX6 shell completely encapsulates CsPbX3 NCs and greatly improves the composition stability of CsPbX3 NCs.Moreover,our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3(M=Cl,Br,I)NCs.展开更多
基金supported by a grant from the Korean Ministry of Education,Science and Technology(The Regional Core Research Program/Center for Healthcare Technology&Development,Chonbuk National University,Jeonju 561-756 Republic of Korea)
文摘We report on the synthesis and characterizations of TiO2 nanoparticles embedded in polyamide-6composite nanofibers by using electrospinning technique. The influence of substrate on the electrical characteristics of polyamide-6/TiO2 composite nanofibers was investigated. The resultant nanofibers exhibit good incorporation of TiO2 nanoparticles. The doping of TiO2 nanoparticles into the polyamide-6 nanofibers were confirmed by high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Photoluminescence（PL） and cathodoluminescence（CL） spectroscopy were also used to characterize the samples.The PL and CL spectra reveal that the as-spun polyamide-6/TiO2 composite nanofibers consisted of overlapping of two broad emission bands due to the contribution of polyamide-6（centered at about 475 nm）, which might originate from organic functional groups of polyamide-6 and TiO2 nanoparticles（centered around 550 nm）. The electrical conductivity of the polyamide-6/TiO2 composite nanofibers on different substrates was carried out.It was found that the electrical conductivity of the polyamide-6/TiO2 composite nanofibers on silicon substrate was in the range of 13 μA, and about 1 to 20 p A for the paper and glass substrates.
基金Project(149929)supported by the Postdoctoral Fund of Central South University,ChinaProject(16C0292)supported by the Hunan Education Department,ChinaProject(2016TP1022)supported by the Hunan Provincial Key Lab of Dark Tea and Jin-hua,China
文摘A series of wear and flame resistant polyamide 6(PA6)composites were prepared using glass fiber(GF)and talc(T)as reinforcer,polytetrafluoroethylene(PTFE)and graphite(Gr)as solid lubricants,red phosphorus(RP)and zinc borate(ZB)as flame retardant.The tribological property,mechanical property,flame retardant property and the flame retardant mechanism were investigated.The tests show that the formula of the wear resistant PA6 composite(WRPA 6)is PA6/GF/T/PTFE/Gr in the ratio of 100/15/5/10/5 by mass.Because this composite exhibits the lowest friction coefficient(0.1429)and no wear mass loss,the introduction of RP and ZB can increase the flame resistance of WRPA6,and the synergistic effect of RP and ZB is obtained.Detailedly,the composite with 4 parts of ZB and 12 parts of RP shows the best flame retardant property,achieving the highest limiting oxygen index(LOI)(30.2 vol%)and a UL94 V-0 rating,and the flame retardant mechanisms may be gas phase along with condense phase mechanism.
文摘The growth kinetics of microarc oxidation(MAO)coatings on Ti6Al4V alloy was studied by designing an electrolyte with low PO_(4)^(3−)content and high B_(4)O_(7)^(2−)content,using scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and potentiodynamic polarization.The results showed that B_(4)O_(7)^(2−)increased the spark intensity and dissolved most of the oxides at high temperatures.Then,a thicker barrier layer at the coating/substrate interface was produced,which increased the polarization resistance of the coating.PO_(4)^(3−)at a low concentration also promoted the uniform growth of the MAO coating and the formation of hat-shaped holes in the outer deposition layer.The thickness of the MAO coatings obtained in Na_(2)B_(4)O_(7) electrolytes exhibited an exponential increase with time at spark discharge stage,while that of the MAO coating obtained in phosphate–tetraborate electrolytes showed a linear trend as the PO_(4)^(3−)content increased.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474018,61704007,and 61575019)the National Key Research and Development Program of China(Grant No.2017YFB0404501)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.2017RC034)the Shenzhen China Star Optoelectronics Technology Co.,Ltd
文摘Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable for their applications in many fields.Hence,impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs.Herein,CsPb X3(X=Cl,Br)NCs are coated with Cs4PbX6 shell to impede anion exchange and reduce anion mobility.The Cs4PbX6 shell is facily fabricated on CsPbX3 NCs through high temperature injection method.Anion exchange experiments demonstrate that the Cs4 PbX6 shell completely encapsulates CsPbX3 NCs and greatly improves the composition stability of CsPbX3 NCs.Moreover,our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3(M=Cl,Br,I)NCs.
文摘首先采用固相接枝法制备丙烯酸接枝聚丙烯 (PP g AA) ,PP g AA再与 2 ,4 甲苯二异氰酸酯(2 ,4 TDI)反应 ,产率为 5 9 3% ,其产物是PP g AA与PA 6进行阴离子聚合的助催化剂。反应时间为30min ,反应温度为 15 0℃时 ,PP g PA 6的接枝率为 2 5 %。并用IR、DSC、SEM表征了PP g PA 6的结构与形态 ,结果表明PA6接枝仅影响了PP的Tc 而不影响其Tm。
