Rheological Behavior of Hybrid Rubber Nanocomposites

2005 ◽  
Vol 78 (5) ◽  
pp. 806-826 ◽  
Author(s):  
Abhijit Bandyopadhyay ◽  
Mousumi De Sarkar ◽  
Anil K. Bhowmick
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Die Swell ◽  
Experimental Conditions ◽  
Shear Rates ◽  
Silica Nanocomposites ◽  
Marginal Increment

Abstract Melt rheological behavior of acrylic rubber (ACM)/ silica and epoxidized natural rubber (ENR)/ silica hybrid nanocomposites prepared by using sol-gel technique at room temperature was studied for the first time in a Monsanto Processability Tester (capillary rheometer) at nine different shear rates and three different temperatures (100 °C, 110 °C and 120 °C). Tetraethoxysilane (TEOS) was used as the precursor for silica, and water to TEOS mole ratio was maintained at 2:1 throughout the experiments. The loading of TEOS was 10, 30 and 50 wt% with respect to the rubber and the pH of the medium was maintained in the range of 1.0–2.0 by the addition of appropriate amount of concentrated HCl. The shear viscosity showed marginal increment even at higher nanosilica loading for the rubber/ silica nanocomposites. All the compositions displayed pseudoplastic behavior and obeyed Power Law model within the experimental conditions. The reinforcement factor (RF) calculated from the ratio of the viscosities of the filled and the unfilled systems was found to increase with nanosilica content at a particular shear rate. ENR/ silica nanocomposites displayed higher increment of RF compared to ACM/ silica system, which may be due to better polymer-filler interaction in the former. The RF remained almost constant for both the systems with the variation of temperature. The die swell of the nanocomposites was always lower than that of the gum rubber sample, though the nature of variation of die swell with shear rates was different for ACM and ENR nanocomposites. In both the cases, the die swell was found to decease with increase in temperature. The variation in activation energy with the experimental shear rates was also calculated, where the hybrids displayed a decreasing trend in activation energy with the increase in shear rate.

Investigation on the Rheological Behavior of Polyamide6/Montmorillonite Nanocomposites by Reactive Extrusion

2011 ◽  
Vol 233-235 ◽  
pp. 1998-2001 ◽  
Author(s):  
Ming Zhao ◽  
Xiao Zhong Lu ◽  
Kai Gu ◽  
Xiao Min Sun ◽  
Chang Qing Ji
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Reactive Extrusion ◽  
Shear Thinning ◽  
Experimental Results ◽  
Montmorillonite Nanocomposites

The rheological behavior of PA6/montmorillonite(MMT) by reactive extrusion was investigated using cone-and-plate rheometer. The experimental results indicated that PA6/MMT exhibited shear-thinning behavior. The shear stress of both neat PA6 and PA6/MMT increased with the increase in the shear rate. The reduction of the viscous activation energy with the increase of shear stress reflected PA6/MMT can be processed over a wider temperature.

Characterization of the Rheological Behavior of Drilling Fluids

2020 ◽  
Author(s):  
Eric Cayeux ◽  
Amare Leulseged
Keyword(s):  
Shear Rate ◽  
Rheological Behavior ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Shear Rates ◽  
Operation Conditions ◽  
Fluid Systems ◽  
Different Temperatures ◽  
The One ◽  
Shear Stress Response

Abstract It is nowadays well accepted that the steady state rheological behavior of drilling fluids must be modelled by at least three parameters. One of the most often used models is the yield power law, also referred as the Herschel-Bulkley model. Other models have been proposed like the one from Robertson-Stiff, while other industries have used other three-parameter models such as the one from Heinz-Casson. Some studies have been made to compare the degree of agreement between different rheological models and rheometer measurements but in most cases, already published works have only used mechanical rheometers that have a limited number of speeds and precision. For this paper, we have taken measurements with a scientific rheometer in well-controlled conditions of temperature and evaporation, and for relevant shear rates that are representative to normally encountered drilling operation conditions. Care has been made to minimize the effect of thixotropy on measurements, as the shear stress response of drilling fluids depends on its shear history. Measurements have been made at different temperatures, for various drilling fluid systems (both water and oil-based), and with variable levels of solid contents. Also, the shear rate reported by the rheometer itself, is corrected to account for the fact that the rheometer estimates the wall shear rate on the assumption that the tested fluid is Newtonian. A measure of proximity between the measurements and a rheological model is defined, thereby allowing the ranking of different rheological behavior model candidates. Based on the 469 rheograms of various drilling fluids that have been analyzed, it appears that the Heinz-Casson model describes most accurately the rheological behavior of the fluid samples, followed by the model of Carreau, Herschel-Bulkley and Robertson-Stiff, in decreasing order of fidelity.

scholarly journals Viscosity and biodiesel characteristics of wild Canarium schweinfurthii Engl. fruit oil  

2018 ◽  
Vol 64 (No. 4) ◽  
pp. 169-175
Author(s):  
Ehiem James Chinaka
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Medical Model ◽  
Temperature Stability ◽  
Oil Viscosity ◽  
Shear Rates ◽  
Flow Behaviour Index ◽  
Different Temperatures ◽  
Fruit Oil ◽  
Behaviour Index

The viscosity of two varieties of Canarium schweinfurthiiEngl. fruits oil (large and long) were studied at four different temperatures (30, 40, 50 and 60<sup>o</sup>C) and three shear rates (7.91, 15.82 and 39.54 s<sup>–1</sup>). SurgiFriend Medical (model NDJ-5S) viscometer was used to carry out the study. Biodiesel characteristics of the oil were also investigated. The results showed that variety had no effect (P &lt; 0.05) on the viscosity of Canarium schweinfurthii Engl. fruit while temperature had especially at 50<sup>o</sup>C and above. The shear rate of 15.82 s<sup>–1 </sup>(12 rps) gave the lowest oil viscosity for both varieties. The oil from large fruit had the best temperature stability, low percentage viscosity (6.33%) variation and least activation energy (796.51 J·mol<sup>–1</sup>·K<sup>–1</sup>) while long variety had best biodiesel characteristic for safe handling. Temperature had no significant (P &lt; 0.05) effect on the consistency coefficient (C) and flow behaviour index (n) of both varieties of Canarium schweinfurthii Engl. fruits oil. Besides, oil from both fruit varieties is Newtonian fluids.

Rheology and Component Interactions in Tape Casting Slurries

1985 ◽  
Vol 60 ◽  
Author(s):  
John R Morris ◽  
W Roger Cannon
Keyword(s):  
Shear Rate ◽  
Rheological Behavior ◽  
Tape Casting ◽  
Relative Viscosity ◽  
Shear Rates ◽  
Viscosity Measurements ◽  
The Stability ◽  
Low Shear

AbstractRheology and the component interactions which affect rheology were studied for a tape casting composition similar to commercial systems. Viscosity measurements at different shear rates were compared to measured tape properties to determine if high or low shear rate rheological behavior controls tape characteristics. Relative viscosity was measured to assess the contribution of each component to the stability of the dispersion.

SHEARING EFFECTS ON THE ELECTRORHEOLOGICAL RESPONSE

2001 ◽  
Vol 15 (06n07) ◽  
pp. 930-937 ◽  
Author(s):  
K. TANAKA ◽  
S. HASHIMOTO ◽  
T. TAKENOUCHI ◽  
I. SUGIMOTO ◽  
A. KUBONO ◽  
...  
Keyword(s):  
Shear Rate ◽  
Electric Field ◽  
Transient Response ◽  
Stress Responses ◽  
Experimental Conditions ◽  
Transient Stress ◽  
Shear Rates ◽  
Lower Shear ◽  
Mason Number ◽  
The Individual

The steady and transient stress responses were investigated from lower shear rates to higher shear rates at a given strength of the electric field, and the individual experimental conditions were reduced to Mason number ( M n). The electro-rheological response was found in the region with higher M n of the order of 10, and the transient response became faster as the shear rate increased. These results show that the effect of chance of collision among the polarized particles would play an important role even in the region.

Effect of temperature on the rheological behavior of sugary cassava

2020 ◽  
pp. 125
Author(s):  
Leiliane do Socorro Sodré Souza ◽  
Tatiane Pereira de Souza ◽  
Rafael Lopes e Oliveira ◽  
Sérgio Duvoisin Junior ◽  
Ari de Freitas Hidalgo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Food Production ◽  
Arrhenius Equation ◽  
Effect Of Temperature ◽  
Rheological Models ◽  
Rate Range ◽  
Fermented Beverages ◽  
Three Samples

The rheological behavior of the juice extracted from sugary cassava roots, a type of cassava that stored the largest amount of sugars and the starch as it was, at various temperatures (9-65ºC) and in concentrations of 5ºBrix, 10.5ºBrix, and 18.5ºBrix. The experiments were performed on a Brookfield viscometer in a shear rate range of 0.01-237.6 s-1. The rheological models of Newton, Bingham, and Ostwald-De-Waele were fitted to the experimental results. The Newton model describes well the rheological behavior of the three samples evaluated. The effect of temperature on viscosity was evaluated using an Arrhenius equation; the viscosity value is influenced by the same temperature. The activation energy values ​​for the concentrations of 5ºBrix, 10.5ºBrix and 18.5ºBrix correspond to 3.14 kcal mol-1, 3.53 kcal mol-1 and 3.71 kcal mol-1. This type of cassava can be used in the production of ethanol, fermented beverages and syrups. It is also an important alternative for food production, as the cultivation of cassava can be classified as less aggressive to the environment, in comparison with sugarcane.

An Influence of a Binder System to the Rheological Behavior of the SS316L Metal Injection Molding (MIM) Feedstock

2011 ◽  
Vol 264-265 ◽  
pp. 554-558 ◽  
Author(s):  
Khairur Rijal Jamaludin ◽  
Norhamidi Muhamad ◽  
Hooman Abolhasani ◽  
Hadi Murthadha ◽  
Mohd Nizam Ab. Rahman
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Injection Molding ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Metal Injection Molding ◽  
Binder System ◽  
Flow Behavior Index ◽  
Injection Molded

The influence of a binder system to the rheological behavior of a Metal Injection Molding (MIM) feedstock is presented in the paper. The binder systems used are: a) PEG & PMMA b) Palm stearin & LLDPE and, c) Tapioca starch & LLDPE. The viscosity and shear rate of the feedstocks were measured at various range of temperature and shear rate across the L/D = 10 capillary rheometer. The flow behavior index, n and activation energy, E of each feedstock were measured to show its significance as MIM feedstock. Generally, the result indicates all feedstock exhibits a shear thinning behavior and the binders are suitable as MIM binder. Additionally, the present paper has discovered that the binder system does not have much influence to the activation energy. In order to show the relevance of the rheological behavior to the actual injection molding performance, green parts has been injection molded and the result shows an agreement with the rheological behavior result.

Solution Rheology of Poly(vinyl alcohol)/Silica Hybrid Nanocomposites

2005 ◽  
Vol 13 (5) ◽  
pp. 429-442
Author(s):  
Abhijit Bandyopadhyay ◽  
Mousumi De Sarkar ◽  
Anil K. Bhowmick
Keyword(s):  
Vinyl Alcohol ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Solution Viscosity ◽  
Poly Vinyl Alcohol ◽  
Silica Nanocomposites ◽  
Teos Concentration ◽  
Ph Range ◽  
Increasing Temperature ◽  
Silica Hybrid

The solution behavior of polymer/silica hybrid nanocomposites was investigated using a Brookfield viscometer. The nanocomposites were prepared using the sol-gel technique with tetraethoxysilane (TEOS) as the precursor for silica. The sol-gel reaction was carried out in the pH range of 1.0-2.0, which was maintained by the addition of concentrated HCl. Poly (vinyl alcohol) (PVA)/silica nanocomposites demonstrated a bigger rise in solution viscosity after continuous measurement for five days than either- acrylic rubber (ACM)/silica or epoxidised natural rubber (ENR)/silica nanocomposites. Detailed investigation of the PVA/silica system indicated that it exhibited Newtonian behaviour when the solutions contained (5 or 7.5 wt% of PVA,) even when increasing the TEOS concentration to 50 wt%, although at one particular TEOS concentration (10 wt%), the nanocomposite was pseudoplastic when the concentration of PVA was increased to 10 wt%. The reinforcement factor [Formula: see text] for those PVA/silica hybrid nanocomposites containing 5 wt% of PVA deviated strongly from the Guth-Smallwood prediction. Instead they obeyed a relationship of the type ηmax = η0(1 + aϕb), where a = 4.45 and b = 0.38, calculated for this system. The viscosity decreased with increasing temperature for both PVA and the representative nanocomposite with 30 wt% TEOS (PVA30), although the activation energy for flow of the nanocomposite did not vary to a great extent.

scholarly journals Study rheological behavior of refined rapeseed oil

2020 ◽  
Vol 2 (2) ◽  
pp. 20-24
Author(s):  
Ioana Stanciu
Keyword(s):  
Shear Rate ◽  
Constant Temperature ◽  
Rheological Behavior ◽  
Dynamic Viscosity ◽  
Rapeseed Oil ◽  
Refining Process ◽  
Shear Rates ◽  
Lower Viscosity ◽  
Viscosity Dependence

Extracted from rapeseed oil was subjected to purification and refining process and then characterized in terms of rheological, ie dynamic viscosity dependence study in terms of speed shear constant temperature. The results show that at 400C, 600C, 800C and 900C dynamic viscosities of oil decreases with shear rate. At higher shear rates of 20s-1 shows lower viscosity oil fluctuations, became almost constant.  

Analysis of the Rheological Behavior and Stability of Inconel 718 Powder Injection Molding (PIM) Feedstock

2014 ◽  
Vol 879 ◽  
pp. 63-72 ◽  
Author(s):  
Ahmad Nizam bin Abdullah ◽  
Nurhaslina binti Johari ◽  
Muhammad Jabir bin Suleiman Ahmad ◽  
Rosdi Ibrahim ◽  
Abdul Rahim Abu Talib
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Inconel 718 ◽  
Powder Injection ◽  
Capillary Rheometer ◽  
Binder System ◽  
Flow Activation Energy ◽  
Flow Activation ◽  
Ability Index

In PIM process, the molding stage is a critical step for the fabrication of sound parts without cracks and distortions. So, this step requires specific rheological behavior. Rheological analysis can be made to quantify the stability of the PIM feedstock during molding process. In this study, an experimental rheological study has been performed to evaluate the influence of palm stearin on the rheological behavior and stability of Inconel 718 powder injection molding (PIM) feedstock. The effects of shear rate and temperature were investigated via capillary rheometer method. The viscosity and shear rate of the feedstock were measured at various range of temperature and shear rate across the L/D = 1 capillary rheometer. The results show that the formulation binder system PSPE 7030 is the best feedstock to be injection molded because it has moderate value of flow sensitivity index, lower value for flow activation energy and higher value for mold ability index. Besides that, the increasing of PS content in the binder system has found reduce viscosity and value of flow activation energy and increase value of mold ability index of feedstock.

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