Intercalation of methylene blue in n-alkanethiolated self-assembled monolayers: Versatile electrochemical platforms for characterizing surfactant adsorption on hydrophobic surfaces

A versatile electrochemical platform for characterizing the adsorption of neutral and positively charged surfactants on hydrophobic surfaces was established using methylene blue (MB) as the probe. As a rigid, planar and electroactive species, MB can intercalate inside the regular self-assembled monolayers (SAMs) of n-hexanethiol and exhibit well-defined electrochemical responses. The adsorption of surfactants on the hydrophobic SAMs through the intercalation interaction between the hydrophobic tails of surfactants and the SAMs might change the density of the SAMs and influence the electrochemical behaviors of MB, providing a simple but effective approach for characterizing surfactant adsorption on hydrophobic surfaces. As an example, the adsorptive behaviors of cetyltrimethylammonium bromide (CTAB), a positively charged surfactant, and Triton X-100, a neutral surfactant, on hydrophobic surfaces were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The results showed that these surfactants generally experienced three different adsorptive behaviors: the monomer adsorption at low concentrations, the loose monolayer adsorption at intermediate concentrations and the dense monolayer adsorption at high concentrations. In the case of CTAB, a new additional submonolayer adsorptive behavior between the monomer and the loose monolayer adsorption was observed for the first time, due to its rather long hydrophobic tail.     

Preparation and properties of nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites

New novel fire‐resistant and heat‐resistant cyclotriphosphazene‐containing polyimide resins were prepared in situ by the polymerization of (p‐aminophenoxy)(phenoxy)cyclotriphosphazenes with 3,3′,4,4′‐benzophenonetetracarboxylic acid or 3,3′,4,4′‐diphenylsulfonetetracarboxylic acid and a crosslink agent, 5‐norbornene‐2,3‐dicarboxylic acid and were used as polymer matrix compositing with a woven carbon fiber to prepare nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites. The thermal stability, flame retardance, morphology of the surface fracture, and some physical properties of the composites were investigated by thermogravimetric analysis, scanning electron microscopy, and a material testing system, respectively. The composites had good thermal stability, flame retardance, and mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 810–818, 2003     

氯醇化管道反应新工艺的压降和传质的研究

氯醇化管道反应新工艺是环氧丙烷生产过程中关键步骤，该反应属气液非均相系统，但装有Ｋｅｎｉｃｓ型静态混合构件的管道反应器用于气液系统还缺乏大量的基础数据。研究以Ｎ２－Ｈ２Ｏ２作为实验系统，测定了不同工况下压降和氧含量，并应用一心均相模型救是了相应的摩擦系数和传质系数。     

Preparation and ionic conductivity of solid polymer electrolyte based on polyacrylonitrile‐polyethylene oxide

The transparent and flexible solid polymer electrolytes (SPEs) were fabricated from polyacrylonitrile‐polyethylene oxide (PAN‐PEO) copolymer which was synthesized by methacrylate‐headed PEO macromonomer and acrylonitrile. The formation of copolymer is confirmed by Fourier‐transform infrared spectroscopy (FTIR) measurements. The ionic conductivity was measured by alternating current (AC) impedance spectroscopy. Ionic conductivity of PAN‐PEO‐LiClO₄ complexes was investigated with various salt concentration, temperatures and molecular weight of PEO (Mn). And the maximum ionic conductivity at room temperature was measured to be 3.54 × 10^?4 S/cm with an [Li⁺]/[EO] mole ratio of about 0.1. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 461–464, 2006     

壳聚糖渗透汽化膜分离醇／水的性能：Ⅱ.壳聚糖复合膜

用聚丙烯腈超滤膜为基膜制成的ＣＳ复合膜，对乙醇／水溶液的分离具有较稳定的透过性，复合膜先后运行于低浓度的乙醇溶液的９５ｗｔ％乙醇溶液，膜的稳定性能优于均质膜。实验还表明用多种交联剂代替硫酸处理超薄复合膜，可有效地提高膜的渗透选择性。     

Synthesis, characterization and thermal properties of hexaarmed star-shaped poly(ε-caprolactone)-b-poly(d,l-lactide-co-glycolide) initiated with hydroxyl-terminated cyclotriphosphazene

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene was prepared by the reaction of hexachlorocycltriphosphaneze with the sodium salt of 4-hydroxybenzaldehyde and subsequent reduction of aldehyde groups to alcohol groups by using sodium borohydride. Hexaarmed star-shaped hydroxyl-terminated poly(ε-caprolactone) (PCL) were successfully synthesized via ring-opening polymerization of ε-caprolactone (CL) with the above hydroxyl-terminated cyclotriphosphazene initiator and stannous octoate catalyst in bulk. The number-average molecular weight of PCL linearly increased with the molar ratio of monomer to initiator. The star-shaped PCL with hydroxy end groups could be used as a macroinitiator for block copolymerization with d,l-lactide (d,l-LA) and glycolide (GA) using stannous octoate catalyst. IR, ¹H NMR and GPC analysis showed the star-block copolymers were successfully synthesized and the molecular weights and the unit composition of the star-shaped block copolymers were controlled by the molar ratios of d,l-LA and GA monomers to CL. The copolymer presented a two-phase structure, namely, PCL crystalline and d,l-LAGA amorphous domains, which made the copolymer different from linear PCL and star-shaped PCL in crystallinity and thermal behaviors.     

Preparation of V doped lanthanum silicate electrolyte ceramics by combustion method and study on conductance mechanism

Vanadium doped La_9.33Si_6−xV_xO_26+0.5x (x = 0.5, 1.0, 1.5) (LSVO) electrolyte powder was prepared by combustion method at 600°C for 5-7 min. The powder was sintered at 1500°C for 3 hours to prepare LSVO ceramics. XPS, IR, XRD, and EIS analysis show that V⁵⁺ doping replaces Si⁴⁺ in [SiO₄] to form [Si(V)O₄] tetrahedron. With the increase in x, the lattice volume increase. When x = 2.0, the LaVO₄ phase was formed, indicating that the limit doping amount of V⁵⁺ replacing Si⁴⁺ is x ≤ 1.5. The conductivity of LSVO increases significantly with the increase in x (x ≤ 1.0), which attributed to the defect reaction caused by V⁵⁺ doping. The addition of the interstitial oxygen Oi* in 6₃ channels and the increase of lattice volume leads to increased conductivity. When x = 1.0, the highest conductivity is 1.46 × 10⁻² S·cm⁻¹ (800°C). The doping enhancement conductivity mechanism is the Interstitial oxygen defect-Lattice volume composite enhancement mechanism.     

国内外强化采油用表面活性剂研究进展

中国石油对外依存度持续上升,而采收率持续下降。中国剩余石油储量中大部分为高温高盐、低渗透、稠油油藏等难以开采的苛刻油藏。化学驱强化采油技术目前所使用的石油磺酸盐、烷基苯磺酸盐等常规表面活性剂由于活性低、耐盐性差而导致低效甚至无效。综述了新型表面活性剂,如阴-非离子表面活性剂、双子及寡聚表面活性剂、甜菜碱型两性表面活性剂、高分子表面活性剂、烷基糖苷表面活性剂、黏弹性表面活性剂、生物表面活性剂、阴阳离子混合表面活性剂等的研究进展。讨论了国内外强化采油用表面活性剂评价方法的差异。最后,对采油用表面活性剂的发展方向进行了展望。     

复配技术在聚烯烃材料抗静电改性中的应用

对常用抗静电改性助剂及其机理、复配抗静电技术作了简要的介绍,并对国内外复配抗静电技术在聚烯烃材料抗静电改性中的应用作了简要的总结。     

曹雨微[1],2,刘远2,孔会民1,2,岳萍2,唐大才2,林彦军1,[3]

以MgCl2为晶面调控剂，利用水热法对氢氧化镁（MH）的（001）晶面选择性生长进行调控，研究了晶面调控剂浓度、反应温度、反应时间等因素对MH颗粒的溶解和结晶作用。调控后产品各晶面的XRD衍射峰强度I001/I101和I001/I110较原料分别提高了214.30%和307.45%，百吨级中试产品的I001/I101和I001/I110较原料分别提高了84.08%和112.99%。采用XRD、FE-SEM、TEM、FTIR、粒度分析仪对MH产品的形貌、结构进行了表征，并对调控机理进行了研究。结果表明，MgCl2可以在水热体系中促进MH的（001）晶面选择性生长。一方面，MgCl2作为强酸弱碱盐降低了体系pH值，同时Cl－可以通过电荷中和效应使MH发生进一步加速溶解。另一方面，MgCl2提供的Cl－作用于MH的结晶过程，通过促进MH边缘生长，强化了（001）晶面的生长。