Rheological Behavior of Highly Filled EPDM Compounds with Calcium Carbonate, Carbon Black, Silica and Zinc Oxide

1996 ◽  
Vol 69 (4) ◽  
pp. 628-636 ◽  
Author(s):  
Li Li Li ◽  
James L. White
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Calcium Carbonate ◽  
Shear Rate ◽  
Carbon Black ◽  
Shear Viscosity ◽  
Volume Fraction ◽  
Carbonate Carbon ◽  
Yield Value ◽  
Yield Values

Abstract The shear viscosity, creep and constant shear rate transients have been measured for 0.20 volume fraction compounds of an EPDM with calcium carbonate, carbon black, silica and zinc oxide of similar particle size at 100°C. Measurements have been made in a creep sandwich instrument, pressurized rotational rheometer and a capillary rheometer and cover nine decades of shear rate. All of the compounds exhibit enhanced viscosities and yield values; i.e. there are stresses below which there is no flow. The greatest yield values and increased viscosities are with the compounds with calcium carbonate and zinc oxide. More extensive studies were made with the EPDM-calcium carbonate system, where it was shown that, increasing particle size reduces shear viscosity and yield values. Further, surface treating calcium carbonate with stearic acid signifcantly reduces the shear viscosity and yield value of the corresponding EPDM compound.

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Comparison of Reinforcing Efficiency between Calcium Carbonate/Carbon Black and Calcium Carbonate/Silica Hybrid Filled Natural Rubber Composites

2018 ◽  
Vol 382 ◽  
pp. 94-98 ◽  
Author(s):  
Sarawut Prasertsri ◽  
Chaiwute Vudjung ◽  
Wunchai Inthisaeng ◽  
Sansanee Srichan ◽  
Kanchana Sapprasert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Hybrid System ◽  
Hybrid Composites ◽  
Strength Increase ◽  
Hybrid Filler ◽  
Carbonate Carbon ◽  
Cure Time

The present research aimed to develop natural rubber (NR) hybrid composites reinforced with calcium carbonate/carbon black (CC/CB) and calcium carbonate/silica (CC/SC). The influence of CC/CB and CC/SC with various filler ratios (120/0, 90/5, 60/10, 30/15 and 0/20) on cure characteristics and mechanical properties of the vulcanizates was investigated and their reinforcing efficiency was compared. It has been found that incorporation of CB in the hybrid filler decreases the scorch time and cure time but increases crosslink density, whereas the incorporation of silica showed cure retardation. As CB or SC content increases, stiffness, tensile strength and tear strength increase, while elongation at break and compression set decrease. Scanning electron microscopy studies also reveal poor filler dispersion and poor adhesion between filler particles and matrix in the vulcanizates with increasing in CC content in a weight filler ratio which causes inferior mechanical properties. Incorporation of CB or SC content enhanced the mechanical properties of the vulcanizates, where CC/CB hybrid system exhibited higher reinforcing efficiency compared with CC/SC hybrid system.

Stability of Zinc Oxide Nanofluids Prepared with Aggregated Nanocrystalline Powders

2008 ◽  
Vol 8 (12) ◽  
pp. 6361-6366
Author(s):  
J. P. Leonard ◽  
S. J. Chung ◽  
I. Nettleship ◽  
Y. Soong ◽  
D. V. Martello ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Zinc Oxide ◽  
Brownian Motion ◽  
Preparation Method ◽  
Volume Fraction ◽  
High Volume ◽  
Nanocrystalline Powders ◽  
Zno Powder ◽  
20 Nm

Aqueous zinc oxide (ZnO) suspensions were prepared using a two-step preparation method in which an aggregated nanocrystalline ZnO powder was dispersed in water using a polyelectrolyte. The fluid showed anomalously high thermal conductivity when compared with the Maxwell and Hamilton-Crosser predictions. However, analysis of the particle size distribution showed that the fluid contained aggregated 20 nm crystallites of ZnO with a high volume fraction of particles larger than 100 nm. Sedimentation experiments revealed that particles settled out of the stationary fluid over times ranging from 0.1 hours to well over 10,000 hours. The size of the particles remaining in suspension agreed well with predictions made using Stoke's law, suggesting flocculation was not occurring in the fluids. Finally, a new concept of nanofluid stability is introduced based on the height of the fluid, sedimentation, Brownian motion and the kinetic energy of the particles.

Research of Thermal Conductivity and Tensile Strength of Carbon Black-Filled Nature Rubber

2009 ◽  
Vol 87-88 ◽  
pp. 200-205 ◽  
Author(s):  
Yan He ◽  
Zhong Yin ◽  
Lian Xiang Ma ◽  
Jun Ping Song
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Volume Fraction ◽  
Carbon Black Particle ◽  
Black Particle ◽  
The Difference ◽  
Thermal Conductivities

Through measuring the thermal conductivities and tensile strength of nature rubbers filled with carbon black and comparing with each other, it is shown that the difference of carbon black particle size and the structure affects on the thermal conductivity and tensile strength of nature rubber. Thermal conductivities of carbon black-filled nature rubber are enhanced with the increase of volume fraction of filler; tensile strength of composite increases first and then decreases with the increase of carbon black volume fraction.

Solvent Crack Growth in NBR Rubber

1976 ◽  
Vol 49 (5) ◽  
pp. 1324-1347 ◽  
Author(s):  
K. Nakashima ◽  
K. Manabe
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Crack Growth ◽  
Linear Function ◽  
Filler Loading ◽  
Square Root ◽  
Extension Ratio ◽  
Straight Lines ◽  
Highly Loaded

Abstract The solvent crack growth of rubber compounded with various carbon blacks or calcium carbonate was investigated. It was found that the rate of crack growth of filler-loaded rubber was linearly related to extension ratio in a manner similar to gum vulcanizates. The rate of crack growth passes through a minimum as the filler loading is increased. It is dependent on the particle size of the filler; smaller particles show much greater effect than coarser ones. When the rates of crack growth of highly loaded samples were plotted against the extension ratio, plots consisting of two straight lines with a bending point were obtained. It was found that the extension ratio at the bending point depended upon the loading and particle size of filler. It was a linear function of the square root of the distance between filler particles. The slope of the line above the bending point varies with type of filler: with carbon black the slope is steeper; with calcium carbonate it is less steep.

The Effect of Nano SiO2 Particle Size Distribution on Rheological Behaviour of Shear Thickening Fluids

2013 ◽  
Vol 58 (4) ◽  
pp. 1323-1326 ◽  
Author(s):  
A. Idźkowska ◽  
M. Szafran
Keyword(s):  
Particle Size ◽  
Shear Rate ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Volume Fraction ◽  
Ceramic Powder ◽  
Shear Thickening ◽  
Measuring System ◽  
Maximum Volume ◽  
Maximum Volume Fraction

Abstract In present work the influence of particle size distribution on the dilatant effect of shear thickening fluid was investigated. As a ceramic powder a mixture of silicas 200 and 7 nm in ratio 95:5, 90:10, 85:15, 80:20, 75:25, 50:50 was used. A dispersing agent was poly (propylene glycol) of a molecular weight of 425 g/mol. The as prepared slurries were examined on a rotational rheometer Kinexus Pro with a plate-plate measuring system at room temperature, where the viscosity as a function of shear rate was investigated. The measurement showed that by partially replacing greater particle size by smaller one, it is possible to shift the onset of shear thickening to the higher value of shear rate, however, the decreases of dilatant effect is observed. The influence of particle size distribution on a maximum volume fraction also was investigated. The maximum volume fraction which was passible to obtain was 35 vol%.

Dielectric Measurements in the Study of Carbon Black and Zinc Oxide Dispersion in Rubber

1939 ◽  
Vol 12 (2) ◽  
pp. 317-331
Author(s):  
A. R. Kemp ◽  
D. B. Herrmann
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Zinc Oxide ◽  
Dielectric Properties ◽  
Carbon Black ◽  
Water Soluble ◽  
Oxide Dispersion ◽  
Dielectric Measurements ◽  
Thermal Decomposition Process ◽  
Rubber Compounds

Abstract The dielectric constant, power factor, conductivity and d.c. resistivity of rubber compounds containing various types and quantities of zinc oxide and carbon pigments have been measured. It has been shown that the dielectric properties of rubber compounds having high loadings of zinc oxide depend on the particle size and purity of the zinc oxide used. The French process oxides with the smallest particle size were found superior to other grades. Water-soluble impurities in zinc oxide are shown to have a deleterious effect on dielectric properties, especially in the presence of moisture. The effect on dielectric properties of adding carbon black to a rubber compound has been shown to be dependent on the type and amount of black added, and on the nature of its dispersion in the rubber. The dielectric properties of rubber compounds containing “soft” black made by the thermal decomposition process are shown to be distinctly superior to, and widely different from, those of the same compounds containing equal amounts of channel process black. The general conclusion has been reached that the smaller the particle size and the better the dispersion of carbon pigments in the rubber, the greater will be the increase in the dielectric constant and conductivity, and the greater will be the decrease in resistivity.

Rheological Properties and Extrudate Swell of PHBV-Bagasse Composites

2014 ◽  
Vol 931-932 ◽  
pp. 83-89
Author(s):  
Rapeephun Dangtungee ◽  
Suchart Siengchin ◽  
Chayada Puritung
Keyword(s):  
Particle Size ◽  
Shear Stress ◽  
Shear Rate ◽  
Surface Treatment ◽  
Shear Viscosity ◽  
Extrudate Swell ◽  
Melt Mixing ◽  
Capillary Rheometry ◽  
Wide Range ◽  
Twin Screw

Polyhydroxybutylate-co-hydroxyvalerate (PHBV) is biodegradable aliphatic polyester that produced by a wide range of microorganism. In this research aims to study the melt rheological and extrudate swelling behavior of PHBV filled with bagasse. The composites prepared by melt mixing (Two roll mill and Twin screw extruder). The effects of processing techniques for PHBV powder and bagasse loading, aspect ratio (particle size i.e. x<150μm, 150<x<250μm and x>250μm) and, surface treatment of bagasse were investigated by capillary rheometry at 180 °C. The dispersion of the bagasse was inspected by the scanning electron microscopy (SEM). A different compositions based on PHBV/bagasse were investigated according to the following weight ratios, i.e. 100/0, 95/5, 90/10, 80/20 and 70/30 wt% respectively. The results showed that the PHBV/bagasse composites exhibit pseudoplastic behaviour as the shear stress and extrudate swell increased with increasing shear rate while shear viscosity decreased. The apparent shear stress and apparent shear viscosity increased with increasing bagasse loading and, at a given apparent shear rate, the apparent shear stress increased slightly with increasing bagasse particle size. However, detrimental bagasse agglomeration was clearly observed to take place for sample with bagasse loading in excess of 20 wt%. The surface treatment of bagasse was carried out using silane coupling agent and benzoic acid. The results proved the effect of functionalization on the interfacial adhesion between PHBV and bagasse. Also, there was also further confirmed by rheology behaviour and SEM-EDS image.

scholarly journals Theory for the rheology of dense non-Brownian suspensions: divergence of viscosities and– rheology

2019 ◽  
Vol 864 ◽  
pp. 1125-1176 ◽  
Author(s):  
Koshiro Suzuki ◽  
Hisao Hayakawa
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Stress Ratio ◽  
Volume Fraction ◽  
Microscopic Theory ◽  
Critical Behaviour

A systematic microscopic theory for the rheology of dense non-Brownian suspensions characterized by the volume fraction $\unicode[STIX]{x1D711}$ is developed. The theory successfully derives the critical behaviour in the vicinity of the jamming point (volume fraction $\unicode[STIX]{x1D711}_{J}$), for both the pressure $P$ and the shear stress $\unicode[STIX]{x1D70E}_{xy}$, i.e. $P\sim \unicode[STIX]{x1D70E}_{xy}\sim \dot{\unicode[STIX]{x1D6FE}}\unicode[STIX]{x1D702}_{0}\unicode[STIX]{x1D6FF}\unicode[STIX]{x1D711}^{-2}$, where $\dot{\unicode[STIX]{x1D6FE}}$ is the shear rate, $\unicode[STIX]{x1D702}_{0}$ is the shear viscosity of the solvent and $\unicode[STIX]{x1D6FF}\unicode[STIX]{x1D711}=\unicode[STIX]{x1D711}_{J}-\unicode[STIX]{x1D711}>0$ is the distance from the jamming point. It also successfully describes the behaviour of the stress ratio $\unicode[STIX]{x1D707}=\unicode[STIX]{x1D70E}_{xy}/P$ with respect to the viscous number $J=\dot{\unicode[STIX]{x1D6FE}}\unicode[STIX]{x1D702}_{0}/P$.

scholarly journals Mechanical and rheological properties of partial replacement of carbon black by treated ultrafine calcium carbonate in natural rubber compounds

2021 ◽  
Author(s):  
Vitor Peixoto Klienchen de Maria ◽  
Fábio Paiva ◽  
Flávio Camargo Cabrera ◽  
Carlos Toshiyuki Hiranobe ◽  
Gabriel Deltrejo Ribeiro ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Hybrid Composites ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Rubber Matrix ◽  
High Concentration ◽  
Carbonate Carbon

Abstract The present research aimed to develop natural rubber (NR) hybrid composites reinforced with treated ultrafine calcium carbonate/carbon black (CC/CB). The influence of CC/CB with various filler ratios (50/0, 40/10, 30/20, 20/30, 10/40 and 0/50) on mechanical properties and cure characteristics of the vulcanizates was investigated and their reinforcing efficiency was compared aiming to achieve the best ratio for CB partial substitution as compared to composites with CC and CB incorporated separately. The CC30/CB20 composites reached around to 17 MPa similar strength at break response compared to CC0/CB50 (16.83 MPa). Elongation at break increased 48% in relation to CC0/CB50. Hardness maintain similar values compare to high concentration of CB composites. Crosslink density results revealed similar chain number in rubber matrix representing better interaction between CC/CB. Scanning electron microscopy studies also reveal a good filler dispersion between filler particles and matrix. The results shown that the new material can be an alternative filler for partial substitution of CB conserving mechanical properties.

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