Development of New Modifiers for Titanium Alkoxide-Based Sol-Gel Process

The effects of several hydroxyketones such as acetol, actoin, -ketobutanol themselves and their combinations with monoethanolamine (MEA) or ethylenediamine (ED) on the stabilization of titanium tetraisopropoxide (TTIP) in isopropanol solution are examined. Acetoin itself and the imine derivatives of acetol and acetoin were found to show extraordinarily strong stabilizing effect for the alkoxide. The properties including the crystal modifications and refractive index of TiO₂ films that were dip-coated using each stabilized solution are examined and discussed in comparison with those of the films obtained from the diethanolamine (DEA) systems. The effect of UV-light irradiation to the gel films on the crystallization of TiO₂ is also examined and discussed.     

Photogreying of TiO<Subscript>2</Subscript> nanoparticles

Photogreying, the change in brightness on UV irradiation in the absence of oxygen, of TiO₂ nanoparticulate dispersions is shown to depend on the nature of the liquid, consistent with a surface reaction. Measurements on a series of TiO₂ particles (mainly 75×10 nm) dispersed in, e.g., alkyl benzoate correlate well with those on the same TiO₂’s dispersed in a second liquid (e.g. propan-2-ol). Photogreying in propan-2-ol is paralleled by photocatalytic-oxidation activity, indicating a common origin – UV-generation of charge carriers. Further, photogreying parallels Ti³⁺ formation. Hence, although appearance and the visible spectra of photogreyed particles both differ from those of Ti³⁺ in ≤10 nm colloidal TiO₂, we suggest that photogreying is caused by capture of UV excited electrons to form Ti³⁺. Surface treatment reduces photogreying, and we speculate that differences between uncoated samples reflect differences in the number of potentially reducible Ti’s.     

生理盐水浸泡对Ti-6Al-4V钛合金超高周疲劳性能的影响

钛和钛合金可作为医用植入材料,有必要对其耐人体体液的侵蚀性能进行研究。用超声疲劳试验技术研究了室温下生理盐水中浸泡24 h后Ti-6A l-4V钛合金(TC4)的超高周疲劳性能,并与未经浸泡的同种材料的超声疲劳性能进行了对比分析。疲劳试验进行到109循环周次以上。结果显示,实验材料的S-N曲线均呈现缓慢下降趋势,材料不存在常规疲劳中的疲劳极限,经生理盐水浸泡24 h后对实验材料的超高周疲劳寿命无明显影响。用电子扫描电镜观测,实验材料表现为穿晶塑性断裂。     

TA6V钛合金疲劳断口形貌及断口分析

在进行TA6V钛合金疲劳小裂纹实验的基础上,使用KYKY2800B型扫描电镜(SEM)对TA6V钛合金疲劳断口形貌进行疲劳源区及其裂纹扩展形状、扩展区、瞬断区形貌的观察,分析TA6V钛合金疲劳断口形貌形成的原因,为其结构疲劳安全设计及可靠性分析提供科学依据,为今后TA6V钛合金在我国的使用提供参考。     

抗坏血酸钛对鱼类、贝类及无尾两栖类的毒性研究

抗坏血酸钛对鲢鱼、草鱼、金鱼及泥鳅的毒性都很低,其96h TLm值为1736～10930mg/l。（敏感性顺序:鲢鱼>草鱼>金鱼>泥鳅）抗坏血酸钛对湖螺的48h TLm值与对蟾蜍蝌蚪的96hTLm值分别为12847.2与1886.5mg/l。经皮下注射,抗坏血酸钛对中华大蟾蜍的LD50为2.87g/kg。微核试验表明,钛试     

Very Facile Polarity Umpolung and Noncovalent Functionalization of Inorganic Nanoparticles: A Tool Kit for Supramolecular Materials Chemistry

The facile assembly of shell‐by‐shell (SbS)‐coated nanoparticles [TiO₂?PAC₁₆]@shell 1 – 7 (PAC₁₆=hexadecylphosphonic acid), which are soluble in water and can be isolated as stable solids, is reported. In these functional architectures, an umpolung of dispersibility (organic apolar versus water) was accomplished by the noncovalent binding of ligands 1 – 7 to titania nanoparticles [TiO₂?PAC₁₆] containing a first covalent coating with PAC₁₆. Ligands 1 – 7 are amphiphilic and form the outer second shell of [TiO₂?PAC₁₆]@shell 1 – 7 . The tailor‐designed dendritic building blocks 3 – 5 contain negative and positive charges in the same molecule, and ligands 6 and 7 contain a perylenetetracarboxylic acid dimide (PDI) core ( 6 / 7 ) as a photoactive reporter component. In the redox and photoactive system [TiO₂?PAC₁₆]@shell 7 , electronic communication between the inorganic core to the PDI ligands was observed.     

二(β-羟亚胺)二氯化钛配合物的合成及催化乙烯聚合

报道了3个β-羟亚胺配体(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂CH(Ph)OH(1a), (2,6-^emPr₂C₆H₃)N＝C·(Ph)CH₂C(Ph)₂OH(1b)和(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂C(C₁₂H₈)OH(1c)及其二(β-羟亚胺)二氯化钛配合物[(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂CH(Ph)O]₂TiCl₂(2a), [(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂C(Ph)₂O]₂·TiCl₂(2b)和[(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂C(C₁₂H₈)O]₂TiCl₂(2c)的合成, 并对其结构进行了表征. 在助催化剂甲基铝氧烷(MAO)作用下, 以化合物2b为主催化剂, 研究了Al/Ti摩尔比、 反应时间、 温度和聚合压力等对乙烯聚合的影响, 发现该催化体系在较宽的反应条件下均可得到很高分子量的聚乙烯, 熔点均在140℃左右. 以化合物2a~2c为主催化剂对乙烯进行催化聚合, 发现在β碳位上取代基的立体位阻对催化剂活性有很大影响. 当化合物2b上引入2个苯基取代基时, 催化剂显示出最佳催化活性.     

光催化降解微囊藻毒素(MC)的研究进展

近年来蓝藻水华现象日益严重,甚至威胁了人类饮用水的安全.传统水处理技术对微囊藻毒素去除效果不明显,新型降解技术亟待研究.本文概述了二氧化钛系列的光催化剂的一些研究进展,并提出了未来光催化氧化法降解微囊藻毒素的主要研究方向.