Surface and interface characterization of polyester‐based polyurethane/nano‐silica composites

Polyester‐based polyurethane/nanosilica composites were prepared via in situ polymerization and investigated by contact angle measurement, transmission electron microscopy (TEM), atomic force microscopy (AFM) and peel testing in an Instron testing machine. The contact angle and surface free energy results show that nanosilica tended to enrich at the interface between nanocomposite polymers and the substrates, TEM indicated that nanosilica particles were evenly dispersed in the bulk and AFM demonstrated that nanoparticles were located at both the surfaces and interfaces of nanocomposite polymers and that the roughness of both the surfaces and interfaces had a decreasing tendency as the nanosilica content increased, as did the adhesion strength between the nanocomposite polymers and substrates. Copyright © 2003 John Wiley & Sons, Ltd.     

Preparation, characterization, and application of multistimuli-responsive microspheres with fluorescence-labeled magnetic cores and thermoresponsive shells

Novel functional microspheres with multistimuli-responsive properties have been prepared and characterized. The as-prepared microspheres respond to an external magnetic field, environmental temperature, and ultraviolet radiation. The in vitro drug-loading efficiency and drug-release behavior of these microspheres demonstrated that they could be used as drug carriers for drug controlled release. The results of in vivo distribution investigations of these microspheres showed that they exhibit a high magnetic-targeting effect, which holds promise for applications in various fields such as magnetic drug targeting and tissue labeling, among others.     

Au/Ag复合纳米笼在表面增强拉曼光谱中的应用

表面增强拉曼光谱（SERS）技术是一种基于贵金属纳米结构基底对被检测物进行高灵敏度检测的一种方法.具有特殊纳米结构的贵金属表面受到激光的照射时，金属表面的自由电子会受到极大的振荡，当入射光频率与振荡频率相近时，则会发生表面等离子体共振现象（SPR），使金属表面的局域电场强度极大增强，入射光强度和散射光强度都得到成倍的放大，从而使吸附在贵金属纳米结构表面的分子的拉曼散射信号得到有效的增强.使用NaBH₄还原-酸刻蚀模板法，制备了八面体Au/Ag复合纳米笼，其形貌规整，尺寸均匀约为600 nm，无Cu₂O模板的残留，Au元素均匀负载在Ag纳米笼上，质量分数约为16.8%；Au/Ag复合纳米笼的紫外可见吸收峰相对于Ag纳米笼发生了红移，更重要的是，Au和Ag元素协同赋予了复合纳米笼超高的SERS灵敏度和重复性，Au/Ag复合纳米笼实现了对罗丹明6G的痕量检测（5×10^-14 mol/L），通过时域有限差分法（FDTD）模拟证实：这主要归因于等离子共振作用产生的高电磁场强度；此外，Au元素的加入使Au/Ag复合纳米笼具有优异的抗氧化性和化学稳定性，即使在1%的H₂O₂溶液中浸泡3 h，仍然能够保持优异的SERS性能.八面体Au/Ag复合纳米笼有望成为一种具有应用前景的高灵敏度、高稳定性的SERS基底.     

Fractionation and Bioaccessibility of Manganese,Copper, Zinc,Cadmium, and Lead in Commercial Vegetable and Rice Baby Foods Using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) with Central Composite Design (CCD)

Abstract

Herein the bioaccessibility of Mn, Cu, Zn, Cd, and Pb, selected from essential and toxic elements, was determined in commercially sold vegetable purees intended for infant and toddler consumption. Chemical fractionation studies using water, acetone, diethyl ether, chloroform:methanol, and n-hexane were employed to predict the importance of the protein and lipid parts of a matrix to assess the bioaccessibility data. In addition, in-vitro gastrointestinal digestion was performed to determine the bioaccessibility of the elements using a five level, three factor central composite design (CCD) to maximize the elemental solubility. The total elemental concentrations in all of the fractions were determined by inductively coupled plasma – mass spectrometry (ICP-MS). Based on the consumption of one jar of vegetable/rice-based baby food, Zn was 1.3% of the recommended dietary allowance and Mn was 4.2% of the adequate intake level, while Cu was almost 100% of the adequate intake level. Additionally, Pb was always below the detection limit and Cd was sometimes under the detection limit for the percent bioaccessibility. However, in some samples, Cd was as high as 80% of the tolerable weekly intake level depending on the body weight.     

基于氮化碳复合材料磁性固相萃取结合高效液相色谱法测定尿液中3种羟基多环芳烃

建立了测定尿液中3种羟基多环芳烃的氮化碳复合材料磁性固相萃取结合高效液相色谱-荧光检测法。所构筑的磁性氮化碳材料，经扫描电子显微镜、X射线衍射仪、振动样品磁强计和比表面积分析仪表征后，用于尿液中3种羟基多环芳烃的富集净化。考察了吸附剂用量、吸附时间、洗脱溶液和洗脱体积（单次洗脱体积×洗脱次数）对萃取效率的影响。结合高效液相色谱-荧光分析，在0.25~250 μg/L范围内线性关系良好（相关系数r=0.999），3种羟基多环芳烃的检出限和定量限分别为0.08和0.25 μg/L，回收率为90.1%~102%，日内和日间精密度分别为1.5%~7.7%和2.2%~8.7%。该本方法简单、快速、高效，可用于尿液中羟基多环芳烃的分析。     

Synthesis and Characterization of Core‐Shell Selenium/Carbon Colloids and Hollow Carbon Capsules

A novel Se/C nanocomposite with core‐shell structures has been prepared through a facile one‐pot microwave‐induced hydrothermal process. The new material consists of a trigonal‐Se (t‐Se) core and an amorphous‐C (a‐C) shell. The Se/C composite can be converted to hollow carbon capsules by thermal treatment. These products were characterized by transmission electron microscopy (TEM), powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction (SAED), energy‐dispersive X‐ray (EDX) spectroscopy, and X‐ray photoelectron spectroscopy (XPS).     

导电高分子材料的应用和进展

论述了复合型及结构型导电高分子材料的导电机理、应用和研究进展。     

热处理对聚乙烯／炭黑导电复合体系形态结构及PTC特性的影响

借助ＷＡＸＤ、ＳＡＸＤ和ＤＳＣ等手段研究了炭黑与聚乙烯复合体系在不同热处理条件下的结晶行为及聚集态结构的大尺寸效应对ＰＴＣ特性的影响。由此提出，不仅结晶度大小，而且聚集大尺寸效应性能对ＰＴＣ行性有重要影响的新观点。     

Comparison between self-reinforced composites based on ultra-high molecular weight polyethylene fibers and isotropic UHMWPE

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Pt3Co核-Pt壳型纳米粒子的制备及磁性

Pt₃Co alloy nanoparticles were prepared by the reduction of H₂PtCl₆ and Co(OOCCH₃)₂ using NaBH₄ as a reducing agent. The Pt₃Co core-Pt shell nanoparticles (Pt₃Co@Pt) were synthesized using hydrogen absorption reduction and characterized by plasma-atomic emission spectrometry (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD) and SQUID magnetometer. The results show that average size of Pt₃Co@Pt nanoparticles is 3.6 nm with a standard deviation of 0.9 nm. Heating Pt₃Co nanoparticles in air at 700 ℃ for 1 h, Co in Pt₃Co nanoparticles was oxidized to Co₃O₄ and CoO; while no oxidation tendency was detected for Pt₃Co@Pt nanoparticles. The crystallize structure of Pt₃Co@Pt changed from the face centered cube (fcc) to the face centered tetragonal (fct) after the heating treatment. The coercivity of the heated Pt₃Co@Pt reached to 276 Oe at room temperature.