磺化聚苯醚的制备与表征

磺化聚苯醚的制备与表征汪传清，黄玉惠，丛广民（中国科学院广州化学研究所广州５１０６５０）关键词聚苯醚，磺化，磺化度，磺化聚苯醚聚苯醚是一种优良的工程塑料，对它进行修饰改性以获得各种功能材料的研究近十多年来十分活跃’‘，’，‘’．磺化聚苯醚（ＳＰＰＯ）...     

磺化聚醚酮酮的合成和表征

研究了以硫酸为磺化剂由聚醚酮酮来合成磺化聚醚酮酮的方法，探讨了硫酸浓度、反应温度、反应时间和聚醚酮酮在硫酸中的浓度等因素对聚醚酮酮的磺化度和离子交换容量的影响，制得了磺化度为１５５ｍｍｏｌ／ｇ、离子交换容量为１５７ｍｍｏｌ／ｇ的磺化聚醚酮酮．用红外光谱表征了其结构，用Ｘ 射线进行了结晶度的分析，用ＤＳＣ进行了热分析     

三磺化三苯基膦（TPPTS）制备方法的改进

量子化学计算结果表明,在三苯基膦磺化过程中,随磺化深度的增加,磺化难度加大,提出了连续通入气态三氧化硫制备三硫化三苯基膦的新工艺,以磷酸三丁酯为萃取剂,ＳＯ３／ＴＰＰ摩尔比为１２,在２０￣２４℃温度下反应６６￣６９ｈ,三磺化产物收率可达９７．６％,将制得的三磺化三苯基膦用于两相氢甲酰化反应的铑／膦催化剂配体,提高了产物的正／异比,有效地控制了铑的流失。     

甲氧基萘的磺化反应

以三甲基硅氯磺酸酯为磺化剂，进行了单和双甲氧基萘的磺化反应研究。用１ＨＮＭＲ测定磺化产物的组成。比较了磺化剂种类和用量对磺化反应的影响。发现了磺化反应中的成酐现象，研究了１，６－二甲氧基萘进行反应时二磺化产物的生成动力学。     

联苯衍生物的磺化反应

研究了一系列联苯衍生物和ＳＯ３在二氯甲烷中进行的磺化反应。联苯的磺化产物为４－磺酸取代物，进一步反应得到４，４′－、２，４，４′－及少量的２，４，２′，４′－多取代物。甲氧基取代的联苯体现了较高的反应活性，３，３′－二甲氧基联苯的彻底磺化得到五磺酸取代产物，２－甲氧基联苯的单磺化主要发生在５位上，４－甲氧基联苯的单磺化先在３位上进行。     

磺化条件对SPEEK膜性能的影响

本文采用浓硫酸作为磺化剂,以聚醚醚酮(PEEK)为原料研究了在25℃、35℃、40℃、45℃、50℃和55℃以及2至24h磺化时间下所获得的SPEEK膜的物理化学性质,探讨了磺化温度、磺化时间对SPEEK膜的各项性能的影响.SPEEK膜的磺化度、离子交换容、含水率、导电率和钒离子渗透率等均随磺化温度和磺化时间的增加而呈...     

13C核磁共振研究磺化脲醛树脂的反应机理

利用^13CNMR数据证实了在低磺化剂用量下脲醛树脂的磺化改性仍可发生,并对磺化脲醛（SUF）树脂制备过程中的羟甲基化、缩合、磺化及缩聚等各步反应机理进行了探讨.明确了SUF树脂的^13CNMR谱图中各峰位所对应的结构单元,认为3个未知峰的出现与磺化改性得到的一些新结构单元有关,并对它们的结构进行了推测.通过对比不同磺化和缩聚反应程度下得到的SUF产物的^13CNMR数据,对磺化和缩聚反应后某些结构的出现和消失进行了解释.     

交联聚苯乙烯小球的微波加热磺化

用微波加热使苯乙烯和二乙烯苯共聚小球磺化。研究了微波功率、加热时间、反应物配比、溶胀剂、反应器在微波炉内的位置等因素对磺化反应的影响。     

聚醚砜的磺化及表征

磺化是芳环聚合物改性的有效方法．引入的磺酸基以酸型、盐型和酯型存在,且可以继续制备其它衍生物．有关聚苯醚［１,２］、聚苯硫醚［３］、聚醚醚酮［４,５］和聚砜［６～８］的磺化研究和表征已有很多报道,这些聚合物引入磺酸基后亲水性增强,广泛用于制备反渗透膜...     

氯磺酸磺化PE非织薄膜及表征

通过磺化反应改善聚乙烯(PE)非织薄膜的亲水性,考察了时间、温度、物料配比等条件对磺化反应的影响,并用红外光谱(FT-IR)、X射线能量色散谱(EDS)及扫描电镜(SEM)对产物进行了表征,同时对PE非织薄膜的亲水性和力学性能进行了测定。结果表明:通过氯磺酸磺化可以将—SO3H基团引入PE大分子,磺化后的PE链段互相聚集无序堆砌形成微小颗粒;PE非织薄膜的断裂强度随磺化反应程度的增加而下降。     

磺化聚苯醚离聚体的合成及溶液性质研究

合成一系列磺化度的磺化PPO(S-PPO),以磺化度为20.9mol％的S-PPO的钠盐和锂盐为代表,研究其在四氢呋喃/甲醇混合溶剂中的离聚体行为。结果表明,S-PPO离聚体在溶液中的链聚集状态与聚合物浓度、反离子半径和温度密切相关。     

Sulfonated carbon catalyzed oxidation of aldehydes to carboxylic acids by hydrogen peroxide

Sulfonated carbon as a strong and stable solid acid catalyst exhibited excellent catalytic performance in various acid-catalyzed reactions. Here, sulfonated carbon, as catalyst for oxidation reaction, was prepared via the carbonization of starch followed by sulfonation with concentrated sulfuric acid. N₂ physisorption, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray fluorescence and acid-base titration were used to characterize the obtained materials. The catalytic activity of sulfonated carbon was studied in the oxidation of aldehydes to carboxylic acids using 30 wt% H₂O₂ as oxidant. This oxidation protocol works well for various aldehydes including aromatic and aliphatic aldehydes. The sulfonated carbon can be recycled for three times without obvious loss of activity.     

Proton conductive membranes of sulfonated poly(ether ketone ketone)

Poly(ether ketone ketone) was sulfonated using fumic sulfuric acid and used for preparation of proton conductive membranes. The sulfonation degree was evaluated by elemental and thermal analysis and the IEC values were determined by titration. The proton conductivity of membranes with sulfonation degrees up to 70% was determined as a function of temperature by impedance spectroscopy. Membranes with sulfonation degree 38–70% were tested in DMFC experiments. Their performance was comparable to Nafion^® with the same pretreatment and clearly better than sulfonated poly(ether ether ketone) membranes with similar functionalization. The methanol crossover was lower than that of Nafion^® in the same conditions.     

Application of highly sulfonated single-walled carbon nanotubes: An efficient heterogeneous catalyst for the one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes under solvent-free conditions

Highly sulfonated single-walled carbon nanotube-catalyzed synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes in excellent yields and very short reaction times. Sulfonated single-walled carbon nanotubes are prepared using a chemical and simple process and it characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Thermal gravimetric analysis (TGA) and acid-base titration. The sulfonated single-walled carbon nanotube was easily separated by simple filtration and was recycled eight consecutive times without any loss in its activity.     

Synthesis of ω‐sulfonated polystyrene via reversible addition fragmentation chain transfer polymerization and postpolymerization modification

The synthesis of chain‐end sulfonated polystyrene [PS (ω‐sulfonated PS)] by reversible addition fragmentation chain transfer (RAFT) polymerization followed by postpolymerization modification was investigated by two methods. In the first method, the polymer was converted to a thiol‐terminated polymer by aminolysis. This polymer was then sulfonated by oxidation of the thiol end‐group with m‐chloroperoxybenzoic acid (m‐CPBA) to produce a sulfonic acid end‐group. In the second method, the RAFT‐polymerized polymer was directly sulfonated by oxidation with m‐CPBA. After purification by column chromatography, ω‐sulfonated PS was obtained by both methods with greater than 95% end‐group functionality as measured by titration. The sulfonic acid end‐group could be neutralized with various ammonium or imidazolium counter ions through acid–base or ionic metathesis reactions. The effect of the ionic end‐groups on the glass transition temperature of the PS was found to be consistent with what is known for PS ionomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Processing, characterization and properties of conducting polyaniline-sulfonated SEBS block copolymers

Incorporation of polyaniline (PAni) into thermoplastic elastomers can be used to produce materials that potentially combine the good mechanical properties and processability of thermoplastic elastomers with electrical, magnetic and optical characteristics of PAni. In this work, a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene copolymer (SEBS) was chemically modified by grafting a sulfonic group onto the chain backbone in order to promote higher levels of compatibility between the thermoplastic elastomer and polyaniline. The sulfonation process was performed by reacting SEBS with acetyl sulfate. Infrared spectroscopy and titration were used to monitor the amount of sulfonic groups successfully grafted on SEBS. Mechanical tests performed in sulfonated SEBS showed that sulfonation levels lower than 15% did not reduce substantially the mechanical properties of SEBS. PAni doped with dodecylbenzenesulfonic acid (PAni·DBSA), used in the preparation of the blends, was prepared by the “in situ doping polymerization” method. PAni·DBSA was then blended in solution with SEBS having different levels of sulfonation. The introduction of sulfonic group into the structure of SEBS improved coulombic interactions between the phases in the blend and enhanced compatibility. As a consequence, higher values of electrical conductivity (measured by the four-probe method) were achieved in blends with sulfonic groups grafted onto polymer chains. Concentrations as low as 20 wt% of PAni were able to lead to electrical conductivities of PAni·DBSA/sulfonated SEBS blends close to 1.2 S/cm. Optical micrographs of the blends showed that PAni·DBSA/sulfonated SEBS microstructure is composed of a very disperse group of small conducting particles. This type of microstructure would then be responsible for the enhanced electrical conductivity and low percolation threshold of PAni·DBSA/sulfonated SEBS, when compared to PAni·DBSA/SEBS blends.     

Synthesis, characterization and investigation of catalytic activity of a highly sulfonated carbon solid acid in the synthesis of dihydropyrimidinones under solvent-free conditions

A highly sulfonated carbon as an efficient, recyclable, nontoxic and green solid acid catalyst was synthesized readily by simultaneous sulfonation, dehydration and carbonization of sucrose C¹²H²²O¹¹ in sulfuric acid and was characterized with Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric and differential thermal gravimetric analysis (TG-DTG), X-ray diffraction (XRD), carbon-hydrogen-nitrogen-sulfur analysis (CHNS), neutralization potentiometric titration and scanning electron microscopy (SEM). This new catalyst was used in one pot three-component condensation reaction of various aromatic aldehydes with ??-ketoester and urea under solvent-free conditions to afford the corresponding dihydropyrimidinones (DHPMs). This catalyst can be reused several times without loss of its activity.     

Analytical methodology for sulfonated lignins

There is a significant need to characterize and classify lignins and sulfonated lignins. Lignins have so far received a good deal of attention, whereas this is not true for sulfonated lignins. There is a clear demand for a better understanding of sulfonated lignins on a chemical as well as physical level. Many of the analytical methods have been developed with different goals in mind, for example, detection of sulfonated lignins in pulp‐mill effluents, elucidation of structural changes in lignosulfonates during a pulping process, or identification of properties that may affect a formulation when sulfonated lignins are used as a dispersant. When sulfonated lignins are used in industrial applications, analytical data obtained using different techniques may be necessary to enable prediction of their behavior in the target application. In the present review, a critical discussion of established and promising analytical techniques for the characterization of sulfonated lignins is presented.     

Chemical Modification of Polystyrene. VI. Thermal Stability Studies of Sulfonic Acid Resins from Anhydride Modified Polystyrene

Thermal stabilities of the H form of sulfonic acid resins from polystyrene electrophilically substituted with phthalic anhydride, pyro-mellitic dianhydride, trimellitic anhydride, and cis-1,2,3,6-tetra-hydrophthalic anhydride have been studied and compared by DTA and TGA. Isothermal degradation studies of these resins at 150 ± 10°C for 72 h in air and nitrogen reveal significant changes in IR, decreases in sulfur content, and increases in ion-exchange capacity values. The pH-metric titration characteristics of the pyro-mellitic-dianhydride-modified sulfonated polystyrene after isothermal heating under the above conditions indicate weak acid behavior, in contrast to the strong acid nature of the original resin.