Microwave Diagnosis of Carbon Black Rubber Compounds and Porosity Estimation in Composites

1994 ◽  
Vol 347 ◽  
Author(s):  
Reza Zoughi ◽  
S. I. Ganchev ◽  
J. Bhattacharyya ◽  
S. Gray ◽  
D. Radford
Keyword(s):  
Dielectric Properties ◽  
Carbon Black ◽  
Volume Fraction ◽  
Wide Frequency Range ◽  
Model Material ◽  
Volume Percentage ◽  
Measurement Analysis ◽  
Rubber Compounds ◽  
Wide Range ◽  
5 Ghz

ABSTRACTThe results of an in depth study of the dielectric properties of various rubber compounds at different microwave frequencies are discussed. Subsequently, the influence of carbon black volume percentage on the dielectric properties of rubber is studied in a wide frequency range (5 -24 GHz). The results show that the real and imaginary parts of rubber dielectric constant increase as a function of increasing carbon black percentage. Frequencies around 5 GHz show more sensitivity to small changes in the carbon volume content. The presence of curatives in uncured rubber samples is detected, which is an indication of the sensitivity of microwaves to the chemical reaction triggered by these curatives. Similar approach is used to measure the air content in specially prepared model material (plastic microbaloon-filled epoxy) samples with varying degrees of uniformly distributed air inclusion. The results of these measurements for a wide range of frequencies is also reported. Measurement analysis resulted in detecting variation in the air volume fraction of around 1.5%. The results confirm the utility of microwave NDE techniques for local porosity detection and evaluation in dielectric composites.

Use of χ As a Function of Volume Fraction of Rubber to Determine Crosslink Density by Swelling

2003 ◽  
Vol 76 (4) ◽  
pp. 832-845 ◽  
Author(s):  
William L. Hergenrother ◽  
Ashley S. Hilton
Keyword(s):  
Carbon Black ◽  
Metal Oxides ◽  
13C Nmr ◽  
Crosslink Density ◽  
Volume Fraction ◽  
Good Measure ◽  
Noticeable Effect ◽  
Wide Range ◽  
The Relationship

Abstract A technique is described allowing a relatively simple determination of χ as a function of vr from swelling in heptane. A good measure of the true νe of the cured elastomer at all values of vr was demonstrated by substituting this relationship for χ in the Flory-Rehner (F-R) equation. The relationship was established over a wide range of vr values by using samples that had the νe of the cured elastomer determined by tensile retraction (TR). Applying this function to samples treated using the thiol probe method of Campbell gave an improved measure of the types of crosslinks present in sulfur-cured stocks. An identical equation describing χ as a function of vr in heptane was obtained with NR, EPDM and SBR containing up to a 0.31 volume fraction of carbon black (CB) and other fillers. The presence of up to 10 % of clay, talc, silica, resins or metal oxides in the CB had no noticeable effect on the relationship measured. However, when the filler contained about 50% silica a distinctly different slope in the relationship was found. The percent S1, S2 and Sx distribution measured was contrasted between measurements made by 13C NMR, swelling with χ = constant or χ as a function of vr.

Carbon-Black-Elastomer Interaction II: Effects of Carbon Black Surface Activity and Loading

1993 ◽  
Vol 66 (5) ◽  
pp. 772-805 ◽  
Author(s):  
J. A. Ayala ◽  
W. M. Hess ◽  
G. A. Joyce ◽  
F. D. Kistler
Keyword(s):  
Surface Energy ◽  
Carbon Black ◽  
Surface Activity ◽  
Volume Fraction ◽  
Heat Treating ◽  
Inert Atmosphere ◽  
Morphological Properties ◽  
Rubber Compounds ◽  
Carbon Black Surface ◽  
Black Surface

Abstract Carbon black morphology, surface activity and loading have been varied systematically to study the effects on an SBR formulation. The surface activity of five commercial grades of carbon black was varied by heat treating the standard grade samples at 1100°C and 1500°C in an inert atmosphere. Measurements on carbon black-elastomer interaction were based on a parameter I, defined elsewhere. The parameter I exhibited the previously reported correlation with known indicators of the surface activity of carbon blacks. The heats of adsorption by inverse gas chromatography at infinite dilution have been found useful as a measure of the carbon-black surface energy related to rubber interaction. These measurements have been employed in conjunction with carbon-black morphology and loading to develop a surface-area-modified and a surface energy-modified effective volume fraction V′ and ψ, respectively. The parameter V′ was utilized to explain the variation of the dynamic elastic modulus E′ at 1 % double strain amplitude (DSA) for all rubber compounds. The parameter ψ was used to explain the variation of E′ at 25% DSA and the factor σ in the calculation of I. The parameters V′ and ψ provide a model for the estimation of I from fundamental carbon-black morphological properties and surface energy.

Solid State Sintering and Microstructural Evolution on Wide Frequency Range Dielectric Responses of Mechanically Activated CaTiO3 Ceramics

2015 ◽  
Vol 1107 ◽  
pp. 38-44
Author(s):  
Wong Yick Jeng ◽  
Hassan Jumiah ◽  
Mansor Hashim
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sintering Temperature ◽  
Microstructural Analysis ◽  
High Energy ◽  
Wide Frequency Range ◽  
Milling Process ◽  
Frequency Range ◽  
Wide Range

The CaTiO3samples were prepared by high-energy ball milling process followed by sintering process from 1040 to 1200°C. X-ray diffraction (XRD), microstructural analysis, and dielectric properties over a wide range of frequency varying from 0.01 Hz to 1 GHz at room temperature were investigated. The formation of a single phase CaTiO3with orthorhombic structure was achieved at 1120°C and above. From a morphological point of view, sintering temperature promoted grain growth. Dielectric properties in the frequency range 0.01 Hz - 1 MHz revealed a relaxation-type process. Interfacial phenomena were the possible physical mechanisms that gave rise to these relaxation-type plots. Extending the frequencies above ~1 MHz yielded a frequency-independent characteristic of dielectric constant (ε'). These turned out to the relatively small dielectric loss (tan δ) values. The origin of the dielectric responses in the frequency range 1 MHz - 1 GHz was attributed to the domination of dipolar polarization. The grain size effect in sintered CaTiO3samples was prominent, notably in dielectric responses above ~1 MHz. Increase in sintering temperature remarkably led to an enhancement in dielectric constant values and reduction in dielectric loss values. Therefore, a significant correlation existed between microstructural features and dielectric properties.

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.

Another Look at S-Type Carbon Blacks

1977 ◽  
Vol 50 (1) ◽  
pp. 211-216
Author(s):  
J. R. Haws ◽  
W. T. Cooper ◽  
E. F. Ross
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Good Adhesion ◽  
Good Resistance ◽  
Carbon Blacks ◽  
Rubber Compounds ◽  
Curing Characteristics ◽  
Wide Range ◽  
Oxidized Carbon

Abstract Oxidized carbon blacks impart unique properties to rubber compounds. The most interesting aspects include modified curing characteristics, good resistance to tear, and the potential to promote good adhesion of rubber compounds to brass-plated metal. When these improvements are considered in conjunction with the wide range of surface area and structure available in carbon black, it is evident that oxidized furnace blacks provide combinations of properties not previously available.

scholarly journals Carbon-Fiber Enriched Cement-Based Composites for Better Sustainability

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1899 ◽  
Author(s):  
Mohamad Atiyeh ◽  
Ertug Aydin
Keyword(s):  
Carbon Fiber ◽  
Volume Fraction ◽  
Bottom Ash ◽  
Physical And Mechanical Properties ◽  
Vital Role ◽  
Fiber Volume ◽  
Volume Percentage ◽  
Wide Range ◽  
Negative Effect ◽  
Marble Dust

Damage caused by global warming is rapidly increasing, and its adverse effects become more evident with each passing day. Although it is known that the use of alternative binder materials in concrete would decrease this negative effect, reluctance to use such new composites continues. Waste plays a vital role in sustainability studies. In this study, pure cement paste was prepared and enriched with carbon fiber. This study also investigated the wide range of volume fraction of carbon fiber in cement-based composites. Two different types of industrial waste, i.e., marble dust and bottom ash, were chosen and mixed with cement and four different (0.3%, 0.75%, 1.5%, and 2.5%) carbon fiber volume fractions. Based on physical, mechanical, and durability tests at 7, 28, and 56 days of curing, the composites were resistant to sulfate and seawater attacks. The 0.75% carbon fiber addition seems to be an optimum volume percentage, beyond which both physical and mechanical properties were adversely affected. The composites with 0.75% carbon fiber reached 48.4 and 47.2 MPa at 56 days of curing for marble dust and bottom ash mixture groups, respectively.

scholarly journals Physical, Mechanical and Durability Performance of Pastes Containing Carbon Fiber

2020 ◽  
Author(s):  
Mohamad Atiyeh ◽  
Ertug Aydin
Keyword(s):  
Carbon Fiber ◽  
Volume Fraction ◽  
Bottom Ash ◽  
Physical And Mechanical Properties ◽  
Vital Role ◽  
Industrial Wastes ◽  
Fiber Volume ◽  
Volume Percentage ◽  
Wide Range ◽  
Marble Dust

The damage caused by global warming is rapidly increasing, and its adverse effects become more evident with each passing day. Although it is known that the use of alternative binder materials in concrete would decrease this negative effect, reluctance to new composites continues. Waste use plays a vital role in sustainability studies. In this study, pure cement paste was prepared and enriched with carbon fiber. This study investigated the wide range of volume fraction of carbon fiber in cement-based composites. Two different industrial wastes, marble dust, and bottom ash were chosen and mixed with cement and four different (0.3%, 0.75%, 1.5%, and 2.5%) carbon fiber volume fractions. Based on physical, mechanical, and durability tests at 7, 28, and 56-days of curing, the composites were resistant to sulfate and seawater attack. The 0.75% carbon fiber addition seems to be an optimum volume percentage beyond which both physical and mechanical properties were adversely affected. The composites with 0.75% carbon fiber have reached 48.4 MPa and 47.2 MPa at 56-days of curing for marble dust and bottom ash mixture groups, respectively.

Partial replacement of carbon black by nanoclay in butyl rubber compounds for tubeless tires

2017 ◽  
Vol 59 (11-12) ◽  
pp. 1054-1060 ◽  
Author(s):  
Mohan Kumar Harikrishna Kumar ◽  
Subramaniam Shankar ◽  
Rathanasamy Rajasekar ◽  
Pal Samir Kumar ◽  
Palaniappan Sathish Kumar
Keyword(s):  
Carbon Black ◽  
Butyl Rubber ◽  
Partial Replacement ◽  
Rubber Compounds

scholarly journals Factors Affecting Acoustic Properties of Natural-Fiber-Based Materials and Composites: A Review

Textiles ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 55-85
Author(s):  
Tufail Hassan ◽  
Hafsa Jamshaid ◽  
Rajesh Mishra ◽  
Muhammad Qamar Khan ◽  
Michal Petru ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Fiber Type ◽  
Alkali Treatment ◽  
Acoustic Properties ◽  
Synthetic Fiber ◽  
Sound Insulation ◽  
Factors Affecting ◽  
Wide Range

Recently, very rapid growth has been observed in the innovations and use of natural-fiber-based materials and composites for acoustic applications due to their environmentally friendly nature, low cost, and good acoustic absorption capability. However, there are still challenges for researchers to improve the mechanical and acoustic properties of natural fiber composites. In contrast, synthetic fiber-based composites have good mechanical properties and can be used in a wide range of structural and automotive applications. This review aims to provide a short overview of the different factors that affect the acoustic properties of natural-fiber-based materials and composites. The various factors that influence acoustic performance are fiber type, fineness, length, orientation, density, volume fraction in the composite, thickness, level of compression, and design. The details of various factors affecting the acoustic behavior of the fiber-based composites are described. Natural-fiber-based composites exhibit relatively good sound absorption capability due to their porous structure. Surface modification by alkali treatment can enhance the sound absorption performance. These materials can be used in buildings and interiors for efficient sound insulation.

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