自组装中孔BCN化合物的合成与表征

以三聚氰胺和硼氢化钠为原料合成具有中孔结构的新颖硼碳氮(BCN)化合物,采用热质量-差示扫描量热(TG-DSC)、X线衍射(XRD)、氮吸附比表面积(BET)、傅立叶红外光谱(FT-IR)、扫描电镜(SEM)、透射电镜(TEM)和荧光光谱(PL)等分析手段对BCN化合物进行表征,研究BCN化合物光致发光性能。结果表明:热分解温度在600℃以上可制备出具有层状石墨结构的BCN化合物。随热分解温度升高至800℃,B、N含量增大,C含量减小,得到化学计量比为2∶1∶2的B2 CN2化合物。荧光光谱(PL)测试证明BCN化合物具有光致发光性。     

先驱体制备富氮BCN化合物的热解过程

以三聚氰胺和硼酸为原料在水溶液中反应合成出了C3N6H6(H3BO3)2先驱体,利用热重-差示扫描量热-质谱(TG-DSC-MS)联用技术及FT-IR, XRD, SEM等对由C3N6H6(H3BO3)2热解制备BCN化合物的过程进行了表征研究. 结果表明,先驱体C3N6H6(H3BO3)2是由C3N6H6分子和H3BO3分子通过分子间氢键作用形成的三维超分子结构化合物. 随热解温度的升高,先驱体中的H3BO3和C3N6H6结构单元逐渐发生分解,同时依次放出H2O, NH3, CO2, NO2等气体. 1000℃之后热解过程基本结束,产物中形成B-N, B-C和C-N化学键,得到B, C, N原子级化合的具有乱层石墨结构的BCN化合物. XPS分析结果表明,1900℃热解得到了组成近似为B3CN3的新型富氮BCN化合物. SEM观察表明,B3CN3具有与先驱体相同的棒状或纤维状形貌,但晶体尺寸较先驱体减小.     

细菌纤维素纳米晶稳定液体石蜡Pickering乳液的制备

采用生物法合成了高纯度的细菌纤维素(BC),通过浓硫酸水解制得细菌纤维素纳米晶(BCN)。以液体石蜡为油相,BCN为固体乳化剂,在超声作用下制得O/W型Pickering乳液。通过SEM,TEM,FT-IR,XRD,接触角测量仪及激光粒度和Zeta电位分析仪对BC及BCN进行了表征。考察了BCN质量浓度、水相p H和离子强度对Pickering乳液稳定性的影响。结果表明,BC在浓硫酸水解过程中发生了氧化反应,其水解主要发生在无定型区,使所得BCN的结晶指数高达97%。BCN悬浮液的粒径和Zeta电位值分别为462.5 nm和-40.8 m V,其三相接触角为95.7°,具有良好的乳化性能。在超声乳化作用下制得的乳液粒径大小为8.6~17.3μm。通过调控水相p H能够改变BCN表面电荷密度,从而改变乳液的稳定性,随着水相p H的增大,乳液相体积分数增大,乳液稳定性增强。随着Na Cl浓度的增大,乳液的稳定性降低,乳液相体积分数减小。此外,SEM的观测结果表明,BCN在稳定Pickering乳液过程中呈现纤维线条和聚集体颗粒2种形态。     

氮化硼晶须的制备及其表征

利用先驱体转化法制备氮化硼晶须。利用三聚氰胺和硼酸为原料,利用水浴加热方法,生成一种BCN化合物先驱体。将该先驱体化合物在不同的温度段进行热处理后得到氮化硼晶须。借助SEM,FT-IR表征手段分析了不同温度热处理后晶须微观形态以及内部分子结构的变化,并用XRD,TEM等测试手段对最终晶须进行了表征。结果表明：所制备的氮...     

硼碳氮多孔材料的制备及其吸附再生性能研究

硼碳氮(BCN)多孔材料因其具有高的比表面积、优异的化学稳定性而被认为是一种优异的吸附材料。本文以废弃椰壳、硼酸(H₃BO₃)和尿素(CO(NH₂)₂)为原料,采用冷冻干燥法制备多孔生胚,并在NH₃气氛下通过高温固相反应法在不同的反应温度下合成BCN多孔材料。结果表明,随着反应温度的升高,BCN多孔材料孔径逐渐变大,当反应温度为950 ℃时平均孔径为2.1 nm。将BCN多孔材料用于吸附水中孔雀石绿(MG)有机染料,其最大吸附量可达1 239.8 mg·g^-1,5次循环再生后吸附量平均值仍高达1 138.6 mg·g^-1,说明BCN多孔材料具有优异的循环吸附性能。采用Langmuir和Freundlich等温吸附模型、准一级和准二级吸附动力学模型研究了浓度、吸附时间和平衡吸附量之间的关系。结果表明,BCN多孔材料的吸附与准二级吸附动力学模型吻合,其对MG的吸附属于均匀表面单层分子的Langmuir等温吸附。BCN多孔材料展现出优异的吸附能力,是一种非常有应用前景的新型吸附剂。     

基于细菌纤维素纳米纤维构建的高吸水性凝胶的研究

以可降解的细菌纤维素纳米纤维（Bacterialcellulosenanofiber,简称BCN）为骨架材料,丙烯酸经热引发自由基聚合方式在BCN上的形成复合水凝胶,探讨了BCN用量对水凝胶的性能影响。在此基础上,改变干燥方式对水凝胶干燥,制备出多孔型水凝胶材料。通过扫描电子显微镜、傅里叶红外光谱仪及热重分析仪对水凝胶进行表征,并结合水凝胶材料的吸水与保水性能的测试结果,探究水凝胶结构与性能间关系。结果表明：丙烯酸溶液中添加2.5%的BCN,聚合得水凝胶,经真空冷冻干燥形成的材料（hy-L-2）,在25℃条件下浸泡48 h,吸水率可达32.82 g/g,较自然干燥的材料（hy-H-2）的吸水率提高了2.47倍。并且hy-L-2在25℃、相对湿度50%的条件下放置6 h,其保水率仍高达93.44%。     

液晶化合物的研究进展

综述了近年液晶化合物的研究和发展现状,从含氟液晶化合物、偶氮苯类液晶化合物和环己烷类液晶化合物三方面介绍了相关液晶化合物的合成及性能,并就液晶化合物今后的发展前景进行了分析与展望。     

液晶化合物的研究进展

综述了近年液晶化合物的研究和发展现状,从含氟液晶化合物、偶氮苯类液晶化合物和环己烷类液晶化合物三方面介绍了相关液晶化合物的合成及性能,并就液晶化合物今后的发展前景进行了分析与展望。     

源于低聚含氟丙烯酸酯的聚氨酯

本发明涉及含氟聚氨酯化合物、其制备方法、应用方法、和包含所述含氟聚氨酯化合物的组合物。含氟聚氨酯化合物和包含该化合物的组合物适合赋予基质以持久的拒油拒水性。     

五味子化学成分的分离和结构鉴定

目的研究五味子中木脂素类化学成分。方法应用正相硅胶柱色谱、ODS柱色谱、制备型和分析型HPLC及重结晶等方法对五味子提取物的乙酸乙酯部位的化学成分进行了系统研究。结果从五味子乙酸乙酯部位中分离得到了8个化合物,鉴定化合物为五味子醇甲(化合物1)、邻苯二甲酸二丁酯(化合物2)、五味子甲素(化合物3)、柠檬酸双甲酯(化合物4)、柠檬酸单甲酯(化合物5)、五味子酯丙(化合物6)、Schinlignan E(化合物7),当归酰戈米辛H(化合物8)。结论化合物2为首次从本植物中分离得到。     

High-performance adsorptive desulfurization by ternary hybrid boron carbon nitride aerogel

Separation of aromatic organosulfur compounds is vital for upgrading the feed to clean fuel products, however, it remains a formidable challenge for the present adsorbents. Herein, a series of novel aerogel-like boron carbon nitride (BCN) with three-dimensional interconnected porous networks were fabricated via a hydrogel template and freeze-casting strategy. The as-prepared aerogel-like BCN had a variable carbon content and a flexible size of graphene domain on its porous structure. The optimal BCN aerogel represents the top-level of adsorptive desulfurization (ADS) capacity for aromatic organosulfur compounds (30.8 mg S/g adsorbent), strikingly higher than the state-of-the-art aerogels adsorbents (17.1 mg S/g adsorbent) reported under similar conditions. A selective adsorption for dibenzothiophene in the presence of aromatic hydrocarbons, nitrogen compounds were also achieved on BCN aerogel. The adsorption isotherm and XPS measurement reveal heterogeneous adsorption on the BCN aerogel via π–π and Lewis acid–base interactions.     

Copper‐Free Click Reactions with Polar Bicyclononyne Derivatives for Modulation of Cellular Imaging

The ability of cells to incorporate azidosugars metabolically is a useful tool for extracellular glycan labelling. The exposed azide moiety can covalently react with alkynes, such as bicyclo[6.1.0]nonyne (BCN), by strain‐promoted alkyne–azide cycloaddition (SPAAC). However, the use of SPAAC can be hampered by low specificity of the cycloalkyne. In this article we describe the synthesis of more polar BCN derivatives and their properties for selective cellular glycan labelling. The new polar derivatives [amino‐BCN, glutarylamino‐BCN and bis(hydroxymethyl)‐BCN] display reaction rates similar to those of BCN and are less cell‐permeable. The labelling specificity in HEK293 cells is greater than that of BCN, as determined by confocal microscopy and flow cytometry. Interestingly, amino‐BCN appears to be highly specific for the Golgi apparatus. In addition, the polar BCN derivatives label the N‐glycan of the membrane calcium channel TRPV5 in HEK293 cells with significantly enhanced signal‐to‐noise ratios.     

Proton-conducting ceramics as electrode/electrolyte materials for SOFC's—part I: preparation,mechanical and thermal properties of sintered bodies

The aim of these investigations was to prepare and to examine compounds of a high temperature solid oxide fuel cell with a proton conducting electrolyte in view of the mechanical and thermal properties. The powders were made by the conventional solid reaction of carbonates and oxides. The stoichiometry of the electrolyte Ba,Ca niobate (BCN) was varied with x=0, x=0.12 and x=0.18. As potential cathode material SrCeO₃ and SrZrO₃ stabilised with 5% Yb was prepared, and as anode material cermet of BCN and Ni with 50:50 wt.% was synthesised. The mechanical properties like bending strength (room and high temperature), Young modulus (E), modulus of rigidity (G), Poison's ratio, micro hardness and fracture toughness were measured on sintered samples. The highest values for bending strength, E and G could be found for BCN12 (156 MPa, 160 GPa, 63 GPa) and the cerate (175 MPa, 145 GPa, 56 GPa), the lowest for the cermet BCN/Ni (72 MPa, 68 GPa, 29 GPa). The investigation of the thermal properties of the bulk material showed a thermal stability to a temperature of 1400 °C. The thermal expansion coefficient measured at 1000 °C was found to be in the range of 10–12×10⁻⁶/K. Further investigations with respect to the mechanical and thermal properties have to be made for the whole system of cathode–electrolyte–anode.     

Influence of atomic bonds on electrical property of boron carbon nitride films synthesized by remote plasma-assisted chemical vapor deposition

Boron carbon nitride (BCN) films are synthesized with various growth conditions by remote plasma-assisted chemical vapor deposition method. The chemical bonding in the BCN film is modified by the growth condition. Optical and electrical properties are investigated for BCN films with various chemical bonding. Electrical characterization is carried out for the BCN films which have the same bandgap energy and different C composition ratio and have the same C composition ratio and different bandgap energy.     

Quantum chemical study of the electronic structure of new nanotubular systems: α-graphyne-like carbon, boron-nitrogen and boron-carbon-nitrogen nanotubes

Single-wall BN and BCN nanotubes in assumed α-graphyne-like wall structures are studied by means of the tight-binding band theory. The electron density of states, total energies and interatomic bond indices (crystal orbital overlap populations) are analyzed as a function of the composition, atomic structure and diameters of zigzag and armchair BN and BCN tubes. The results obtained are compared with the electronic properties of α-graphyne carbon- and graphite-like BN nanotubes.     

Study of Some Low Temperature Gas‐Generating Compositions

Some low temperature gas‐generating compositions, comprised of guanidine nitrate (GN), basic cupric nitrate (BCN), and ferric oxide (Fe₂O₃), were studied herein. The thermal decomposition properties and burning characteristics of GN/BCN/Fe₂O₃ mixtures were investigated by thermogravimetry/differential scanning calorimetry (TG/DSC), burning temperature measurements, automatic calorimetry, and X‐ray diffraction (XRD). This study showed that the maximum burning temperature of GN/BCN/Fe₂O₃ mixture (613 °C) was 31 % lower than that of GN/BCN mixture and the corresponding heat of combustion (2647 J g⁻¹) decreased by 15 %. When the GN/BCN/Fe₂O₃ mixtures were burning, Fe₂O₃ did not directly react with GN but with Cu (or CuO), which was produced by reaction between GN and BCN. The combustion process of GN/BCN/Fe₂O₃ grains could be divided into four stages: pre‐heated, condensed, combustion, and cooling.     

Influence of the methyl group on the dielectric constant of boron carbon nitride films containing it

LSI interconnect insulators made using low dielectric constant (low-k) materials are required for high performance devices with a small RC delay. We investigated a boron carbon nitride film containing the methyl group (Me–BCN) using tris-di-methyl-amino-boron (TMAB: B[N(CH₃)₂]₃) gas as a low-k material. In addition, we studied the influence of the methyl group on the dielectric constant (k-value) and the properties of the Me–BCN films. It was found that the k-value of the Me–BCN films decreases with increasing number of C–H bonds due to the methyl group (CH₃). The number of O–H bonds due to water incorporation is suppressed by increasing the number of C–H bonds. Consequently, we suggested that a lower k-value can be realized by the suppression of water invasion by a hydrophobic surface due to methyl bonds. Thus, the control of the methyl group is important to achieve a low-k material using Me–BCN films.     

Synthesis of BCN ceramics from pyrrolidine–Borane complex

BCN ceramics were prepared from pyrrolidine–borane complex. Its complex was a new product and has not appeared on the market. The chemical compositions of the BCN ceramics were BC_1·5N_0·4 obtained at 1000°C in Ar, BC_0·9N_0·4 obtained at 1000°C in NH₃. Boron was a mixture of trigonal and tetragonal BN bonds. Electrical conductivity, of the BCN ceramics showed semiconductive properties. ©     

Preparation and enhanced adsorption properties for CO2 and dyes of amino-decorated hierarchical porous BCN aerogels

Adsorption process is a cost-effective way to the dye removal and CO₂ capture. Improvements of the adsorption performance and conformance to the practical application conditions are necessary steps to approach practicality. Herein, hierarchical porous carbon-doped boron nitride (BCN) aerogels with amino modification were synthesized for the first time by freeze drying and carbothermal reduction method. As-prepared BCN aerogels exhibited superior adsorption performance for CO₂ and dyes. Compared with BN aerogel, notwithstanding the lower surface area, the as-prepared BCN aerogel exhibited 6-fold-enhanced CO₂ capture and higher dyes adsorption capacity, delivering a more than 150 times adsorption rate with methylene blue (MB) as the adsorbent. The reinforced adsorption properties were demonstrated to be primarily from the synergistic effect of carbon doping and amino decoration on the obviously improved adsorption energy, hydrophilicity and mesopore volume, accelerating the kinetics of dye and gas molecules diffusion. This work provides a new way on the design of high-efficiency absorbent materials.     

Microstructure and tribological properties of ternary BCN thin films with different carbon contents

Boron carbon nitrogen (BCN) thin films with different carbon contents are deposited on high-speed steel substrates by reactive magnetron sputtering (RMS) and their microstructure and tribological properties are studied. The BCN films with carbon contents from 26.9 wt.% to 61.3 wt.% have an amorphous structure with variable amounts of carbon bonds (sp²C–C, sp²C–N and sp³C–N bonds). A higher carbon content enhances the film hardness but reduces the friction coefficient against GCr15 steel balls in air. BCN films with higher hardness, lower friction coefficient, and better wear resistance can be obtained by increasing the carbon content.