scholarly journals Influence of hydroxypropylmethyl cellulose-sodium laurylsulfate interaction on rheological properties of the solution

2004 ◽  
Vol 58 (11) ◽  
pp. 521-525 ◽  
Author(s):  
Jelena Saletic ◽  
Verica Sovilj ◽  
Lidija Petrovic
Keyword(s):  
Rheological Properties ◽  
Pharmaceutical Formulations ◽  
Critical Aggregation Concentration ◽  
Saturation Point ◽  
Rotational Viscometer ◽  
Hydroxypropylmethyl Cellulose ◽  
Rheological Measurements ◽  
Nonionic Polymer ◽  
Linear Relationships ◽  
Viscosity Changes

Interactions between the polymers and surfactants in solution have widely been investigated because of their scientific and technological importance. These interactions can be utilized to modify the physicochemical properties of system in many food products, pharmaceutical formulations, personal care products, paints, pesticides, etc. Interaction between nonionic polymer - hydroxypropylmethyl cellulose (HPMC) and anionic surfactant - sodium laurylsulfate (SDS) in solution has been investigated in this paper by rheological measurements. Rheological measurements are performed by rotational viscometer at 20?C and changes of rheological characteristics of HPMC solutions (0.5-1.5%) with increasing SDS concentrations (0-4.0%) were determined. The results of these investigations showed that viscosity of the solution is dependant on HPMC-SDS interaction. At particular SDS concentration viscosity increases, reach maximum and after that decreases until reach constant value. From the viscosity changes the characteristic concentrations of SDS, critical aggregation concentration (cac) and polymer saturation point (psp), were determined. These concentrations are in linear relationships with HPMC concentrations. Rheological properties of the solution are strong influenced by HPMC-SDS interaction and exhibits more or less pronounced pseudoplastic behavior, which changes to Newtonian one after the psp has been reached.

The Use of Rheology for Sludge Characterization

1982 ◽  
Vol 14 (6-7) ◽  
pp. 475-489 ◽  
Author(s):  
H W Campbell ◽  
P J Crescuolo
Keyword(s):  
Particle Size ◽  
Sewage Sludge ◽  
Test Procedures ◽  
Particle Size Reduction ◽  
Rotational Viscometer ◽  
Polymer Addition ◽  
Rheological Measurements ◽  
Acceleration Rate ◽  
Sludge Characterization ◽  
Potential Use

Rheological measurements were conducted on a variety of anaerobically digested sewage sludges to evaluate the potential use of rheology in describing the effects of chemical conditioning on the physical characteristics of sludges. The objectives of the study were to evaluate the influence of the method of chemical conditioning on rheological measurements; to determine the response of the viscometer system to changes in the instrument variables; and to evaluate interrelationships between rheology and other physical properties. All rheological measurements were made using a coaxial rotational viscometer. Evaluation of a variety of test procedures identified that both the method of adding chemical conditioners, and the acceleration rate of the rotational viscometer, could significantly alter the shape of the rheograms. A suggested methodology was identified and selected samples were analyzed in triplicate to test the reproducibility of the procedures. Existing mathematical models do not adequately describe the variety of flow behaviour patterns observed with sewage sludge. The concepts of yield stress and apparent viscosity also have limited value due to problems of definition and calculation. A parameter termed the “instantaneous viscosity”, defined as the derivative of the flow curve, is suggested as being more suitable for describing sludge behaviour. The relationships between chemical conditioning, particle size distribution and applied shear were explored. As polymer addition increased, the sludge particles became more susceptible to shear breakup. The extent of particle size reduction was a function of the rate of shear and the time during which the shear was maintained.

scholarly journals Rheological properties of hydroxypropylmethyl cellulose/sodium dodecylsulfate mixtures

2014 ◽  
Vol 79 (4) ◽  
pp. 457-468 ◽  
Author(s):  
Jaroslav Katona ◽  
Sandra Njaradi ◽  
Verica Sovilj ◽  
Lidija Petrovic ◽  
Brankica Marceta ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Sodium Dodecylsulfate ◽  
Shear Thinning ◽  
Cellulose Ether ◽  
Flow Profile ◽  
Hydroxypropylmethyl Cellulose ◽  
Shear Rates ◽  
Newtonian Liquids ◽  
Shear Induced Structure ◽  
Induced Structure

Rheological properties of mixtures of hydroxypropylmethyl cellulose (HPMC), a nonionic associative cellulose ether, and sodium dodecylsulfate (SDS), an anionic surfactant, were investigated by viscosity measurements performed at different shear rates (0.1-6000 s-1). HPMC/SDS mixtures containing different concentrations of SDS (CSDS=0.00-3.50 % w/w) and HPMC concentrations which corresponded to the overlap parameter c/c*=3, 6, and 12 were prepared. All HPMC/SDS mixtures were found to be shear-thinning when examined in a low-end-to mid-range of the applied shear rates. The degree of shear-thinning, n, and viscosity of the mixtures were influenced by composition of HPMC/SDS mixtures and HPMC-SDS complex formation. The changes in n ranged from values typical for highly shear thinning to almost perfectly Newtonian liquids, and were more pronounced as c/c* was increased from 3 to 6 and 12. A change in flow profile and a buildup of the first normal stress difference (N1) was observed in HPMC/SDS mixtures with c/c*=6 and 12 and CSDS 0.55-1.00 % and 0.55-2.50 %, respectively, when a critical shear rate, crit. was exceeded, suggesting that a shear-induced structure formation in the mixtures took place.

Rheological Properties of Tomato Concentrate

2008 ◽  
Vol 4 (7) ◽  
Author(s):  
Manish Dak ◽  
Radha Charan Verma ◽  
S N A Jaaffrey
Keyword(s):  
Rheological Properties ◽  
Absolute Temperature ◽  
Power Law Model ◽  
Arrhenius Model ◽  
Rotational Viscometer ◽  
Consistency Coefficient ◽  
Flow Behaviour Index ◽  
Different Temperatures ◽  
Wide Gap ◽  
Good Agreement

Rheological properties of tomato concentrate were evaluated using a wide-gap rotational viscometer (Brookfield Engineering Laboratories: Model LVDV-II) at different temperatures of 20, 30, 40, 50, and 60oC, at concentration of 18, 12.18 and 8.04 % total solids, and at appropriate shear rate(1-100 RPM). The power law model was fitted to the experimental results. The values of flow behaviour index (n) were found less than unity (0.23 to 0.82) at all the temperature and the concentration indicating shear-thinning (pseudoplasticity) behaviour of the concentrate. The correlation between the observed consistency coefficient ranging from 0.09 to 65.87 Pa.sn and the inverse absolute temperature has been exhibited by Arrhenius model. Consistency coefficient increased exponentially with increase in the concentration. Statistical model was used for prediction of the consistency coefficient as a function of temperature and concentration which showed a good agreement (r2=0.99) between experimental and theoretical values. The magnitude of activation energy were found to be in the range of 8.6 to 14.08 kJ/mol.K.

scholarly journals Effect of Temperature and Used Ingredients on Rheological Parameters of Pancake Dough

2013 ◽  
Vol 16 (3) ◽  
pp. 63-66
Author(s):  
Peter Hlaváč ◽  
Monika Božiková
Keyword(s):  
Rheological Properties ◽  
Dynamic Viscosity ◽  
Kinematic Viscosity ◽  
Fat Content ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Rotational Viscometer ◽  
Two Samples ◽  
Dynamic And Kinematic Viscosity ◽  
Temperature Dynamic

Abstract This paper presents the selected rheological properties of pancake dough such as dynamic and kinematic viscosity and fluidity. The effect of used ingredients and temperature on rheological properties is investigated. Measurements were performed on three pancake dough samples. In two samples, there was used milk with a different fat content, and in the third sample, all ingredients were in a powder state. A digital rotational viscometer Anton Paar DV-3P was used for measuring the rheological properties. The principle of viscometer measurement is based on the dependence of sample resistance to probe rotation. Results of measurements are shown as graphical dependencies of rheological parameters on temperature. Exponential functions were used to express the dependencies of all rheological parameters on temperature. Dynamic and kinematic viscosity decreased, and fluidity increased with temperature. The highest values of dynamic viscosity were obtained for pancake dough from powder ingredients. A higher fat content of used milk caused higher values of dynamic viscosity.

scholarly journals Analysis of Structural and Functional Differences of Glucans Produced by the Natively Released Dextransucrase of Liquorilactobacillus hordei TMW 1.1822

2020 ◽  
Vol 193 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Jonas Schmid ◽  
Daniel Wefers ◽  
Rudi F. Vogel ◽  
Frank Jakob
Keyword(s):  
Molecular Weight ◽  
Secondary Structure ◽  
Rheological Properties ◽  
Viscoelastic Fluid ◽  
Size Structure ◽  
Molecular Size ◽  
Molecular Structures ◽  
Rheological Measurements ◽  
Functional Differences ◽  
Functionally Diverse

AbstractThe properties of the glucopolymer dextran are versatile and linked to its molecular size, structure, branching, and secondary structure. However, suited strategies to control and exploit the variable structures of dextrans are scarce. The aim of this study was to delineate structural and functional differences of dextrans, which were produced in buffers at different conditions using the native dextransucrase released by Liquorilactobacillus (L.) hordei TMW 1.1822. Rheological measurements revealed that dextran produced at pH 4.0 (MW = 1.1 * 108 Da) exhibited the properties of a viscoelastic fluid up to concentrations of 10% (w/v). By contrast, dextran produced at pH 5.5 (MW = 1.86 * 108 Da) was gel-forming already at 7.5% (w/v). As both dextrans exhibited comparable molecular structures, the molecular weight primarily influenced their rheological properties. The addition of maltose to the production assays caused the formation of the trisaccharide panose instead of dextran. Moreover, pre-cultures of L. hordei TMW 1.1822 grown without sucrose were substantial for recovery of higher dextran yields, since the cells stored the constitutively expressed dextransucrase intracellularly, until sucrose became available. These findings can be exploited for the controlled recovery of functionally diverse dextrans and oligosaccharides by the use of one dextransucrase type.

scholarly journals Stability-Indicating Methods for Determination of Pyritinol Dihydrochloride in the Presence of Its Precursor and Degradation Product by Derivative Spectrophotometry

2005 ◽  
Vol 88 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Mostafa A Shehata ◽  
Mohammad A El-Sayed ◽  
Mohammad G El-Bardicy ◽  
Mohammad F El-Tarras
Keyword(s):  
Hydrochloric Acid ◽  
Degradation Product ◽  
Pharmaceutical Formulations ◽  
Zero Crossing ◽  
Stability Indicating ◽  
First Derivative ◽  
Linear Relationships ◽  
Assay Methods ◽  
Powdered Form

Abstract A first-derivative spectrophotometric (1D) method and a derivative-ratio zero-crossing spectrophotometric (1DD) method were used to determine pyritinol dihydrochloride (I) in the presence of its precursor (II) and its degradation product (III) with 0.1N hydrochloric acid as a solvet. Linear relationships were obtained in the ranges of 6–22 μg/mL for the (1D) method and 6–20 μg/mL for the (1DD) method. By applying the proposed methods, it was possible to determine pyritinol dihydrochloride in its pure powdered form with an accuracy of 100.36 ± 1.497% (n = 9) for the (1D) method and an accuracy of 99.92 ± 1.172% (n = 8) for the (1DD) method. Laboratory-prepared mixtures containing different ratios of (I), (II), and (III) were analyzed, and the proposed methods were valid for concentrations of ≤10% (II) and ≤50% (III). The proposed methods were validated and found to be suitable as stability-indicating assay methods for pyritinol in pharmaceutical formulations.

Effects of Aging on the Physical and Rheological Properties of Asphalt Binder Incorporating Rediset®

2014 ◽  
Vol 70 (7) ◽  
Author(s):  
Mohamad Yusri Aman ◽  
Zulkurnain Shahadan ◽  
Munzilah Md. Ruhani ◽  
Rosnawati Buhari
Keyword(s):  
Statistical Analysis ◽  
Rheological Properties ◽  
Asphalt Binder ◽  
Dynamic Shear ◽  
Short Term ◽  
Rotational Viscometer ◽  
Aging Index ◽  
Modified Binders ◽  
Before And After ◽  
Effects Of Aging

This paper focuses on physical and rheological properties of virgin asphalt binder blended with different percentage of Rediset® content. The rheological properties of the Rediset® modified binders were characterized before and after being subjected to short-term aging using rotational viscometer (RV) and dynamic shear rheometer (DSR) according to SuperpaveTM test protocols. The results indicated that the penetration and softening point were consistently decreased and increased, respectively for unaged and short-term aged samples. The penetration index (PI) and viscosity aging index (VAI) were increased as the Rediset® modified binders aged and showed a high significance correlation. The addition of Rediset® in asphalt binder exhibited change in binder rheology after subjected to short-term aged which influenced the rutting parameter. A statistical analysis showed that Rediset® used as warm asphalt additive had significantly increased the G*/Sin δ parameter which indicated greater resistance to rutting.

Rheological Properties and Microstructures of Thermo-Sensitive Microemulsion-Based Gels

2012 ◽  
Vol 557-559 ◽  
pp. 1009-1012
Author(s):  
Xue Yan Zhao ◽  
Yu Rong Cao ◽  
Rui Jie Xiao ◽  
Gui Rong Cao
Keyword(s):  
Fluorescence Spectroscopy ◽  
Rheological Properties ◽  
Viscoelastic Properties ◽  
Isopropyl Myristate ◽  
Rheological Measurements ◽  
Pluronic P123

Thermo-sensitive microemulsion-based gels (MBGs) were prepared by the addition of Pluronic P123 (PEO20PPO70PEO20) into O/W microemulsion composed of isopropyl myristate (IPM)/Span20/Tween20/H2O. The results of rheological measurements indicate that the viscoelastic properties of the systems increase and the gelation temperatures decrease with increasing P123 concentration. Fluorescence spectroscopy was used to study the micropolarity of the hydrogel (P123/H2O), microemulsion and MBGs systems. The results show that the microstructures of microemulsion droplets are maintained in MBGs.

Filler Content, Surface Microhardness, and Rheological Properties of Various Flowable Resin Composites

2016 ◽  
Vol 41 (6) ◽  
pp. 655-665 ◽  
Author(s):  
S Jager ◽  
R Balthazard ◽  
A Dahoun ◽  
E Mortier
Keyword(s):  
Rheological Properties ◽  
Filler Content ◽  
Resin Composite ◽  
Resin Composites ◽  
Surface Microhardness ◽  
Fissure Sealant ◽  
Rheological Measurements ◽  
Low Viscosity ◽  
Lower Viscosity ◽  
Pit And Fissure Sealant

SUMMARY Objectives: The objectives of this study were to determine the filler content, the surface microhardness (at baseline and after immersion in water for 2 years), and the rheological properties of various flowable resin composites. Methods: Three flowable resin composites (Grandioso Heavy Flow [GHF], Grandio Flow [GRF], Filtek Supreme XTE Flow [XTE]), one pit and fissure sealant resin composite (ClinPro [CLI]), and three experimental flowable resin composites with the same matrix and a variable filler content (EXPA, EXPB, EXPC) were tested. The filler content was determined by calcination. The Vickers surface microhardness was determined after polymerization and then after immersion in distilled water at 37°C for 7, 60, 180, 360, and 720 days. The rheological measurements were performed using a dynamic shear rheometer. Results: The determined filler contents differed from the manufacturers' data for all the materials. The materials with the highest filler content presented the highest microhardness, but filler content did not appear to be the only influencing parameter. With respect to the values recorded after photopolymerization, the values were maintained or increased after 720 days compared with the initial microhardness values, except for GHF. For the values measured after immersion for 7 days, an increase in microhardness was observed for all the materials over time. All the materials were non-Newtonian, with shear-thinning behavior. At all the shear speeds, GRF presented a lower viscosity to GHF and XTE. Conclusions: GRF presented a low viscosity before photopolymerization, associated with high filler content, thereby providing a good compromise between spreadability and mechanical properties after photopolymerization.

scholarly journals Role of Charge of Micellar Worms in Modulating Structure and Rheological Properties of Their Mixtures with Nonionic Polymer

2017 ◽  
Vol 51 (1) ◽  
pp. 213-221 ◽  
Author(s):  
Andrey V. Shibaev ◽  
Anton V. Makarov ◽  
Alexander I. Kuklin ◽  
Ilias Iliopoulos ◽  
Olga E. Philippova
Keyword(s):  
Rheological Properties ◽  
Nonionic Polymer
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