纳米TiO2/P(MMA-BA-MAA)复合粒子的制备及聚合动力学

用乳液聚合法制备了纳米TiO₂/甲基丙烯酸甲酯-丙烯酸丁酯-甲基丙烯酸共聚物［TiO₂/P(MMA-BA-MAA)］复合粒子。考察了乳化剂的浓度、单体的用量比对复合粒子形貌的影响。系统研究了乳化剂浓度、引发剂用量、单体用量比、共乳化剂浓度、反应温度对TiO₂/P(MMA-BA-MAA)复合粒子包覆反应动力学影响。用TEM、FTIR及TG分析等证实P(MMA-BA-MAA)包覆在TiO₂表面形成表面光滑、分散性好的球形核 壳复合粒子。根据动力学实验结果,求出整个乳液聚合包覆反应的反应速率方程,反应的表观活化能为163.0 kJ.mol^-1。推测可能的包覆反应机理应为无机纳米TiO₂表面吸附乳化剂分子形成所谓的TiO₂/surfactant胶束成核或均相凝聚成核。TG结果显示,复合粒子的热稳定性高于相同条件下得到的共聚物的稳定性。ζ电位、接触角实验表明,与纳米TiO₂相比,复合粒子亲水性能下降、亲油性能提高。     

TiO2纳米管/UV/O3对腐殖酸的降解动力学

用自制的TiO₂纳米管（TNTs）作为催化剂,对腐殖酸进行TNTs/UV/O₃工艺降解研究.从动力学角度分析了光催化、臭氧化的协同作用及催化剂煅烧温度的影响,考察了反应温度、初始pH值、催化剂投加量和臭氧投加量对降解速率的影响,建立了新型动力学模型.结果表明,光催化和臭氧化有很强的协同作用,催化剂最佳煅烧温度为400℃,腐殖酸的TOC降解过程符合零级反应,模型显示当原水pH值为7.35,TNTs投加量0.806g·L^-1,O₃投加量0.49g·h^-1时TNTs/UV/O₃对腐殖酸TOC的降解取得最佳反应速率,当反应温度T为25℃时,最佳k为0.8095mg·L^-1·min^-1,当反应温度T为30℃时,最佳k为0.8231mg·L^-1·min^-1.试验结果和模型结果对比得出试验值基本符合动力学模型.     

TiO2纳米管/UV/O3对腐殖酸的降解动力学

用自制的TiO₂纳米管（TNTs）作为催化剂,对腐殖酸进行TNTs/UV/O₃工艺降解研究.从动力学角度分析了光催化、臭氧化的协同作用及催化剂煅烧温度的影响,考察了反应温度、初始pH值、催化剂投加量和臭氧投加量对降解速率的影响,建立了新型动力学模型.结果表明,光催化和臭氧化有很强的协同作用,催化剂最佳煅烧温度为400℃,腐殖酸的TOC降解过程符合零级反应,模型显示当原水pH值为7.35,TNTs投加量0.806g·L^-1,O₃投加量0.49g·h^-1时TNTs/UV/O₃对腐殖酸TOC的降解取得最佳反应速率,当反应温度T为25℃时,最佳k为0.8095mg·L^-1·min^-1,当反应温度T为30℃时,最佳k为0.8231mg·L^-1·min^-1.试验结果和模型结果对比得出试验值基本符合动力学模型.     

基于细乳液聚合法TiO2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯（TiO2/PMMA）纳米复合粒子,考察了引发剂、助乳化剂、乳化剂、单体结构和种类对TiO2/PMMA纳米复合粒子性能的影响。结果表明与十二醇和十六醇相比,十六烷（HD）更能抑制甲基丙烯酸甲酯（MMA）液滴的Ostwald熟化效应,当MMA占TiO2质量分数的60%,HD对单体质量分数的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵（DNS-86）占整个体系的质量分数为2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

La掺杂纳米TiO2的制备及光催化性能研究

采用溶胶-凝胶法制备了纯TiO₂和不同La掺杂量的TiO₂纳米粒子，对样品进行了TG-DTA、XRD和UV-Vis 吸收光谱分析，并以染料废水甲基橙为目标降解物，考察了样品的光催化性能。结果发现，La的掺杂抑制了TiO₂粒径的长大，细化了晶粒；La掺入到TiO₂的晶格中，引起了晶格的畸变和膨胀；La的掺杂使TiO₂的吸收带边发生了红移；适量La的掺杂可提高TiO₂的光催化性能。试验条件下，最佳掺杂摩尔分数为0.1％。     

纳米TiO2在有机材料上的固定化研究进展

对纳米TiO₂在有机材料上的固定化研究进展进行了概述，并就光催化氧化对有机材料的降解等问题进行了讨论。主要介绍了光活性纳米TiO₂的制备方法、纳米TiO₂在有机材料上的固定化方法、纳米TiO₂对有机膜的降解以及纳米TiO₂/有机复合材料的应用领域，并对纳米TiO₂在抗菌方面的应用前景进行了阐述。     

V2O5/TiO2基SCR脱硝催化剂的制备及其催化性能

采用纳米TiO₂为催化剂载体原料,V₂O₅为催化剂,通过混合、球磨、干燥和焙烧等工艺制备选择性催化还原脱硝法催化剂,研究了催化剂的制备工艺和催化性能。通过差热分析研究催化剂的相变和烧结温度,通过模拟烟气分析装置表征催化剂的催化性能。结果表明,加入V₂O₅可以提高催化性能,以6%V₂O₅-94%TiO₂为配方的催化剂对NO的脱除率达97.5%,温度窗口为（300～420） ℃。     

TiO2/SiO2的制备及其对茜素红溶液的降解动力学

以钛酸四丁酯和正硅酸乙酯为前驱体，冰醋酸为水解抑制剂，采用溶胶-凝胶法制备了TiO₂/SiO₂复合物。X射线衍射和红外光谱等表征结果表明，纳米TiO₂/SiO₂粒子焙烧后主要以锐钛型存在，有Ti—O—Si键产生。在实验浓度范围，光催化降解茜素红反应符合一级动力学规律，采用半衰期法确定反应级数为0.82。     

水相介质中纳米TiO2粒子软团聚体的解团聚

纳米TiO₂等无机粒子在水相介质中极易发生团聚,进而会严重影响其功效的充分发挥。本文考察了TiO₂水分散液体系中TiO₂粒子的团聚形式,比较了几种常规分散技术以及表面锚固改性技术对这些团聚体的解团聚效果。结果发现：大部分TiO₂粒子在水相介质中以软团聚体形式存在,高速剪切和添加分散剂对这些软团聚体的解团聚作用有限,超声分散可产生暂时性的解团聚效应,但随着超声场的去除,被分散的TiO₂粒子又会再次逐渐聚集。TiO₂粒子表面的聚合物原位锚固改性可改变其表面性质,因而对软团聚体具有更为高效稳定的解团聚作用,从而可明显提高复合粒子中的TiO₂粒子在水相介质和目标织物表面的分散性和分散稳定性。     

掺杂铁纳米TiO2的制备及其光催化性能研究

分别采用水热法和溶胶-凝胶法制备了纳米级TiO₂和不同掺铁量的TiO₂纳米粒子。通过纯TiO₂和掺铁TiO₂分别作光催化剂时甲基橙溶液在紫外光下的光催化降解试验发现，溶胶-凝胶法掺杂铁离子可以有效地提高TiO₂光催化活性，而水热法掺杂铁使TiO₂的光催化活性明显降低。Fe/TiO₂摩尔比为0.01％～0.1％，随掺杂量的增大,TiO₂光催化活性逐渐降低。     

TiO2及TiO2-SiO2复合氧化物特性及其降解水中有机污染物的光催化活性

TiO2 and TiO2-SiO2 photocatalysts were prepared by sol-gel and supercritical CO2 fluid drying method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), etc. Their catalytic properties were tested through the photocatalytic degradation of phenol and aniline in wastewater. The results show that the developed fluidized photocatalytic reactor (FPR) and TiO2 catalyst had better performance in degrading pollutants as compared with slurry photocatalytic reactor (SPR) and commercial TiO2 catalyst. The composition and crystal form of TiO2-SiO2 composite oxide had obvious influence on catalytic effect and TiO2-SiO2 photocatalysts showed better catalytic activity and stability.     

Preparation of polystyrene/poly(methyl methacrylate) core‐shell composite particles by suspension‐emulsion combined polymerization

Suspension‐emulsion combined polymerization process, in which methyl methacrylate (MMA) emulsion polymerization constituents (EPC) were drop wise added to styrene (St) suspension polymerization system, was applied to prepare polystyrene/poly(methyl methacrylate) (PS/PMMA) composite particles. The influences of the feeding condition and the composition of EPC on the particle feature of the resulting composite polymer particles were investigated. It was found that PS/PMMA core‐shell composite particles with a narrow particle size distribution and a great size would be formed when the EPC was added at the viscous energy dominated particle formation stage of St suspension polymerization with a suitable feeding rate, whereas St‐MMA copolymer particles or PS/PMMA composite particles with imperfect core‐shell structure would be formed when the EPC was added at the earlier or later stage of St suspension polymerization, respectively. It was also showed that the EPC composition affected the composite particles formation process. The individual latex particles would exist in the final product when the concentrations of MMA monomer, sodium dodecyl sulfate emulsifier, and potassium persulfate initiator were great in the EPC. Considering the feature of St suspension polymerization and the morphology of PS/PMMA composite particles, the formation mechanism of PS/PMMA particles with core‐shell structure was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Morphological characterization of attapulgite/poly(methyl methacrylate) particles prepared by soapless emulsion polymerization

BACKGROUND: The synthesis of core–shell inorganic/polymer nanocomposites, in which the polymer shell determines the chemical properties and the interaction with the environment, whereas their physical properties are governed by both the size and shape of the inorganic core and the surrounding organic layer, is an area of increasing research activity. RESULTS: Core–shell and bead–string shaped attapulgite/poly(methyl methacrylate) (ATP/PMMA) nanocomposite particles were prepared by soapless emulsion polymerization in an aqueous suspension of attapulgite organically modified with cetyltrimethylammonium bromide. CONCLUSION: Transmission electron microscopy analysis results showed that the amounts of the monomer added had no influence on the morphologies of the ATP/PMMA particles. The morphologies only depended on the length/diameter ratio of the attapulgite fibrillar single crystal used. Long ATP needles formed the bead–string structure while short ATP needles formed the core–shell structure. Copyright © 2007 Society of Chemical Industry     

无皂乳液聚合制备亚微米级单分散聚苯乙烯微球

采用无皂乳液聚合法制备了具有单分散性的亚微米级聚苯乙烯微球,考察了聚合体系pH值、单体及引发剂用量对聚合转化率、微球粒径及其分布的影响。结果表明,采用NaOH和NaHCO,复合溶液调节聚合体系pH值是控制聚合动力学、微球粒径及单分散性的有效手段,当其质量比为1：1时效果较好。随碱性复合溶液加入量的增加,最终转化率下降,微球粒径则由于复合溶液同时起到电解质的作用而存在极大值。随过硫酸钾(KPS)质量分数的增加,反应前期聚合转化率增大,但其用量过大,会导致体系pH值偏低,KPS过早消耗完毕,故反应后期最终转化率偏低;其用量过低,会影响粒径的单分散性。当KPS质量分数为单体的2％～3％时,聚合体系稳定性增加并改善了微球的单分散性,粒径趋小。单体用量的变化对聚合速率影响不大,随单体质量分数的提高,微球最终粒径增大,当单体质量分数过高,会影响微球的单分散性乃至体系失稳,一般以不超过10％为宜。     

Preparation of poly(methyl methacrylate)/titanium oxide composite particles via in‐situ emulsion polymerization

Poly(methyl methacrylate) (PMMA)/Titanium oxide (TiO₂) composite particles were prepared via in‐situ emulsion polymerization of MMA in the presence of TiO₂ particles. Before polymerization, the TiO₂ particles was modified by the silane coupling agent, which is crucial to ensure that PMMA reacts with TiO₂ via covalent bond bindings. The structure of the obtained PMMA/TiO₂ composite particles was characterized using Fourier transform infrared spectra (FTIR) and thermogravimetric analysis (TGA). The results indicate that there are covalent bond bindings between PMMA macromolecules and TiO₂ particles. Based on these facts, several factors affecting the resulting PMMA/TiO₂ composite system, such as the type of coupling agents, the mass ratio of the MMA to the modified TiO₂, the emulsifier concentration, and the initiator concentration, etc., were examined by the measurement of conversion of monomers, the gel content of polymers, the percentage of grafting, and the grafting efficiency, using gravity method or TGA method. As a result, the optimized recipe was achieved, and the percentage of grafting and the grafting efficiency could reach 216.86 and 96.64%, respectively. In addition, the obtained PMMA/TiO₂ composite particles were found to a stable colloidal dispersion in good solvent for PMMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4056–4063, 2006     

An experimental investigation of poly(vinyl chloride) emulsion polymerization: Effect of initiator and emulsifier concentrations on polymerization kinetics and product particle size

Effects of concentration changes in initiator species Na₂SO₃, (NH₄)₂S₂O₈ and CuSO₄, and emulsifier, ammonium stearate, on poly(vinyl chloride) (PVC) emulsion polymerization kinetics and on product particle size were experimentally investigated. It was observed that to obtain industrially significant rates and overall conversions, not only an optimum concentration ratio of Na₂SO₃/(NH₄)₂S₂O₈/CuSO ₄ must be used, but also the concentrations of these species must be above certain limits. Increasing the concentration of the emulsifier used did not influence the rate of polymerization, but led to increases in limiting conversions. Product particle size analyses indicate that average particle size is independent of initiator concentration and rate of initiation. An increase in the emulsifier concentration on the other hand appears to lead to an increase in number of particles in the system and thus promotes smaller particle sizes.     

Preparation and characterization of titanium dioxide core/polymer shell hybrid composite particles prepared by emulsion polymerization

Titanium dioxide inorganic core and polymer shell composite poly(methyl methacrylate‐co‐butylacrylate‐co‐methacrylic acid) [P(MMA‐co‐BA)‐MAA] particles were prepared by emulsion copolymerization. Fourier transform IR (FTIR) spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering (DLS) characterized the composite particle size and size distribution. The field emission SEM (FE‐SEM) results of the composite particles showed regular spherical shape and no bare TiO₂ was detected on the whole surface of the samples. The composite particles were produced, showing good spectral reflectance compared with bare TiO₂. TGA results indicated the encapsulation efficiency and estimated density of composite particles. Encapsulation efficiency was up to 78.9% and the density ranged from 1.76 to 1.94 g/cm³. Estimated density of the composite particles is suitable to 1.73 g/cm³, due to density matching with suspending media. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2970–2975, 2004     

表面活性剂辅助水热法中TiO2的形状控制

By hydrolysing titanium isopropoxide in a long hydrocarbon chain surfactant-containing solution, TiO2 fine particles with a diversity of well-defined morphologies was synthesized in this study by a hydrothermal route. The structural change during the formation process was monitored by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. TiO2 with various morphologies such as particle, sheet, rod, tube and flower-like shape was obtained by carefully controlling the preparation conditions. The experimental results show that the pH value is crucial for shape control of the produced TiO2 because it can change the charge state of the surfactant in the solution and the adsorption potential of the surfactant on the TiO2 surface. The shape evolvement of anatase TiO2 was elucidated by quenching the reaction at different stage and the formation mechanism of different shaped TiO2 was suggested.