Viscoelastic and Deformation Characteristics of Structurally Different Commercial Topical Systems

Rheological characteristics and shear response have potential implication in defining the pharmaceutical equivalence, therapeutic equivalence, and perceptive equivalence of commercial topical products. Three creams (C1 and C3 as oil-in-water and C2 as water-in-oil emulsions), and two gels (G1 and G2 carbomer-based) were characterized using the dynamic range of controlled shear in steady-state flow and oscillatory modes. All products, other than C3, met the Critical Quality Attribute criteria for high zero-shear viscosity (η0) of 2.6 × 104 to 1.5 × 105 Pa∙s and yield stress (τ0) of 55 to 277 Pa. C3 exhibited a smaller linear viscoelastic region and lower η0 (2547 Pa∙s) and τ0 (2 Pa), consistent with lotion-like behavior. All dose forms showed viscoelastic solid behavior having a storage modulus (G′) higher than the loss modulus (G″) in the linear viscoelastic region. However, the transition of G′ > G″ to G″ > G′ during the continual strain increment was more rapid for the creams, elucidating a relatively brittle deformation, whereas these transitions in gels were more prolonged, consistent with a gradual disentanglement of the polymer network. In conclusion, these analyses not only ensure quality and stability, but also enable the microstructure to be characterized as being flexible (gels) or inelastic (creams).

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SYNTHESIS AND VISCOELASTIC BEHAVIORS OF POLY(ANILINE-CO-O-ETHOXYANILINE) PARTICLES SUSPENDED ELECTRORHEOLOGICAL FLUID

International Journal of Modern Physics B ◽

10.1142/s0217979201005118 ◽

2001 ◽

Vol 15 (06n07) ◽

pp. 649-656 ◽

Cited By ~ 10

Author(s):

H. J. CHOI ◽

J. W. KIM ◽

M. S. SUH ◽

M. J. SHIN ◽

K. TO

Keyword(s):

Particle Size ◽

Silicone Oil ◽

Loss Modulus ◽

Chemical Oxidation ◽

Steady Shear ◽

Rheological Parameters ◽

Linear Viscoelastic Region ◽

Linear Viscoelastic ◽

Er Fluids ◽

Poly Aniline

Copolyanilines are synthesized by a chemical oxidation of aniline and o-ethoxyaniline with various molar ratios in an acidic media, and then characteristics of these polymers such as chemical structure, particle size and the particle size distribution were examined by using FT-IR, SEM and particle size analyzer, respectively. Suspensions of copolyaniline containing ethoxy group, namely poly(aniline-co-o-ethoxyaniline), in silicone oil have been investigated as one of many potential candidates for dry-base electrorheological (ER) fluid systems. Rotational rheometer (Physica) equipped with a high voltage generator was used to characterize the rheological properties of ER fluids from both steady shear and dynamic tests. From the steady shear experiment, we obtained flow properties and found that ER fluids exhibited the yield phenomenon. On the other hand, viscoelastic property was also obtained from the dynamic experiment. Since viscoelastic properties for ER fluids are mainly dominated by the particle chain structure, the state at different time scale was analyzed from the rheological parameters such as storage modulus (G'), loss modulus (G'') and tan δ. We conducted a strain amplitude sweep at 1 Hz under an applied electric field to determine a linear viscoelastic region first. The G' and G'' were then measured by a frequency sweep from 0.1 to 100 Hz in the linear viscoelastic region.

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Viscoelastic analysis of oat grain within linear viscoelastic region by using dynamic mechanical analyzer

International Journal of Food Engineering ◽

10.1515/ijfe-2018-0350 ◽

2020 ◽

Vol 16 (4) ◽

Author(s):

Nan Zhao ◽

Bo-wen Li ◽

Ying-dan Zhu ◽

Dong Li ◽

Li-jun Wang

Keyword(s):

Moisture Content ◽

Storage Modulus ◽

Heating Temperature ◽

Loss Modulus ◽

Creep Recovery ◽

Dynamic Mechanical Analyzer ◽

Frequency Sweep ◽

Dynamic Mechanical ◽

Linear Viscoelastic Region ◽

Linear Viscoelastic

AbstractThe stress relaxation, creep-recovery, temperature, and frequency sweep tests were performed within the linear viscoelastic region by using a dynamic mechanical analyzer to investigate the viscoelastic characteristic of oat grain. The result showed that 5-element Maxwell and Burgers model were able to describe viscoelastic behaviors better. The relaxation stress decreased with the increasing moisture content from 6.79 to 23.35%, while the creep strain increased as well as the final percentage recovery decreased from 58.61 to 32.50%. In frequency sweep, storage modulus increased with the increasing frequency. In temperature sweep, there was a clear turning point in storage modulus, loss modulus, and tan delta curves with increasing temperature. The turning value of 167.47, 147.44, 134.27, 132.41, 110.28, and 92.62 °C detected in the tan delta were regarded as the best glass transition temperatures. This temperature was found to be lower than gelatinization heating temperature and decrease with the increase of moisture content. The crystalline structure of oat exhibited a typical A-type pattern and corresponding crystallinity increased from 22.03 to 31.86% with increasing moisture content. The scanning electron microscopy (SEM) micrograph of oat section was found that the size and adhesive effect of starch granules increased due to hydration.

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Visual Appearance of Oil on the Sea

Journal of Marine Science and Engineering ◽

10.3390/jmse9010097 ◽

2021 ◽

Vol 9 (1) ◽

pp. 97

Author(s):

Merv Fingas

Keyword(s):

Water Surface ◽

Oil Spills ◽

Discharge Rate ◽

Physical Explanation ◽

Visual Appearance ◽

Oil In Water ◽

Other Information ◽

Surface Discharges ◽

Oil Emulsions ◽

Spilled Oil

The visual appearance of oil spills at sea is often used as an indicator of spilled oil properties, state and slick thickness. These appearances and the oil properties that are associated with them are reviewed in this paper. The appearance of oil spills is an estimator of thickness of thin oil slicks, thinner than a rainbow sheen (<3 µm). Rainbow sheens have a strong physical explanation. Thicker oil slicks (e.g., >3 µm) are not correlated with a given oil appearance. At one time, the appearance of surface discharges from ships was thought to be correlated with discharge rate and vessel speed; however, this approach is now known to be incorrect. Oil on the sea can sometimes form water-in-oil emulsions, dependent on the properties of the oil, and these are often reddish in color. These can be detected visually, providing useful information on the state of the oil. Oil-in-water emulsions can be seen as a coffee-colored cloud below the water surface. Other information gleaned from the oil appearance includes coverage and distribution on the surface.

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Oxazoline-based crosslinking reaction for coatings

Journal of Coatings Technology and Research ◽

10.1007/s11998-021-00479-9 ◽

2021 ◽

Author(s):

Philipp Knospe ◽

Patrick Böhm ◽

Jochen Gutmann ◽

Michael Dornbusch

Keyword(s):

Mechanical Properties ◽

Loss Modulus ◽

New Technology ◽

Sol Gel ◽

Polymer Network ◽

Time Dependent ◽

Crosslinking Reaction ◽

Coating Materials ◽

Rheological Measurements ◽

Excellent Adhesion

AbstractNowadays, coating materials must meet high demands in terms of mechanical, chemical and optical properties in all areas of application. Amongst others, amines and isocyanates are used as crosslinking components for curing reactions, meeting the highly demanding properties of the coatings industry. In this work, a new crosslinking reaction for coatings based on oxazoline chemistry is investigated with the objective to overcome disadvantages of established systems and fulfill the need for sustainable coating compounds. The oxazoline-group containing resin, synthesized from commercially available substances, undergoes cationic self-crosslinking polymerization to build up a network based on urethane and amide moieties. NMR-, IR- and ES-mass spectroscopy are suitable techniques to characterize the synthesized oxazoline monomers, which are linked to polyisocyanates and polymerized afterwards via self-polymerization. The progress of crosslinking is followed by changes in IR spectra and by rheological measurements to calculate time dependent values for storage and loss modulus. The glass transition temperature of the resulting coating is determined, too. Furthermore, sol–gel-analysis is performed to determine the degree of crosslinking. After application on steel and aluminium panels, application tests are performed. In addition to excellent adhesion to the substrate, the polymer network shows promising mechanical properties and with that it could represent a new technology for the coatings industry.

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An Oligoimide Particle as a Pickering Emulsion Stabilizer

Polymers ◽

10.3390/polym10101071 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1071 ◽

Cited By ~ 3

Author(s):

Yu-Jin Cho ◽

Dong-Min Kim ◽

In-Ho Song ◽

Ju-Young Choi ◽

Seung-Won Jin ◽

...

Keyword(s):

Particle Concentration ◽

Pickering Emulsion ◽

Pickering Emulsions ◽

Step Method ◽

Wetting Properties ◽

Emulsion Droplets ◽

Step Procedure ◽

Oil In Water ◽

One Step ◽

Oil Emulsions

A pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA)-based oligoimide (PMDA-ODA) was synthesized by a one-step procedure using water as a solvent. The PMDA-ODA particles showed excellent partial wetting properties and were stably dispersed in both water and oil phases. A stable dispersion was not obtained with comparison PMDA-ODA particles that were synthesized by a conventional two-step method using an organic solvent. Both oil-in-water and water-in-oil Pickering emulsions were prepared using the oligoimide particles synthesized in water, and the size of the emulsion droplet was controlled based on the oligoimide particle concentration. The oligoimide particles were tested to prepare Pickering emulsions using various kinds of oils. The oil-in-water Pickering emulsions were successfully applied to prepare microcapsules of the emulsion droplets. Our new Pickering emulsion stabilizer has the advantages of easy synthesis, no need for surface modification, and the capability of stabilizing both oil-in-water and water-in-oil emulsions.

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Naphthenic Acids: Formation, Role in Emulsion Stability, and Recent Advances in Mass Spectrometry-Based Analytical Methods

Journal of Analytical Methods in Chemistry ◽

10.1155/2021/6078084 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Roselaine Facanali ◽

Nathália de A. Porto ◽

Juliana Crucello ◽

Rogerio M. Carvalho ◽

Boniek G. Vaz ◽

...

Keyword(s):

Analytical Methods ◽

Oil And Gas ◽

Oil Quality ◽

Economic Value ◽

Oil And Gas Industry ◽

Naphthenic Acids ◽

Gas Industry ◽

Oil In Water ◽

Oil Emulsions ◽

Modern Analytical

Naphthenic acids (NAs) are compounds naturally present in most petroleum sources comprised of complex mixtures with a highly variable composition depending on their origin. Their occurrence in crude oil can cause severe corrosion problems and catalysts deactivation, decreasing oil quality and consequently impacting its productivity and economic value. NAs structures also allow them to behave as surfactants, causing the formation and stabilization of emulsions. In face of the ongoing challenge of treatment of water-in-oil (W/O) or oil-in-water (O/W) emulsions in the oil and gas industry, it is important to understand how NAs act in emulsified systems and which acids are present in the interface. Considering that, this review describes the properties of NAs, their role in the formation and stability of oil emulsions, and the modern analytical methods used for the qualitative analysis of such acids.

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