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.

scholarly journals The Influence of the Addition of Nuts on the Thermal and Rheological Properties of Wheat Flour

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3969
Author(s):  
Karolina Pycia ◽  
Lesław Juszczak
Keyword(s):  
Rheological Properties ◽  
Wheat Flour ◽  
Viscoelastic Properties ◽  
Control Sample ◽  
Scanning Calorimetry ◽  
Creep And Recovery ◽  
Research Material ◽  
Pasting Characteristics ◽  
Tan Δ ◽  
Weak Gels

The aim of the study was to assess the influence of replacing wheat flour with hazelnuts or walnuts, in various amounts, on the thermal and rheological properties of the obtained systems. The research material were systems in which wheat flour was replaced with ground hazelnuts (H) or walnuts (W) in the amount of 5%, 10%, and 15%. The parameters of the thermodynamic gelatinization characteristics were determined by the differential scanning calorimetry method. In addition, the pasting characteristics were determined with the use of a viscosity analyzer and the viscoelastic properties were assessed. Sweep frequency and creep and recovery tests were used to assess the viscoelastic properties of the tested gels. It was found that replacing wheat flour with nuts increased the values of gelatinization temperature, gelatinization, and retrogradation enthalpy, and the degree of retrogradation. The highest viscosity was characteristic of the control sample (2039 mPa·s), and the lowest for the paste with 15% addition of walnuts (1120 mPa·s). Replacing the flour with nuts resulted in a very visible reduction in the viscosity of such systems. In addition, gels based on the systems with the addition of H and W were weak gels (tan δ = G″/G′ > 0.1), and the values of G′ and G″ parameters decreased with the increased share of nuts in the systems. Creep and recovery analysis indicated that the systems in which wheat flour was replaced with hazelnuts were less susceptible to deformation compared to the systems with the addition of W.

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.

Rheological Characterization of Body Lotions

2001 ◽  
Vol 11 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Ming Long Yao ◽  
Jayesh C. Patel
Keyword(s):  
Thermal Stability ◽  
Temperature Sensitivity ◽  
Viscoelastic Properties ◽  
Rheological Characterization ◽  
Performance Properties ◽  
Rheological Measurements ◽  
End Use ◽  
And Storage

Abstract This study is attempted to demonstrate the application of rheological measurements in characterization of cosmetics products. As part of this study, several rheological tests were carried out on three common, commercially available body lotions to analyze their complex properties. The tests described in this study were simple and predictive in which the viscoelastic properties were successfully related with the end-use performance properties such as applicability, processing behavior, temperature sensitivity and storage and thermal stability.

The Effect of Refrigerated Storage on the Rheological Properties of Three Commercial Mozzarella Cheeses

2008 ◽  
Vol 4 (4) ◽  
Author(s):  
Edward B Muliawan ◽  
Savvas G Hatzikiriakos
Keyword(s):  
Rheological Properties ◽  
Viscoelastic Properties ◽  
Elevated Temperatures ◽  
Maxwell Model ◽  
Model Parameters ◽  
Refrigerated Storage ◽  
Mozzarella Cheese ◽  
Relaxation Dynamics ◽  
Generalized Maxwell Model ◽  
Linear Viscoelastic

The linear and non-linear viscoelastic properties and the effect of refrigerated storage on the rheological properties of three commercial mozzarella cheeses was studied. The linearity of the rheological behavior of mozzarella cheese increases with temperature because of the ability for the cheese to flow easier at higher temperatures as well as the lack of yield stress at elevated temperatures. The generalized Maxwell model parameters obtained from the linear viscoelastic data were found to describe the linear relaxation dynamics of the mozzarella cheese satisfactorily. It is also shown that the damping function of mozzarella cheese, which is a measure of the degree of non-linearity, can be described by a generalized Zapas model. Although, the different commercial mozzarella cheeses do not exhibit linear viscoelastic differences at room temperature, they do show significant differences at 60°C. The effect of refrigerated storage on the linear viscoelastic properties is brand-dependent and indicates structural differences among cheese samples. Finally it is shown that the dynamic moduli decrease with longer refrigerated storage due to proteolysis activities and/or weakening of the casein matrix.

Rheological properties of anionic polystyrenes. 7. Viscoelastic properties of six-branched star polystyrenes and their concentrated solutions

1981 ◽  
Vol 14 (2) ◽  
pp. 354-360 ◽  
Author(s):  
Toshiro Masuda ◽  
Yasuhiko Ohta ◽  
Mitsunobu Kitamura ◽  
Yoichiro Saito ◽  
Kyoko Kato ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Viscoelastic Properties ◽  
Concentrated Solutions

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.

Scaling Behaviour of the Viscoelastic Properties of a Biopolymer System Near the Gel Point

1989 ◽  
Vol 177 ◽  
Author(s):  
M. A. V. Axelos ◽  
M. Kolb
Keyword(s):  
Steady State ◽  
Percolation Theory ◽  
Viscoelastic Properties ◽  
Sol Gel ◽  
Oscillatory Shear ◽  
Gel Point ◽  
Rheological Measurements ◽  
Scaling Behaviour ◽  
Sol Gel Transition ◽  
Gel Transition

ABSTRACTRheological measurements have been performed on pectin-calcium systems close to the sol-gel transition. Two different experimental setups - steady state and oscillatory shear measurements - show scaling of the viscoelastic properties. The results of both types of measurements are consistent with each other and with scalar percolation theory.

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