磁性羧甲基化壳聚糖纳米粒子的制备与表征

以化学共沉淀法制备了Fe3O4纳米粒子,壳聚糖经羧甲基化改性后接枝在Fe3O4颗粒表面,得到了磁性羧甲基化壳聚糖(Fe3O4/CMC)纳米粒子.利用透射电镜(TEM)、X射线衍射(XRD)、傅立叶红外光谱(FT-IR)及磁性测试对产物进行了表征.TEM表明Fe3O4纳米粒子被CMC包覆,粒径约10 nm;XRD分析表明复合纳米粒子中磁性物质为Fe3O4;FT-IR表明壳聚糖发生羧甲基反应以及在Fe3O4表面的接枝反应.Fe3O4/CMC纳米粒子具有超顺磁性,比饱和磁化强度25.73 emu/g,有良好的磁稳定性.     

聚苯乙烯/Fe3O4纳米复合材料的制备与表征

采用油酸为表面活性剂表面处理Fe3O4纳米粒子,将其分散在苯乙烯单体中,进行原位聚合,制备PS/Fe3O4纳米复合材料,对该复合材料的分散均匀性和结构进行了表征.实验结果显示,Fe3O4粒子在PS基体中分散均匀;包覆油酸的Fe3O4纳米粒子在基体中起到物理和化学交联点的作用,使得聚合物产生交联,并提高了其耐热性.     

巯基表面修饰磁性复合纳米粒子用于重金属离子去除的研究

采用化学共沉淀法合成磁性Fe3O4纳米粒子,并且利用正硅酸乙酯（TEOS）的水解和凝聚作用在Fe3O4纳米粒子表面沉积包覆一层SiO2,合成核壳式的Fe3O4@SiO2复合纳米粒子。以Fe3O4@SiO2纳米粒子为基体,将（3-巯基丙基）三乙氧基硅烷嫁接到纳米粒子表面,制备出巯基功能化的纳米材料,将其应用于对重金属离子...     

Co_3O_4纳米粒子的表面接枝改性研究

以含乙烯基的硅烷偶联剂(A-151)处理Co3O4纳米粒子,在Co3O4粒子表面引入乙烯基,然后以K2S2O8为引发剂,十二烷基苯磺酸钠(SDBS)为乳化剂,采用乳液聚合,在Co3O4粒子表面接枝甲基丙烯酸丁酯,研究了影响Co3O4纳米粒子表面接枝的有关因素,并优化工艺参数。采用红外光谱、X射线光电子能谱等手段对表面接枝进行了表征。结果表明,甲基丙烯酸丁酯已经被成功地接枝到纳米Co3O4粒子的表面。热流传感器的热流灵敏度测试结果表明,Co3O4粒子表面改性后,它与硅树脂的复合涂层提高了热流传感器的热流灵敏度,相对于未处理的Co3O4粒子涂层,传感器灵敏度从0.052 mV.cm2/W提高到了0.065 mV.cm2/W。     

环糊精功能化的Fe_3O_4@Au纳米粒子

制备了Fe3O4@Au纳米粒子,再通过两步法制备了全-6-硫代-β-环糊精,并用自组装法将β-环糊精修饰在纳米粒子表面,获得了环糊精功能化的Fe3O4@Au纳米粒子(Fe3O4@Au-β-CD)。实验发现,外界磁场作用下,复合纳米粒子具有快速响应性能;Fe3O4@Au-β-CD的紫外可见光谱中出现了Au特征吸收峰;透射电镜显示该粒子形貌呈球形,粒径在15.5nm左右;X射线光电子能谱中表明β-CD已修饰到纳米粒子表面;通过分别对比修饰前后Au、S的单谱,可知是β-CD通过Au-S键修饰到Fe3O4@Au表面;Fe3O4@Au-β-CD的红外光谱中出现了β-CD的特征峰,而且巯基吸收峰消失,确证了β-CD修饰到粒子表面;热重分析表明粒子表面β-CD的含量约为26.4%。     

热分解法制备多壁碳纳米管负载铁氧体纳米粒子复合材料

以乙酰丙酮铁作为铁源,三甘醇作为溶剂,采用热分解法制备了原始以及酸化后的多壁碳纳米管负载铁氧体纳米粒子的复合材料。并用扫描电子显微镜(TEM)、X射线衍射(XRD)、穆斯堡尔谱等分析了材料的微观结构和特性。结果表明,铁氧体纳米粒子均匀地修饰在碳纳米管表面,没有明显团聚现象产生,酸化后的碳纳米管表面生成的纳米粒子中包含了Fe3O4与Fe2O3两种粒子。碳纳米管经酸化后,其表面生成了许多缺陷,缺陷处的活泼电子更容易与生成的Fe3O4纳米粒子的外层电子之间进行快速的电子交换,使得Fe3O4纳米粒子中的FeⅡ被部分氧化,使生成的铁氧体纳米粒子更多地表现为Fe2O3的特性。     

纳米Fe3O4/聚苯胺复合粒子的制备及其磁性能研究

用水解沉淀法制备纳米Fe3O4,然后在其溶液中原位合成聚苯胺,得到纳米Fe3O4/聚苯胺复合粒子.通过XRD、TEM、JDM等测试对纳米复合粒子的形态、结构及磁性能进行了研究.实验制备的纳米Fe3O4粒子粒径为30nm左右,在其表面沉积聚苯胺后,复合粒子的粒径达到了50nm左右.与纳米Fe3O4粒子相比,纳米Fe3O4/聚苯胺复合粒子的XRD峰形变得更为明锐.纳米复合粒子的磁性能表现出软磁性,与纳米Fe3O4粒子相比,矫顽力减小为0,这可以大大减小材料的磁滞损耗和退磁难度,性能得到改善.     

Fe2O3纳米粒子的醋酸改性对其催化高氯酸铵热分解的影响

利用表面改性法对Fe2O3纳米粒子进行醋酸改性,用TEM和纳米粒度测试仪对Fe2O3纳米粒子进行了形貌和粒度表征,用FTIR和XPS对改性后的Fe2O3纳米粒子进行了结构表征,用DTA研究了醋酸改性处理对Fe2O3纳米粒子的高氯酸铵(AP)热分解催化性能的影响.结果表明,用凝胶-溶胶法制备了平均粒径为40nm,窄粒度分布的Fe2O3纳米粒子,醋酸改性处理改善了Fe2O3纳米粒子的分散性.FTIR和XPS结果表明,Fe2O3纳米粒子与醋酸分子发生了化学键合.DTA结果表明,Fe2O3纳米粒子的醋酸改性能提高Fe2O3纳米粒子的AP热分解催化性能;随着Fe2O3纳米粒子含量的增加,醋酸改性的效果越明显.     

聚苯胺/Fe3O4纳米复合材料在初始中性溶液中的制备与表征

在没有加酸并含有阳离子表面活性剂十六烷基三甲基溴化铵的Fe3O4纳米粒子悬浮液中,采用原位化学氧化聚合法制备了聚苯胺/Fe3O4纳米复合材料,并用高分辨透射电镜(HRTEM)、红外(FT-IR)、X射线衍射(XRD)、振动样品磁强计等对此纳米复合材料的形貌、结构和电磁性能进行了研究,对此纳米复合材料的形成机理也作了分析.研究结果表明Fe3O4纳米粒子被聚苯胺所包覆.Fe3O4纳米粒子和聚苯胺之间存在着一定的相互作用,以利于Fe3O4纳米粒子被聚苯胺所包覆.此纳米复合材料兼具导电性和磁性,Fe3O4的含量对其电磁性能影响很大,随着Fe3O4含量的增加,其室温电导率随之降低,而其饱和磁化强度则随之增加.     

油酸对微波水热法制备的纳米Fe_3O_4的影响

采用微波水热法制备纳米Fe3O4,并用油酸对其进行表面改性,获得油酸包覆的Fe3O4纳米粒子。利用XRD、FT-IR、TEM和振动样品磁强计对Fe3O4纳米粒子的结构、形貌、磁性能进行表征。结果表明:表面改性使得油酸分子中—COOH和Fe离子形成化学键;改性后的纳米Fe3O4粒子为粒度均匀的球形,具有良好的分散性,平均粒径约8nm;该产物具有超顺磁性,饱和磁化强度为61.8emu/g。     

Mn4+-掺杂锂钒氧化物的合成及其电化学性能

以LiOH·H2O、NH4VO3和Mn(CH3COO)2·4H2O为原料,以柠檬酸(C6H8O7·H2O)为络合剂,用凝胶溶胶法按xLiV3O8·yLiMn2O4(x∶y=1∶0,4∶1,8∶l,12∶1,16∶1)合成出锂离子电池正极材料Mn4+-LiV3O8,并对其结构和电化学性能进行了研究.结果表明,用该法制备的...     

Investigation of a new In2O3-based selective H2 gas sensor with low power consumption

The nanometer-size In₂O₃ was synthesized via a reverse microemulsion. A new catalytic combustion-type In₂O₃-based H₂ gas sensor was developed based on the technology for fabricating the direct-heating-type sensor and a surface-modifying process. A dense SiO₂ layer near the surface of the sensor was formed by chemical vapor deposition (CVD) of hexamethyldisiloxane (HMDS). The SiO₂ layer, which acted as a molecular sieve, reduced the penetration of large molecular, such as C₂H₅OH, CH₄, i-C₄H₁₀, into the sensing layer, resulting in the improvement of selectivity to H₂. The sensitive properties and the working mechanism of the sensor were presented. The In₂O₃ nanoparticles prepared by microemulsion were characterized by transmission electron microscopy and X-ray diffraction.     

INCORPORATED C70 IN SOL AND GEL

C₇₀ is incorporated in gel by a sol-gel process with using 3-amino-propyltriethoxysilane (NH₂(CH₂)₃Si(OC₂H₅)₃, APTS) and 3-glycidoxypropltrimethoxysilane (CH₂OCHCH₂O(CH₂)₃Si(OCH₃)₃, GPTMS) as precursors. C₇₀ is firstly mixed with APTS to form C₇₀-NH₂(CH₂)₃Si(OC₂H₅)₃ compound by the reaction between C₇₀ and amino-group of APTS, and then the compound is hybridized with GPTMS to form solid gel. The linkage of C₇₀ and APTS is estimated and confirmed with FT-IR spectra, and the UV/Visible spectra of the sol and gel are measured.     

An investigation by electron spectroscopy for chemical analysis of chemical treatments of the (100) surface of n-type InP epitaxial layers for Langmuir film deposition

The surface chemistry of InP substrates used for the fabrication of electronic devices (MIS structures) was examined by ESCA. Spectroscopic data on related materials such as indium metal, plasma-oxidized indium metal, In₂O₃, InPO₄(xH₂O), P₄O₁₀, AlPO₄, (C₆H₅O)₃PO and (C₆H₅)₃P were collected so as to aid the assignment of components in the spectra of as-received and etched InP surfaces on the basis of the chemical shifts and the intensity ratios. Surface features of InP substrates from several batches were examined in the as-received and the chemically etched forms. The effectiveness of several types of etchants and the features thus produced on the substrate surface were evaluated and are discussed.     

几种改性剂对稻草纤维/ABS复合材料挥发性有机化合物释放的影响

以稻草纤维及丙烯腈-丁二烯-苯乙烯（ABS）为原料,分别以活性炭、Al₂O₃、SiO₂为改性剂,通过混炼-模压工艺制备了稻草纤维/ABS复合材料,采用热重-质谱联用仪对复合材料的挥发性有机化合物（VOC）释放情况进行对比分析,探讨了几种改性剂对稻草纤维/ABS复合材料VOC释放的影响。研究发现:ABS及稻草纤维均能在热解过程中释放CH₂O、C₂H₄O及C₃H₄O,而C₆H₆、C₇H₈、C₈H₈等苯类及烷烃类物质的释放源则主要为ABS;活性炭的添加能够显著降低稻草纤维/ABS复合材料的VOC释放,其VOC释放总量降低了55.5%;Al₂O₃和SiO₂虽然能比较明显地降低复合材料中苯类物质的释放含量,分别降低了32.4%和30.9%,但是其中的Fe、Cu等金属杂质却能够催化醛类物质的产生,导致VOC释放总量分别增加了11.8%和235.7%。      

Effect of preparation conditions on properties of atomic layer deposited TiO2 films in Mo–TiO2–Al stacks

TiO₂ films were grown by atomic layer deposition on Mo electrodes in order to elucidate the dominating conductance mechanism and its dependence on the growth chemistry. TiCl₄ and Ti(OC₂H₅)₄ served as titanium precursors, and H₂O or H₂O₂ as oxygen precursors. The films grown at lower temperatures were amorphous. With increasing growth temperatures the crystallization first started in the TiCl₄–H₂O process. The films grown in this process were clearly leakier compared to the films grown from Ti(OC₂H₅)₄ and H₂O and from Ti(OC₂H₅)₄ and H₂O₂. In the Ti(OC₂H₅)₄-based processes, the application of H₂O₂ instead of H₂O resulted in the films with considerably lowered conductivity, although structural differences in these films were insignificant. Space–charge-limited currents were prevailing in all our amorphous Mo–TiO₂–Al packages. Measurements at different temperatures suggested quite high trap densities likely due to the presence of impurities and structural disorder, while the strong differences in conductivity seemed to be due to different densities of gap states.     

Fe3O4/PNIPAM纳米复合微球的制备

用化学共沉淀法制备Fe₃O₄磁性纳米粒子,以N-异丙基丙烯酰胺（NIPAM）、N,N′-亚甲基双丙烯酰胺（MBA）和偶氮二异丁腈（AIBN）为原料,用种子乳液聚合法制备了具有温敏性的Fe₃O₄/PNIPAM纳米复合微球。用红外光谱仪（FTIR）、透射电镜（TEM）、热重分析仪（TGA）及Zeta粒度仪（DTS）等手段对复合微球进行了表征,研究了单体（NIPAM）、交联剂（MBA）、乳化剂（SDBS）用量对复合微球粒径及磁含量的影响。结果表明:Fe₃O₄/PNIPAM纳米复合微球呈球形,具有温敏性,反应条件对复合微球的结构和形貌有较为显著的影响,其粒径和磁含量随着单体浓度的减少、交联剂和乳化剂用量的增加而变小。     

苯胺-SrTi(C2O4)2颗粒制备及其电流变性能

用沉淀法制备了苯胺-草酸氧钛锶（SrTi（C₂O₄）₂）颗粒。FTIR分析表明,苯胺已引入到SrTi（C₂O₄）₂颗粒的表面;XRD分析表明,苯胺-SrTi（C₂O₄）₂颗粒为含少量结晶的无定形态。采用SEM观察颗粒的形貌,结果表明,随反应体系中苯胺与钛原子物质的量比n_aniline/n_Ti的增大,苯胺-SrTi（C₂O₄）₂颗粒由近似球状（n_aniline/n_Ti =0）变为多面体状（n_aniline/n_Ti =2）,而后变为棒状与团簇状颗粒的混合体系（n_aniline/n_Ti =3）。以苯胺-SrTi（C₂O₄）₂颗粒为分散相制备颗粒质量分数为66.7%电流变液,电流变性能测试结果表明,在n_aniline/n_Ti =2时,电流变液具有较高的剪切应力和剪切屈服强度、较大的漏电流密度。苯胺在颗粒制备过程中起控制颗粒形貌的作用,在电流变液体系中起极性分子的作用,其对苯胺-SrTi（C₂O₄）₂电流变液性能的影响是两种效应综合作用的结果。     

Fe3O4-MWCNTs在环氧树脂中的定向排列

用共沉淀法制备了具有超顺磁性Fe₃O₄-MWCNTs（多壁碳纳米管）复合粒子,加入环氧树脂（EP）中,在0.6 T的弱定磁场下固化成型。采用TEM研究其定向程度及分散性,并进行动态热机械分析、差热分析和导热率测试。结果表明,MWCNTs表面包覆了磁性Fe₃O₄纳米粒子,Fe₃O₄-MWCNTs复合物按照首尾衔接的方式沿着磁场方向定向排列。Fe₃O₄-MWCNTs/EP纳米复合材料表现出明显的各向异性,垂直于Fe₃O₄-MWCNTs轴向导热率低于平行方向的导热率,Fe₃O₄-MWCNTs的加入对于平行方向的导热率影响不大。Fe₃O₄-MWCNTs的加入使环氧树脂的储能模量变小,损耗模量变大,损耗因子均大于纯环氧树脂,表现出良好的阻尼性能。当Fe₃O₄-MWCNTs与EP质量比为0.3%时,损耗因子在20 ℃的温域内大于0.7,最高值达到1.16。     

Arylation of [60]Fullerene with Br2/FeCl3/PhH: Formation of C58 Derivatives via CO Loss

Heating a mixture of [60]fullerene, bromine, ferric chloride and benzene under reflux for 24 h products a range of phenylated [60]fullerene derivatives. The main product is C₆₀Ph₅H but other components identified by mass spectrometry (and in some cases separated by HPLC) are: C_6oPh_n(n = 4, 6, 8, 10, 12), C₆₀Ph_nO₂(n = 4, 6, 8, 10, 12), C₆₀Ph_nOH (n = 7, 9, 11), C₆₀Ph_nH₂ (n = 4, 10), C₆₀Ph₄H₄, C₆₀Ph₅H₃, C₆₀Ph_n0₂H (n = 5, 9), C₆₀Ph₄C₆H₄O₂, C₆₀Ph₉OH₃, and C₆₀Ph₁₁ O₃H₂. In the corresponding reaction with toluene, the crude reaction mixture contained C₆₀(MeC₆H₄)₄ as a main product; C₆₀(ClC₆H₄)₅H was obtained from the reaction with chlorobenzene. Formation of these derivatives is believed to involve radical bromination of the fullerene, followed by electrophilic substitution of the hatogenofullerene into the aromatic, accompanied in some case by hydrolysis, elimination and epoxide formation; oxidation may also introduce ketone/dioxetane functionality. The EI mass spectra of C₆₀Ph₄O₂ and C₆₀Ph₈O₂show degradation to C₅₈Ph_n (n = 0-8), having structures believed to be related to the pseudofollerenes C₆₈Ph_n (n = 0-8) reported recently. These results suggest that some derivatisations of fullerenes confer stability, due to the relief of strain.