纳米TiO2表面接枝聚苯乙烯及其抗紫外老化研究

利用偶联剂γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)对纳米TiO₂进行表面预处理, 在此基础上通过分散聚合工艺制备聚苯乙烯(PSt)接枝包覆纳米TiO₂. 运用红外光谱、热重分析及透射电镜对处理前后纳米TiO₂进行了表征, 并通过紫外人工加速老化试验比较了表面处理前后纳米TiO₂对聚丙烯/聚苯乙烯(PP/PSt)体系的抗紫外老化性能. 结果显示: KH570与纳米TiO₂表面羟基进行了缩合, PSt在粒子表面实现了接枝聚合, 接枝率约为60% (w); PSt接枝包覆纳米TiO₂呈均匀的微球形, 纳米TiO₂被包覆于微球内部; PSt接枝包覆后纳米TiO₂在PP/PSt中的分散效果较改性前有显著的改进, 其抗紫外老化性能明显优于改性前体系.     

Au改性TiO2纳米复合物对人结肠癌细胞的光催化杀伤作用

提出了通过TiO₂表面修饰纳米Au的方法来提高纳米TiO₂光催化杀伤癌细胞的效率. 采用化学还原法合成了Au改性的TiO₂ (Au/TiO₂)纳米复合物, 并研究了不同掺杂量(1 wt%, 2 wt%, 4 wt%)的Au/TiO₂对人结肠癌LoVo细胞的光催化杀伤效应. 结果显示, Au的掺杂大大地提高了TiO₂纳米粒子光催化杀伤结肠癌LoVo细胞的效率, 而且Au掺杂量的高低影响Au/TiO₂光催化杀伤癌细胞的效率, 掺金量为2%的Au/TiO₂对结肠癌LoVo细胞具有最高的光催化杀伤效率. 在光强为1.8 mW/cm²的紫外灯(λ_max＝365 nm)下光照110 min, 50 μg/mL掺金量为2%的Au/TiO₂能够杀死所有的癌细胞, 而同样浓度的TiO₂只能杀死70%的癌细胞.     

溶胶-凝胶法制备纳米TiO2/丝素复合膜及结构性能研究

用溶胶凝胶法制备不同比例纳米TiO₂改性再生蚕丝丝素蛋白复合膜. UV和AFM测试结果表明, 该丝素膜中纳米TiO₂均匀分散在丝素中, TiO₂粒径约为80 nm; 同时该丝素膜的结构和热性能用FTIR, XRD, EDS, TGA和DTG进行表征. XRD测试结果表明, 随着纳米TiO₂的加入, 复合丝素膜的结晶结构从Silk I向Silk II转化, 但当纳米TiO₂的加入超过一定量时, 又破坏复合丝素膜的结晶结构; FTIR和EDS测试结果表明, TiO₂与丝素形成较好的键合; TGA和DTG测试表明复合丝素膜的热转变温度相比于纯丝素膜有所提高.     

溶胶-凝胶-水热晶化法制备锐钛矿TiO2纳米膜的耐蚀性能

以钛酸正丁酯为前驱体, 采用溶胶-凝胶-水热晶化法在不锈钢(SS)表面制备TiO₂纳米膜. 利用X射线衍射(XRD)、Raman光谱、场发射扫描电子显微镜(SEM)、原子力显微镜(AFM)和俄歇电子能谱(AES)表征了TiO₂纳米膜的晶型、表面形貌和表面化学组成. 通过极化曲线和电化学阻抗谱(EIS)研究了TiO₂纳米膜的耐蚀性能. 170 °C下水热晶化制备的锐钛矿TiO₂与450 °C焙烧制备的锐钛矿TiO₂的结晶度类似, 但两种TiO₂薄膜的表面结构存在明显差异, 水热晶化法制备的TiO₂纳米膜在3.5% (w) NaCl溶液中的耐蚀性能优于焙烧法制备的.     

高度分散的Pt/TiO2的制备及光催化活性

用柠檬酸作为空穴捕获剂和分散剂, 在温和条件下用光催化还原法将3 nm金属铂沉积在7 nm的锐钛矿相及介孔二氧化钛纳米晶表面. TEM观察显示铂的负载量为w＝1.0%时, 多数二氧化钛纳米晶表面沉积了岛状的铂团簇, XPS和电子衍射结果表明铂以游离态存在. 负载w＝1.0%～2.0%铂的TiO₂在苯酚光氧化反应中活性显著提高. Pt/TiO₂在氨气中经550 ℃氮化, 可制得氮掺杂的Pt/TiO₂可见光光催化剂, 氮化过程中铂团簇没有烧结和显著长大.     

溶胶-凝胶法制备纳米TiO2/丝素复合膜及结构性能研究

用溶胶凝胶法制备不同比例纳米TiO₂改性再生蚕丝丝素蛋白复合膜. UV和AFM测试结果表明, 该丝素膜中纳米TiO₂均匀分散在丝素中, TiO₂粒径约为80 nm; 同时该丝素膜的结构和热性能用FTIR, XRD, EDS, TGA和DTG进行表征. XRD测试结果表明, 随着纳米TiO₂的加入, 复合丝素膜的结晶结构从Silk I向Silk II转化, 但当纳米TiO₂的加入超过一定量时, 又破坏复合丝素膜的结晶结构; FTIR和EDS测试结果表明, TiO₂与丝素形成较好的键合; TGA和DTG测试表明复合丝素膜的热转变温度相比于纯丝素膜有所提高.     

纳米金属氧化物：复合分散法制备及分散性

通过采用水热晶化与荷电复合分散法制备γ-AlOOH、R-TiO₂和α-Al₂O₃纳米晶体粉末,利用TEM和激光粒度分析仪等手段研究了纳米颗粒水热晶化与荷电复合分散的分散效果及其工艺条件,并探讨了金属氧化物纳米颗粒水热晶化与荷电复合分散机理。结果表明,晶化与荷电复合分散可明显改善金属氧化物纳米颗粒在液相中的分散稳定性,所制得的AlOOH、TiO₂和Al₂O₃纳米颗粒在水中分散放置24 h后的透光率的变化率D₂₄还可分别保持为94.1%、87.7%和82.2%;在水中分散后的粒径分布统计的平均粒径分别为67、70和143 nm。     

超声场中纳米TiO2表面包覆氧化硅的研究

在超声场中，通过硅酸钠水解生成的无定形氧化硅对金红石相纳米TiO₂进行表面包覆，利用红外光谱、X射线光电子能谱、X射线衍射和透射电镜对所得样品进行了表征，并对纳米TiO₂的光稳定性和分散性进行了评价。红外光谱和X射线光电子能谱表明，氧化硅以化学键合的方式沉积在纳米TiO₂的表面，在包覆层和纳米TiO₂颗粒之间的界面上形成了Ti-O-Si键。TEM照片、表面元素分析和光稳定性实验显示，氧化硅在纳米TiO₂表面形成了均匀的包覆层，超声场有助于提高包覆层的均匀性和致密性。氧化硅的表面包覆提高了纳米TiO₂在水中的分散性、紫外线屏蔽能力和可见光透过性。随着氧化硅含量的增加，纳米TiO₂的光稳定性逐渐提高，当m(SiO₂)∶m(TiO₂)>1∶5时，纳米TiO₂的光稳定性基本不变，而且在热处理过程中纳米TiO₂的晶粒生长得到有效抑制。     

聚3-甲基噻吩修饰硫化物量子点连接纳米结构TiO2膜的光电化学研究

采用原位化学法在纳米结构TiO₂膜上制备了量子点CdS, PbS (Q-CdS, Q-PbS), 并用电化学方法在TiO₂/Q-CdS, TiO₂/Q-PbS表面聚合3-甲基噻吩[poly(3-Methylthiophene, PMeT)]. 用光电化学方法研究了PMeT修饰Q-CdS, Q-PbS连接TiO₂纳米结构膜, 实验结果表明, PMeT和Q-CdS, Q-PbS单独修饰纳米结构TiO₂电极和PMeT修饰Q-CdS, Q-PbS连接纳米结构TiO₂电极的光电流产生的起始波长都向长波方向移动; 一定条件下在可见光区光电转换效率均较纳米结构TiO₂的光电转换效率有明显的提高; 聚3-甲基噻吩(PMeT)与Q-CdS, Q-PbS连接的纳米结构TiO₂之间存在p-n异质结. 在一定条件下p-n异质结的存在有利于光生电子/空穴的分离, 在本文实验条件下PMeT修饰Q-CdS, Q-PbS连接纳米结构TiO₂电极最高的单色光的光电转换效率分别为11%和7%.     

Impact of TiO2 nanoparticles on morphology and performance of crosslinked polyimide organic solvent nanofiltration (OSN) membranes

Chemically crosslinked polyimide organic–inorganic composite nanofiltration membranes suitable for application in harsh organic solvents were successfully prepared by phase inversion of dope solutions. TiO₂ nanoparticles were dispersed in these dope solutions, comprising polyimide (PI) in N,N-dimethylformamide/1,4-dioxane. The impact of TiO₂ on the resulting PI membranes was investigated using SEM, TGA, water contact angle, dope viscosity measurements and mechanical strength. The presence of TiO₂ nanoparticles within the membrane matrix was proved by the detection of a peak characteristic of TiO₂ in the WAXS pattern. SEM pictures of the cross-section of the PI/TiO₂ membranes showed dramatically changed morphology compared to reference membranes with no TiO₂ addition. Macrovoids present in reference membranes were suppressed by increasing loading of TiO₂ nanoparticles, and eventually disappeared completely at a TiO₂ loading above 3 wt.%. Decreasing water contact angle and an increase in ethanol flux indicated that hydrophilicity increased as nanoparticle loading increased. The effect of TiO₂ on the functional performance of the membranes was evaluated by measuring flux and rejection using cross-flow filtration. Perhaps surprisingly, the presence of TiO₂ improved the compaction resistance of the membranes, whereas rejection and steady flux were almost unaltered.     

Blend membranes from cellulose/konjac glucomannan cuprammonium solution

The blend membranes were prepared from cellulose/konjac glucomannan (KGM) cuprammonium solution by coagulating with aqueous 10 wt% NaOH solution, 20°C and 40°C water, respectively. Miscibility, pore morphology, structure, water permeability and mechanical properties of the blend membranes were investigated. The complex forms of cellulose/KGM in the mixed solutions, the effect of various coagulants and the percent content of KGM (w_KGM) on the structure and properties of the blend membrane are discussed. SEM and mechanical relaxation analysis indicate that the blend membranes are miscible in the range of 0–30 wt% of w_KGM. When w_KGM was smaller than 20 wt%, the tensil strength of the blend membrane coagulated by alkali aqueous solution was enhanced, corresponding to homogeneous structure and small pore size. However, blend membranes having a larger pore size (366 nm by SEM) and water permeability (560 ml/m² h mmHg) were obtained by coagulating the cellulose/KGM (70:30) cuprammonium solution with 40°C water, where ca. 20% of KGM as pore former were removed from the membrane.     

Polysulfone membranes <Emphasis Type="Italic">via</Emphasis> thermally induced phase separation

Polysulfone (PSF) membranes have gained great attention in the fields of ultrafiltration, microfiltration, and thin film composite membranes for nanofiltration or reverse osmosis. For the first time, it is proposed to fabricate PSF membranes via thermally induced phase separation (TIPS) process using diphenyl sulfone (DPSO2) and polyethylene glycol (PEG) as mixed diluent. DPSO2 is chosen as a crystallizable diluent, while PEG is considered in terms of molecular weight (M _w) and dosage. We systematically investigate the interactions between PSF, DPSO2 and PEG based on the simulation calculations and solubility parameter theory. It is inferred that DPSO2 has an excellent compatibility with PSF, and the addition of PEG results in the ternary system thermodynamically less stable and then facilitates its liquid-liquid (L-L) phase separation. SEM images indicate that cellular-like pores are obvious throughout the membrane when the PEG content in the mixed diluent is 25 wt%?35 wt%. We can facilely manipulate the pore size, water flux and mechanical properties of PSF membranes with the dosage of PEG-200, the M _w of PEG or the cooling rate. The successful application of TIPS can provide a new approach for structure manipulation and performance enhancement of PSF membranes.     

溶胶凝胶法制备杯[6]芳烃乙酸/二氧化钛杂化材料

采用溶胶-凝胶法制备了不同TiO₂含量的杯[6]芳烃乙酸/TiO₂ (CA/TiO₂)杂化材料. 通过溶剂抽提实验和FT-IR测试表明杂化材料中有机无机两相间存在着化学键. 通过XRD, SEM, TGA对材料的结构和性能进行表征. 结果表明: 当TiO₂的含量w为60%时, 材料表面均匀光滑, 有机无机两相相容性和材料的热稳定性能最好, 但w(TiO₂)≤40%时, 难以获得两相均一的杂化材料.     

Crosslinked poly(ethylene oxide) fouling resistant coating materials for oil/water separation

Potential fouling reducing coating materials were synthesized via free-radical photopolymerization of aqueous solutions of poly(ethylene glycol) diacrylate (PEGDA). Crosslinked PEGDA (XLPEGDA) exhibited high water permeability and good fouling resistance to oil/water mixtures. Water permeability increased strongly with increasing the water content in the prepolymerization water mixture, going from 10 to 150 L μm/(m² h bar) as prepolymerization water content increased from 60 to 80 wt.%. However, molecular weight cutoff decreased as water content increased. These materials were applied to polysulfone (PSF) UF membranes to form coatings on the surface of the PSF membranes. Oil/water crossflow filtration experiments showed that the coated PSF membranes had water flux values 400% higher than that of an uncoated PSF membrane after 24 h of operation, and the coated membranes had higher organic rejection than the uncoated membranes.     

负载型CuO/TiO2催化剂催化CO2加氢制甲醇

采用浸渍法制备了CuO/TiO_2负载型催化剂,并将其用于CO2加氢制甲醇反应。重点考察了铜的负载量对催化剂性能的影响,并对其物化性能和催化性能之间的关系进行了讨论。结果发现,随着铜负载量的增加,催化剂中金属铜的比表面先增加后减小,当铜的负载量为10%(质量百分数)时达到最大值。催化剂的表面碱性位数量随铜含量的增加持续减小,中等碱位和强碱位的强度下降。当铜的负载量不高于10%时,CO2的转化率与铜的比表面积呈线性关系。甲醇选择性与催化剂的表面碱位性质有关,过强的碱性位会降低甲醇选择性。     

Preparation and characterization of ternary composite films of polyvinyl alcohol/sodium alginate/TiO<Subscript>2</Subscript>

Nano-TiO₂ with anionic surface active agent sodium dodecylsulfate (SDS) modified, the poly(vinyl alcohol)/sodium alginate/TiO₂ composite films were prepared by method of solution blending representing. The structure of the films was analyzed by XRD and SEM. In addition, air permeability rate, swelling ratio, light transmittance, mechanical properties, and antibacterial properties were tested. The results showed that in compound membrane there was a strong force between poly(vinyl alcohol)/sodium alginate and TiO₂ particles, indicating that there was good compatibility between the sodium alginate and the poly(vinyl alcohol). The mixed membranes were of good water resistance, tensile strength, and closure. When the titanium dioxide content increased appropriately, they had very good mechanical properties. In addition, the antibacterial properties of composite membrane gradually increased with the increase in the TiO₂content.     

Nanofibrous polysulfone/TiO2 nanocomposites: Surface properties and their relation with E. coli adhesion

Solution blow spinning, SBS, was used to prepare fibrous films of thermoplastic nanocomposites with potential antibacterial properties based on polysulfone, PSF, filled with well dispersed TiO₂ nanoparticles. The PSF/TiO₂ nanocomposites were produced with different nanoparticles content up to 10% by weight. A wide characterization was carried out focusing on the morphology at the nanoscale, roughness, contact angles, and surface free energy. Cell adhesion was studied by inspection by scanning electron microscopy (SEM). A uniform dispersion of the nanofiller was achieved, with the nanoparticles evenly embedded in the polymer along the fibers when they were created during the blow spinning process. TiO₂ content influenced the topography of the films, most likely due to a direct effect on the solvent evaporation rate. The results obtained pointed out that an increase of the surface hydrophobicity as a result of the increased roughness induced by the presence of TiO₂ nanoparticles was the main contribution to the reduction of DH5α Escherichia coli cells adhesion. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1575–1584     

Preparation and properties of polysulfone/TiO2 composite ultrafiltration membranes

The influence of inorganic filler TiO₂ nanoparticles on the morphology and properties of polysulfone (PS) ultrafiltration membranes was investigated. PS/TiO₂ composite membranes were prepared by a phase‐inversion method. TiO₂ nanoparticles modified by sodium dodecyl sulfate were uniformly dispersed in an 18 wt % PS casting solution. The addition of TiO₂ resulted in an increase in the pore density and porosity of the membrane skin layer. The pore size distribution changed from the log‐normal distribution to the bimodal distribution because of the presence of TiO₂ nanoparticles, and some large pores were observed when the concentration of the filler was over 3 wt %. The skin layer was gradually thickened; meanwhile, the morphology sublayer changed from macrovoids to spongelike pores, in comparison with PS membranes without the filler. The addition of TiO₂ also induced increases in the hydrophilicity, mechanical strength, and thermal stability. The ultrafiltration experiments showed when the concentration of TiO₂ was less than 2 wt %, the permeability and rejection of the membrane was enhanced and then decreased drastically with a higher filler concentration (>3%). © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 879–887, 2006     

Effect of TiO2 nanoparticles on structure and properties of high density polyethylene membranes prepared by thermally induced phase separation method

Polyethylene/TiO₂ membranes were fabricated via thermally induced phase separation (TIPS) method. A set of characterization tests including FE‐SEM, EDX, XRD, DSC, TGA, DMA, mechanical test and relative pure water flux for characterization of membranes were carried out to investigate the effect of TiO₂ nanoparticles on membrane properties. The results of EDX, XRD and TGA analyses confirmed the presence of TiO₂ nanoparticles in the polymer matrix. The results of DSC analysis revealed that the melting point as well as the crystallinity of the membranes increased slightly with increasing TiO₂ content. However, the glass transition temperature of the membranes was not affected by the presence of particles. Addition of nanoparticles also increased storage modulus, loss modulus and tensile strength at break of the membranes due to the stiffness improvement effect of inorganic TiO₂. Finally, it was observed that incorporation of the nanoparticles improved pure water flux of the membranes. Copyright © 2015 John Wiley & Sons, Ltd.