Chemical Composition and Some Rheological Properties of Mesona Blumes Gum

2007 ◽  
Vol 13 (1) ◽  
pp. 55-61 ◽  
Author(s):  
T. Feng ◽  
Z. B. Gu ◽  
Z. Y. Jin
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Uronic Acid ◽  
Extraction Yield ◽  
Total Sugar ◽  
Distilled Water ◽  
Crude Fibre ◽  
Sugar Addition

A gum was extracted from the leaves of Liangfen Cao ( Mesona Blumes), the extraction yield was 29.36%. The crude gum contains 9.74% protein, 30.89% ash, 2.98% crude fibre and 42.19% total sugar (w/w). Monosaccharide components of the gum were mainly galactose, glucose, arabinose and uronic acid with mole ratios of 3.1:2.3:2.3:1.4, respectively. Minerals in the ash were mainly 40.26mg/g sodium, 10.57mg/g potassium, 1.42mg/g magnesium and 2.81mg/g calcium. Molecular weight of the two fractions of the gum were 16,264 and 7,372 Da, respectively. The intrinsic viscosity of the gum was 91.01 mL/g in distilled water at 25°C. Its rheological properties were dependent on shear rate, gum concentration, sugar, temperature, pH, and salt. The gum exhibited pseudoplastic behaviour with shear rate increment. The apparent viscosity increased with the increase of the gum concentration, also increased with the sugar addition and varied according to pH, the highest viscosity was reached at pH 10.0 and the lowest at pH 6.0. Decrease of apparent viscosity was observed with increase of temperature. The activation energy of 10% (w/w) gum was 17.58kJ/mol. The apparent viscosity decreased with Na+ addition and also with the addition of [Ca++]<1%, while it increased with the addition of [Ca++]> 1% (w/w).

Rheological Study on of PBT with High Melt Flow Index

2012 ◽  
Vol 487 ◽  
pp. 644-648
Author(s):  
Yuan Liu ◽  
Lin Wang ◽  
Qing Yan Xu ◽  
Pei Jie Lin ◽  
Zhi Hong Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Apparent Viscosity ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Flow ◽  
Flow Activation Energy ◽  
Nonwoven Fabrics ◽  
Flow Activation ◽  
High Flexibility

Melt-blown generated PBT nonwoven fabrics usually have small fibril diameter, high flexibility, well heat and oil resistance. Therefore, they would have promising application such as vehicle filtering media. The rheological behavior of PBT with High Melt Flow Index for Melt-blown is investigated in this paper. It is a direction of the technology design and fabrication parameters .The relation of apparent viscosity and shear rate is analyzed, as well as flow activation energy and Non-Newtonian indexes. The results suggest that PBT with High Melt Flow Index is Non-Newtonian fluid. Apparent viscosity and flow activation energy show gradually decrease with increasing shear rate, exhibiting typical shear-thinning behavior.

Effect of glycerol concentration and temperature on the rheological properties of cassava starch solutions

2013 ◽  
Vol 33 (2) ◽  
pp. 141-148 ◽  
Author(s):  
Germán Ayala Valencia ◽  
Ana Cecilia Agudelo Henao ◽  
Rubén Antonio Vargas Zapata
Keyword(s):  
Activation Energy ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Weight Ratio ◽  
Exponential Model ◽  
Cassava Starch ◽  
Flow Index ◽  
Glycerol Concentration ◽  
Glycerol Content ◽  
All Solutions

Abstract Glycerol/starch (G/S) solutions were prepared at different concentrations, with a weight ratio of G/S=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, and rheological properties were analyzed at 30, 40, 50, 60 and 70°C. Power law dependency of the apparent viscosity as a function of the shear rate is the most appropriate model for describing the rheological behavior of cassava starch solutions as a function of glycerol concentrations. All solutions showed a pseudoplastic behavior; the flow index (n) did not show significant changes as a function of temperature and glycerol concentration. However, the apparent viscosity (μa) and the consistency coefficient (K) did show strong variations with temperature and glycerol content. The temperature variation of both μa and K were better fitted to an exponential model type exp(Ea /RT), logμa(K) vs. 1000/T. The activation energy of the K data for the solution without glycerol (G/S=0.0) was 13.64 KJ/mol, and it decreased with increasing the content of glycerol in the solutions, becoming 6.14 KJ/mol for G/S=0.5. On the contrary, the activation energy for the μa data increased when increasing the glycerol concentration. The effect of glycerol concentration was also modeled using polynomial and exponential fittings.

Torque rheological properties of polypropylene/cocoa pod husk composites

2015 ◽  
Vol 30 (9) ◽  
pp. 1217-1227 ◽  
Author(s):  
Koay Seong Chun ◽  
Salmah Husseinsyah ◽  
Chan Ming Yeng
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Properties ◽  
Filler Content ◽  
Wood Composites ◽  
Rotor Speed ◽  
Processing Parameter ◽  
Maleated Polypropylene ◽  
Cocoa Pod Husk ◽  
Power Law Index

The torque rheological properties of plastic wood composites are important to practical processing, but the research in this field is rare. In present, a Brabender plastrograph torque rheometer was used to analyse the rheological behavior of polypropylene (PP)/cocoa pod husk (CPH) composites. The effect of processing parameter, filler content, and addition of maleated polypropylene (MAPP) on torque rheological properties was investigated. The torque rheological data found that the processing torque increased with the increases of rotor speed, filler content, and addition of MAPP. The PP/CPH composites melt behavior as pseudoplastics and shear thinning occurred at higher shear rate. The decrease of power law index ( n) evidenced the pseudoplasticity of PP/CPH composites increased at higher filler content and presence of MAPP. The increase of viscosity on PP/CPH was due to filler–filler interaction at higher filler content and strong filler–matrix adhesion after addition of MAPP. The activation energy of PP/CPH composites also increased with higher amount of CPH and addition of MAPP.

Rheology of pulp suspensions of bleached sugarcane bagasse: Effect of consistency and temperature

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 601-606 ◽  
Author(s):  
JORGE H. SÁNCHEZ ◽  
GERMÁN C. QUINTANA ◽  
MERY E. FAJARDO
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Sugarcane Bagasse ◽  
Power Law ◽  
Apparent Viscosity ◽  
Power Law Model ◽  
Pulp Suspensions ◽  
Concentric Cylinders ◽  
Rate Controlled

Rheological properties, such as yield stress and apparent viscosity, of pulp suspensions of bleached sugarcane bagasse were studied in a stress-shear rate controlled rheometer using concentric cylinders geometry. Results were statistically analyzed and presented as a function of the suspension consistency (0.5% ≤ Cm ≤ 4.0%) and temperature (20°C, 40°C, and 60°C). The yield stress was influenced by the consistency and temperature. The apparent viscosity was influenced only by the consistency. A power law model was fitted to the experimental results of yield stress. In flow tests, all the suspensions showed shear-thinning behavior, which was in agreement with the Carreau-Yasuda model.

Flow Properties and Melt Distortion in Molten Rubber Compounds under Capillary Extrusion

2013 ◽  
Vol 747 ◽  
pp. 627-630
Author(s):  
Watcharapong Chookaew ◽  
Yanichsa Sukniyom ◽  
Somjate Patcharaphun ◽  
Narongrit Sombatsompop
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Wall Slip ◽  
Skin Layer ◽  
Rubber Compound ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
Capillary Extrusion

The influences of shear rate and vulcanizing system on the rheological properties and melt fracture of natural rubber compounds were investigated by using a rate-controlled capillary rheometer. The rheological properties of rubber compounds were characterized with respect to the apparent viscosity and extrudate swell. The measured results indicated that the apparent viscosity tended to decrease with increasing shear rate. This was due to the pseudoplastic behavior of molten rubber compound. It was evident that rubber compound using EV system showed the lowest apparent viscosity as compared to those obtained by CV and NS systems, respectively. This was due to the occurrences of premature crosslink at the skin layer and the wall slip of rubber compound during the flow in capillary die. Furthermore, the onset of smooth surface was also observed which depending on the types of crosslink at the skin layer.

The Rheological Behaviors of Nylon610 and Nylon610/Montmorillonite Nanocomposites

2011 ◽  
Vol 183-185 ◽  
pp. 1726-1730 ◽  
Author(s):  
Qian Wang ◽  
Cheng Shen Zhu ◽  
Ping Du ◽  
Su Qin He
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Apparent Viscosity ◽  
Effect Of Temperature ◽  
Pseudoplastic Fluid ◽  
Rheological Behaviors ◽  
Lower Shear ◽  
Lower Shear Rate ◽  
Montmorillonite Nanocomposites

The rheological behaviors of nylon610 and nylon610/montmorillonite nanocomposites had been studied by means of HAAKE-Ⅱrheometer. The results showed that nylon610 and nylon610/montmorillonite composites were pseudoplastic fluid. The non-Newtonian indexes, which were in the range of 0.49～0.82 at differern temperatures, decreased with the addition of montmorillonite. What is more, the apparent viscous activation energy decreased, which showed the effect of temperature on apparent viscosity of the nanocomposites was weaker than that of pure nylon610, apparent viscosity increased with the increase of montmorillonite, especially at the lower shear rate.

Effect of Drying Methods on the Rheological Properties of Sugar Beet Pulp Pectin

2017 ◽  
Vol 13 (4) ◽  
Author(s):  
Xin Huang ◽  
Dong Li ◽  
Li-jun Wang ◽  
Benu Adhikari ◽  
Xiao Dong Chen
Keyword(s):  
Activation Energy ◽  
Sugar Beet ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Angular Frequency ◽  
Sugar Beet Pulp ◽  
Creep Recovery ◽  
Drying Methods ◽  
Hot Air ◽  
Beet Pulp

Abstract The effect of drying methods on the rheological properties (apparent viscosity, storage (G′) and loss (G″) moduli, creep behavior) of sugar beet pulp pectin (SBPP) was investigated using steady shear, frequency sweep, activation energy and creep-recovery tests. SBPP was extracted from sugar beet and dried using freeze (FD), hot air (HD), vacuum (VD) and spray (SD) drying methods. The HD sample showed highest apparent viscosity and the VD sample had the highest activation energy. The 1 % (w/v) samples had higher activation energy than 2 % (w/v) samples. The G′ and G″ versus angular frequency data followed the Power Law model reasonably well (R2 > 0.915). The FD sample deformed the most during the creep test.

A Rheological Model of Semisolid Magnesium Alloy Slurries

2005 ◽  
Vol 488-489 ◽  
pp. 333-336 ◽  
Author(s):  
L. Li ◽  
X.W. Zhou ◽  
J.Y. Chen
Keyword(s):  
Magnesium Alloy ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Rheological Model ◽  
The State ◽  
Simple Shearing ◽  
Flow Conditions ◽  
Rheological Behaviors ◽  
Microstructure Model

In this paper a rheological model is presented which describes the rheological behaviors of liquid-like semisolid magnesium alloy under a simple shearing flow. On the basis of Chen and Fan’s mono-dispersion microstructure model of semisolid metal slurry, the particle size distribution is considered in this model. It is believed that it is the state of agglomeration which determines the rheological behaviors of the slurry, whereas the external flow conditions such as shear rate and shearing time, affect the rheological properties by changing the state of agglomeration. The expressions of collision rate between two agglomerates, effective solid fraction and the formula of apparent viscosity of Chen and Fan’s model are corrected according to the experimental results and statistical mechanics. Finally calculated apparent viscosity and the average number of the particles of AZ91D by the developed model as functions of shear rate are presented. These results show that there is a one to one coupling between the rheological properties of the magnesium alloy slurries and the state of the agglomeration.

Physical and Rheological Properties of Animal Manure: A Review

2018 ◽  
Vol 61 (3) ◽  
pp. 1113-1120
Author(s):  
Ibrahim Denka Kariyama ◽  
Xiaodong Zhai ◽  
Binxin Wu
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Pressure Head ◽  
Animal Manure ◽  
Anaerobic Treatment ◽  
Pseudoplastic Fluid ◽  
Power Law Equation

Abstract. This literature review was conducted on the physical and rheological properties of animal manure slurries and their applications. The review revealed the importance of these properties in the design of anaerobic treatment plants, pipe systems to transport slurries to treatment and storage units, and other applications and management of raw and treated slurries. The selection of pumping and mixing equipment and their power requirements, the flow behavior, mass, and heat transfer, the quality of mixing, pressure head loss, and other applications of manure slurries are affected by the physical and rheological properties. The review shows that manure slurries generally exhibit non-Newtonian pseudoplastic fluid behavior with a decreasing apparent viscosity as the shear rate increases and that the power law equation can successfully be used to describe the relationship between shear stress and shear rate, especially for low total solids concentrations. Keywords: Animal manure slurries, Apparent viscosity, Non-Newtonian pseudoplastic fluids, Power law equation, Rheological properties.

Characterization of Cellulose Nanocrystal Suspension Rheological Properties Using a Rotational Viscometer

2021 ◽  
Vol 71 (3) ◽  
pp. 290-297
Author(s):  
Yucheng Peng ◽  
Changlei Xia ◽  
Brian Via
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Cellulose Nanocrystal ◽  
Rotational Viscometer ◽  
Spindle Rotation ◽  
Quality Control Tool ◽  
Calculation Results

Abstract Interest in cellulose nanocrystal (CNC) recently has been growing significantly. Many applications have been developed for CNC and appropriate procedures to handle the CNC suspensions are critical for these applications. In this study, we explored a method evaluating CNC suspensions based on rheological property characterization. We used a rotational viscometer to characterize CNC suspensions at concentrations of 3, 4, 5, and 6 wt.%. We collected primary readings from the rotational viscometer, including spindle rotation speed and torque, to generate apparent viscosity and shear rate for CNC suspensions. We applied three different methods summarized from the literature to calculate apparent viscosity and real shear rate. We critically analyzed differences among calculation results from the three methods. Shearing thinning behaviors obeyed the power law flow model for all CNC suspensions in the shear rate tested. At different concentrations, consistency and flow behavior indices in the model differed in the measured shear rate range. With the same shear rate, higher concentration CNC suspension had a higher apparent viscosity. The apparent viscosity of the CNC suspension was associated with its weight concentration in a power law relationship. This study indicated that a rotational viscometer can be used as a quality control tool for characterizing the rheological properties of the CNC suspensions. We made recommendations for using appropriate calculation methods to obtain shear rate and apparent viscosity of CNC suspensions from the primary readings of a rotational viscometer under different situations.

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