PREPARATION OF NANOMETER TiO2 ORGANIC SOLUTION —EFFECT OF ORGANIC SILOXANE ON SOL PROPERTIES*

A homogeneous longtime stabilized transparent nanometer TiO2 organic solution was obtained by means of the simultaneous hydrolysis and co-polycodensation of tetrabutyltitanate (TBT) and methacryloxypropyltrimethoxysilane (MAPTMS) by the sol-gel process. The particle size of nanometer titanium dioxide was controlled by use of bifunctional silanes, such as diphenyldimethoxysilane (DPDMS), diphenyldiethoxysilane (DPDES) and dimethyldiethoxysilane (DMDES). The effect of TiO2 content in the solution on the refractive index of system was discussed in detail. The result shows that the refractive index of solution increases linearly with TiO2 content. The refractive index of the three hybrid nanometer materials attained 1.6053, 1.5846 and 1.5346, respectively. The size of nanometer particles was characterized by TEM and the particle diameter thus obtained is in the range of 20-90 nm. FT-IR spectra of the materials show that the TiO-Si bond is formed.     

高折射率有机/无机纳米杂化透明膜层材料的制备与性质研究

采用溶胶-凝胶法,将钛酸酯和硅烷偶联剂(KH-560)进行共水解,经涂膜、固化,制备了一系列含有无机二氧化钛纳米相的无机/有机杂化膜层材料,通过不同方法对杂化膜层的微结构、光学、机械和热性质进行了表征.结果表明,所得到的有机/无机纳米复合膜层,在可见光范围内的透过率均在90%以上,同时具有较好的耐热性和较高的折射率(nd=1.47~1.73),并且膜层与基材的附着性好,铅笔硬度达到4~5H.     

聚合物与纳米晶的杂化及性能优化

聚合物-纳米晶杂化材料因结合了有机和无机材料的优点而逐渐地受到了人们普遍的关注,聚合物为纳米晶的形成与生长提供了优良的环境,纳米晶的引入同样也增加和强化了聚合物的功能特性.如聚硫代氨基甲酸酯与TiO2杂化的高折射率薄膜,该薄膜不仅保持了原有的性能,而且有较高的折射率.此外,还有许多不同纳米粒子与不同聚合物的杂化体系.如...     

高折射率聚合物-无机纳米光学杂化材料的设计与制备及其应用

传统的高折射率聚合物光学材料,可以通过向聚合物中引入一些芳香环,含硫基团以及除氟以外的其他卤素原子来提高聚合物光学材料的折射率,但是就目前的研究现状来看,这类纯聚合物光学材料的折射率一般都低于1.8.而将具有高折射率的无机纳米粒子引入到聚合物中,所制备的聚合物-无机纳米光学材料的折射率能够达到1.8以上.而且这类高折射率聚合物-无机纳米光学杂化材料同时具有高分子光学材料和无机材料的双重优点,具有广泛的应用前景.鉴于当前高折射率聚合物-无机纳米光学杂化材料发展之迅速和其研究与开发的重要性,并结合目前国内外的研究现状,本文就高折射率聚合物-无机纳米光学杂化材料的设计、制备方法及其相关应用做一个比较系统的介绍,同时对这类材料在未来研究中所应注意的问题也提出了相应的看法.     

纳米二氧化硅标准物质候选物的制备

以正硅酸乙酯和去离子水为反应物,氨水为催化剂,乙醇为共溶剂,通过沉淀反应制备窄分布的纳米二氧化硅标准物质候选物。利用扫描电子显微镜分析考察了氨水的用量对制备的二氧化硅粒度的影响。     

Three-Dimensional Arrays Formed by Monodisperse TiO(2) Coated on SiO(2) Spheres

Uniform coatings of TiO(2) on monodisperse spheres of silica have been obtained. The resulting particle sizes are within the range 0.4 to 1 μm. The thickness of the coating can be controlled by adjusting nuclei sizes (silica sphere), reaction times, and water and surfactant concentrations. The TiO(2)/SiO(2) spheres were sedimented to achieve structures with three-dimensional order. Three-dimensional ordered materials with higher refractive index were obtained by transforming the amorphous titania layer to rutile by thermal treatment with improved mechanical rigidity. The sphere composition, quality, and morphology have been assessed by different techniques. Copyright 2000 Academic Press.     

表面活性剂辅助水热合成氧化钛纳米针溶胶

TiO₂ nanoneedles sol with particle size of 10～15 nanometer was synthesized by hydrothermal method using peroxo titanic acid as the precursor, cetyltrimethyl ammonium bromide(CTAB) as the surfactant. The product was characterized by XRD, TEM, HRTEM and selected area electron diffraction(SAED). The results show that the as-prepared products have high crystallinity and grow along the c-axis, with homogeneous morphology and good monodispersity. In addition, TiO₂ hydrosol possessed good photocatalytic activity for the photocatalytic degradation of methyl orange aqueous solution under the sunlight illumination.     

TiO2 *nH2 O凝胶预处理对水热合成SrTiO3 粉的影响

以TiCl4为钛源, 首先制备TiO2 * nH2O凝胶, 然后在80℃的水热条件下制备了SrTiO3粉.利用X射线衍射(XRD)、透射电子显微镜(TEM)和红外光谱(FTIR)研究了TiO2 * nH2O凝胶水洗方式、阴离子(Cl-和NO3-)以及TiO2 * nH2O热处理对SrTiO3粉性能的影响.结果表明, 水洗和热处理都能使TiO2 * nH2O凝胶产生晶化; TiO2 * nH2O的晶化程度对产物SrTiO3颗粒的粒度和粒度分布有很大影响,以非晶质TiO2 * nH2O为钛源制备的SrTiO3颗粒粒度大且粒度分布宽.以结晶TiO2 * nH2O为钛源制备的SrTiO3颗粒粒度小且粒度分布窄,而且可以得到纳米颗粒.水热反应液相中存在Cl-或NO3-能使产物SrTiO3颗粒粒度稍有增大.综合以上结果, TiO2 * nH2O凝胶水洗对产物颗粒的影响主要是由于使凝胶产生了晶化,而由阴离子脱除产生的影响很小.因此,在不考虑阴离子对其它工程化影响(如设备腐蚀等)的前提下,可采用热处理代替水洗.     

Synthesis and properties of photosensitive polyimide-nanocrystalline titania optical thin films

In this study, synthesis, morphology, and properties of high refractive index photosensitive polyimide-nanocrystalline titania hybrid materials are reported. A soluble polyimide grafted with carboxylic acid or methacrylate groups (P1) was first synthesized from 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,5-diaminobenzoic acid (DABA), 4-aminobenzoic acid (4ABA), and 2-hydroxyethyl methacrylate (2HEMA). The residual carboxylic acid groups could undergo an esterification reaction with titanium butoxide to provide an organic-inorganic bonding. On the other hand, the grafted methacrylate groups rendered photosensitive property for photopatterning. A homogeneous hybrid solution was obtained through the formulation on different mole ratios of titanium butoxide/carboxylic acid, water/acid content in a mixed solvent. It was followed by spin-coating, photocuring and post-baking. The titania domain size in the hybrid materials analyzed by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) was around 4-7 nm. The prepared optically transparent films had tunable refractive index (1.583 < n < 2.029), relatively good surface planarity and high thermal stability. A fine pattern with a line width of 50 μm was produced by direct lithographic process on the hybrid films. The present study demonstrates a novel approach for preparing high refractive index hybrid photosensitive materials with patternability.     

Ag-TiO2纳米催化剂的制备、表征及环氧化催化性能

环氧化合物是一类重要的有机合成中间体。工业上环氧乙烷是以Ａｇ ＳｒＯ ＣａＯ作催化剂 ,通过多相催化由乙烯和氧气氧化得到 ,其它的Ｃ2以上烯烃不能用该法生产 ,因为反应温度高 ,选择性很差。高温下的银催化乙烯的分子氧环氧化 ,选择性高于 80 % ,而用于丙烯的环氧化时 ,选择性大大降低[1] ,银多相催化分子氧环氧化烯烃的研究较活跃[2 5] 。本文合成了Ａｇ ＴｉＯ2 纳米催化剂 ,对其进行了表征 ,并初步研究了其环氧化催化性能。1　实验部分1 .1　仪器药品ＴｅｓｔｓｃａｎＳｈｉｍａｄｚｕＦＴＩＲ 80 0 0ｓｅｒｉｅｓ红外光谱仪 (ＫＢ…     

Sol-gel自蔓燃法控制合成二氧化钛纳米粉体及性能

采用化学络合溶胶-凝胶法,结合自蔓燃合成工艺制备了结构可控、分散性良好的TiO2纳米粉体.考察了原料组成、凝胶膨胀程度和温度机制对粉体结构、分散性的影响,用漫反射光谱测试了所制备粉体的光吸收性能. 结果表明,将原料中氧化剂与还原剂的摩尔比从2增加到7,在600 ℃的煅烧温度下可以得到金红石含量在25％～68.2％之间的TiO2,这些结构不同的粉体粒度为30 nm左右;凝胶前驱体经过150 ℃充分膨胀炭化,能有效阻止胶粒间氢键的形成,并且能够防止因毛细管作用而导致的凝胶网络坍塌,从而得到单分散无团聚粉体;提高煅烧温度,金红石含量增多、颗粒粒度增大,800 ℃时出现团聚体;用该工艺制备的粉体的光吸收范围发生明显红移,与市售金红石型TiO2相比,反光率下降10％以上;金红石含量为55.5％的混晶型粉体显示出最好的光吸收性能.     

新型复合环氧光学树脂的制备与性能研究

通过2,2-二巯基乙硫醚(MES)与环氧氯丙烷反应合成了2,2-二巯基二乙硫醚二缩水甘油醚型环氧树脂(DGEMES),通过FTIR和MS对其进行表征;用乙二胺作为固化剂,将DGEMES与双酚A型环氧树脂(DGEBA)复合固化,得到了新型高折射率和低色散的光学树脂.DGEMES是一种较好的共聚单体,可以同时提高共聚树脂的折射率和阿贝数;DGEBA/DGEMES/乙二胺共固化树脂的nd=1.59～1.62,νd=35～39;当DGEMES的质量分数为40%时,固化树脂的折射率达到1.60以上,冲击强度22.5kJ/m₂,且其它性能较均衡.此外,以甲基六氢苯酐(B-650)为固化剂,还合成了具有中等折射率的DGEBA/DGEMES/B-650共固化树脂(nd=1.54～1.56,νd=38～40),并对其光学和机械性能进行了研究.     

高折射率高透明性半脂环聚酰亚胺的合成与性能

采用脂环二酐单体2,3,5-三羧基环戊烷基乙酸二酐(TCAAH)分别与两种含硫芳香族二胺单体,4,4′-双(4-氨基苯硫基)二苯硫醚(3SDA)与2,7-双(4-氨基苯硫基)噻蒽(APTT)通过两步法制备了两种半脂环聚酰亚胺(PI).制备的PI薄膜在可见光波长范围内(400~700 nm)具有优良的透明性,400 nm处的透过率超过85%.此外,该系列薄膜还具有良好的耐热稳定性,氮气中的起始热分解温度超过480℃,玻璃化转变温度超过250℃.PI薄膜在632.8 nm处的折射率大于1.68,双折射小于0.006.为了进一步提高PI薄膜的折射率,初步考察了PI前体溶液聚酰胺酸(PAA)与高折射率无机TiO2纳米粒子的复合工艺.结果表明,PI-TiO2薄膜同样具有良好的透明性,632.8 nm处的折射率达到1.76.     

Catalysis of SO42--ZrO2/TiO2 nanometer solid superacid

Superacid catalyst SO42--ZrO2/TiO2 was applied in esterification of Acetic Acid and Butanol. The particle size of ZrO2 in the catalyst was about 12.5 nm. In catalyst preparation conditions, the effect factor order on catalytic activity is H2SO4 concentration ＞ calcination temperature ＞ ZrO2 supported content. The optimum preparation condition is as follows: ZrO2 content 3.5g/g; calcination temperature 600℃, and H2SO4 concentration 0.5mol/L. The catalytic activity is 96.5 vol%.SO42-/MxOy solid superacid is a kind of green catalyst, whose application perspective is bright. In this paper, SO42--ZrO2/TiO2 solid superacid was prepared with nanometer compound carrying method. The acidic strength of catalysts was measured with the following Hammett indicators, 2,4-dinitrofluorobenzene (H0=-14.52) and p-nitrochlorobenzene (H0=-12.70). Catalytic activity was evaluated with esterification reaction of Acetic Acid and Butanol. Reaction temperature was at 105℃, and reaction time was only 1h. The conversion rate of Acetic Acid was analyzed by a gas chromatograph (GC-14C SHIMADZU in Japan)The experimental results showed that H2SO4 concentration had more influences on catalytic activity than other two factors, calcination temperature and ZrO2 supported content. Since sulfur absorbed on the surface of metal oxides is necessary to the acidity of SO42-/MxOy solid superacid,H2SO4 concentration in impregnation solution is needed enough high. But, it can't be too much high,otherwise, Zirconium sulfate formed on the catalyst surface will be harmful influences on catalytic activity. In researched cover, 0.5mol/L H2SO4 concentration is the most suitable, and the catalyst prepared with this concentration has very strong acidity.The optimum preparation condition is as follows: ZrO2 content 3.5g/g; calcination temperature 600℃, and H2SO4 concentration 0.5mol/L. In the catalyst prepared with above conditions, the acidic strength (H0) of the catalyst is smaller than ＜-14.52, and catalytic activity is 96.5 vol%. When it was re-used in esterification reaction, catalytic activity decreased gradually with re-used times increasing(seen in Table 1). But after catalyst is used repeatedly up to five times, catalytic activity (84.3 vol %)is still higher than that of H2SO4 catalyst.The X-ray diffraction patterns showed that ZrO2 supported in TiO2 belonged tetragonal zirconia phases. Through the calculation of Scherrer formula, the particle size of ZrO2 in the catalyst is about 12.5 nm. After SO42- promoted nanometer ZrO2/TiO2 compound carrier, the diffraction peaks of tetragonal zircoma become broader and the strength weaker. It shows that adding SO4 ions restrains the crystallization of ZrO2, diminishes the size of particles. This might be why SO42--ZrO2/TiO2 has high catalytic activity and stability in acidic catalysis reaction.     

复合微乳液聚合制备P(MMA-UA)纳米乳胶粒子的研究

将聚氨酯预聚体可聚合乳化剂 (APUA)和甲基丙烯酸甲酯 (MMA)的复合微乳液体系 ,分别用水溶性过硫酸钾 (K2 S2 O8)和油溶性偶氮二异丁腈 (AIBN)作引发剂 ,进行微乳液聚合研究 ,制备了P(MMA UA)复合纳米乳胶粒子 .研究了APUA用量、聚合温度对聚合动力学的影响 ;用透射电子显微镜 (TEM)观察了不同乳化剂浓度及引发剂体系对胶粒形态、大小及分布的影响 .结果表明 ,用可聚合乳化剂APUA可制得稳定性很好的P(MMA UA)纳米级核 壳型乳胶粒子 ,乳胶粒径在 5 0nm左右 .随着乳化剂用量增加 ,粒子变小 ;不同类型的引发剂对胶乳的性质有较大影响 ,以APUA为乳化剂 ,K2 S2 O8为引发剂 ,在聚合反应过程中或在聚合反应后的放置中 ,会出现P(MMA UA)的纳米水凝胶 (Nanogel)现象 .     

纳米二氧化钛催化苯乙烯环氧化反应的研究(Ⅰ)

通过烯烃的环氧化反应可制得一系列活泼的有机中间体--环氧化物,再通过选择性开环或功能团转化可方便地合成多种有价值的化合物.含钛催化剂对烯烃环氧化催化效果较好,如Ti-ZSM-5、Ti-ZSM-11、α-和β-[SiW₉Ti₃O₄₀]^10-.     

ZnTiO3-TiO2纳米复合材料的光催化性能

通过溶胶 凝胶（Sol-Gel）法制备了ZnTiO3-TiO2纳米复合光催化剂,利用透射电子显微镜、X射线衍射、紫外-可见吸收光谱和ζ电位等测试技术对其形貌、晶体结构及其光谱响应特性进行了表征。 以亚甲基蓝（MB）溶液的脱色降解为模型反应,考察了光源和焙烧温度对该纳米复合材料光催化性能的影响。 结果表明,所得纳米复合材料的催化性能与材料的尺寸、在介质中的分散性能、表面荷电性质等有关。 600 ℃下焙烧3 h所得的ZnTiO3-TiO2纳米复合材料尺寸小（约60 nm）、分散性能好、表面荷负电荷量最高、催化性能最好,且在太阳光下的活性高于紫外光下的。 如太阳光下7 h可使亚甲基蓝（MB）溶液的脱色降解率达到93%,而在紫外光下只有82%;并且其催化活性高于纯TiO2和ZnO的。 该纳米复合催化剂重复使用4次仍能使亚甲基蓝（MB）溶液的脱色降解率在80%以上。 因此,具有较好的光催化稳定性能。     

Rayleigh scattering study and particle density determination of a high refractive index TiO2 nanohybrid polymer

We have experimentally carried out a Rayleigh scattering study of a high refractive index TiO(2) nanohybrid polymer. By employing the Rayleigh scattering technique with at least three different wavelengths, we can obtain the Rayleigh ratio of the TiO(2) nanohybrid polymer at each utilized wavelength. These measured Rayleigh ratios are then used to estimate the size of the nanoparticle and determine the number of nanoparticles per unit volume or particle density. Furthermore, this technique can be used to evaluate the dominant size of nanoparticles in the nanohybrid polymer mainly contributed to Rayleigh scattering.     

紫外/可见光谱在有机光纤研制中的应用

有机光导纤维是近十几年来在新型光功能性高分子材料领域中的一支独秀.相对于玻璃光导纤维,有机光导纤维加工容易、口径大、轻而柔软、抗挠曲、抗冲击、耦合容易,更重要的因素是制作成本低和用途广泛.通常光导纤维是一种带包层的透明圆柱型的细丝.芯子的折射率高于包层并且是不变的,这种纤维称为突变型(SI)光纤.由于SI型光纤的带宽小,不能满足高信息量传输的需要,因而渐变型(GI)有机光纤得以发展.在这种光导纤维中,纤芯的折射率是呈抛物线型分布的,其轴心的折射率最大,折射率由纤维轴心沿径向到包层逐渐变小,在芯/包层界面处折射率无突变,光线在这种光纤的传播路径近似正弦波.沿正弦波处的折射率均小于轴心区的折射率.由于光速是反比于折射率的,因此当光沿着正弦途径传输时,其速度大于光沿着轴心传输的速度.于是,较长的光路被较大的光速所补偿,结果是光在正弦波处的传输时间与在轴心处的传输时间上没有大的区别,而脉冲加宽是正比于传输时间的差值,因此有望在GI型有机光纤中得到较小的脉冲加宽.GI型有机光纤的制备一般可在GI型有机预制棒的基础上通过熔融热拉技术拉制而成.因此,制备GI型有机预制棒及其折射率分布的检测成为关键步骤.折射率分布的测量方法有很多,如近场扫描法、折射近场法、切片干涉法等.本文首次介绍了将紫外/可见吸收光谱应用于预制棒折射率分布的定性测试上,得到了在预制棒芯区沿径向掺杂剂分子溴苯的吸收强度呈抛物线型分布.因测试折射率分布的其他方法较为繁杂以及受仪器的限制,所以利用紫外/可见吸收光谱这一非常普通的仪器来估计折射率分布的情况不失为一种简单易行的方法.     

纳米二氧化钛催化苯乙烯环氧化反应的研究

通过烯烃的环氧化反应 ,可制得活泼的有机合成中间体——环氧化物 ,再通过选择性开环或功能团转化 ,可以方便地合成多种有价值的化合物 .因此 ,催化烯烃环氧化的反应得到广泛的研究 ,其中含钛催化剂具有较好的催化性能 ,如 Ti- ZSM- 5沸石 [1,2 ] 、Ti- ZSM- 1 1沸石[3 ,4 ] 在 H2 O2 存在下就有高的催化活性 ;α-和β- [Si W9Ti3 O4 0 ]10 -也有一定的催化活性 [5] ;Sharpless等人 [6]采用 Ti[OCH( CH3 ) 2 ]4和酒石酸二乙酯诱导体 ,可高选择性催化烯丙醇的不对称环氧化反应 .纳米 Ti O2 ,由于颗粒小 ,处于固体表面的原子多 ,表…