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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 2427-2434 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A new theory is developed which relates the graft level, graft molecular weight, and particle size to the probability of hitting a rubber particle as a crack propagates in a two-phase impact-modified plastic. It is shown theoretically that the particle size average of interest in evaluating the impact properties of two-phase plastics is the surface-average particle size Ds. The theory predicts a maximum probable impact at a specific particle size that depends on the graft level required to achieve compatibility between the two phases.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 25-36 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Several suspension equations available in the literature have been found to have a common derivative form. This common derivative was found to be equivalent to a ratio of the intrinsic viscosity, [η], and a quantity, Vint, defined as the ldquo;relative suspension interaction volume” available for particle flow. Vint was, in general, found to be a relatively simple function of the suspension particle volume fraction, ϕ, the maximum particle packing fraction, ϕn, and a new variable, σ, defined as the particle interaction coefficient. Different forms of this common derivative were obtained by modifying VInt with a simple adjustment for the value for the interaction coefficient, σ. Integration of this generalized derivative yielded a generalized suspension viscosity equation that was found to predict the form of many suspension equations that have previously appeared in the literature. For example, by varying the interaction coefficient, σ, the Arrhenius equation resulted when σ = 0, the Kreiger-Dougherty equation resulted when σ = 1, and when σ = 2, the Mooney equation resulted. Fractional values for the particle interaction coefficient were also found to be useful when optimizing the empirical fit of the literature data of Vand and Eiler. Additional insight from such a data fit can also be obtained from the magnitude of both the particle interaction coefficient, σ, and the packing fraction, ϕn. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1243-1262 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The theoretical relationship between the shear modulus of a particulate reinforced composite and the viscosity of a solution with suspended particles was first proposed by Goodier. Since that time several partially successful attempts have been made in the literature to derive equations to describe the available relative shear modulus-particulate concentration data. Recently a new generalized suspension viscosity equation appeared in the literature which for the first time addresses the detailed effects of particle size, particle size distribution, and packing fraction. This new viscosity equation was applied to available modulus literature on particulate composites in this study. Four significant particulate composite modulus derivations in the literature were all shown in this study to yield the same theoretical “intrinsic modulus” of a particulate composite. The generalized viscosity-modulus equation yielded an excellent fit of the shear modulus-particulate concentration data of both Smallwood and Nielsen using a variable intrinsic modulus. Some fillers predicted the Einstein limiting value of the intrinsic modulus while other fillers yielded intrinsic modulus values that were either larger or smaller than this value. The intrinsic modulus for carbon black in rubber was much larger than Einstein's predicted value. However, intrinsic modulus values smaller than Einstein's prediction were obtained at temperatures below the glass transition temperature of the matrix. Unfortunately, the previously obtained direct relationship between the particle interaction coefficient and particulate size for suspension viscosities with a constant intrinsic viscosity was not obtaind for shear modulus - particulate concentration data using a variable intrinsic modulus. © 1994 John Wiley & Sons, Inc.
    Additional Material: 17 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 985-996 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A new approach has been introduced to establish the optimum composition for all particles within a mixture or suspension to achieve the optimum packing fraction, ϕn, and/or the minimum viscosity, η. The derivation to obtain the optimum particle volume fraction assumed that a previously developed optimum composition for binary particles applied to any two particle volumes Vi and Vj in the mixture. The composition of the maximum packing fraction for a mixture of more than two particles was then assumed to be calculable from the optimized relationship of each separate binary pair of particle volumes Vi and Vi in the mixture. This derived equation was successfully shown to predict the optimum particle-to-particle composition of McGeary's experimentally measured binary, tertiary, and quaternary mixtures. The difference between the calculated and measured volume fractions was no greater than 3.85% and, in most instances, was significantly less than 3.85%. The maximum packing fractions, ϕn, determined experimentally by McGeary, were also successfully predicted to better than 3.26%. Theoretical particle-to-particle volume fractions evaluated for an example pressure-agglomerated latex appeared to predict the particle-size distribution only within a narrow range of particle sizes. However, when the theoretical and experimental results were evaluated as a function of the number of particles for each particle diameter, it was apparent that the agglomerated distribution closely approximated the theoretical optimum distribution above 600 Å. Agreement with theory below 600 Å was unsatisfactory. The decrease in viscosity of the example agglomerated latex appeared to have been enhanced as the optimum theoretical particle-size distribution was approached. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1573-1584 
    ISSN: 0887-6266
    Keywords: particle size distribution ; molecular weight distribution ; particle interaction coefficient ; latex blending ; suspension viscosity ; particle packing fraction ; optimized blending fractions ; polyisobutylene ; steady-state elastic compliance ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been shown in this study that the effects of particle size distribution or molecular weight distribution on selected physical properties can be related by a generalized blending approach that involves similar equations. The blending equations developed involve different z-fractions where z = 3 for volume blending of spherical particles, or z = 2 for surface blending of spherical particles, or z = 1 for the weight blending of molecular weights. This new analysis approach addresses the magnitude of the ratios of particle size averages, Dx/Dy, or ratios of molecular weight averages, Mx/My, as well as the location of this maximum, the level of distribution information available for the starting materials, and the type of z-fraction blending. To illustrate this approach suspension viscosity/concentration data was used to show how the Dx/Dy ratio could be introduced successfully to analyze latex volume blending where z = 3. In addition, the maximum steady-state elastic compliance, Je, as a function of weighted blends (z = 1) of two different molecular weights of polyisobutylene was shown to fit the simple equation Je = 1.187 (M3/M2) (M4/M1) reasonably well. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 37-55 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A new analysis technique has been developed in this paper to evaluate the upper limit of the packing fraction, ϕn utilized in the prediction of suspension viscosities. The semiempirical equation developed for the upper limit of the packing fraction, ϕn was generated initially from McGeary's binary particle packing fraction data. All possible Dx/Dy ratios of particles size averages were evaluated and analyzed in this formulation development. Only the D5/D1 and D4/D2 ratios of particle diameter averages were found to accurately predict the proper particle volume fraction location obtained in McGeary's data for the correct upper limit packing fraction ϕn. After developing methodology to calculate ϕn for binary particle distributions, an extension was made to include distributions with any number n of different particle size diameters. One of the more general of the suspended particle viscosity equations, as developed in a previous paper by this author, was used to demonstrate the application of this new ϕn methodology to the evaluation of suspension viscosity properties. The blended binary suspension viscosity results of Johnson and Kelsey for near monodisperse latexes were shown to be satisfactorily predicted as a function of the binary volume composition. © 1993 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 50 (1993), S. 123-147 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The generalized suspension viscosity equation utilized in this study was evaluated with both a packing fraction, ϕn, and a particle interaction coefficient, σ, as a function of suspension blend composition, f2T. The estimation of the packing fraction, ϕn, in turn, required the further elucidation of the D5/D1 ratio of particle diameter averages. Blend constants developed in this study allowed evaluation of both the Dx/Dy ratio of particle diameter averages as well as the number-average particle diameter, D1, as a function of the fraction of one suspension in a blend, f2T. These blend constants were shown to be easily evaluated from each individual suspension prior to blending. The viscosity data of Johnson and Kelsey were shown to be generally predicted as a function of the volume composition when a constant particle interaction coefficient, σ, was assumed. However, a better prediction of the results of Johnson and Kelsey was obtained by assuming that the particle interaction coefficient, σ, was a function of the number-average particle diameter, D1, of the suspension mixture composition. Consequently, a new approach was identified to evaluate the simultaneous effects of small particles to both increase viscosity as a result of increasing particle interaction as well as to decrease viscosity as a result of improving the particle-size distribution. © 1993 John Wiley & Sons, Inc.
    Additional Material: 16 Ill.
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  • 8
    Publication Date: 2003-04-01
    Print ISSN: 1472-7978
    Electronic ISSN: 1875-8983
    Topics: Computer Science , Technology
    Published by IOS Press
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  • 9
    Publication Date: 1984-01-01
    Print ISSN: 0021-9673
    Electronic ISSN: 1873-3778
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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  • 10
    Publication Date: 2013-08-31
    Description: In general, the results from the Long Duration Exposure Facility (LDEF) have provided much useful information on material sensitivity in the low-Earth orbit (LEO) environment. This is particularly true for selected materials such as thermal control coatings, composites, polymers, fasteners and solar cells. However, LDEF material sensitivity data for other materials like glasses, glass coatings, lubricants, adhesives and seal materials were limited. Some of this important LDEF material sensitivity data has not yet been addressed in detail at the LDEF meetings. The type of material information needed in the design and development of a new spacecraft in LEO depends to a large extent on program phase. In early program phases it is only necessary to have material sensitivity data to determine what materials may or may not work. Later program phases require details on the material strength, optical properties, and/or other long term survivability requirements for materials in LEO. Unfortunately, documentation of exposure results for many materials sensitivity experiments that flew on LDEF has not yet been summarized in a convenient form for use by multiple users. Documentation of this data in a form convenient for scientists, engineers as well as technicians remains a significant area of concern for the aerospace industry. Many of the material experiments that flew on LDEF were only designed to measure material sensitivity for one year in an LEO environment. However, some materials expected to survive one year simply did not survive the 5.8 years that LDEF eventually remained in orbit. Therefore the survivability of several materials in an LEO environment was determined by default. Most of the LDEF materials experiments were not designed to establish long term material survivability data. This long term material survivability data is particularly useful in later program phases of spacecraft development. The lack of more controlled materials experiments to determine long term material survivability was one of the major limitations of many LDEF experiments. The identified need for this critical information on the long term survivability offers a challenge to possible future LDEF type experiments.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center, LDEF Materials Results for Spacecraft Applications; p 511-523
    Format: application/pdf
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