聚吡咯/Ba_(0.9)Nd_(0.1)Fe_(11.5)Cr_(0.5)O_(19)复合物的可控合成及电磁性能

用溶胶凝胶法制备了一系列Nd掺杂Ba-铁氧体粉末(Ba1-xNdxFe11.5Cr0.5O19,x=0.00,0.05,0.10,0.15,0.20),选取磁性能相对较好的Ba0.9Nd0.1Fe11.5Cr0.5O19作为磁核,通过原位聚合法制备了不同铁氧体含量的聚吡咯/Ba0.9Nd0.1Fe11.5Cr0.5O19(PPy/BNFCO)复合物.用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、红外光谱(FTIR)、振动样品磁强计(VSM)、四探针测试仪和矢量网络分析仪等表征了铁氧体粉末和复合物微粒的结构、形貌以及电磁性能.结果表明,Nd的掺杂明显改变了Ba-铁氧体的饱和磁化强度和矫顽力;PPy/BNFCO复合物具有比较明显的核壳结构;复合物的饱和磁化强度随BNFCO含量的增加而增大;电导率则与PPy含量成正比,mpy/mBNFCO=5/1为复合体系渗流阈值;复合物对电磁波的反射损耗和有效带宽是PPy和ZCGFO协同作用的结果,当mpy/mBNFCO为5/1时,PPy/ZCGFO复合物中组分间的协同作用达到最大,其反射峰值和有效带宽分别达到-27.68dB和9.04GHz.PPy/ZCGFO复合物由于良好的微波吸收性能,有望成为电磁波吸收与屏蔽领域的候选材料.     

Zn(0.6Mn0.2Ni0.2Fe2O4/聚邻甲基苯胺复合物的制备和电磁性能

用化学沉淀法和原位聚合法分别制备了Zn0.6Mn0.2Ni0.2Fe2O4铁氧体纳米粒子和Zn0.6Mn0.2Ni0.2Fe2O4铁氧体/聚邻甲基苯胺复合微粒(ZMNF/POT).通过现代测试技术表征了样品组成、结构、形貌和电-磁性能.结果表明,POT对ZMNF粒子具有较好的包覆作用;复合物电导率与POT的含量成正比,而磁性能与ZMNF粒子的含量相关;在1～15MHz频段内,POT和ZMNF/POT复合物的介电损耗与其电导率表现出一致性;复合物具有可观的磁损耗,比磁介质型ZMNF的大,且ZMNF含量为31.74 wt%的复合物的磁损耗最大,有望作为屏蔽和吸收电磁波材料获得应用.     

镍钴锌纳米铁氧体的制备及磁热性能

以乙酰丙酮盐为前驱体,三乙二醇为溶剂,采用多元醇法制备了纳米Ni0.5-xCoxZn0.5Fe2O4(x=0,0.1,0.2,0.3和0.4)铁氧体.通过X射线衍射仪(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FTIR)和振动样品磁强计(VSM)等对样品的结构、形貌和磁性能进行了表征.结果表明,所得纳米Ni0.5-xCoxZn0.5Fe2O4铁氧体的分散性较好,尺寸均一.在室温下产物的剩磁和矫顽力均较小,表现出亚铁磁性.纳米Ni0.3Co0.2Zn0.5Fe2O4铁氧体的饱和磁化强度达到41.34 A·m2·kg-1,其在交变磁场中升温可达到55℃,表现出较好的磁热性能.     

聚苯胺/聚丙烯酰胺/镍锌铜铁氧体复合物的制备及电磁性能

采用溶液聚合法制备了聚苯胺/聚丙烯酰胺/镍锌铜铁氧体(PANI/PAM/Zn0.4Ni0.5Cu0.1Fe2O4)三元复合物. 利用X射线衍射仪、红外光谱仪、扫描电子显微镜和振动样品磁强计分别表征了样品的结构、形貌和磁性能, 用阻抗/材料分析仪测定了复合物在1 MHz～1 GHz的频率范围内的磁损耗和介电损耗, 并研究了聚苯胺和引发剂的相对含量对复合物的磁损耗和介电损耗的影响. 结果表明复合物中磁性粒子和聚合物之间具有一定的相互作用, 复合物在1 MHz～1 GHz的频率范围内具有较大电磁损耗能力.     

钴铁氧体/膨胀石墨及其聚吡咯复合物的制备和油水分离性能

用化学共沉淀法和原位乳液聚合法分别制备了钴铁氧体/膨胀石墨复合微粒(CF/EG)和钴铁氧体/膨胀石墨/聚吡咯复合物(CF/EG/PPy)。用现代分析技术表征了样品的组成、结构、形貌、电-磁性能和油水分离性能。结果表明,CF粒子已填嵌入到膨胀石墨的层间,CF/EG/PPy复合物的核(CF/EG)和壳(PPy)之间存在着一定的相互作用,样品的油水分离效果与膨胀石墨的层间空隙成正比,其次序为:EG>CF/EG>CF/EG/PPy。磁性的CF/EG微粒回收容易,重复使用性能优良,循环5次的效率不低于90%。     

聚苯胺-LiNi铁氧体复合纳米微粒的原位合成及其键合机制

通过原位溶液聚合法制备了聚苯胺-LiNi铁氧体(LiNi_0.5Fe₂O₄)复合纳米微粒, 用X射线衍射(XRD)、红外光谱(FTIR)、拉曼光谱(Raman)、紫外-可见光谱(UV-Vis)、透射电子显微镜(TEM)以及振动样品磁强计(VSM)等技术表征了复合物的结构、形貌和磁性能. 结果表明, 复合物在室温外加磁场下表现出亚铁磁性物质具有的磁滞现象, 铁氧体颗粒对苯胺的聚合起到了核的作用; 复合物中铁氧体与聚苯胺之间存在着比较明显的键合作用, 探讨了铁氧体与聚合物分子链之间的键合机制.     

原位聚合法制备聚吡咯-钴铜锌铁氧体复合材料及其电磁性能

采用自蔓延燃烧法和原位聚合法分别制备纳米Co0.7Cu0.1Zn0.2Fe2O4铁氧体和聚吡咯(PPy)-Co0.7Cu0.1Zn0.2Fe2O4纳米复合材料.采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和傅里叶红外光谱(FTIR)对材料的结构和形貌进行表征,使用波导法和振动样品磁强计(VSM)研究了材料的介电性能、微波吸收性能和磁性能.结果表明,制得了纯相的尖晶石结构Co0.7Cu0.1Zn0.2Fe2O4铁氧体,少量Cu2+离子替代了铁氧体八面体位置上的Co2+离子,使得材料的晶格常数减小;2种粉体粒子分散性较好,它们的平均粒径分别约为15 nm和50 nm;在5.0~20.0 GHz频率范围内,PPy-Co0.7Cu0.1Zn0.2Fe2O4复合材料的反射损耗在-16.25dB到-20.27 dB之间,且在18 GHz处出现极大值-20.27 dB,带宽为2.0 GHz(最强峰的半高宽),PPyCo0.7Cu0.1-Zn0.2Fe2O4复合材料的反射损耗明显大于铁氧体;PPy-Co0.7Cu0.1Zn0.2Fe2O4的饱和磁化强度(Ms)和剩余磁化强度(Mr)分别为12.9 A/g和4.29 A/g,小于Co0.7Cu0.1Zn0.2Fe2O4铁氧体的相应值,但复合材料的矫顽力大于Co0.7Cu0.1Zn0.2Fe2O4铁氧体的,为38.96 kA/m.     

Zn-Ni-Cu铁氧体/聚邻甲氧基苯胺复合物的制备及电磁性能

用共沉淀法和溶液原位聚合法分别制备了锌镍铜铁氧体粉末(ZNCF)及其聚邻甲氧基苯胺(POMA)复合物.用粉末X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、振动样品磁强计(VSM)等分别表征了产物的结构、形貌、电磁性能.结果表明,ZNCF/POMA复合物的组分之间存在一定的相互作用;POMA对ZNCF粒子的包覆能起到调控样品电磁性能的作用,复合物的磁性能随POMA含量的增加而减小,而电导率则相反;与单一组分相比,POMA/ZNCF复合物表现出更优良的电磁波吸收性能,ωZNCF为20%的复合物的反射损耗峰值和有效带宽分别为-27.32 dB和8.81 GHz,峰值对应的共振频率为11.61 GHz,是颇具应用前景的电磁波吸收材料.     

新颖的电磁波吸收材料:Ba_(1-x)La_xFe_(10)Al_2O_(19)铁氧体的制备和性能

用溶胶-凝胶法合成了Ba1-xLaxFe10Al2O19铁氧体(x=0.00,0.05,0.10,0.15,0.20,0.25).通过粉末X射线衍射仪、扫描电子显微镜、透射电子显微镜、振动样品磁强计和矢量网络分析仪表征了样品的结构、形貌、磁性和电磁波吸收性能.结果表明,La含量显著地影响Ba1-xLaxFe10Al2O19铁氧体的磁性和电磁波吸收性能.Ba1-xLaxFe10Al2O19铁氧体的饱和磁化强度随La含量的增加而减小,而矫顽力则增大.当BaFe10Al2O19吸收剂的涂层厚度为2mm时,在8～18GHz范围内,反射损耗的峰值在13.45GHz处达到-26.3dB,有效带宽为8.9GHz.Ba1-xLaxFe10Al2O19铁氧体对电磁波的反射损耗和有效带宽低于母体BaFe10Al2O19.由于Ba1-xLaxFe10Al2O19样品良好的吸波性能,建议可以作为吸收和屏蔽电磁波的候选材料.     

聚苯胺钡铁氧体纳米复合材料的制备、表征及性能

采用原位掺杂聚合法, 将聚苯胺(PANI)对粒径在60~80 nm的M型钡铁氧体颗粒(BaFe12O19)进行了包覆, 得到了具有棒状结构的复合材料. 通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等测试手段对材料的形貌和结构进行了表征. 结果表明, PANI链段与BaFe12O19颗粒之间存在作用力. 使用振动磁强计和四探针法测定了复合材料的磁性能与电性能后发现, 饱和磁化强度与矫顽力均随聚苯胺含量的增加呈规律性下降趋势, 而电导率呈上升趋势. 复合材料的吸收特性测试结果表明, 该材料反射率小于-20 dB时, 带宽可以达到15.07 GHz. 同时详细地讨论了纳米复合材料的聚合机理及相互作用.     

磁性Fe_3O_4-聚吡咯纳米微球的合成与表征

报道了具有核壳结构的Fe3O4 聚吡咯磁性纳米微球的合成方法和表征结果 .微球同时具有导电性和磁性能 .在优化的实验条件下 ,可得到饱和磁化强度为 2 3 4emu g ,矫顽力为 45 2Oe的磁性微球 .微球的导电性随着微球中Fe3O4含量的增加而下降 .微球的磁性能则随着Fe3O4含量的增加而增大 .Fe3O4磁流体的粒径和磁性聚吡咯微球的粒径均在纳米量级 .纳米Fe3O4粒子能够提高复合物的热性能 .实验表明 ,磁流体和聚吡咯之间存在着一定的相互作用 ,正是这种相互作用使磁性聚吡咯纳米微球的热稳定性提高 .     

Synthesis of electromagnetic functionalized barium ferrite nanoparticles embedded in polypyrrole

With flaky BaFe12O19 nanoparticles (BF NPs, 10-20 nm in thickness) as polymerization seeds, electromagnetic functionalized and microstructured quasi-spherical PPY/BF (PPY: polypyrrole) organic-inorganic composites were prepared by a conventional in situ chemical oxidative polymerization. X-ray diffraction and Fourier transform infrared analyses interpreted that there was no obvious chemical interaction between BF NPs and PPY in the composites but that BF NPs only served as the nucleation sites for the polymerization of pyrrole. As compared to pure BF NPs, PPY/BF composites showed distinct increases in electrical conductivities and decreases in magnetization and thus improved the matched characteristic impedance of the free space, leading to a substantial enhancement of reflection loss at 2-18 GHz. For the first time, multi-layered and single-layered films formed at different places on the reaction flask were studied by scanning electron microscopy and energy dispersive X-ray analysis, indicating that the films composed of quasi-spherical microstructures can be very different in morphology but surprisingly contain no BF NPs.     

聚吡咯(PPY)/聚己内酰胺(Nylon 6)——导电复合材料的研究

本文用电化学氧化聚合的方法制备出了既具有优良的导电性能又具有良好机械性能的聚吡咯(PPY)/聚己内酰胺(Nylon 6)的复合材料,该复合材料的导电率可达119s/cm,并对聚吡咯/聚己内酰胺导电复合材料进行了扫描电子显微镜、电导率及机械性能的测试及表征。     

Preparation and Characterization of Polypyrrole Microbelt via Cotton Template

Polypyrrole (PPY) microbelts are synthesized via the absorbent cotton template for the first time. PPY microbelts are characterized by Fourier transform infrared spectroscopy.The stability, the morphology and electrical conductivity of such microbelts are evaluated by means of scanning electron microscope, thermo-gravimetric analysis and four-probe con-ductivity. A possible mechanism for the formation of PPY microbelts are proposed. The conductivity is measured, and the conductivity variation mechanism of the PPY microbelts with the pyrrole monomer concentrations is analyzed.     

La-Ni-Al钙钛矿氧化物中Sr和Ca取代La对甲醇重整的影响

Mixed perovskite oxides with CaxLa1-xNi0.3Al0.7O3-d and SrxLa1-xNi0.3Al0.7O3-d(x=0,0.2,0.5,0.8,and 1.0;d=0.5x)components have been prepared by a sol-gel method.The effects of the partial substitution of La by Ca and Sr in dry CH4 reforming were investigated at 500-800 ℃ and 101 kPa.The resulting oxides were examined by Fourier-transform infrared spectroscopy,X-ray diffraction,temperature-programmed reduction,scanning electron microscopy,energy dispersive X-ray spectrometry,and BET surface area analysis.Studies following the catalytic tests by carbon analysis show some carbon deposition on this catalytic system.The results indicate that all initial salt entered into a propionate structure,and that most of the solid solution has well defined perovskite structure with surface areas between 3.5 and 9.5 m2/g.Most of the catalysts performed well in the dry reforming,with CH4 conversions up to 90%,H2 yields up to 80%,and H2 selectivity up to 90%.Among the samples,Sr0.2La0.8Ni0.3Al0.7O2.9 showed an excellent catalytic performance in CH4 dry reforming,with a H2/CO ratio of 1,whereas Ca0.8La0.2Ni0.3Al0.7O2.6 showed the lowest coke formation(approximately 0.71%).     

Novel core-shell-structured Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 via coprecipitation as positive electrode material for lithium secondary batteries

We have successfully synthesized a spherical core-shell structure based on Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 via a coprecipitation route. According to the careful examination by scanning electron microscopy (SEM), transmission electron microscopy energy-dispersive spectroscopy (TEM-EDS), and X-ray diffraction (XRD), it was found that the core-shell particle consisted of Li[Ni0.8Co0.2]O2 as the core and Li[Ni0.5Mn0.5]O2 as the shell, of which the thickness was estimated to be 1 to approximately 1.5 microm. Both the core and shell were dense as confirmed by SEM. Though the core-shell-structured Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 delivered a slightly reduced initial discharge capacity, the capacity retention and thermal stability were significantly improved relative to those of the Li[Ni0.8Co0.2]O2 electrode without the Li[Ni0.5Mn0.5]O2 shell. The carbon/Li[Ni0.8Co0.2]O2 pouch cell underwent an explosive ignition during the nail penetration test, whereas the carbon/Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 cell remained stable, demonstrating the superior thermal stability of the core-shell electrode. As a new positive electrode material, the core-shell-structured Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 is a significant breakthrough in the development of high-capacity lithium secondary batteries.     

SDC和SSC在低温常压电化学合成氨中的性能研究

用溶胶—凝胶法制备了Ce0.8Sm0.2O2-δ(SDC)和Sm0.5Sr0.5CoO 3-δ（SSC）超细粉体,采用XRD、TEM和SEM等对粉体进行了观察和表征。分别以Ni-SDC和SSC为阴极, 磺化聚砜质子交换膜为电解质, Ni- SDC金属陶瓷为阳极,银-铂网做集流体组成单电池,在25℃～120℃温度范围内研究了其电导率随温度变化关系及在电化学合成氨中的性能。结果表明：在25℃～120℃温度范围内,使用Ni-SDC和SSC为阴极均有氨气生成,而SSC对电化学合成氨的性能优于Ni-SDC, 在80℃时氨产率达到了6.5×10-9 mol•s-1•cm-2。     

La-Co共掺杂的M型锶铁氧体纳米纤维的制备和磁性能

以聚乙烯吡咯烷酮(PVP)和金属盐为原料,采用静电纺丝、溶胶-凝胶技术以及随后的热处理工艺,制备了La、Co共掺杂的M型锶铁氧体Sr1-xLaxFe12-xCoxO19(x=0.12)(SLFC)纳米纤维.利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和超导量子干涉仪(SQUID)技术对纳米纤维样品的结构、形貌和磁学性能进行了观测,系统地研究了不同温度下样品的磁性能变化.结果表明:经过950°C焙烧2h后,得到纯相的M型锶铁氧体纳米纤维,纤维呈竹节状结构,直径约55nm;室温下测得矫顽力(Hc)为498.53kA·m-1,饱和磁化强度(Ms)为70.76A·m2·kg-1,剩磁(Mr)为36.35A·m2·kg-1,这比未掺杂SrFe12O19(SF)时纳米纤维的磁性能有明显的改善,并且与在相同温度下制得的相应纳米粉体样品相比,磁性能明显提高.