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.

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.

Effect of Brown Vulcanized Vegetable Oil on Ozone Resistance, Aging, and Flow Properties of Rubber Compounds

1987 ◽  
Vol 60 (1) ◽  
pp. 159-175 ◽  
Author(s):  
Samir H. Botros ◽  
Fawzia Fabd El-Mohsen ◽  
Eberhard A. Meinecke
Keyword(s):  
Tensile Strength ◽  
Soybean Oil ◽  
Linseed Oil ◽  
Acetone Extract ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
High Concentrations ◽  
Ozone Resistance ◽  
Free Sulfur

Abstract The addition of accelerator to vegetable oils during the preparation of brown V.V.O. results in a decrease of the free sulfur and the acetone extract values of the obtained V.V.O. In addition, the reaction time necessary to achieve the gel state is reduced. NR vulcanizates containing brown V.V.O. based on soybean oil are superior in retention of their tensile strength and 100% modulus after aging to those containing V.V.O. based on boiled linseed oil and dehydrated castor oil. The heat resistance of NR vulcanizates which contain brown V.V.O. increases as the amounts of the free sulfur and the acetone extract in the V.V.O. decrease. Addition of small amounts of brown V.V.O. to NR and SBR compounds helps to maintain the tensile strength after aging. However, the addition of high concentrations of the V.V.O. reduces the aging properties. The addition of brown V.V.O. based on soybean oil and TMTD to NR compounds used for the manufacture of printer rolls and rubber hoses enhances the ozone resistance of the rubber vulcanizates. Furthermore, the addition of this type of V.V.O. to NR and SBR compounds is advantageous because of: (1) delay of the onset of melt fracture, (2) reduction of extrudate swell, (3) smoother extrudate surfaces, (4) dimensional stability of NR and SBR extrudates.

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.

scholarly journals Rheological Properties of Polysaccharides from Longan (Dimocarpus longanLour.) Fruit

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Xingxun Liu ◽  
Yongyue Luo ◽  
Chunjie Zha ◽  
Sumei Zhou ◽  
Liya Liu ◽  
...  
Keyword(s):  
Shear Rate ◽  
Chemical Analysis ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Small Amplitude ◽  
Flow Behavior ◽  
Viscoelastic Behavior ◽  
Dynamic Shear ◽  
Small Amplitude Oscillatory Shear

Longan polysaccharide (LP) was extracted from longan (Dimocarpus longanLour.) pulp. The composition and rheological properties were determined by chemical analysis and dynamic shear rheometer. The flow behavior and viscoelastic behavior of longan polysaccharide (LP) solution were investigated by steady shear and small amplitude oscillatory shear (SAOS) experiments, respectively. The result shows that the solution is a pseudoplastic flow in a range of shear rate (1–100 s−1). The rheological behavior of LP was influenced by cations such as Na+and Ca2+. With an increase of apparent viscosity,G′andG′′were accompanied by addition of Na+and Ca2+.

Study on the Rheological Properties of PTFE/PVA Blended Solution

2011 ◽  
Vol 233-235 ◽  
pp. 2934-2937
Author(s):  
Yao Wu Wang ◽  
Run Jun Sun ◽  
Zhao Huan Zhang ◽  
Li Ping Chen ◽  
Mu Yao
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Shear Thinning Fluid

PTFE suspension latex and PVA solution are blended at different ratio, and the rotary rheometer is used to test the rheological properties of these solutions. The result shows that both PTFE suspension latex and PTFE/PVA blended solution are all shear thinning fluid; with increasing shear rate, apparent viscosity decreases; with increase of PVA content in blended solution, apparent viscosity and Non-Newtonian index increase, and spinnability of blended solution can be improved; with increase of temperature, the apparent viscosity decreases.

Rheological Properties of all Para-Position Polysulfonamide Spinning Solutions

2014 ◽  
Vol 941-944 ◽  
pp. 1233-1236
Author(s):  
Hu Min Li ◽  
Jiong Xin Zhao
Keyword(s):  
Mechanical Properties ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Solvent System ◽  
Para Position ◽  
Aprotic Solvents ◽  
Terephthaloyl Chloride ◽  
Static State

Our previous research showed that the presence of more rigid segments of p-phenylene in the PSA copolymer backbone enhanced the strength and modulus of the fiber. Poly (4,4'-diphenylsulfone terephthalamide) referred to as all para-position PSA, which was synthesised only by 4,4'-diaminodiphenylsulfone (4,4’-DDS) and terephthaloyl chloride (TPC), and it was expected to have best mechanical properties. As it cannot be easily dissolved in common amide-type polar aprotic solvents, N,N-dimethylacetamide (DMAc)/LiCl and DMAc/CaCl2 solvent system was used to solve this problem. Static state rheological properties of all para-position PSA spinning solutions were investigated by measuring the apparent viscosity versus shear rate at different concentrations and temperatures. The effectiveness of cosolvent like LiCl and CaCl2 in the solvent system were investigated, the results showed that LiCl was more effective than CaCl2.

scholarly journals Study on the Effect of the Oil-Water Ratio on the Rheological Properties of Hydroxyethyl Cellulose (HEC)

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Xiaoming Su ◽  
Zhanghua Lian ◽  
Yuan Yuan
Keyword(s):  
Thermal Stability ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Water Solution ◽  
Drilling Fluid ◽  
Hydroxyethyl Cellulose ◽  
Water Emulsion ◽  
Oil Water ◽  
Water Ratio

Hydroxyethyl cellulose (HEC) is widely used in water-base drilling fluid as tackifier because of its good fluidity, stability, prop-carrying capacity, and good reservoir protection, while it has insufficient rheological property under higher temperature. In order to make use of its advantages and improve thermal stability, an innovative method that HEC was dissolved in the emulsion was proposed. Research indicated that compared with traditional water solution, the oil-water emulsion as solution could effectively improve the rheological properties and thermal stability. The oil-water ratio has an obvious effect on rheological properties. Firstly, with the decrease in the oil-water ratio, the apparent viscosity and shear stress were decreased; secondly, under constant oil-water ratio or temperature, the larger the shear rate, the lower the apparent viscosity, and the greater the shear strength; lastly under extremely low shear rate, HEC emulsion’s viscosity peaked at more than 50000 mPa·s, which can effectively solve the problem of sand carrying difficulty and being easy to form sand bed in horizontal well and high angle hole. In addition, the emulsifying stability was degradative with the increase in the oil-water ratio. The degradation was not obvious when the oil-water ratio was less than 30 : 70. On the contrary, the performance deteriorated drastically when the oil-water ratio was greater than 30 : 70. The separator liquid was more than 2 cm and was even about 1/3 when the oil-water was 50 : 50. On the basis of analysis of the experimental results, we can see that oil-water emulsion could effectively improve the rheological stability and thermal stability of HEC and the optimal oil-water ratio was 30 : 70. This study provided a new thought for application of HEC or other polymers in drilling fluid.

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).

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