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1.
In this work, we examine the effect of small additions of cationic quaternary ammonium salts (QAS) of different molecular weight on the rheology of an industrial ceramic suspension deflocculated with sodium polyacrylate and sodium metasilicate. The observed shear thinning behaviors obey the typical power law of fluid rheology. In order to characterize the rheological behavior of these slurries, three new parameters are introduced: a low shear rate consistency index and two transient viscosities, distant from the equilibrium, after increasing and decreasing the shear rates. These parameters vary with polyacrylate molecular weight and on additions of small quantities of QAS, which we found to be useful for decreasing the slurry viscosity. 相似文献
2.
A remarkable nonlinearity has been observed for electric transport in K-TCNQ (potassium tetracyanoquinodimethane) quasi-one-dimensional
conductor. The negative differential resistance region appears afterV
m (turn over voltage), beyond which voltage goes down with increase of current. A possible mechanism is discussed in terms
of dynamics of charged solitons and domain walls in one-dimensional molecular stacks of these types of crystals. 相似文献
3.
A series of long-chain quaternary ammonium halogen esters (UKK-chemicals), quaternary dimethyl tallow epoxypropyl ammonium
halogens (EPK1), quaternary ditallow methyl epoxypropyl ammonium halogens (EPK2), and EPK2 oligomers (EPK2P) were synthesized.
At acidic, neutral, or slightly basic conditions, EPK1-, EPK2-, EPK2P-, and UKK-chemicals operate as cationic chemicals. They
can be used, for example, as stock sizings, surface sizings, or fixatives. Stock sizing, surface sizing, and fixative experiments
indicate that EPK1-, EPK2-, EPK2P-, and UKK-chemicals function at least as well as or better than the corresponding synthetic
chemicals used in papermaking. 相似文献
4.
二芳基碘鎓盐型阳离子光引发剂的
合成和光引发性能测试 总被引:2,自引:0,他引:2
通过两步反应合成了6种二芳基碘鎓盐, 研究了4,4′-二乙酰胺基苯基碘六氟磷酸盐的合成,确定了最佳工艺条件:乙酰苯胺与碘酸钾的摩尔比为2.2∶1.0,15 ml乙酸在25 ℃反应24 h,产率为47.6%。通过应用实验,测试了6种产物的光引发剂性能,对碘鎓盐光引发剂的构效关系进行了探讨。实验证明4种负离子为PF-6和BF-4的产物具有较好光引发性和抗氧阻能力。引入共轭基团的二芳基碘鎓盐其最大吸收波长明显增大,光引发性增强。 相似文献
5.
6.
Nucleation effects of 2,2′‐methylene‐bis (4,6‐di‐tert‐butylphenyl) phosphate metal salts as a nucleating agent for isotactic polypropylene (iPP) were investigated with differential scanning calorimeter and polarized optical microscope, and their effects on mechanical, optical, and heat resistance properties of iPP were also studied. The results showed that monovalent metal salts of substituted aromatic heterocyclic phosphate such as sodium salt, lithium salt, and potassium salt had a good performance. With 0.2 wt % of sodium salt, lithium salt, or potassium salt incorporated into iPP, the crystallization peak temperature of iPP could be increased by 13.5, 13.6, and 15.0°C, respectively; the mass fraction of crystallinity of iPP could be increased by about 5%; and crystallization rate was enhanced increasingly. Meanwhile the tensile strength and flexural modulus of iPP could be increased by about 10 and 30%, respectively, and the clarity and heat distortion temperature of iPP could also be improved significantly. But bivalent and trivalent metal salts of substituted aromatic heterocyclic phosphate had little effect on properties of iPP. Meanwhile the morphology study showed that the addition of monovalent sodium salt could decrease the spherulite size of iPP significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4868–4874, 2006 相似文献
7.
8.
分子内敏化鎓盐的合成及光敏性研究 总被引:3,自引:0,他引:3
二芳基碘鎓盐和三芳基硫鎓盐是阳离子聚合的光引发剂和光敏产酸物,但他们在300nm以上的光吸收很低,限制了对紫外光的利用效率。为解决此问题,本文合成了一些新的碘鎓盐和硫鎓盐,并用凝胶时间方法考察了它们的光引发效率。实验结果表明,2-苯硫基甲基,2′,4′-二甲基二苯碘鎓盐和9-蒽丙基,二苯基硫鎓盐具有特别高的光引发效率,这归之于光照时这些鎓盐发生了分子内电荷转移反应,即发生了分子内敏化。9-蒽丙基二苯硫鎓盐分子中的蒽基(An)是电子给体也是敏化基团,光照时可发生如下反应: 相似文献
9.
Baishen Liang Alessandro Gomez Jose L. Castillo Daniel E. Rosner 《Chemical Engineering Communications》1989,85(1):113-133
In carrying out partial vapor condensations using actively cooled surfaces it is known that 'mist' formation can occur within thermal boundary layers (Rosner and Epstein, 1968), dramatically modifying total deposition fluxes. Using a combination of flash-evaporation (Rosner and Liang, 1986) and laser probing techniques, we report new experimental results on binary alkali salt (K2SO4 + Na2SO4) deposition from combustion gases showing that the deposition rate of potassium sulfate first increases with the addition of sodium sulfate until the concentration of Na2SO4 reaches a (target surface temperature dependent) 'threshold' value. Further increases in the concentration of Na2SO4 dramatically decrease the total deposition rate of K2SO4, implying that potassium sulfate-containing microdroplets are formed within the thermal boundary layer, which, despite their thermophoretic drift toward the target, are not collected as effectively as the 'parent' K2SO4-vapor species. Laser light scattering measurements clearly reveal that suspended particles exist near the deposition surface under these conditions. Our experimental results on mass transfer rate and light scattering are consistent with those predicted using laminar boundary layer theory (Castillo and Rosner, 1989b) coupling both binary salt vapor deposition with particle vapor scavenging and deposition. Comparisons of our observed mist onset conditions (implying critical supersaturations near unity) with those expected using homogeneous nucleation theory suggest that the binary alkali sulfate mist nucleation mechanism is, instead, heterogeneous, even in our relatively 'clean' combustion products. Because of the; well-known vapor pressure reduction phenomenon associated here with the formation of non-ideal solutions, binary systems are shown to provide convenient 'vehicles' to investigate BL mist formation onset conditions and CVD-rate consequences without requiring the more extreme surface coolings characteristic of unary condensible vapor systems. An understanding of this dramatic phenomenon, obtained via such laboratory experiments and calculations, will allow its inclusion in future deposition rate calculations of engineering importance. 相似文献
10.
Jairton Dupont Paulo A.Z. Suarez Alexandre P. Umpierre Roberto F. de Souza 《Catalysis Letters》2001,73(2-4):211-213
The combination of 1-n-butyl-3-methylimidazolium chloride with ZnCl2 affords ionic mixtures with different melting point temperatures depending on the zinc molar fraction. RuCl2(PPh3)3 immobilised in the low melting mixture (60°C) promotes the 1-hexene hydrogenation (turnover frequencies up to 44 min–1) and the recovered solid catalyst phase can be reused several times. 相似文献