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71.
羧甲基纤维素系列高分子表面活性剂超声合成的研究 总被引:27,自引:2,他引:27
研究了在超声波作用下羧甲基纤维素的降解反应及CMC与具有不同亲水亲油比值的活性大单体「烷基醇(酚)聚氧乙烯醚丙烯酸酯及第三单体」的超声共聚反应。经萃取提纯的共聚产物用IR,^13C NMR和UV等方法进行表证,证实通过超声反应制得了二元和三元共聚物。 相似文献
72.
Marina S. Fonari Victor Ch. Kravtsov Yurii A. Simonov Edward V. Ganin Vladimir O. Gelmboldt Janusz Lipowski 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(1-2):85-89
The crystalline host–guest type complex [(18-crown-6NH4)2][SiF6]4H2Ohas been obtained as the result of the interaction of SiF42NH3 with 18-crown-6 (18C6) in an aqueous medium. Crystal data: monoclinic, space groupC 2 c, a=26.541(2), b=8.363(2), c=20.469(2) Å, = 122.43(1)°and Z=4. The final R-value is 0.070 for 3253 reflections with I 2(I).The crystals consist of the complex [NH418C6]+ cations, [SiF6]2-anions and water molecules. The ammonium cation is hydrogen bonded by three of its H-atoms to the crown ether oxygen atoms with N(1) O separations2.923(5)–2.940(5) Å and by the fourth H-atom to the fluorine atom of thehexafluorosilicate anion, the N(1)F(4) distance being 2.797(6) Å.The conformation of the macrocycle and the hydrogen-bond geometry in thecomplex cation closely resemble those in related adducts between 18-crown-6and ammonium salts. All crystal components are connected via a system of hydrogen bonds into a ribbon along the b axis in the unit cell. 相似文献
73.
采用弱碱性阴离子交换树脂HJ-30对发酵液中1,6-二磷酸果糖的分离进行了研究。详细地研究了树脂的吸附和脱附性能。实验结果表明,HJ-30树脂对FDP的吸附量达0.28gFDP/g湿树脂,以0.05mol/LNaCl洗脱光机磷和1mol/LNaCl洗脱1,6-二磷酸果糖,产品的收率和纯度分别为92%和99.4%。 相似文献
74.
本文报道了一种光敏型的阳离子表面活性剂(AZO),其分子结构中含有偶氮苯基团,并研究了光照对表面活性和泡沫性能的影响。经紫外光照射后,表面活性剂的饱和吸附量(Гmax)减小,临界胶束浓度(cmc)、最低表面张力(γcmc)和分子极限占有面积(Amin)增大;气泡数目增多,直径变小,发泡能力和泡沫稳定性降低。实验结果证实,该表面活性剂的表面活性和泡沫稳定性可以用光照进行调控。 相似文献
75.
G. A. Gainanova E. P. Zhil’tsova L. A. Kudryavtseva S. V. Kharlamov Sh. K. Latypov A. P. Timosheva A. I. Konovalov 《Russian Chemical Bulletin》2006,55(8):1411-1418
Micelle formation in a cetyltrimethylammonium bromide-poly(ethylene glycol)-600 monolaurate-chloroform system in the absence
and presence of hydroxybenzylated polyethylenimines (PEI) was studied by dielcometric titration, NMR self-diffusion, light
scattering, and kinetic methods. A catalytic effect of mixed micelles on the reaction of 4-nitrophenylbis(chloromethyl)phosphinate
with PEI was shown. The catalytic effect depends on the degree of substitution of PEI and composition of a surfactant mixture.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1359–1365, August, 2006. 相似文献
76.
77.
The interaction of a nonionic polymeric surfactant with an anionic surfactant at the oil–water interface has been studied
by its effects on the droplet size, stability and rheology of emulsions. Oil-in-water (o/w) emulsions were prepared using
isoparaffinic oil and mixtures of a nonionic polymeric surfactant with an anionic surfactant. The macro-molecular surfactant
was a graft copolymer with a backbone of polymethyl methacrylate and grafted polyethylene oxide (a graft copolymer with PEO
chains of MW=750). The anionic surfactant was sodium dodecyl sulfate (SDS). The stabiliza-tion of the emulsion droplets was
found to be different when using one or the other surfactant. The mechanism of stabilization of emulsion droplets by the macro-molecular
surfactant is of the steric type while the stabilization by anionic surfactant is of the electrostatic repulsion type. Emulsions
stabilized with mixtures present both types of stabilization. Other effects on the preparation and stabilization of emulsions
were found to be dependent on properties associated with the surfactant molecular weight such as the Marangoni effect and
Gibbs elasticity. The initial droplet size of the emulsions showed a synergistic effect of the surfactant combination, showing
a minimum for the mixtures compared to the pure components. Emulsion stability also shows a synergistic interaction of both
surfactants. Rheological measurements allow for the estimation of the interparticle interaction when measured as a function
of volume fraction. Most of the effects observed can be attributed to the differences in interfacial tension and droplet radius
produced by both surfactants and their mixtures. The elastic moduli are well explained on the basis of droplet deformation.
Ionic versus steric stabilization produce little difference in the observed rheology, the only important differences observed
concerned the extent of the linear viscoelasticity region.
Received: 22 November 1996 Accepted: 24 March 1997 相似文献
78.
Formation at low surfactant concentrations and characterization of mesoporous MCM-41 总被引:2,自引:0,他引:2
At low concentrations of cetyltrimethylammonium bromide,all silica-based mesoporous materials with hexagonal phase have been synthesized via interactions between self-assembled surfactant molecule aggregates and aniomc silicate polymers.The resulting materials are characterized by XRD,FT-IR,solid state 29Si MAS NMR,thermal analysis and N2 adsorption-desorption measurements.After soluble ions are removed,the interactors between surfactant micelles and silicate polymers are reorganized and then form mesostructures 1 he hexagonal framework is sonsistent with amorphous silica gel.The structures of materials depend on the synthesis conditions Hydrothermal process improves the interactions between molecules and increases the degree of framework silicon atom polymerization The.surface area and the mesopore volume of the material prepared at 100℃ increase by 87% and 71 %,respectively,compared with those obtained at room temperature. 相似文献
79.
羰基化合物的氟烷基化反应是把含氟基团引入有机分子中去的一个重要手段。文献报道的主要是通过氟烷基金属试剂来进行此反应。但氟烷基金属试剂不太稳定,容易分解。这就给它们的应用带来了许多不便。我们发现,氟烷基三甲基硅化合物(1)作为氟烷基阴离子前体,在比较温和的条件下,便可使醛发生氟烷基化反应。首先,参照文献方法,通过氟烷基格氏试剂与三甲基氯硅烷反应,方便地制得了两个新的氟烷基三甲基硅化合物 R_F-SiMe_3(1)。 相似文献
80.
Highly hydrophobically modified (with n-dodecylamide chain) linear poly(acrylic acid)s (HHMPAAH) and poly(sodium acrylate)s (HHMPAANa) with various degrees of grafting
(τ) were synthesized and used as emulsifiers of the n-dodecane/water system. The type of emulsion, oil in water (O/W) or water in oil (W/O), was investigated as a function of
the polymer chemical structure (τ, salt or acid form of the copolymer) and aqueous phase electrolyte concentration (NaNO3). Increasing τ and/or salt concentration was found to favor the formation of inverse emulsions. Direct liquid–liquid dispersions
are more likely to form with poly(sodium acrylate)s than with poly(acrylic acid)s. Hence, field variables such as τ, pH and
ionic strength are relevant parameters to control emulsion type. Moreover, a balanced polyelectrolyte neither soluble in oil
nor in water was synthesized for the first time. With this original emulsifier, the dispersion type was found to change from
O/W to W/O with polymer salting out. The work provides convenient model system for fundamental studies of polymer conformation
at liquid–liquid interfaces.
Received: 31 March 1998 Accepted: 30 April 1998 相似文献