Relative Viscosity Measurements Research Articles

Photocytotoxicity of a New Rh2(II,II) Complex: Increase in Cytotoxicity upon Irradiation Similar to That of PDT Agent Hematoporphyrin

A new type of heteroleptic dirhodium complex cis-[Rh(2)(mu-O2CCH3)2-(bpy)(dppz)]2+ (3) was synthesized and its potential as a photodynamic therapy (PDT) agent was investigated. Although 27% hypochromicity of the absorption of 3 in the near-UV and visible regions is observed in the presence of duplex DNA, relative viscosity measurements reveal that the complex does not intercalate between the DNA bases. The DNA photocleavage with visible light by 3 proceeds via both oxygen dependent and independent mechanisms, and it is more efficient than that of related complexes. The increase in the cytotoxicity of 3 towards human skin cells is similar to that of hematoporphyrin, a key ingredient in a PDT drug currently in use. This feature makes this complex a useful candidate for further PDT studies.

Study on hydration layers near nanoscale silica dispersed in aqueous solutions through viscosity measurement

On the basis of the Einstein theory of viscosity of dispersion, a parameter, termed as solvation factor, is presented to evaluate the solvation degree of nanoscale particles dispersed in a liquid in this work. The value of the parameter is obtained through the measurements of relative viscosity of the dispersions as a function of the volume fraction of dry particles. The solvation factor has been used to study the hydration layers near nanoscale silica particles dispersed in water and aqueous electrolyte (NaCl and CaCl 2) solutions in this work. The experimental results have shown that a strong hydration indeed applied to the silica surfaces in aqueous solutions, leaving a large volume of hydration layers on the surfaces. Also, it has been found that the hydration of the nanoscale silica particles could be greatly enhanced if they were dispersed in aqueous NaCl or CaCl 2 solutions, which might be attributed to that the hydrated cations (Na + or Ca 2+) bind onto the silica/ water interface and thus increase the volume of the hydration layers.

Thickness of Solvation Layers on Nano‐scale Silica Dispersed in Water and Ethanol

In this work, the thickness of solvation layers on nano‐scale silica dispersed in water, ethanol, and water‐ethanol mixture (1∶1 by volume) have been determined with the viscosity method, which is based on the Einstein equation of viscosity of dispersion. This determination was carried out on a nano‐scale silica with the specific surface area of 189 m2/g through the measurements of relative viscosity of the silica dispersion as the function of volume fraction of the dry silica in the dispersion. The experimental results and the calculations showed that the thickness of the solvation layer on the nano‐scale silica was 12.8 nm in water, 11.9 nm in ethanol, and 13.2 nm in the water‐ethanol mixture. The results suggest that water‐ethanol mixture (1∶1 by volume) should be used as the liquid medium in order to prepare a high stability nano‐scale silica suspension.

Synergistic interactions in mixed micelles of alkyltriphenylphosphonium bromides and triblock polymers

The mixed micelle formation of hexadecyltriphenylphosphonium (HTPB) and tetradecyltriphenylphosphonium (TTPB) bromides with triblock polymers such as (PEO) 18(PPO) 31(PEO) 18 (18–31–18), (PEO) 2(PPO) 15(PEO) 2 (2–15–2), (PEO) 2(PPO) 31 (PEO) 2 (2–31–2), and (PEO) 77(PPO) 29(PEO) 77 (77–29–77) have been carried out with the help of fluorescence, relative viscosity, and cloud point measurements. The binary mixtures have been analyzed on the basis of regular solution approximation and by determining the aggregation numbers. It has been observed that the mixtures of HTPB + 18–31–18/2–15–2 and TTPB + 18–31–18/2–15–2 undergo mixed micellization due to synergistic interactions, whereas the mixtures of HTPB/TTPB + 2–31–2/77–29–77 demonstrate antagonistic or ideal mixing. The relative viscosity and cloud point measurements fully support these results. The results also suggest that the favorable mixed micellization with triblock polymers can be achieved if the number of PPO groups are not very large from that of the PEO groups and vice versa as in the case of mixtures of 18–31–18 and 2–15–2 in comparison to that of 2–31–2 and 77–29–77.

Poly (amidoamine) dendrimer interactions with sodium dodecyl sulfate studied by viscosity measurements

The relative viscosity ( η r) measurements of poly (amidoamine) (PAMAM) dendrimers + sodium dodecyl sulfate (SDS) + water systems were carried out at 25 °C with the help of capillary viscometer by changing the concentrations of SDS and PAMAM, and by changing the number of generations from 0G to 1G of PAMAM. The η r plots of SDS in aqueous PAMAM show clear aggregation process in the case of 0G and 0.5G. Evaluation of intrinsic viscosity demonstrates that it is much higher both for SDS ([ η] SDS) as well as for PAMAM ([ η] PAMAM) in the case of 0.5G rather than 0G and 1G. It indicates a stronger electrostriction effects operating between SDS and 0.5G PAMAM. This has been attributed to the favorable adsorption of Na + counterions on the ester terminated surface groups of 0.5G, thus generating electropositive character.

Shear response of concentrated calcium carbonate suspensions

The rheology of concentrated calcium carbonate suspensions is investigated with respect to addition of solution and dispersion polymers. System materials and composition are chosen to be similar, generically, to those in use in the coating of paper. Specifically, we investigate the particle volume fraction dependence of the relative viscosity, using both capillary and steady-shear concentric cylinder measurement methods to cover a broad range of concentrations. The results are interpreted in terms of semi-empirical models, such as the Krieger–Dougherty model. Oscillatory shear measurements are also employed to investigate the viscoelastic behavior of the concentrated suspensions. The measurements indicate that a common solution polymer thickener, carboxymethyl cellulose (CMC), causes depletion flocculation of calcium carbonate suspensions.

Effects of PVB on the gelation behavior of BaTiO3-based dielectric particles and glass suspension

Abstract The effect of polyvinyl butyral (PVB) resins on the gelation behavior of the BaTiO 3 -based dielectric particles and borosilicate glass particulate suspensions was investigated in a system where organic solvents, dispersant, binder and gelation modifier were used as processing additives in a low temperature cofired ceramic fabrication processes. The strong flocculation, gels of the suspension without a modifier was attributed to the reaction and strong linkage between the boron in the borosilicate glass and the functional hydroxyl group of PVB resins, which was confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. When the butyral content of PVB employed in each slurry formulation diminish by approximately 8%, it caused the concentrated suspension to gel. The butyral content of PVB had a much greater impact on gelation than did the molecular weight of PVB. As the molecular weight of PVB was increased, the apparent viscosities of the slurries increased due to the broader chain length of higher molecular weight of PVB. According to the relative viscosity measurement results, both suspensions with high and low PVB molecules had similar viscosity values and it might be regarded as the more viscous feature of PVB polymer solution.

Emulsion Flow Behavior of Crude Oil-Alcoflood Polymers.

The fundamental aspects controlling the rheology of crude oil-Alcoflood polymer emulsions are investigated. Several crude oil concentrations are covered over the range of 10-75% by volume. Three types of Alcoflood polymers of AF1235, AF1275, and AF1285 are employed over the concentration range of 0-10,000 ppm. A cone and plate of RS100 rheometer under constant rate mode is employed for this emulsion investigation. During the shear rate sweep over the range of 0.1-1000 s -1 , the measurements of shear stress, viscosity, and relative viscosity of different emulsions are extensively investigated. A Zeiss optical microscope is used to investigate the distribution and interaction of crude oil droplets within the polymer solution in order to help understanding of the rheological behavior of these emulsions.

Compatibility and biodegradability of blendsof starch cinnamate with various polymers

The compatibility of blends of starch cinnamate (StCn) with polyvinyl chloride (PVC), polystyrene (PS), and styrene acrylonitrile copolymer (SAN) has been examined through viscometry at 30°C. The results of the three systems are compared with the already reported PMMA/StCn system. From the intrinsic viscosity, relative viscosity, reduced viscosity, and density measurements the PVC/StCn and SAN/StCn blends were found to be compatible while PS/StCn blend was found to be incompatible. The compatibility of the blends was also confirmed by SEM analysis. The compatibility of these blends based on heat of mixing and polymer-polymer interaction parameter was also examined. Blends were observed to be compatible on the basis of heat of mixing theory but not on the basis of polymer - polymer interaction parameters. Biodegradation studies of compatible blends containing 30% StCn showed 13%, 15%, 18%, and 23% weight loss in case of PMMA, SAN, and PVC blends after 120 days.

Comparison of relative viscosity measurement of polyvinylpyrrolidone in water by glass capillary viscometer and differential dual‐capillary viscometer

AbstractThe relative viscosity (RV) of polyvinylpyrrolidone (PVP) with different molecular weights was measured with a glass capillary viscometer and with a differential dual‐capillary viscometer in water at different concentrations. For the differential dual‐capillary viscometer, RV increases with a decreasing flow rate, especially for high molecular weight PVP at a 1% concentration. A good agreement in the RV between the two methods can be obtained for PVP with different molecular weights and at various concentrations if an appropriate flow rate is selected for the differential dual‐capillary viscometer. Special precaution is needed when using the differential dual‐capillary viscometer to measure the viscosity of a pure solvent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1312–1315, 2002

Synthesis, Characterization, and Binding of [Cr(naphen)(H2O)2]+ with DNA: Experimental and Modeling Study

Abstract A chromium(III) complex of naphen, where naphen denotes 1,2-bis(naphthylideneamino)ethane having the basic salen structure, with an extended aromatic system, has been synthesized and characterized using UV–visible, infrared and ESI mass spectra. Absorption titration and thermal denaturation studies revealed that [Cr(naphen)(H2O)2]+ binds to DNA with moderate strength. Relative viscosity measurements clearly indicate that it binds to DNA by an intercalative mode. This observation is in contrast to an observation with the parent complex, [Cr(salen)(H2O)2]+, which prefers groove binding. Intercalation of the complex results in a change in the helicity of CT DNA, which is reflected in the CD spectrum of DNA in the presence of [Cr(naphen)(H2O)2]+. The binding constant of the complex to CT DNA has been estimated to be (0.51 ± 0.07)×104 M-1 (1 M = mol dm-3), which is lower than the values reported for classical intercalators. Modeling studies with the dodecamer d(GCGCAATTGCGC)2 show that as a result of the intercalation of [Cr(naphen)(H2O)2]+ the vertical separation of the bases increases by 2.67 Å in one strand and by 1.89 Å in the other.

Investigation of Association in Coal Extract Solution by the Measurement of Relative Viscosity

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTInvestigation of Association in Coal Extract Solution by the Measurement of Relative ViscosityMasaharu NishiokaView Author Information 19069 McFarlin Drive, Germantown, Maryland 20874 Cite this: Energy Fuels 2001, 15, 5, 1313–1316Publication Date (Web):July 13, 2001Publication History Received21 February 2001Published online13 July 2001Published inissue 1 September 2001https://doi.org/10.1021/ef010041wCopyright © 2001 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views62Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (43 KB) Get e-AlertsSUBJECTS:Absorption,Coal,Pyridines,Solvents,Viscosity Get e-Alerts

Viscosity of the binary mixture propane - isobutane in the gaseous state

Results of new relative high-precision viscosity measurements on the binary gaseous mixture propane-isobutane are reported. Eight series were carried out in an all-quartz oscillating-disk viscometer for an equimolar mixture from 297 K to 627 K and for densities between 0.009 and 0.042 mol l -1 . The uncertainty is estimated to be ±0.15% at ambient temperature increasing up to ±0.30% at the highest temperatures. Isothermal values were analysed with a density series for the viscosity in which only a linear contribution is included. The zero-density and initial-density viscosity coefficients for the equimolar mixture, η (0) mix and η (1) mix , were deduced and used, including the coefficients of its pure components, η (0) i and η (1) i , to derive values of the interaction viscosity in the limit of zero density, η (0) if , as a function of temperature. Then the Enskog-Thorne equations for hard-sphere systems were applied after a modification to describe the composition and density dependence of the viscosity of the real moderately dense gaseous mixture propane-isobutane. The values of η (0) if were further used to calculate binary diffusion coefficients which were compared with data from the literature.

Compatibility and biodegradability of PMMA-starch cinnamate blends in various solvents

The compatibility of PMMA and starch cinnamate (STCN) blends prepared in tetrahydrofuran, 1,4-dioxane, and N,N-dimethylformamide has been examined through viscometry at 30°C. From the intrinsic viscosity, relative viscosity, reduced viscosity, and density measurements, the blends of the two polymers were observed to be compatible in all three solvents. The compatibility of the blends was also confirmed through FTIR and SEM studies. The blends were observed to be compatible on the basis of heat of mixing, but they were observed to be incompatible on the basis of polymer–polymer interaction parameters. Results obtained show that the compatibility predicted on the basis of viscometric and density measurements is not affected by the choice of solvents. Biodegradation studies showed 13% weight loss within 120 days in the case of the blend containing 30% STCN. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 488–496, 2001

Properties that characterize the propagation of cracks of recycled glass fiber reinforced polyamide 6

Industrial wastes of glass fiber reinforced polyamide 6 originating from injection molding were reprocessed and characterized by measurements of relative viscosity, impact strength, fiber average length and fiber length distribution. The results show that the set of characterization techniques used are efficient to reproduce the behavior of reprocessed polymeric composites and to compare them with the virgin material.

The wall effect on viscosity measurement of dilute aqueous solutions of polyethylene glycol and polyvinyl alcohol using a paraffin-coated capillary viscometer

The relative viscosities of aqueous solutions of a polyethylene glycol sample and a polyvinyl alcohol sample were measured in a viscometer, the capillary wall surface of which was coated with paraffin. The results were compared with the data obtained from the original non-coated viscometer. Slippage occurs in the former case due to the hydrophobic nature of paraffin, while in the latter case, conventional viscous flow operates since both the solvent water and solution either wet and/or are adsorbed on to the glass capillary surface of the viscometer. The experimental data were analyzed with the aid of the recently proposed theory of the effect of solute adsorption on relative viscosity measurements. The formula, accounting for the effect of solute adsorption of polymer solutions down to the extremely dilute concentration region, are also applicable to non-wetting polymer solutions in which solute adsorption is eliminated. The results obtained were compared and analyzed using the idea of extrapolation length of slip flow proposed by de Gennes PG. CR Acad Sci Paris 1979;288B:219. The extrapolation length could be evaluated unambiguously from the relative or reduced viscosity data for polymer solutions down to the extremely dilute concentration region.

Genetic analysis of water-extractable arabinoxylans in bread wheat endosperm

Two mapping populations were used for the analysis of the water-extractable arabinoxylans. One originated from a cross between the hexaploid cultivars ‘Courtot’ and ‘Chinese Spring’ and the other from a cross between an amphiploid (Synthetic) and cv ‘Opata’. Arabinose (Ara), and xylose (Xyl) contents were quantified for the 91 and 76 lines obtained from the two crosses, respectively. Relative viscosity (ηrel) of the wheat flour aqueous extract was evaluated by capillary viscometry. Both crosses gave similar correlation coefficients between sugar contents and relative viscosity. There were strong positive relationships between arabinose, xylose and arabinoxylan contents. The relative viscosity was strongly and positively related to the arabinoxylan content and strongly and negatively related to the Ara/Xyl ratio (arabinose content to xylose content). For one of the two crosses two measurements of relative viscosity were generated from 2 years of consecutive harvesting. As a strong correlation was observed between these two measurements, an important genotypic effect can be deduced for the relative viscosity of water-extractable arabinoxylans. QTL (quantitative trait locus) research did not reveal any chromosomal segments that were strongly implicated in variations in sugar content. However, a QTL was found for relative viscosity values and the Ara/Xyl ratio on the long arm of the 1B chromosome for the two crosses considered. This QTL explained 32–37% of the variations in relative viscosity and 35–42% of the variations in the Ara/Xyl ratio. Genes located at this QTL controlled relative viscosity through modifying the Ara/Xyl ratio. Variations in the Ara/Xyl ratio were supposedly related to differences in the molecular structure of water-extractable arabinoxylans. Minor QTLs were also obtained for relative viscosity and Ara/Xyl ratio, but the chromosomes concerned were different for the two populations evaluated.

Method for reducing surface-tension effects in relative viscosity measurements with Ostwald-type viscometers

The reference for (relative) measurements of the viscosity of liquids is the viscosity of bi-distilled water at 20 °C. Applying the so-called step-up method to calibrate a series of capillary viscometers can result in deviations of roughly 0,2 % in the first liquid, normally an oil, that is used after the distilled water. This error is mainly caused by the difference in surface tension between water and oil. This report shows that with a special Ostwald-type viscometer, this deviation can be reduced significantly.

Effect of Sodium Chloride and Varied Alkyl Chain Length on Aqueous Cationic Surfactant−Bile Salt Systems. Cryo-TEM and Fluorescence Quenching Studies

The changes in size and microstructure of alkyltrimethylammonium halide (CnTAX) micelles as a function of alkyl chain length (even number of carbons between 12 and 18) and NaCl concentration (0−2 M) in aqueous mixtures with and without trihydroxy or dihydroxy bile salts, sodium cholate or sodium desoxycholate (NaC or NaDOC), have been investigated by cryo-TEM, time-resolved fluorescence quenching, and relative viscosity measurements. Without additions, dilute solutions (25 mM) of all the surfactants form globular micelles, with aggregation numbers increasing with the chain length (to 230 ± 3 in C18TAB at 40 °C). Addition of NaCl results in a growth of the micelles. For C16TA+ a transition to long threadlike micelles occurred in 2 M NaCl, whereas the micelles remain globular at shorter chain lengths. For C18TA+ a mixture of globular micelles and large structures was observed at 0.5 and 1. 0M NaCl. The pseudoternary CnTAB/NaC/NaCl systems showed results dependent on the alkyl chain length. On addition of NaC to C12TA+ and C14TA+, in the presence of salt, a monotonous decrease in aggregation numbers with increasing concentration of NaC is found. For the longer alkyl chains, a micellar growth resulting in a transition to threadlike cylindrical micelles occurs first, giving a peak in the viscosity. The transition is most pronounced in the C18TA+ case. Further addition of NaC give smaller micelles. The various stages in the transition are seen from cryo-TEM results. In the pseudoternary C16TAB/NaDOC/NaCl system, the viscosity was orders of magnitude higher than in the corresponding compositions of the NaC system. The structure of the cylindrical micelles depend on the composition and mole fraction of NaDOC. The change in size and structure on a molecular level is discussed in terms of the structure of bile salt anions and its preferred modes of orientation in the mixed micelle under different conditions.

Damping and gas viscosity measurements using a microstructure

Abstract The equations for squeeze-film damping of a microstructure comprising two plates oscillating normal to each other are used to derive the damping, and hence the viscosity, of six different gases under flow conditions ranging from molecular to almost viscous flow. For all the gases, the effective viscosity, normalized to the free gas viscosity, for flow in the gap between the plates is the same function of pressure when this is expressed as the inverse Knudsen number. The function is identifical in form to Knudsen's pipe-flow correction, but requires a scale change that effectively defines an equivalent diameter for parallel plates. Relative viscosity measurements are made with an accuracy of 1% by the phase technique used, and with a time resolution of 1 s. The possibility of a gas sensor based on the method is discussed.