Viscoelastic Properties of Rubberlike Composite Propellants and Filled Elastomers

1962 ◽  
Vol 35 (2) ◽  
pp. 291-310 ◽  
Author(s):  
Robert F. Landel ◽  
Thor L. Smith
Keyword(s):  
Volume Fraction ◽  
Small Deformation ◽  
Universal Function ◽  
Glass Temperature ◽  
Quasi Equilibrium ◽  
Temperature Function ◽  
Hencky Strain ◽  
Filled Elastomers ◽  
Equilibrium Modulus ◽  
Filler Particles

Abstract The mechanical properties of rubberlike composite propellants and similar filled elastomers are determined largely by the volume fraction of filler, the visco-elastic properties of the binder, and the interactions between the binder and filler particles. The ratio of the quasi-equilibrium modulus of the composite to that for the unfilled elastomer increases with the volume fraction of the filler, apparently according to an equation of the form proposed by Eilers and Van Dyck. However, the same ratio for the dynamic storage modulus decreases as the frequency is increased or the temperature is decreased. The time-dependent tensile properties can be characterized by stress-strain curves measured at different strain rates and temperatures. Both the small deformation and ultimate properties can be represented by master curves, which are functions only of the experimental time scale, along with a temperature function which is a near-universal function of the glass temperature. Propellants under constant loads initially exhibit creep which is qualitatively similar to that of unfilled elastomers, but subsequently dewetting of the filler particles may begin and this causes the deformation to increase exponentially with time. A discussion is given of the use of Poisson's ratio, defined in terms of Hencky strain and measured as a function of extension, to indicate the initiation of dewetting and the subsequent volume increase.

scholarly journals XPCS Investigation of the Dynamics of Filler Particles in Stretched Filled Elastomers

2012 ◽  
Vol 45 (21) ◽  
pp. 8691-8701 ◽  
Author(s):  
Françoise Ehrburger-Dolle ◽  
Isabelle Morfin ◽  
Françoise Bley ◽  
Frédéric Livet ◽  
Gert Heinrich ◽  
...  
Keyword(s):  
Filled Elastomers ◽  
Filler Particles

Binder/Filler Interaction and the Nonlinear Behavior of Highly-Filled Elastomers

1990 ◽  
Vol 63 (4) ◽  
pp. 488-502 ◽  
Author(s):  
R. G. Stacer ◽  
C. Hübner ◽  
D. M. Husband
Keyword(s):  
Surface Area ◽  
Strain Amplitude ◽  
Nonlinear Response ◽  
Volume Fraction ◽  
Viscoelastic Behavior ◽  
Interaction Model ◽  
Nonlinear Behavior ◽  
Small Deformation ◽  
Amplitude Dependence ◽  
Filled Rubbers

Abstract 1. The small-deformation-viscoelastic response of elastomers containing nonreinforcing filler has been investigated. Nonlinear viscoelastic behavior was observed as a pronounced strain-amplitude dependence. The degree of this dependence was quantified using a power-law representation as a single nonlinear parameter, m. 2. The magnitude of m was a function of formulation variables. It was found that m increased with the volume fraction and particle size of filler material, as well as the volume fraction of plasticizer. Reduced values of m were observed in the presence of bonding agent and with greater degrees of apparent crosslinking. The latter was controlled in this study through imbalanced urethane cures. 3. Nonlinear behavior of elastomers containing nonreinforcing filler has been compared and contrasted with the data base for carbon-black-reinforced elastomers. The major difference is in the effect of the surface area of filler particles. Nonlinear response in black-filled rubbers increases with surface area, while the opposite is reported in this study. Additionally, the relationship between viscoelastic dissipation and the magnitude of nonlinear response, well established for black-filled rubbers, was not observed. These results indicate that the response of elastomers containing nonreinforcing filler, although nearly identical in appearance to that seen with reinforcing filler, is not driven by the same mechanism. 4. A binder/filler interaction model is proposed for materials containing nonreinforcing filler. This model is based on the ideal adhesive strength of the binder/filler interface. In this model, greater attraction between polymer and particle surfaces reduces molecular slippage during deformation, leading to a decreased dependence of the modulus on strain amplitude, or decreased nonlinearity. It is shown that the model provides reasonable predictions for the observed phenomena.

scholarly journals Amorphous alloys and differential scanning calorimetry (DSC)

2021 ◽  
Author(s):  
Dora Janovszky ◽  
Maria Sveda ◽  
Anna Sycheva ◽  
Ferenc Kristaly ◽  
Ferenc Zámborszky ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Volume Fraction ◽  
Data Interpretation ◽  
Glass Temperature ◽  
Scanning Calorimetry ◽  
Scientific Papers ◽  
Kinetics Of ◽  
Temperature Crystallization

AbstractA remarkable number of scientific papers are available in the literature about the bulk amorphous alloys and metallic glasses. Today, DSC is an essential tool for amorphous alloys research and development, and of course for quality assurance. In many cases, users seek to examine the determination of only one or two properties, although much more information can be obtained from the measurements. The research involved structural relaxation, Curie temperature, glass temperature, crystallization, phase separation, nanocrystalline volume fraction, melting point and liquidus temperature determination subjects and kinetics of microstructural transformations induced by thermal treatment. We collected and present the information that can be obtained with this technique and draws the reader’s attention to some potential problems related to data interpretation.

scholarly journals Slowing down of dynamics and orientational order preceding crystallization in hard-sphere systems

2020 ◽  
Vol 6 (43) ◽  
pp. eabc5916
Author(s):  
Felix Lehmkühler ◽  
Birgit Hankiewicz ◽  
Martin A. Schroer ◽  
Leonard Müller ◽  
Beatrice Ruta ◽  
...  
Keyword(s):  
Hard Sphere ◽  
Soft Matter ◽  
Volume Fraction ◽  
Orientational Order ◽  
Strong Increase ◽  
Quasi Equilibrium ◽  
Slowing Down ◽  
X Ray Scattering ◽  
Matter System ◽  
Scattering Study

Despite intensive studies in the past decades, the local structure of disordered matter remains widely unknown. We show the results of a coherent x-ray scattering study revealing higher-order correlations in dense colloidal hard-sphere systems in the vicinity of their crystallization and glass transition. With increasing volume fraction, we observe a strong increase in correlations at both medium-range and next-neighbor distances in the supercooled state, both invisible to conventional scattering techniques. Next-neighbor correlations are indicative of ordered precursor clusters preceding crystallization. Furthermore, the increase in such correlations is accompanied by a marked slowing down of the dynamics, proving experimentally a direct relation between orientational order and sample dynamics in a soft matter system. In contrast, correlations continuously increase for nonequilibrated, glassy samples, suggesting that orientational order is reached before the sample slows down to reach (quasi-)equilibrium.

Tailoring anisotropic thermal conductivity by varying filler particle organization in nickel-polydimethylsiloxane composites

2019 ◽  
Vol 53 (18) ◽  
pp. 2569-2577
Author(s):  
Peiying J Tsai ◽  
Souvik Pal ◽  
Suvojit Ghosh ◽  
Ishwar K Puri
Keyword(s):  
Thermal Conductivity ◽  
Additive Manufacturing ◽  
Volume Fraction ◽  
Filler Particle ◽  
Material Design ◽  
Interparticle Spacing ◽  
Element Analysis ◽  
Anisotropic Thermal Conductivity ◽  
Transverse Conductivity ◽  
Filler Particles

Anisotropic properties can be imparted to composite materials by arranging filler particles along specific directions inside the polymer matrix. These anisotropic patterns can be produced through dynamic field-assisted assembly of the filler particles during additive manufacturing. Using finite element analysis, we explore how chainlike arrangements of nickel particles embedded in a polydimethylsiloxane matrix modify bulk thermal conductivities in the axial and transverse directions. The axial conductivity increases up to nine times of the matrix conductivity with increasing filler volume fraction. While the axial conductivity decreases with increasing interparticle spacing, the transverse conductivity is uninfluenced. When particles within a chain are arranged in a zigzag pattern, increasing the interparticle zigzag angle decreases axial conductivity but increases transverse conductivity. As that angle increases to ∼55 º, the axial conductivity approaches a minimum, while the transverse conductivity approaches its maximum. An empirical model that includes effects of interparticle spacing and zigzag angle to predict the anisotropic thermal conductivity of a composite containing particle chains is presented. These results are relevant for the material design of particulate-reinforced polymer composites for advanced field-assisted additive manufacturing strategies.

Finite Element Analysis on Microstructure Evolution of Hot Ring Rolling Process

2008 ◽  
Vol 575-578 ◽  
pp. 1455-1460 ◽  
Author(s):  
Zhi Chao Sun ◽  
He Yang ◽  
Xin Zhe Ou
Keyword(s):  
Grain Size ◽  
Microstructure Evolution ◽  
Volume Fraction ◽  
Small Deformation ◽  
Local Area ◽  
Rolling Process ◽  
Ring Rolling ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Average Grain Size

Hot ring rolling (HRR) is a 3D unsteady-state and coupled thermo-mechanical process, the metal undergoes complicated unequal deformation and microstructure evolution. In this paper a 3D rigid-plastic and coupled thermo-mechanical FEM model for hot ring rolling was developed based on DEFORM3D platform, taking dynamic recrystallization (DRX) volume fraction, DRX grain size, recystallization volume fraction and average grain size as objects, the mechanism of material microstructure evolution and distributions in HRR process are thoroughly studied. The results show that: with the HRR progressing, the DRX volume fraction, volume fraction, DRX grain size and average grain size have the similar distributing characteristic, and the distribution zones expand from a small local area into the whole ring strip, then diffuse to the mid-layer of ring with small deformation, their distributions become more uniform. Meanwhile with increase of deformation, the values of the DRX volume fraction and recrystallization volume fraction augment, i.e. the degree of recystallization increases. The DRX grain size also augments due to local high temperature, while the average grain size decreases. In general during HRR process the distributions of DRX volume fraction, recrystallization volume fraction, DRX grain size, and average grain size are ununiform due to unequal deforming in HRR process.

The nonlinear dynamics of solidification of a binary melt with a quasi-equilibrium mushy region

1990 ◽  
Vol 68 (9) ◽  
pp. 790-793 ◽  
Author(s):  
Yu. A. Buyevich ◽  
L. Y. Iskakova ◽  
V. V. Mansurov
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Volume Fraction ◽  
Solid Phase ◽  
Internal Heat ◽  
Solid Particles ◽  
Mushy Region ◽  
Parameter Method ◽  
Quasi Equilibrium ◽  
Phase Volume Fraction

A mushy region (a two-phase zone) between the solid and liquid phases occurs often in the process of solidification of a binary melt. An analysis of the structure of the mushy region, which includes the liquid, solid particles, and dendrites extending from the bulk solid surface, is suggested. The processes of heat and mass transfer in the mushy region are considered on the basis of the small parameter method. The analysis leads to equations governing unsteady heat and mass transfer with internal heat, and mass sources within the mushy region, and it includes the condition for the absence of supercooling (the condition for the zone quasi-equilibrium), convection being neglected. The temperature, concentration of solute, and solid phase volume fraction are found. On the basis of this solution a new model of the process is formulated. Within the scope of this model the mushy region is replaced by a liquid–solid interface with discontinuous boundary conditions.

Surface Energy Effects for Small Holes or Particles in Elastomers

1970 ◽  
Vol 43 (4) ◽  
pp. 873-877 ◽  
Author(s):  
A. N. Gent ◽  
D. A. Tompkins
Keyword(s):  
Surface Energy ◽  
Carbon Black ◽  
Rigid Inclusion ◽  
Elastic Solid ◽  
Surface Forces ◽  
Simple Liquids ◽  
Filled Elastomers ◽  
Large Size ◽  
Filler Particles ◽  
Small Holes

Abstract Expansion of a small spherical hole in a highly elastic solid is treated theoretically. Both elastic and surface energy terms are considered; the corresponding surface forces are assumed to be additive. The surface energy of the elastomer is assumed to be similar to that of simple liquids. Pressures or triaxial tensions required to inflate pre-existing holes to an indefinitely large size are calculated. Small holes require extremely large pressures, of the order of 1000 atm for holes of 10 A˚ radius. These results suggest a means of determining the distribution of hole sizes in elastomers and account, in principle, for experimental observations of cavitation processes. Detachment of the elastomer from a small rigid inclusion is treated in a similar way. The general absence of dilation or cavitation on stretching carbon black filled elastomers is thus accounted for solely in terms of the small size of these filler particles.

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