混合溶剂对磺化聚苯乙烯水基微乳液体系形态的影响

利用相反转技术制备磺化聚苯乙烯(SPS)水基微乳液,研究发现,通过选择溶剂和控制混合溶剂的组成,可制备不同颗粒形态结构的SPS水基微乳液,并研究了相反转过程、乳液稳定性与混合溶剂组成之间的关系。     

磺化聚苯乙烯镧离子型聚合物的稀溶液性质

聚电解质行为;比浓粘度;电解质;磺化聚苯乙烯镧离子型聚合物的稀溶液性质     

Study on Fe3O4/polyaniline electromagnetic composite hollow spheres prepared against sulfonated polystyrene colloid template

Fe₃O₄/polyaniline (PANI) composite hollow spheres were prepared by using sulfonated polystyrene (SPS) microspheres as templates. The sulfonic acid groups were applied to induce absorbing Fe₃O₄ nanoparticle, and subsequently, conductive PANI was grown. Finally, the polystyrene cores were selectively dissolved to yield composite hollow microspheres with electromagnetic properties. The analysis results indicated that the adsorption of Fe₃O₄ on template core by electrostatic interaction resulted in magnetic composite microspheres. The conductivity of composite hollow spheres was remarkably increased after polyvinylpyrrolidone modification which favored the growth of PANI on SPS/Fe₃O₄ and enhanced the integrity of hollow microspheres. The saturated magnetization of the composite hollow microspheres was tuned from 2.7 to 9.1 emu/g, and the conductivity was in the range from 10^?2 to 10⁰?S/cm.     

聚苯乙烯/银纳米粒子复合微球的合成及催化性能

首先通过乳液聚合和浓硫酸酸化制备表面富含磺酸根的磺化聚苯乙烯(PS)微球(直径532 nm),再用其静电吸附[Ag(NH_3)_2]~+离子,最后采用聚乙烯吡咯烷酮还原表面吸附的[Ag(NH_3)_2]~+离子,得到了负载银纳米粒子的PS/AgNPs复合微球.采用扫描电子显微镜、透射电子显微镜、紫外-可见光谱、红外光谱和X射线衍射表征了PS/AgNPs复合微球,并考察了其对甲基蓝(MB)的催化性能.结果表明,Ag纳米粒子高度分散在磺化PS微球表面;该PS/AgNPs复合微球对催化转化MB有较高的催化活性,并可多次重复利用.本研究在催化降解有机污染物方面有一定的实用价值.     

Partially Sulfonated Polystyrene and Poly(2,6‐dimethyl‐1,4‐phenylene oxide) Blend Membranes for Fuel Cells

Summary: Based on Flory–Huggins parameters (χ), the miscibility and the effect of morphological change on proton conductivity and methanol permeability of partially sulfonated polystyrene (SPS) and partially sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO), having an identical ion exchange capacity, were investigated. When 50 wt.‐% of SPPO was blended, both the proton conductivity and methanol permeability had the highest values, which resulted from the change of amorphous domains and the hydrogen bonding between the two ionomers.

The proton conductivities, water uptake and methanol permeability for the SPPO/SPS blend membranes studied here. The membranes with 50 wt.‐% SPPO clearly showed the greatest increase in these properties.     

Polyaniline/Au composite hollow spheres: synthesis, characterization, and application to the detection of dopamine

Polyaniline (PANI)/Au composite hollow spheres were successfully synthesized using polystyrene/sulfonated polystyrene core/shell gel particle templates. The PANI shell thickness and the number of Au nanoparticles decorating the PANI could be controlled effectively by adjusting the experimental conditions. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption spectra. It was found that the electrical conductivity of the PANI/Au composite hollow spheres was more than 3 times higher than that of the pure PANI hollow spheres. Furthermore, PANI/Au composites were immobilized on the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI/Au-modified GCEs showed one pair of redox peaks and high catalytic activity for the oxidation of dopamine. The possible formation mechanism of the PANI/Au composite hollow spheres was also discussed.     

轻度磺化聚苯乙烯与聚苯乙烯共混物的流变性能表征

采用DSR-200动态应力流变仪研究了磺化度为0.98%(摩尔分数)的轻度磺化聚苯乙烯(SPS)离聚物及其锌盐(ZnSPS)与聚苯乙烯(PS)的共混物(PS/SPS,PS/ZnSPS)的流变性能.由于离聚物中离子聚集的物理交联作用,使其流变性能与PS相比有明显差别.动态频率实验结果表明,所有样品均可采用时温等效处理.另外,在与分子链运动相关的低频区,由于离子聚集的作用使得离聚物的模量远大于PS的模量.离聚物在稳态剪切作用下,由于离子聚集的破坏而表现出明显的屈服现象,并能用Utracki的屈服应力公式表征其屈服应力和零切粘度.此外,离聚物的屈服现象还与温度相关.由于动态和稳态实验分别测试离子聚集存在和破坏的不同材料状态,因此对离聚物无法应用Cox-Merz规则.动态和稳态实验结果均表明,PS/SPS和PS/ZnSPS的性能与组成的变化规律不同,意味着二者之间存在不同的离子聚集结构或相互作用.     

Ternary Ag/Polyaniline/Au nanocomposites: Preparation,characterization and electrochemical properties

Ternary Ag/Polyaniline/Au nanocomposites were synthesized successfully by immobilizing of Au nanoparticles (NPs) on the surface of Ag/Polyaniline (PANI) nanocomposites. Ag/PANI nanocomposites were prepared via in situ chemical polymerization of aniline in the presence of 4-aminothiophenol (4-ATP) capped silver colloidal NPs. Then, uniform gold (Au) NPs were assembled on the surface of resulted Ag/PANI nanocomposites through electrostatic interaction to get Ag/Polyaniline/Au nanocomposites. The nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), ultraviolet visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Moreover, Ag/PANI/Au nanocomposites were immobilized on the surface of a glassy carbon electrode and showed enhanced electrocatalytic activity for the reduction of H₂O₂ compared with Ag/PANI.     

Structure and dielectric relaxations of antibacterial sulfonated polystyrene and silver nanocomposites

Structure and dielectric relaxations of antibacterial sulfonated polystyrene (SPS) and silver nanocomposites (SPS/Ag) were investigated via broadband dielectric spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, differential scanning calorimetry, scanning electron microscopy, and wide‐angle X‐ray diffraction. SPS/Ag nanocomposites were prepared from SPS containing 2, 4, and 7 mol% of acid contents, followed by ion exchange and a reduction process. Silver nanoparticles were formed in the structural cavities of SPS films. The single glass transition temperature of the SPS copolymers was observed and increased with increasing acid contents and more enhanced with embedded silver nanoparticles because of the restriction of the polymer chain movement. The particle size of embedded silver nanoparticles was about 10 nm and well dispersed in SPS matrices. Four dielectric relaxations were observed above the glass transition temperature, and they were attributed to the fast segmental relaxation, the slow‐hindered segmental relaxation, relaxations associated with Maxwell–Wagner–Sillars interfacial polarization and electrode polarization. Weak local relaxations were observed due to the motion of sulfonated phenyl groups. Copyright © 2014 John Wiley & Sons, Ltd.     

Constructing magnetic polyaniline/metal hybrid nanostructures using polyaniline/Fe3O4 composite hollow spheres as supports

Polyaniline (PANI)/Fe₃O₄ composite hollow spheres have been successfully synthesized in one step using sulfonated polystyrene (PS) spheres as templates. The magnetic PANI hollow spheres were used as supports for noble metal nanoparticles (NPs) such as Au and Pd. The morphology, composition and magnetic properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma (ICP) atomic spectra and vibrating sample magnetometer. The catalytic activity of magnetic PANI/Au composite shells on the oxidation of dopamine was investigated by cyclic voltammetry. The obtained results provide our product with a practical application for the detection of dopamine. On the other hand, the catalytic activity of magnetic PANI/Pd composite shells on the reduction of 4-nitroaniline was investigated by spectroscopic methods and compared with Pd/C catalyst which was already widely used in industrial production.     

New Composite Proton-Conducting Membranes Based on Nafion and Cross-Linked Sulfonated Polystyrene

New composite membranes based on commercial perfluorinated Nafion-115 membrane and cross-linked sulfonated polystyrene were synthesized and investigated. The membranes were prepared by radical polymerization of styrene in the presence of a cross-linking agent divinylbenzene in Nafion polymer matrix and subsequent sulfonation of formed polystyrene. The membranes containing approximately 5 and 10 wt % of cross-linked polystyrene with ion-exchange capacity of 1.1 to 1.3 mg-eq/g were obtained. Modification with sulfonated polystyrene leads to an increase in the moisture content and proton conductivity of membranes in the humidity range of 15 to 100 RH.     

Cross‐linked waterborne alkyd hybrid resin coatings modified by fluorinated acrylate‐siloxane with high waterproof and anticorrosive performance

Waterborne alkyd resin coatings are ideal for use as corrosion protection coatings because of its high cost‐effective and environmental advantages. However, their uses are restricted to general applications due to their poor acid, water, and alkali resistance. In this work, waterborne alkyd hybrid resins modified with fluorinated acrylate‐siloxane were synthesized via a surfactant‐free miniemulsion polymerization process using maleic anhydride and silicon modified alkyd resin, dodecafluoroheptyl methacrylate, methyl methacrylate, and butyl acrylate as monomers. And then, crosslinking alkyd resin films were prepared at room temperature using trimethylolpropane‐tris‐(β‐N‐azir‐idinyl) propionate (XR‐100) as the crosslinking agent. The acquired films had lower water absorption and higher water contact angles and had better mechanical/thermal properties, as well as good waterproof property. Most importantly, the electrochemical corrosion studies revealed that the cross‐linked coating exhibited superior corrosion resistance performance with an inhibition efficiency of 99.95% and a corrosion rate of 6.95 × 10^?3 mm per year.     

Preparation of Antibacterial Waterborne Polyurethane/silver Nanocomposite

Stable aqueous dispersions of silver (Ag) nanoparticles were prepared by reducing silver nitrate solutions with sodium borohydride (NaBH₄) in the presence of waterborne polyurethane as a stabilizing agent. WPU/Ag nanocomposites were obtained after evaporating water. Transmission electron microscope (TEM) shows nanoscale Ag particles are well dispersed in WPU matrix at a lower concentration, while particles exhibit a little aggregation at a higher concentration. UV‐visible spectra, X‐ray powder diffraction, and energy dispersive X‐ray spectrometer (EDS) confirm the existence of Ag particle in WPU matrix. The WPU/Ag composite films show good antibiotic ability.     

不同质子酸掺杂对银/聚苯胺纳米复合材料结构和导电性的影响

利用紫外光作为辅助条件,在反胶束体系中采用一步双原位法合成了硝酸(HNO3)、对甲基苯磺酸(TSA)和5-磺基水杨酸(SSA)掺杂的银/聚苯胺(Ag/PANI)纳米复合材料.通过对复合材料进行红外光谱(FTIR)、紫外光谱(UV-Vis)、扫描电镜(SEM)、X射线衍射(XRD)和导电性能的测试,研究了不同质子酸对Ag/PANI纳米复合材料结构、形貌和导电性能的影响.测试结果表明,3种酸掺杂制备的Ag/PANI纳米复合材料均为聚苯胺包覆银粒子的核-壳结构.不同的质子酸掺杂会对Ag/PANI纳米复合材料的电性能有重要影响.在3种酸掺杂的复合材料中,TSA掺杂的复合材料的电导率最佳,为215.14 S·cm-1.     

磺化聚苯乙烯的无溶剂制备及其催化性能研究

本文以聚苯乙烯为底物,发烟硫酸为磺化剂,在无溶剂和无催化剂条件下制得了磺化聚苯乙烯,对其酸度和结构性能进行了表征,并详细研究了其催化肉桂酸与正丁醇酯化反应的性能。在醇酸摩尔比为15∶1、环己烷作带水剂的条件下,分别考察了催化剂用量、回流温度、回流时间对酯化反应的影响,优化了反应条件,并在优化条件下,探究了其重复催化使用性能,结果表明,该催化剂重复使用15次,产率基本保持不变,仍可达到69.6%。该催化剂对肉桂酸与其他低级脂肪醇的酯化反应也具有良好的催化效果,是一种环境友好型具有潜在应用价值的固体酸催化剂。     

Fe–Co/sulfonated polystyrene as an efficient and selective catalyst in heterogeneous Baeyer–Villiger oxidation reaction of cyclic ketones

A highly efficient catalyst Fe–Co/sulfonated polystyrene (Fe–Co/SPS) was introduced and synthesized, which catalyzed BV oxidation of ketones with aqueous hydrogen peroxide to give the corresponding lactones in high yield and selectivity. Solid acid catalyst of Fe–Co/SPS has been prepared by using the 98-wt% sulfuric acid as the sulfonating agent and CoCl₂ combined FeCl₃ as sources of metal ions. Various physical–chemical characterizations including FT-IR, XRD, SEM and TGA, revealed that bimetallic ions Fe³⁺–Co²⁺ species in the sulfonated polystyrene framework were responsible for the catalytic activities. The BV reaction catalyzed by Fe–Co/SPS highlighted the special effects between metal ions and protonic acids as well as solvent-free heterogeneous catalytic oxidation with excellent conversion.     

Synthesis and characterization of polyaniline/graphite conducting nanocomposites

A new method for the synthesis of exfoliated graphite and polyaniline (PANI)/graphite nanocomposites was developed. Exfoliated graphite nanosheets were prepared through the microwave irradiation and sonication of synthesized expandable graphite. The nanocomposites were fabricated via the in situ polymerization of the monomer at the presence of graphite nanosheets. The as-synthesized graphite nanosheets and PANI/graphite nanocomposite materials were characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis (TGA). The conductivity of the PANI/graphite nanocomposites was dramatically increased over that of pure PANI. TGA indicated that the incorporation of graphite greatly improved the thermal stability of PANI. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1972–1978, 2004     

Preparation and characterization of microcellular polystyrene/polystyrene ionomer blends with supercritical carbon dioxide

The preparation of microcellular polystyrene (PS), lightly sulfonated polystyrene (SPS), zinc‐neutralized lightly sulfonated polystyrene (ZnSPS), and blends of PS/SPS and PS/ZnSPS via supercritical CO₂ was carried out with the pressure‐quench process. Both higher foaming temperature and lower pressure result in larger cell sizes, lower cell densities, and lower relative density for microcellular ionomers and blends as for microcellular PS. The difference among various microcellular samples is the change of cell size with the sample composition. The cell size decreases in the sequence from SPS, through PS/SPS blends, PS and PS/ZnSPS blends, to ZnSPS. The diffusivity of CO₂ in samples also decreases in the sequence from SPS, through PS/SPS blends, PS and PS/ZnSPS blends, to ZnSPS. For this series of samples with similar structure and identical solubility of CO₂, the varying diffusivity is responsible for the difference of cell sizes. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 368–377, 2003     

Synthesis,characterization and antibacterial properties of a novel nanocomposite based on polyaniline/polyvinyl alcohol/Ag

In this study, a novel nanocomposite based on polyaniline/polyvinyl alcohol/Ag (PANI/PVA/Ag) has been successfully synthesized. The chemical reduction method was used to produce Ag nanoparticle colloidal solution from Ag⁺ ions. The polymerization of aniline occurred in situ for the preparation of polyaniline (PANI) in the presence of ammonium persulfate. With exposure to Ag nanoparticles on the PANI/PVA composite, a new nanocomposite was obtained. The morphology and particle size of the novel nanocomposite was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) analyses. According to XRD analysis, the size of nanoparticles was found to be in the range of 10–17 nm. SEM images showed the favored shape of nanoparticles as triangle which is a benign shape for antibacterial analysis. The antibacterial activity of the obtained nanocomposite was also evaluated against Gram positive bacteria Staphylococcus aureus (Staph. aureus) and Gram negative Escherichia coli (E. coli) using the paper disk diffusion method. The antibacterial study showed that the PANI/PVA composite did not have a very good antibacterial activity but PANI/PVA/Ag nanocomposites were found to be effective against two bacteria.     

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.