Self-assembled monolayers of a disulphide-derivatised cobalt-porphyrin on gold

A self-assembled monolayer (SAM) of a novel cobalt(II)porphyrin disulphide derivative was prepared on flat gold(1 1 1) electrode. Evidence for surface modification was provided by electrochemical reductive desorption of the monolayer and ellipsometry, consistent with a coverage of 2.5 × 10⁻¹⁰ mol cm⁻² and a thickness of 13 Å, respectively. Both results support the presence of SAMs where the molecules share an intermediate position between perpendicular and flat orientation. Scanning tunnelling microscopy have also proven the formation of CoPSS SAMs, however high-resolution images could only be obtained when the CoPSS molecules were diluted in an hexanethiol SAM. The electrocatalytic activity of the surface confined Co-porphyrin was evaluated for the oxygen reduction. Voltammetric data indicate that reaction involves two electrons consistent with the formation of hydrogen peroxide. Under similar experimental conditions the data obtained for an iron-porphyrin analogue points for a full reduction of dioxygen to water.     

Structure and conductivity of multi-walled carbon nanotube/poly(3-hexylthiophene) composite films

This work reports a structure-property investigation of a conjugated polymer nanocomposite with enhanced conductivity. Regioregular poly(3-hexylthiophene) (rrP3HT) was used to prepare composites with thin, short, multi-walled carbon nanotube (MWNT) addition over a wide range of concentrations. Scanning and transmission electron microscopies demonstrated an excellent dispersion and good wetting properties within the carbon nanotube composites. Coated MWNTs showed superstructures of P3HT self-organized on nanotube surfaces. Changes in the long range order and on the self-ordered mesophase of the bulk material were investigated by infrared and Raman spectroscopies, differential scanning calorimetry and X-ray diffraction. Interplay between charge transport through the semiconducting polymer and carbon nanotube network increased the composite's conductivity after percolation to values close to 10⁻² S cm⁻¹.     

Preparation and characterization of polypropylene/layered silicate nanocomposites using an antioxidant

Polypropylene (PP)/layered silicate nanocomposites were prepared via simple melt mixing of three components, PP, layered silicates modified with octadecylamine (C18-MMT) and antioxidant, to investigate the role of antioxidant. TEM and X-ray scattering results confirmed the intercalated state of silicates in PP/layered silicate nanocomposites with antioxidant. In rheological and mechanical study, the nanocomposites with antioxidant showed higher properties than those of the unfilled PP. The nanocomposite with 5 wt% C18-MMT and 0.5 phr antioxidant exhibited about 1.4 times higher tensile modulus and 1.3 times higher storage modulus than the unfilled PP. However, PP/C18-MMT without antioxidant showed lower rheological values owing to the thermal decomposition of PP and the poor compatibility between PP and C18-MMT. It could be concluded that antioxidants played an important role in enhancing the compatibility between PP and C18-MMT. According to the real time X-ray diffraction, the nanocomposite showed the weak ordering of PP crystals than the unfilled PP in the load-extension plateau region of elongation.     

Supercritical CO2‐assisted synthesis of poly(acrylic acid)/Antheraea pernyi SF blend

Monomer acrylic acid (AA) and initiator azo‐bis(isobutyronitrile)were carried into Antheraea pernyi silk fibroin (SF) fibers using supercritical CO₂ as a solvent and carrier, followed by free radical polymerization at a suitable temperature, resulting in PAA/SF blends. The binary system of CO₂/AA and the ternary system of CO₂/AA/AIBN systems were studied. Different impregnation conditions, such as time, pressure, and concentration of AA in the fluid phase on mass uptake, were studied. Fourier transform infrared spectroscopy and X‐ray diffraction results confirmed that PAA was indeed present in the silk and that there were intermolecular hydrogen bonds between PAA and SF. According to thermogravimetry and DTG, blending with PAA could enhance the thermal stability of SF slightly. The water retention values indicated that the hydrophilic nature of the fibers was improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 864–868, 2005     

新显色剂4—（2—苯并噻唑偶氮）邻苯二酚—钼（Ⅵ）—OP体系的分光光度研究

在ｐＨ５．０～５．７范围内，新显色剂４－（２－苯并噻唑偶氮）邻苯二酚（ＢＴＡＰＣ）与钼（Ⅵ）和非离子表面活性剂ＯＰ反应，形成稳定的、带负电荷的、紫红色三元胶束配合物。该配合物中Ｍｏ（Ⅵ）与ＢＴＡＰＣ的组成比为１∶２；其λｍａｘ为５６０ｎｍ，对比度（Δλ）为１２８ｎｍ；在２０℃、ｐＨ５．２和μ０．１时，配合物的表观稳定常数为３．０２×１０１０，表观摩尔吸光系数ε５６０为８．１１×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，真实ε５６０为７．６７×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。钼含量在０～０．７２ｍｇ／Ｌ范围内遵从比耳定律。建议了配合物的结构。本法简便、快速、准确，用于合金钢试样中痕量或小量钼的测定，取得了满意的结果。     

ATP的分析方法综述

本文综述了当前的ATP分析方法，比较了各方法的分析原理，优缺点及使用范围。     

Recent advances in the rheooptical characterization of silicon-containing networks

Recent advances in the various theories of strain-birefringenece of polymer networks are presented. The classical theories as well as the more advanced models are outlined together with some recent theoretical results on poly (dimethylsiloxane). Reference to work on other Si-containing polymers is made. The problems of intermolecular correlations occurring in polymer networks and their effect on the observed optical properties are discussed with reference to the optical-configuration parameter. Conclusions report areas of current research.This review was presented at the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.     

高效液相色谱法在氟铃脲标准样品制备中的应用研究

标准样品是农残分析巾的必要条件。应用高效液相色谱法进行氟铃脲的纯化、制得氟铃脲标准样品，用DELTA PAK C18柱，以乙腈-水(68：32)为流动相，在波长254nm，室温下进行了保留值定性、定值分析、均匀性及稳定性考察，效果良好。     

Modification of the polarity of isotactic polypropylene through blending with oxidized paraffin wax

The modification of the polarity of isotactic polypropylene (iPP) through blending with oxidized paraffin wax (Fischer–Tropsch synthesis) was investigated. The oxidized paraffin wax significantly increased the polar component of the total surface free energy of polypropylene. Modified iPP also showed significantly higher adhesion to the polar substrate, as represented by a crosslinked epoxy‐based resin. The conservation of the good mechanical properties of the blends was observed up to 6 wt % wax. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 529–533, 2004     

饲料级磷酸氢钙中钙含量偏高的原因

通过不同温度下的烘干、灼烧实验 ,分析饲料级磷酸氢钙中钙含量偏高的主要原因是产品结晶水含量少 ,仅 0 .3个结晶水。取消中和槽蒸汽加热 ,保持常温反应 ;改闪蒸干燥为气流干燥 ;用氢氧化钙作中和剂 ;使饲钙产品中钙含量由平均约 2 8%降至 2 2 %。