碘掺杂的聚二茂铁基席夫碱的合成与性能研究

利用二茂铁甲醛与对、间、邻苯二胺在中性条件下缩合,得到了3种小分子二茂铁基席夫碱,利用Friedel-Crafts反应合成了一类新型的导电聚二茂铁基席夫碱,然后用碘对其进行掺杂,得到了系列电荷转移配合物.聚合物的电导率经碘掺杂后可提高几个数量级,同时均有紫外吸收功能;其中碘掺杂聚对二茂铁基席夫碱配合物的电导率最高,达3.17×10-4S/cm,而碘掺杂聚邻二茂铁基席夫碱配合物的磁增重另外2种配合物的2～3倍.     

含双噻唑和二茂铁聚席夫碱及Fe2+配合物的合成和性能

合成了一种新型的含二茂铁和双噻唑结构的聚合席夫碱,采用红外光谱、核磁技术对产物进行了表征,研究了温度、时间和催化剂对产率的影响. 结果表明,在80℃下反应6 h生成的二茂铁席夫碱的产率达到87.2%;采用AlCl3为催化剂时聚合效果最好,聚二茂铁席夫碱的产率达到72.4%. 热重分析表明聚合物具有较好的热稳定性;常温下聚二茂铁夫碱配合亚铁金属离子后的电导率下降,但掺杂I2后的电导率可提高到2.14×10-3 S/cm,同时亚铁金属配合物的磁性测试发现其具有S形特征磁滞回线,磁饱和强度为0.612 emu/g,剩余磁场强度为0.0257 emu/g,矫顽力为130 Oe,表明聚合席夫碱的亚铁配合物是一种有机软铁磁体.     

聚合长链席夫碱盐的合成与性能

在0℃和弱酸催化下利用乙二醛和乙二胺合成聚合长链席夫碱,再用FeCl3掺杂上述中间产物制得聚合长链席夫碱铁盐。阐述了聚合长链席夫碱的合成机理,分析了合成温度对反应的影响以及掺杂剂用量对产物电导率的影响,并表征产物的结构与组成。当掺杂剂FeCl3的用量达到饱和掺杂率时,该方法制得的聚合长链席夫碱铁盐,其电导率为3.02×10-3S/cm。     

新型含二茂铁基席夫碱的合成与表征

以乙炔基二茂铁和对碘苯胺为原料,通过Sonogashira反应制得对二茂铁乙炔基苯胺,然后分别与苯甲醛和二茂铁甲醛进行缩合,合成了两种二茂铁基席夫碱,通过元素分析,1H NMR和13C NMR对产物进行了表征。对合成目标化合物的反应条件进行了筛选,确定了合成含二茂铁基席夫碱的最佳合成条件。     

新型视黄基席夫碱盐的合成与吸波性能研究

以维生素A乙酸酯为原料,通过水解、活性二氧化锰氧化得视黄醛,醛与联苯胺反应合成席夫碱,席夫碱掺杂金属银化合物制得新型视黄基席夫碱盐。研究了活性二氧化锰氧化试剂对产物产率的影响,并通过元素分析、红外光谱等对产物结构进行了表征。结果表明,以活性二氧化锰为氧化剂,在常温下氧化反应26 h；合成视黄基席夫碱银盐的条件为80℃,反应4 h；在2～18 GHz范围内测定掺杂银盐的吸波性能,最好的反射率为～16 dB。     

新型视黄基席夫碱盐的合成与吸波性能研究

以维生素A醋酸酯为原料,通过水解,利用活性二氧化锰氧化得视黄醛,醛与联苯胺反应合成席夫碱,席夫碱掺杂金属银化合物制得新型视黄基席夫碱盐.研究了活性二氧化锰氧化试剂对产物产率的影响,并通过元素分析、红外光谱等对产物结构进行表征.研究结果表明,以活性二氧化锰为氧化剂,在常温下氧化时间为26 h;合成视黄基席夫碱银盐的条件为80 ℃反应4 h;测定掺杂银盐在2～18 GHz范围内最好的反射率为-16 dB.     

新型视黄基席夫碱盐的合成与吸波性能研究

以维生素A醋酸酯为原料,通过水解、利用活性二氧化锰氧化得视黄醛,醛与联苯胺反应合成席夫碱,席夫碱掺杂金属银化合物制得新型视黄基席夫碱盐;研究了活性二氧化锰氧化试剂对产物产率的影响,并通过元素分析、红外光谱等对产物结构进行表征。研究结果表明:以活性二氧化锰为氧化剂,在常温下氧化时间26 h;合成视黄基席夫碱银盐的条件为80℃反应4 h;测定掺杂银盐在2~18GHz范围内最好的反射率为-16 dB。     

含芳醚配体的芳茂铁盐的合成研究

以Lewis酸AlCl3为催化剂,分别考察了二茂铁与苯甲醚、二苯醚、苯基正丁基醚、苯基正辛基醚和苯基正十六烷基醚的配体交换反应.发现二茂铁与苯甲醚和二苯醚反应可以合成出带有醚键的芳茂铁盐,即(环戊二烯基-铁-苯甲醚)盐和(环戊二烯基-铁-二苯醚)盐,而二茂铁与苯基正丁基醚、苯基正辛基醚和苯基正十六烷基醚的反应产物均为(环戊二烯基-铁-苯酚)盐.通过FT-IR和 1HNMR对上述产物进行了结构表征,并提出了可能的反应机理.     

一种含二茂铁基水杨醛席夫碱的合成及性质表征

通过4-(2-二茂铁乙炔基)苯胺与水杨醛缩合反应得到一种新的含二茂铁基水杨醛席夫碱1,并研究了其对不同金属离子电化学及紫外-可见光谱的识别性质。结果表明,1对Cr3+有很好的紫外-可见光谱及电化学信号响应:其位于467nm的Fe(Ⅱ)→Cp的荷移光谱红移至502nm,同时Fe(Ⅲ)/Fe(Ⅱ)电位发生了～20mV的阳极移动。     

一种新型含硫二茂铁基席夫碱的合成、表征及配位反应

合成了4-氨基-3-苯基-5-巯基-1,2,4-三氮唑,并与乙酰二茂铁反应,制备了二茂铁基的4-氨基-3-苯基-5-巯基-1,2,4-三氮唑Schiff碱,并以此席夫碱作为新型配体,研究了其与过渡金属Cd的配位作用,全部产物用IR进行了表征。     

十二烷基苯磺酸掺杂聚苯胺的性能研究

用十二烷基苯磺酸 (DBSA)对本征态聚苯胺 (PAn)进行掺杂 ,得到溶解性、成膜性和光电性能俱佳的掺杂态聚苯胺。红外光谱研究表明 :DBSA掺杂PAn的吸收峰都向低频方向移动。探讨DBSA浓度、掺杂温度和时间以及洗涤滤液pH值对聚苯胺电导率的影响。结果表明 :当c(DBSA) =1 0mol/L ,T =32 3K ,t=8h ,洗涤滤液 pH =3时 ,聚苯胺的电导率为 0 90 9S/cm。紫外 -可见吸收光谱表明 ,掺杂态聚苯胺的吸收峰变宽而且发生红移。X射线衍射在 2θ =8 86°,1 7 7° ,2 1 4°和 2 6 7°处出现 4个较强的低角度衍射峰 ,表明DBSA掺杂的聚苯胺具有较强的结晶性能。     

Tuning of BiFeO3 multiferroic properties by light doping with Nb

Bulk ceramic samples of BiFeO₃ were light doped (up to 1%) with Nb⁵⁺ in the place of Fe³⁺ (B-site doping) and their multiferroic properties were investigated using XRD, SEM, polarization (PMTS) and magnetization (SQUID) techniques. It is shown that even the small percentages of doping can notably change electric and magnetic behavior. Electric conductivity differs by two orders of magnitude between samples doped with 0.2% and 1% Nb. The ferroelectric behavior strongly depended on conduction mechanism, and transition from space-charge-limited current (SCLC) conduction to trap-filled limited (TFL) conduction regime reflected on a change in hysteresis patterns, particularly for the samples with 0.2% and 0.5% Nb. Separation of ZFC-FC magnetization curves occurred for all Nb concentrations and increased with Nb doping. Weak ferromagnetic behavior and the increase of remnant magnetization with Nb concentration was observed from the hysteresis measurements. Coercive field changed drastically compared to the pure BiFeO₃, namely, the sample with 1% Nb exhibited very high coercive magnetic field of ~ 10?kOe.     

Conductivity Studies of Silver‐, Potassium‐, and Magnesium‐Doped Hydroxyapatite

We report the electrical transport properties of silver‐, potassium‐, and magnesium‐doped hydroxyapatites (HAs). While Ag+ or K⁺ doping to HA enhances the conductivity, Mg⁺² doping lowers the conductivity when compared with undoped HA. The mechanism behind the observed differences in ionic conductivity has been discussed using the analysis of high‐temperature frequency‐dependent conductivity data, Cole–Cole plots of impedance data as well as on the basis of the frequency dependence of the imaginary part (M″) of the complex electric modulus. The f_max of modulus M″ decreased in silver‐ and potassium‐doped samples in comparison with the undoped HA.     

流延法制备8YSZ薄膜

采用非水基流延法制备了8mol%氧化钇稳定氧化锆薄膜,研究了球磨时间、固含量、有机添加剂含量及除泡工艺对8YSZ浆料流变性能的影响,通过SEM表征烧结体表面形貌,用电化学阻抗仪对烧结体进行电导率测试。结果表明:分散剂用量1.25wt%,球磨时间15h,浆料的粘度最小,分散效果最好;增塑剂与粘结剂比例为0.7,粘结剂加入量6.5～8.5wt%,二次球磨后,真空除泡可获得适合流延的浆料;生坯1450℃烧结4h,烧结体晶界清晰、致密度较好;烧结体在300～800℃随温度的升高电导率逐渐增大,在800℃时离子电导率达0.046S/cm。     

Electrical charge transport and optical properties of a poly(methacrylate) with a new side chain and its Ni(II) complex

The electronic conductivity of poly[2‐(2‐hydroxybenzyliden hydrazino)thiazole‐4‐yl methyl methacrylate] bearing a thiazole ring, Schiff base, and hydroxyl group in its side chain and its Ni(II) complex were measured as functions of temperature and frequency. The electrical measurements show the semiconducting nature of the samples as their electrical conductivity increased with increased temperature. Also, the activation energies were below 2 eV, which places them in the semiconductor regime. The conduction mechanism in the samples is discussed. Although extrinsic conduction mechanism occurs in the polymer, intrinsic conduction mechanism take places in its metal complex. The optical absorption spectra were recorded at room temperature and the optical energy gaps of samples were determined by optical spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 741–746, 2003     

Structural,optical, and magnetic studies of manganese-doped zinc oxide hierarchical microspheres by self-assembly of nanoparticles

In this study, a series of manganese [Mn]-doped zinc oxide [ZnO] hierarchical microspheres [HMSs] are prepared by hydrothermal method only using zinc acetate and manganese acetate as precursors and ethylene glycol as solvent. X-ray diffraction indicates that all of the as-obtained samples including the highest Mn (7 mol%) in the crystal lattice of ZnO have a pure phase (hexagonal wurtzite structure). A broad Raman spectrum from as-synthesized doping samples ranges from 500 to 600 cm^-1, revealing the successful doping of paramagnetic Mn²⁺ ions in the host ZnO. Optical absorption analysis of the samples exhibits a blueshift in the absorption band edge with increasing dopant concentration, and corresponding photoluminescence spectra show that Mn doping suppresses both near-band edge UV emission and defect-related blue emission. In particular, magnetic measurements confirm robust room-temperature ferromagnetic behavior with a high Curie temperature exceeding 400 K, signifying that the as-formed Mn-doped ZnO HMSs will have immense potential in spintronic devices and spin-based electronic technologies.     

Effect of composition on the conductivity and morphology of ligno sulfonic acid sodium salt doped polyaniline

A systematic approach is developed to study the ligno sulfonic acid sodium salt (LSA) protonation or doping process with polyaniline emeraldine base (Pani‐EB) in organic solvents like dimethyl sulfoxide, and the influence of LSA‐doping on the properties of polyaniline was investigated in detail. The composition of Pani‐EB and LSA was varied in the weight ratio of 1:1 to 1:50 to investigate the effect of the dopant concentration on the conductivity and morphology. The doping process was confirmed by UV–vis and FTIR spectroscopes. The composition analysis indicates that only 50% of the LSA is used for the doping process irrespective of the weight ratio of LSA/Pani‐EB in the feed. The four probe conductivity measurement suggests that the conductivity of the doped samples are increasing with the increase in the ratio of Pani‐EB/dopant composition, and the high conductivity of the doped material was obtained in the range of 1.0 × 10^?2 S/cm. Scanning electron microscopy reveals that LSA induces a selective aggregation in the polyaniline chains to produce needlelike or rod‐shape morphology of sizes having ～0.2 μm diameter and 1 μm length. At very higher amount of LSA, the microrods are completely collapsed and form uniform continuous morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2650–2655, 2006     

Electrically conductive foamed polyurethane/silicone rubber/graphite nanocomposites as radio frequency wave absorbing material: The role of foam structure

Radio frequency wave absorber nanocomposites based on a flexible polyurethane (PU) foam has been manufactured by impregnation of the foam in n‐hexane solution of room temperature vulcanizing silicone rubber (SR), hybridized with graphite nanosheets (GNs) called doping solution. After impregnation, dried samples were kept at ambient temperature for the curing of the soaked graphitized SR. To evaluate the influences of the PU foam structural parameters on electrical conductivity, permittivity, and reflection loss characteristics, various foams with different structures were impregnated in the crosslinkable doping solution. Electrical conductivity, real, and imaginary parts of permittivity were measured within the frequency range of 4–6 GHz via performing waveguide measurements. The coarse thick wall PU foam sample exhibited higher conductivity and permittivity than the fine wire mesh sample having similar amounts of conductive SR/GN doping agent. Moreover, nanocomposites based on coarse foam samples showed higher potential for the wave absorption at lower absorber thickness than the fine wire mesh PU foam. The higher conductivity and hence imaginary permittivity of the coarse structure is attributed to the better coincidence of conductive paths in the PU/SR/GN nanocomposite foam with lines of electric field of the incident wave. The higher real permittivity of the coarse nanocomposite is suggested to be related to the more mutual interactions between graphite nanolayers and aggregates which form a network of minicapacitors in the structure of nanocomposites, leading to a higher capacitance and hence more real permittivity. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Dy-modified barium calcium titanate sintered in a reducing atmosphere: Crystal structure,microstructure, and electrical characteristics

The microstructure, crystal structure, and electrical properties of calcium-doped BaTiO₃ (BCT) sintered at 1180 °C for 1 h in a reducing atmosphere were investigated in this study. A detailed mechanism for improving the reliability of Dy-modified BCT sintered in a reducing atmosphere has been proposed. Ca in BCT mostly substituted for Ba and occupied A-site, according to the Rietveld analysis. The Dy³⁺-added sample revealed a core-shell structure with lamellar domain walls in the core region, as seen in TEM images. Curie temperature and dielectric constant increased as calcium concentration increased. Dy³⁺ doped samples had a higher Curie temperature and dielectric constant than non-doped samples. The Dy-doping and substitution of Ca²⁺ for Ba²⁺ can significantly increase the grain conductivity activation energy for Dy-doped BCT sintered under reduction atmosphere. It suggests that Dy³⁺ and Ca²⁺ doping can effectively suppress the formation of oxygen vacancies and inhibit their movement, potentially improving the HALT of BME-MLCC.