Photoresponsive peptide and polypeptide systems: part II. Photochromism of poly(l-ornithine) containing various azo-contents in side chains

Poly(L-ornithine)s having various azo-contents in the side chains were synthesized by the water-soluble carbodiimide procedure. The photochemical properties of the polypeptides poly[N^δ-p-(phenylazo)benzoyl-L-ornithine] (PPABLO) containing 3–77 mol% azobenzene were investigated by absorption and circular dichroism spectroscopy in hexafluoro-2-propanol (HFIP) or water, and in HFIP-water or methanol-water solvent mixtures. The photochromism of the dichroic bands of the PPABLOs containing 20–77 mol% azobenzene in the visible and ultraviolet wavelength regions was found to be mostly reversible as a function of irradiation time at different wavelengths due to the photostationary state (above 80% trans-cis photoisomerization) of the azo aromatic moieties. The PPABLO containing 3.2 mol% azobenzene in water exhibited conformational changes from random coil to helix by the addition of methanol or sodium dodecyl sulphate (SDS). The photo-induced conformational change was observed in HFIP-water-SDS solvent mixtures, while no conformational change was seen in water and HFIP-water solvent mixtures.     

Micellar polymerisation of ionic surfactants studied by conductimetry

The micellar polymerisation of ionic surfactants such as allyldodecyl-dimethylammonium bromide and 3-dodecyl-1-vinyl imidazolium iodide has been studied by conductimetry in aqueous solution. The polymerisation was carried out using two different sources of γ rays directed into solutions of surfactant above the critical micellar concentration. Conductimetry is shown to be a very good physicochemical method for analysis of these solutions. The results showed different behaviour for the two surfactants, which has highlighted a change in the structure of their aggregates which led to the assumption of an interaction between the polymers of high mass and different products of the polymerisation (oligomers, products of degradation, monomers etc.). Ultrafiltration experiments coupled with ¹H-NMR and conductivity analysis confirm these assumptions.     

Liquid–liquid extraction of a recombinant protein with reverse micelles

Recombinant cytochrome b₅ was extracted into the reversed micelle phase of an anionic surfactant (AOT) in octane and back-extracted to a final aqueous phase. The extraction of the protein was controlled by an electrostatic mechanism, since it was dependent on the global charge of the protein. This was directly demonstrated by experiments with native and mutant cytochromes obtained by site directed mutagenesis. The back-extraction of cytochrome b₅ to a fresh aqueous phase was decreased by factors that reduced the size of the water pool of the organic phase, such as high salt concentrations (1–2 mol dm^?3 NaCl) and low temperatures (4°C), probably because of an increase in a favourable interaction of this protein with the surfactant at closer distances.     

有关助剂、添加剂及表面活性剂发展概况和投资热点分析

综述了助剂、添加剂和表面活性剂的发展概况和投资热点。     

HDTMA改性沸石吸附水中Cr（VI）研究

摘要：研究以阳离子表面活性剂HDTMA改性天然斜发沸石,制得HDTMA改性沸石,进而研究HDTMA改性沸石对废水中Cr（VI）的吸附特征。结果表明：HDTMAL改性沸石对cr（VI）吸附符合Langmuir等温式和拟二级动力学方程,饱和吸附量为10．99mg／g,吸附主要为化学吸附,但温度、pH值和干扰离-~HDTMA沸石吸附cr（VI）具有明显影响。     

TURBULENCE TRANSPORT OF SURFACTANT SOLUTION FLOW DURING DRAG REDUCTION DEGENERATION

Turbulence transport of surfactant solution flow during drag reduction degeneration is investigated experimentally in a two-dimensional channel.Particle Image Velocimetry (P1V) system is used to take t...     

阳离子Gemini对固体表面润湿性的影响

研究了阳离子双子表面活性剂对固体表面润湿性的影响,并从机理上进行了探讨,结果表明,与普通表面活性剂相比,阳离子双子表面活性剂在很低浓度时就能将油湿的固体表面转化为强水湿表面,并且不会改变水湿表面的润湿性;另外,对联接基长度相同但是疏水烷基链长度不同的双子表面活性剂对固体表面的润湿性影响进行了考察,结果发现疏水烷基链短的双子表面活性剂较疏水烷基链长度长的双子表面活性剂更能显著影响固体表面的润湿性。     

Experimental investigation of turbulent boundary layer flow with surfactant additives using PIV and PDA

Drag reduction of turbulent water flow with surfactant (CTAC) additives was experimentally investigated. By using PIV and PDA measurements, the spatial velocity distribution of surfactant solution flow was clarified in a two‐dimensional water channel. With an increasing Reynolds number, it was found that drag reduction of surfactant solution flow is enhanced within the region of drag reduction. However, in the region of post drag reduction, the drag‐reducing coefficient approaches one without surfactant when Reynolds number is increased. In the near‐wall region, velocity profiles of the drag‐reducing fluid are similar to, but not the same as, the laminar profiles of the Newtonian fluid. When compared to the case of water flow without surfactant, the velocity contour lines of the drag‐reducing fluid run approximately parallel to the wall. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(2): 99–107, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20047     

用水解鸭油研制纸张柔软剂

用鸭油为原料,净化水解后合成双烷基酰胺咪唑啉季铵盐柔软剂。实验室及工厂试验结果说明该柔软剂性能优良,很适合草类浆抄造中高档卫生纸。重点介绍了鸭油的水解工艺条件,并对该柔软剂的作用机理作了探讨。     

A comparison between microwave-assisted and thermally synthesized esterquat softeners used as textile softening agents

Triethanolamine-based esterquat softener was synthesized by two different methods, microwave irradiation and conventional thermal methods. FT-IR spectra and critical micelle concentration were employed to investigate chemical and physical properties of the synthesized softeners. Softening power, wettability, bending rigidity, yellowness, and anti-wrinkling properties of the synthesized softeners were also evaluated. It was found that microwave-synthesized softener posses better softening, wettability, and anti-wrinkling properties whilst shorter reaction time with higher yield, less cost, and higher purity of the synthesized product were the other advantages of this method over the conventional thermal method.