钨磷酸/聚乙烯基吡咯烷酮纳米复合膜的光致变色性能

制备了一系列不同配比的钨磷酸/聚乙烯基吡咯烷酮纳米复合薄膜.通过原子力显微镜、红外光谱和紫外-可见吸收光谱对复合薄膜的结构和光致变色性能进行了研究.AFM结果表明,复合前后聚乙烯基吡咯烷酮表面形貌因杂多酸的掺杂而发生了显著变化.红外光谱分析结果表明,Keggin结构钨磷酸和聚乙烯基吡咯烷酮分子的基本结构在复合薄膜中仍然存在,乙烯基吡咯烷酮分子基团质子化后与杂多阴离子成盐,形成电荷转移桥.在紫外光照射下,复合薄膜由无色变为蓝色,在空气中暗处放置后复合膜重新恢复为无色.复合膜的升色速度和褪色速度均随着杂多酸含量的增加而加快.结果表明,杂多酸含量对复合膜的光致变色性能存在显著影响.     

光致变色化合物螺萘并噁嗪的合成及光谱性能研究

合成了一种含萘并螺噁嗪的光致变色化合物N-乙基-3,3-二甲基-5-甲氧基螺吲哚啉-2,3’-[3H]萘并[2,1-b][1,4]噁嗪。通过^1H NMR,IR和元素分析表征了它的分子结构,利用紫外光谱和荧光光谱初步探索了目标产物的光致变色性能。吸收光谱结果表明,目标分子的氯仿溶液经紫外光照射后,其开环体在587nm处有较强的吸收而呈现蓝色,停止紫外光照射,溶液恢复为无色,显示了良好的光致变色性能;发光光谱结果显示,目标分子经紫外光激发后其开环体在435nm处有较强的蓝光发射。     

Preparation and radar-absorbing properties of Al<Subscript>2</Subscript>O<Subscript>3</Subscript>/TiO<Subscript>2</Subscript>/Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>/Yb<Subscript>2</Subscript>O<Subscript>3</Subscript> composite powder

Al₂O₃/TiO₂/Fe₂O₃/Yb₂O₃ composite powder was synthesized via the sol-gel method. The structure, morphology, and radar-absorption properties of the composite powder were characterized by transmission electron microscopy, X-ray diffraction analysis and RF impedance analysis. The results show that two types of particles exist in the composite powder. One is irregular flakes (100-200 nm) and the other is spherical Al₂O₃ particles (smaller than 80 nm). Electromagnetic wave attenuation is mostly achieved by dielectric loss. The maximum value of the dissipation factor reaches 0.76 (at 15.68 GHz) in the frequency range of 2-18 GHz. The electromagnetic absorption of waves covers 2-18 GHz with the matching thicknesses of 1.5-4.5 mm. The absorption peak shifts to the lower-frequency area with increasing matching thickness. The effective absorption band covers the frequency range of 2.16-9.76 GHz, and the maximum absorption peak reaches -20.18 dB with a matching thickness of 3.5 mm at a frequency of 3.52 GHz.     

CNTs/TiO2 composites and its elect rochemical properties after UV light irradiation

Due to the unique structure and special physical and chemical properties, carbon nanotubes (CNTs) have potential applications in supercapacitors. Recently, CNTs and their composites as a kind of supercapacitor electrode material have been made many achievements. In this paper, a CNTs/TiO2 composite was prepared successfully with hydrothermal method, and was used as a supercapacitor electrode material. After the tests on surface chemistry and electrochemical property, it was found that: (1) the capacitance of the CNTs/TiO2 composite electrode increased by 56%, compared with pure CNTs electrode, (2) after UV light irradiation pretreatment, due to the special photoelectric effect of TiO2 which improves the interfacial property and electrochemical property of the composite electrode, the capacitance further increased by 53% when compared with the electrode without the pretreatment, and meanwhile, the cycle life also increased significantly, i.e., the capacitance was up to 97%, after 100 cycles of charge and discharge, (3) due to the improvement of the interfacial property, the ion transport in the composite electrode became smoother, and the pore utilization was also effectively enhanced during high-current charge and discharge, and (4) due to the generation of a large amount of oxygen-containing groups on the TiO 2 surface after UV pretreatment, the CNTs/TiO2 composite electrode earned extra large pseudo capacitance, and therefore the capacitance of the composite electrode was further increased. Based on the experimental results in the present study a new process to improve surface character and electrochemicalproperty of the electrode has been developed by using a metal oxide as both pseudo capacitive material and surface modification material of the composites with a UV light irradiation.     

Structure and photocatalytic properties of TiO<Subscript>2</Subscript>-Graphene Oxide intercalated composite

TiO2-Graphene Oxide intercalated composite (TiO2-Graphene Oxide) has been successfully prepared at low temperature (80°C) with graphite oxide (GO) and titanium sulfate (Ti(SO4)2) as initial reactants.GO was firstly exfoliated by NaOH and formed single and multi-layered graphite oxide mixture which can be defined as graphene oxide,[TiO]2+ induced by the hydrolysis of Ti(SO4)2 diffused into graphene oxide interlayer by electrostatic attraction.The nucleation and growth of TiO2 crystallites took place at low temperature and TiO2-Graphene Oxide composite was successfully synthesized.Furthermore,the photocatalytic properties of TiO2-Graphene Oxide under the irradiation of UV light were also studied.The results show that the degradation rate of methyl orange is 1.16 mg min-1 g-1(refer to the efficiency of the initial 15 min).Compared with P25 powder,this kind of intercalation composite owns much better efficiency.On the other hand,the reusable properties and stable properties of TiO2-Graphene Oxide intercalated composite are also discussed in this paper.At last,crystalline structure,interface status,thermal properties and microscopic structure of TiO2-Graphene Oxide were characterized by X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),thermogravimetric analysis (TGA),field emission scanning electron microscopy (FESEM) and high-resolution Transmission Electron Microscopy (HRTEM).Also,we have analyzed major influencing factors and mechanism of the composite structures which evidently improve the photocatalytic properties.     

Preparation of Photochromic Waterborne Polyurethane Films: Effect of Spiropyran Concentration on Photochromic Properties

Incorporation of photochromic compounds to the polymer through chemical bonding will result in an enhancement of photoactivity and stabilization of optical properties. Here, spiropyran(SP) was introduced into polyurethane(PU) through semi-continuous emulsion copolymerization to get waterborne polyurethane dispersion(SPU). Studies on photochromic properties by UV-vis technique demonstrated the absorption intensity increased with the increasing of SP concentration and the colorless film turned to purple under UV irradiation. The kinetics for ring-opening and ring-closing reaction against SP were both first order, but the rate constants decreased with the increasing of SP concentration. The prepared SPU films showed reasonable photostability and photoreversibility according to the convenient test methods under UV-vis irradiation. Temperature dependence studies demonstrated that the photobleaching rate increased at higher temperatures with the same SP concentration. The chemical combination between SP and isocyanate(NCO) end group of polyurethane was confirmed through swelling experiments. Morphology studies were conducted by scanning electron microscope(SEM) micrographs and showed good compatibility between SP and PU.     

含羟基螺吡喃的合成及动力学研究

根据羟醛缩合原理,应用2-亚甲基-1,3,3-三甲基吲哚啉和2,5-二羟基苯甲醛一步合成了1′,3′,3′-三甲基-6-羟基-螺-(2-氢-1-苯吡喃-2,2′-二吲哚啉),简称为羟基螺吡喃.该合成产物是一种新型的在苯环上带有羟基官能团的光致变色化合物.合成过程的反应条件温和又易于控制.应用红外(IR)、核磁共振(NMR)、质谱(MS)等分析方法对该化合物的结构进行表征;通过紫外(UV)分析,对其光致变色性能和变色反应动力学进行了研究.结果发现合成产物在紫外光照射下具有良好的光致变色性能,而且不同浓度羟基螺吡喃在溶剂中光变性能与变色速率明显不同.     

Photocatalytic degradation of metronidazole in aqueous solution by niobate K<Subscript>6</Subscript>Nb<Subscript>10.8</Subscript>O<Subscript>30</Subscript>

The photocatalytic degradation of antibiotic metroni-dazole in aqueous solution by niobate K6Nb10.8O30 photocatalyst that was prepared using a soft-chemical method was studied by Fourier transform infrared spectroscopy and UV-Vis absorption spectrum. Metronidazole is very stable and is difficult to degrade under UV irradiation. K6Nb10.8O30 photocatalyst cannot degrade metronidazole without UV irradiation and shows very high photo-catalytic activity for the degradation of metronidazole under UV irradiation. The photocatalytic degradation rate of metronidazole increased with increasing the dosage of K6Nb10.8O30 photocatalyst. The photocatalytic degradation reaction of metronidazole by nio-bate K6Nb10.8O30 follows the first-order kinetic equation.     

LDPE/沸石分子筛复合膜性能研究

采用熔融共混和挤出吹膜成型工艺方法,制备低密度聚乙烯(LDPE)/沸石分子筛(ZMS)复合膜.对膜试样的力学性能、结晶性能和透湿性能进行测试.采用DSC方法研究试样的结晶性能并用非等温结晶动力学对其进行分析.结果表明:随着ZMS用量的增加,LDPE/ZMS复合膜的拉伸强度及断裂伸长率先略增后呈现降低趋势.ZMS的加入使得LDPE的结晶速率增加,起到了异相成核的作用.随着ZMS用量的增加,复合膜透湿能力逐渐增强.采用修正Ozawa方程的Jeziorny法对复合膜的结晶性能可以进行很好的表征.     

Effects of Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> on the properties of ceramics from steel slag

Ferric oxide is one of the key factors affecting both the microstructure and the properties of CaO-MgO-SiO₂-based ceramics. Research on this effect is significant in the utilization of iron-rich solid wastes in ceramics. Ceramic samples with various Fe₂O₃ contents (0wt%, 5wt%, and 10wt%) were prepared and the corresponding physical properties and microstructure were studied. The results indicated that Fe₂O₃ not only played a fluxing role, but also promoted the formation of crystals. Ceramics with 5wt% of Fe₂O₃ addition attained the best mechanical properties with a flexural strength of 132.9 MPa. Iron ions were dissolved into diopside, consequently causing phase transformation from diopside and protoenstatite to augite, thereby contributing to the enhancement of its properties. An excess amount of Fe₂O₃ addition (10wt% or more) resulted in deteriorated properties due to the generation of an excess volume of liquid and the formation of high-porosity structures within ceramics.     

ZnTe/ZnO类球状复合材料的制备及其光催化性能

以亚碲酸钠,氧化锌为前驱体,采用溶剂热法合成了ZnTe/ZnO类球状复合材料,通过控制合成ZnTe颗粒的量来研究复合样的光催化性能.XRD确定合成样品为ZnTe/ZnO复合材料,SEM表征样品形貌为类球状复合物,UV-Vis测试样品光学特性,PL和EIS测试解释复合样光催化增强的原因,实验结果验证了在紫外光照射下光催化性能复合样优于纯相,而且以ZnO和Na_2TeO_3物质的量比为1∶0.4时合成的ZnTe/ZnO类球状复合样表现出最佳光催化活性,40min降解亚甲基蓝达到91%.     

紫外光辐照对聚苯硫醚/纳米氧化钛复合材料的影响

采用FTIR、DSC、DMA对不同紫外光辐照时间的聚苯硫醚/纳米氧化钛复合材料的性能进行研究。随着纳米氧化钛含量的增加,材料的结晶度和贮能模量增加。纳米氧化钛的加入抑制了因紫外光引发造成的聚苯硫醚分子链的降解。紫外光辐照后,聚苯硫醚/6%纳米氧化钛复合材料的结晶度明显降低。     

紫外光辐照对聚苯硫醚／纳米氧化钛复合材料的影响

采用FTIR、DSC、DMA对不同紫外光辐照时间的聚苯硫醚／纳米氧化钛复合材料的性能进行研究。随着纳米氧化钛含量的增加，材料的结晶度和贮能模量增加。纳米氧化钛的加入抑制了因紫外光引发造成的聚苯硫醚分子链的降解。紫外光辐照后，聚苯硫醚／6％纳米氧化钛复合材料的结晶度明显降低。     

Synthesis and characterization of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@SiO<Subscript>2</Subscript> magnetic composite nanoparticles by a one-pot process

Fe₃O₄@SiO₂ core–shell composite nanoparticles were successfully prepared by a one-pot process. Tetraethyl-orthosilicate was used as a surfactant to synthesize Fe₃O₄@SiO₂ core–shell structures from prepared Fe₃O₄ nanoparticles. The properties of the Fe₃O₄ and Fe₃O₄@SiO₂ composite nanoparticles were studied by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The prepared Fe₃O₄ particles were approximately 12 nm in size, and the thickness of the SiO₂ coating was approximately 4 nm. The magnetic properties were studied by vibrating sample magnetometry. The results show that the maximum saturation magnetization of the Fe₃O₄@SiO₂ powder (34.85 A·m2·kg–1) was markedly lower than that of the Fe₃O₄ powder (79.55 A·m2·kg–1), which demonstrates that Fe₃O₄ was successfully wrapped by SiO₂. The Fe₃O₄@SiO₂ composite nanoparticles have broad prospects in biomedical applications; thus, our next study will apply them in magnetic resonance imaging.     

木材表面原位生长WO3纳米片及其光响应行为

 采用乙醇作为诱导剂,利用简单的低温水热合成法在木材表面原位生长无机WO₃纳米片,探讨WO₃/木材的光响应功能。使用扫描电镜（SEM）、X射线衍射（XRD）、紫外-可见光（UV-vis）、色差仪和热重分析（TG）分别表征了此复合材料形貌、相结构、紫外光吸收、光响应和热稳定性能,并进一步探讨了此复合材料的疏水功能。SEM表明WO₃纳米片均匀的生长在木材表面;XRD表明WO₃具有六方晶相结构;UV-vis表明WO₃处理后的木材与素材相比,其最大吸收波长出现蓝移;光响应测试表明,WO₃/木材在紫外光照射下具有明显的变色功能;TG表明WO₃涂层对木材成分降解起到一定的抑制作用。此外,经过十八烷基三氯硅烷改良后,此复合材料具有超疏水功能。     

Preparation and photocatalytic properties of ilmenite NiTiO<Subscript>3</Subscript> powders for degradation of humic acid in water

The powders of ilmenite structure NiTiO₃ were prepared by a modified Pechini process using tetrabutyl titanate and nickel acetate as raw materials, and using citric acid and ethanol as a chelating agent and a solvent respectively. The powder samples were characterized by thermogravimetric and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The photocatalytic activity of NiTiO₃ under the irradiation of ultraviolet rays (UV) light was evaluated by degrading humic acid (HA) in water as a probe reaction. The possible photodegradation mechanism was studied by the examination of active species ·OH, ·O₂⁻, and holes (h⁺) through adding scavengers. The TG-DTA and XRD results indicated that the good crystal structure of ilmenite phase NiTiO₃ could be obtained when the Ni-Ti citrate complex was calcined at 600°C. The photocatalytic activity experiments indicated that NiTiO₃ had favourable photocatalytic activity under the irradiation of UV light, and the photocatalytic degradation rate of HA reached 95.3% after a 2.5 h reaction with the photocatalyst calcined at 600°C and a photocatalyst dosage of 0.4 g/L. The possible photocatalytic mechanism was deduced that holes (h⁺) and ·OH radicals are the major reactive active species in the photocatalytic reaction, and dissolved oxygen plays a weak role in the degradation of HA.     

Keggin结构钒取代硅钨酸/聚丙烯酰胺复合膜的制备及光致变色性能研究

制备了一、三钒取代的Keggin结构硅钨酸(SiW12-nVn,n=1,3)/聚丙烯酰胺(PAM)复合膜,采用红外光谱对其进行了表征.并研究了杂多酸的种类、含量以及照射光波长对SiW12-nVn/PAM复合膜光致变色性能的影响,通过ESR光谱推断了其可能的变色机理.结果表明:高含量、强氧化能力的多酸以及短波长的照射光波有利于SiW12-nVn/PAM复合膜的光致变色发生.     

Hydrogen storage properties of MgH<Subscript>2</Subscript> co-catalyzed by LaH<Subscript>3</Subscript> and NbH

To improve the hydrogen storage properties of Mg-based alloys, a composite material of MgH₂ + 10wt%LaH₃ + 10wt%NbH was prepared by a mechanical milling method. The composite exhibited favorable hydrogen desorption properties, releasing 0.67wt% H₂ within 20 min at 548 K, which was ascribed to the co-catalytic effect of LaH₃ and NbH upon dehydriding of MgH₂. By contrast, pure MgH₂, an MgH₂ + 20wt%LaH₃ composite, and an MgH₂ + 20wt%NbH composite only released 0.1wt%, 0.28wt%, and 0.57wt% H₂, respectively, under the same conditions. Analyses by X-ray diffraction and scanning electron microscopy showed that the composite particle size was small. Energy-dispersive X-ray spectroscopic mapping demonstrated that La and Nb were distributed homogeneously in the matrix. Differential thermal analysis revealed that the dehydriding peak temperature of the MgH₂ + 10wt%LaH₃ + 10wt%NbH composite was 595.03 K, which was 94.26 K lower than that of pure MgH₂. The introduction of LaH₃ and NbH was beneficial to the hydrogen storage performance of MgH₂.     

Bi2O3/Bi2WO6复合物的制备及其光催化活性

以Na2WO4·2H2O和Bi（NO3）3·5H2O为原料,采用机械球磨和煅烧两步法制备Bi2O3/Bi2WO6复合物。通过XRD和DRS对产物进行表征,研究制备条件（如球磨时间、煅烧时间）对复合物组成结构的影响。在可见光的照射下,以Bi2O3/Bi2WO6催化剂光催化降解罗丹明B溶液,结果表明,光照2 h后Bi2O3/Bi2WO6对罗丹明B的降解率达到98%。     

纳米微晶纤维素替代炭黑补强天然橡胶

采用纳米微晶纤维素(NCC)部分替代炭黑,制备了天然橡胶/纳米微晶纤维素/炭黑复合材料(NR/NCC/CB),研究了NCC对NR/CB复合材料性能的影响.结果表明,NCC提高了CB补强NR的扯断伸长率,并保持在500%以上,永久变形下降至30%以下,且NR/NCC/CB的拉伸强度和撕裂强度基本保持或略优于NR/CB,硬度则基本保持不变;NCC替代炭黑的量为5phr～20phr时,材料仍能保持良好的耐磨耗性能;NCC替代炭黑的量低于15phr时,材料的抗曲挠龟裂性能得到改善;NCC的加入还改善了材料的热空气老化性能,降低了材料的压缩疲劳生热,当NCC取代CB的量为10 phr时,复合材料的生热达到最低值13.0℃.